2472 lines
74 KiB
C
2472 lines
74 KiB
C
/*
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* random.c -- A strong random number generator
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*
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* Version 1.89, last modified 19-Sep-99
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*
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* Copyright Theodore Ts'o, 1994, 1995, 1996, 1997, 1998, 1999. All
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* rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, and the entire permission notice in its entirety,
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* including the disclaimer of warranties.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* ALTERNATIVELY, this product may be distributed under the terms of
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* the GNU General Public License, in which case the provisions of the GPL are
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* required INSTEAD OF the above restrictions. (This clause is
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* necessary due to a potential bad interaction between the GPL and
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* the restrictions contained in a BSD-style copyright.)
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
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* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*/
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/*
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* (now, with legal B.S. out of the way.....)
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*
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* This routine gathers environmental noise from device drivers, etc.,
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* and returns good random numbers, suitable for cryptographic use.
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* Besides the obvious cryptographic uses, these numbers are also good
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* for seeding TCP sequence numbers, and other places where it is
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* desirable to have numbers which are not only random, but hard to
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* predict by an attacker.
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*
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* Theory of operation
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* ===================
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*
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* Computers are very predictable devices. Hence it is extremely hard
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* to produce truly random numbers on a computer --- as opposed to
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* pseudo-random numbers, which can easily generated by using a
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* algorithm. Unfortunately, it is very easy for attackers to guess
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* the sequence of pseudo-random number generators, and for some
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* applications this is not acceptable. So instead, we must try to
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* gather "environmental noise" from the computer's environment, which
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* must be hard for outside attackers to observe, and use that to
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* generate random numbers. In a Unix environment, this is best done
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* from inside the kernel.
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*
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* Sources of randomness from the environment include inter-keyboard
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* timings, inter-interrupt timings from some interrupts, and other
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* events which are both (a) non-deterministic and (b) hard for an
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* outside observer to measure. Randomness from these sources are
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* added to an "entropy pool", which is mixed using a CRC-like function.
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* This is not cryptographically strong, but it is adequate assuming
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* the randomness is not chosen maliciously, and it is fast enough that
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* the overhead of doing it on every interrupt is very reasonable.
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* As random bytes are mixed into the entropy pool, the routines keep
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* an *estimate* of how many bits of randomness have been stored into
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* the random number generator's internal state.
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*
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* When random bytes are desired, they are obtained by taking the SHA
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* hash of the contents of the "entropy pool". The SHA hash avoids
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* exposing the internal state of the entropy pool. It is believed to
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* be computationally infeasible to derive any useful information
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* about the input of SHA from its output. Even if it is possible to
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* analyze SHA in some clever way, as long as the amount of data
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* returned from the generator is less than the inherent entropy in
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* the pool, the output data is totally unpredictable. For this
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* reason, the routine decreases its internal estimate of how many
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* bits of "true randomness" are contained in the entropy pool as it
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* outputs random numbers.
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*
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* If this estimate goes to zero, the routine can still generate
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* random numbers; however, an attacker may (at least in theory) be
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* able to infer the future output of the generator from prior
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* outputs. This requires successful cryptanalysis of SHA, which is
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* not believed to be feasible, but there is a remote possibility.
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* Nonetheless, these numbers should be useful for the vast majority
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* of purposes.
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*
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* Exported interfaces ---- output
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* ===============================
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*
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* There are three exported interfaces; the first is one designed to
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* be used from within the kernel:
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*
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* void get_random_bytes(void *buf, int nbytes);
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*
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* This interface will return the requested number of random bytes,
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* and place it in the requested buffer.
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*
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* The two other interfaces are two character devices /dev/random and
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* /dev/urandom. /dev/random is suitable for use when very high
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* quality randomness is desired (for example, for key generation or
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* one-time pads), as it will only return a maximum of the number of
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* bits of randomness (as estimated by the random number generator)
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* contained in the entropy pool.
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*
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* The /dev/urandom device does not have this limit, and will return
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* as many bytes as are requested. As more and more random bytes are
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* requested without giving time for the entropy pool to recharge,
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* this will result in random numbers that are merely cryptographically
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* strong. For many applications, however, this is acceptable.
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*
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* Exported interfaces ---- input
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* ==============================
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*
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* The current exported interfaces for gathering environmental noise
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* from the devices are:
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*
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* void add_keyboard_randomness(unsigned char scancode);
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* void add_mouse_randomness(__u32 mouse_data);
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* void add_interrupt_randomness(int irq);
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*
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* add_keyboard_randomness() uses the inter-keypress timing, as well as the
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* scancode as random inputs into the "entropy pool".
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*
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* add_mouse_randomness() uses the mouse interrupt timing, as well as
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* the reported position of the mouse from the hardware.
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*
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* add_interrupt_randomness() uses the inter-interrupt timing as random
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* inputs to the entropy pool. Note that not all interrupts are good
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* sources of randomness! For example, the timer interrupts is not a
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* good choice, because the periodicity of the interrupts is too
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* regular, and hence predictable to an attacker. Disk interrupts are
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* a better measure, since the timing of the disk interrupts are more
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* unpredictable.
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*
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* All of these routines try to estimate how many bits of randomness a
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* particular randomness source. They do this by keeping track of the
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* first and second order deltas of the event timings.
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*
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* Ensuring unpredictability at system startup
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* ============================================
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*
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* When any operating system starts up, it will go through a sequence
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* of actions that are fairly predictable by an adversary, especially
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* if the start-up does not involve interaction with a human operator.
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* This reduces the actual number of bits of unpredictability in the
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* entropy pool below the value in entropy_count. In order to
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* counteract this effect, it helps to carry information in the
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* entropy pool across shut-downs and start-ups. To do this, put the
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* following lines an appropriate script which is run during the boot
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* sequence:
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*
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* echo "Initializing random number generator..."
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* random_seed=/var/run/random-seed
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* # Carry a random seed from start-up to start-up
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* # Load and then save the whole entropy pool
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* if [ -f $random_seed ]; then
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* cat $random_seed >/dev/urandom
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* else
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* touch $random_seed
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* fi
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* chmod 600 $random_seed
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* poolfile=/proc/sys/kernel/random/poolsize
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* [ -r $poolfile ] && bytes=`cat $poolfile` || bytes=512
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* dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
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*
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* and the following lines in an appropriate script which is run as
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* the system is shutdown:
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*
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* # Carry a random seed from shut-down to start-up
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* # Save the whole entropy pool
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* echo "Saving random seed..."
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* random_seed=/var/run/random-seed
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* touch $random_seed
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* chmod 600 $random_seed
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* poolfile=/proc/sys/kernel/random/poolsize
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* [ -r $poolfile ] && bytes=`cat $poolfile` || bytes=512
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* dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
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*
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* For example, on most modern systems using the System V init
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* scripts, such code fragments would be found in
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* /etc/rc.d/init.d/random. On older Linux systems, the correct script
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* location might be in /etc/rcb.d/rc.local or /etc/rc.d/rc.0.
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*
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* Effectively, these commands cause the contents of the entropy pool
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* to be saved at shut-down time and reloaded into the entropy pool at
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* start-up. (The 'dd' in the addition to the bootup script is to
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* make sure that /etc/random-seed is different for every start-up,
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* even if the system crashes without executing rc.0.) Even with
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* complete knowledge of the start-up activities, predicting the state
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* of the entropy pool requires knowledge of the previous history of
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* the system.
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*
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* Configuring the /dev/random driver under Linux
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* ==============================================
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*
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* The /dev/random driver under Linux uses minor numbers 8 and 9 of
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* the /dev/mem major number (#1). So if your system does not have
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* /dev/random and /dev/urandom created already, they can be created
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* by using the commands:
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*
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* mknod /dev/random c 1 8
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* mknod /dev/urandom c 1 9
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*
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* Acknowledgements:
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* =================
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*
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* Ideas for constructing this random number generator were derived
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* from Pretty Good Privacy's random number generator, and from private
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* discussions with Phil Karn. Colin Plumb provided a faster random
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* number generator, which speed up the mixing function of the entropy
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* pool, taken from PGPfone. Dale Worley has also contributed many
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* useful ideas and suggestions to improve this driver.
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*
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* Any flaws in the design are solely my responsibility, and should
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* not be attributed to the Phil, Colin, or any of authors of PGP.
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*
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* The code for SHA transform was taken from Peter Gutmann's
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* implementation, which has been placed in the public domain.
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* The code for MD5 transform was taken from Colin Plumb's
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* implementation, which has been placed in the public domain.
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* The MD5 cryptographic checksum was devised by Ronald Rivest, and is
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* documented in RFC 1321, "The MD5 Message Digest Algorithm".
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*
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* Further background information on this topic may be obtained from
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* RFC 1750, "Randomness Recommendations for Security", by Donald
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* Eastlake, Steve Crocker, and Jeff Schiller.
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*/
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#include <linux/utsname.h>
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/major.h>
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#include <linux/string.h>
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#include <linux/fcntl.h>
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#include <linux/slab.h>
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#include <linux/random.h>
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#include <linux/poll.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/workqueue.h>
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#include <linux/genhd.h>
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#include <linux/interrupt.h>
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#include <linux/spinlock.h>
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#include <linux/percpu.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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#include <asm/irq.h>
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#include <asm/io.h>
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/*
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* Configuration information
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*/
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#define DEFAULT_POOL_SIZE 512
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#define SECONDARY_POOL_SIZE 128
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#define BATCH_ENTROPY_SIZE 256
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#define USE_SHA
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/*
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* The minimum number of bits of entropy before we wake up a read on
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* /dev/random. Should be enough to do a significant reseed.
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*/
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static int random_read_wakeup_thresh = 64;
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/*
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* If the entropy count falls under this number of bits, then we
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* should wake up processes which are selecting or polling on write
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* access to /dev/random.
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*/
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static int random_write_wakeup_thresh = 128;
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/*
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* When the input pool goes over trickle_thresh, start dropping most
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* samples to avoid wasting CPU time and reduce lock contention.
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*/
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static int trickle_thresh = DEFAULT_POOL_SIZE * 7;
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static DEFINE_PER_CPU(int, trickle_count) = 0;
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/*
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* A pool of size .poolwords is stirred with a primitive polynomial
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* of degree .poolwords over GF(2). The taps for various sizes are
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* defined below. They are chosen to be evenly spaced (minimum RMS
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* distance from evenly spaced; the numbers in the comments are a
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* scaled squared error sum) except for the last tap, which is 1 to
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* get the twisting happening as fast as possible.
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*/
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static struct poolinfo {
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int poolwords;
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int tap1, tap2, tap3, tap4, tap5;
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} poolinfo_table[] = {
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/* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */
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{ 2048, 1638, 1231, 819, 411, 1 },
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/* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */
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{ 1024, 817, 615, 412, 204, 1 },
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#if 0 /* Alternate polynomial */
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/* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */
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{ 1024, 819, 616, 410, 207, 2 },
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#endif
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/* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */
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{ 512, 411, 308, 208, 104, 1 },
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#if 0 /* Alternates */
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/* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */
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{ 512, 409, 307, 206, 102, 2 },
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/* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */
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{ 512, 409, 309, 205, 103, 2 },
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#endif
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/* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */
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{ 256, 205, 155, 101, 52, 1 },
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/* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
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{ 128, 103, 76, 51, 25, 1 },
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#if 0 /* Alternate polynomial */
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/* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */
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{ 128, 103, 78, 51, 27, 2 },
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#endif
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/* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */
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{ 64, 52, 39, 26, 14, 1 },
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/* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
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{ 32, 26, 20, 14, 7, 1 },
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{ 0, 0, 0, 0, 0, 0 },
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};
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#define POOLBITS poolwords*32
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#define POOLBYTES poolwords*4
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/*
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* For the purposes of better mixing, we use the CRC-32 polynomial as
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* well to make a twisted Generalized Feedback Shift Reigster
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*
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* (See M. Matsumoto & Y. Kurita, 1992. Twisted GFSR generators. ACM
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* Transactions on Modeling and Computer Simulation 2(3):179-194.
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* Also see M. Matsumoto & Y. Kurita, 1994. Twisted GFSR generators
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* II. ACM Transactions on Mdeling and Computer Simulation 4:254-266)
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*
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* Thanks to Colin Plumb for suggesting this.
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*
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* We have not analyzed the resultant polynomial to prove it primitive;
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* in fact it almost certainly isn't. Nonetheless, the irreducible factors
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* of a random large-degree polynomial over GF(2) are more than large enough
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* that periodicity is not a concern.
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*
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* The input hash is much less sensitive than the output hash. All
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* that we want of it is that it be a good non-cryptographic hash;
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* i.e. it not produce collisions when fed "random" data of the sort
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* we expect to see. As long as the pool state differs for different
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* inputs, we have preserved the input entropy and done a good job.
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* The fact that an intelligent attacker can construct inputs that
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* will produce controlled alterations to the pool's state is not
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* important because we don't consider such inputs to contribute any
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* randomness. The only property we need with respect to them is that
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* the attacker can't increase his/her knowledge of the pool's state.
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* Since all additions are reversible (knowing the final state and the
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* input, you can reconstruct the initial state), if an attacker has
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* any uncertainty about the initial state, he/she can only shuffle
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* that uncertainty about, but never cause any collisions (which would
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* decrease the uncertainty).
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*
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* The chosen system lets the state of the pool be (essentially) the input
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* modulo the generator polymnomial. Now, for random primitive polynomials,
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* this is a universal class of hash functions, meaning that the chance
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* of a collision is limited by the attacker's knowledge of the generator
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* polynomail, so if it is chosen at random, an attacker can never force
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* a collision. Here, we use a fixed polynomial, but we *can* assume that
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* ###--> it is unknown to the processes generating the input entropy. <-###
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* Because of this important property, this is a good, collision-resistant
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* hash; hash collisions will occur no more often than chance.
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*/
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/*
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* Linux 2.2 compatibility
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*/
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#ifndef DECLARE_WAITQUEUE
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#define DECLARE_WAITQUEUE(WAIT, PTR) struct wait_queue WAIT = { PTR, NULL }
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#endif
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#ifndef DECLARE_WAIT_QUEUE_HEAD
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#define DECLARE_WAIT_QUEUE_HEAD(WAIT) struct wait_queue *WAIT
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#endif
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/*
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* Static global variables
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*/
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static struct entropy_store *random_state; /* The default global store */
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static struct entropy_store *sec_random_state; /* secondary store */
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static struct entropy_store *urandom_state; /* For urandom */
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static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
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static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
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/*
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* Forward procedure declarations
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*/
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#ifdef CONFIG_SYSCTL
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static void sysctl_init_random(struct entropy_store *random_state);
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#endif
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/*****************************************************************
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*
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* Utility functions, with some ASM defined functions for speed
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* purposes
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*
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*****************************************************************/
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/*
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* Unfortunately, while the GCC optimizer for the i386 understands how
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* to optimize a static rotate left of x bits, it doesn't know how to
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* deal with a variable rotate of x bits. So we use a bit of asm magic.
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*/
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#if (!defined (__i386__))
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static inline __u32 rotate_left(int i, __u32 word)
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{
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return (word << i) | (word >> (32 - i));
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}
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#else
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static inline __u32 rotate_left(int i, __u32 word)
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{
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__asm__("roll %%cl,%0"
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:"=r" (word)
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:"0" (word),"c" (i));
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return word;
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}
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#endif
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/*
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* More asm magic....
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*
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* For entropy estimation, we need to do an integral base 2
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* logarithm.
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*
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* Note the "12bits" suffix - this is used for numbers between
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* 0 and 4095 only. This allows a few shortcuts.
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*/
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#if 0 /* Slow but clear version */
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static inline __u32 int_ln_12bits(__u32 word)
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{
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__u32 nbits = 0;
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while (word >>= 1)
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nbits++;
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return nbits;
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}
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|
#else /* Faster (more clever) version, courtesy Colin Plumb */
|
|
static inline __u32 int_ln_12bits(__u32 word)
|
|
{
|
|
/* Smear msbit right to make an n-bit mask */
|
|
word |= word >> 8;
|
|
word |= word >> 4;
|
|
word |= word >> 2;
|
|
word |= word >> 1;
|
|
/* Remove one bit to make this a logarithm */
|
|
word >>= 1;
|
|
/* Count the bits set in the word */
|
|
word -= (word >> 1) & 0x555;
|
|
word = (word & 0x333) + ((word >> 2) & 0x333);
|
|
word += (word >> 4);
|
|
word += (word >> 8);
|
|
return word & 15;
|
|
}
|
|
#endif
|
|
|
|
#if 0
|
|
#define DEBUG_ENT(fmt, arg...) printk(KERN_DEBUG "random: " fmt, ## arg)
|
|
#else
|
|
#define DEBUG_ENT(fmt, arg...) do {} while (0)
|
|
#endif
|
|
|
|
/**********************************************************************
|
|
*
|
|
* OS independent entropy store. Here are the functions which handle
|
|
* storing entropy in an entropy pool.
|
|
*
|
|
**********************************************************************/
|
|
|
|
struct entropy_store {
|
|
/* mostly-read data: */
|
|
struct poolinfo poolinfo;
|
|
__u32 *pool;
|
|
const char *name;
|
|
|
|
/* read-write data: */
|
|
spinlock_t lock ____cacheline_aligned_in_smp;
|
|
unsigned add_ptr;
|
|
int entropy_count;
|
|
int input_rotate;
|
|
};
|
|
|
|
/*
|
|
* Initialize the entropy store. The input argument is the size of
|
|
* the random pool.
|
|
*
|
|
* Returns an negative error if there is a problem.
|
|
*/
|
|
static int create_entropy_store(int size, const char *name,
|
|
struct entropy_store **ret_bucket)
|
|
{
|
|
struct entropy_store *r;
|
|
struct poolinfo *p;
|
|
int poolwords;
|
|
|
|
poolwords = (size + 3) / 4; /* Convert bytes->words */
|
|
/* The pool size must be a multiple of 16 32-bit words */
|
|
poolwords = ((poolwords + 15) / 16) * 16;
|
|
|
|
for (p = poolinfo_table; p->poolwords; p++) {
|
|
if (poolwords == p->poolwords)
|
|
break;
|
|
}
|
|
if (p->poolwords == 0)
|
|
return -EINVAL;
|
|
|
|
r = kmalloc(sizeof(struct entropy_store), GFP_KERNEL);
|
|
if (!r)
|
|
return -ENOMEM;
|
|
|
|
memset (r, 0, sizeof(struct entropy_store));
|
|
r->poolinfo = *p;
|
|
|
|
r->pool = kmalloc(POOLBYTES, GFP_KERNEL);
|
|
if (!r->pool) {
|
|
kfree(r);
|
|
return -ENOMEM;
|
|
}
|
|
memset(r->pool, 0, POOLBYTES);
|
|
r->lock = SPIN_LOCK_UNLOCKED;
|
|
r->name = name;
|
|
*ret_bucket = r;
|
|
return 0;
|
|
}
|
|
|
|
/* Clear the entropy pool and associated counters. */
|
|
static void clear_entropy_store(struct entropy_store *r)
|
|
{
|
|
r->add_ptr = 0;
|
|
r->entropy_count = 0;
|
|
r->input_rotate = 0;
|
|
memset(r->pool, 0, r->poolinfo.POOLBYTES);
|
|
}
|
|
#ifdef CONFIG_SYSCTL
|
|
static void free_entropy_store(struct entropy_store *r)
|
|
{
|
|
if (r->pool)
|
|
kfree(r->pool);
|
|
kfree(r);
|
|
}
|
|
#endif
|
|
/*
|
|
* This function adds a byte into the entropy "pool". It does not
|
|
* update the entropy estimate. The caller should call
|
|
* credit_entropy_store if this is appropriate.
|
|
*
|
|
* The pool is stirred with a primitive polynomial of the appropriate
|
|
* degree, and then twisted. We twist by three bits at a time because
|
|
* it's cheap to do so and helps slightly in the expected case where
|
|
* the entropy is concentrated in the low-order bits.
|
|
*/
|
|
static void __add_entropy_words(struct entropy_store *r, const __u32 *in,
|
|
int nwords, __u32 out[16])
|
|
{
|
|
static __u32 const twist_table[8] = {
|
|
0, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
|
|
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
|
|
unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
|
|
int new_rotate, input_rotate;
|
|
int wordmask = r->poolinfo.poolwords - 1;
|
|
__u32 w, next_w;
|
|
unsigned long flags;
|
|
|
|
/* Taps are constant, so we can load them without holding r->lock. */
|
|
tap1 = r->poolinfo.tap1;
|
|
tap2 = r->poolinfo.tap2;
|
|
tap3 = r->poolinfo.tap3;
|
|
tap4 = r->poolinfo.tap4;
|
|
tap5 = r->poolinfo.tap5;
|
|
next_w = *in++;
|
|
|
|
spin_lock_irqsave(&r->lock, flags);
|
|
prefetch_range(r->pool, wordmask);
|
|
input_rotate = r->input_rotate;
|
|
add_ptr = r->add_ptr;
|
|
|
|
while (nwords--) {
|
|
w = rotate_left(input_rotate, next_w);
|
|
if (nwords > 0)
|
|
next_w = *in++;
|
|
i = add_ptr = (add_ptr - 1) & wordmask;
|
|
/*
|
|
* Normally, we add 7 bits of rotation to the pool.
|
|
* At the beginning of the pool, add an extra 7 bits
|
|
* rotation, so that successive passes spread the
|
|
* input bits across the pool evenly.
|
|
*/
|
|
new_rotate = input_rotate + 14;
|
|
if (i)
|
|
new_rotate = input_rotate + 7;
|
|
input_rotate = new_rotate & 31;
|
|
|
|
/* XOR in the various taps */
|
|
w ^= r->pool[(i + tap1) & wordmask];
|
|
w ^= r->pool[(i + tap2) & wordmask];
|
|
w ^= r->pool[(i + tap3) & wordmask];
|
|
w ^= r->pool[(i + tap4) & wordmask];
|
|
w ^= r->pool[(i + tap5) & wordmask];
|
|
w ^= r->pool[i];
|
|
r->pool[i] = (w >> 3) ^ twist_table[w & 7];
|
|
}
|
|
|
|
r->input_rotate = input_rotate;
|
|
r->add_ptr = add_ptr;
|
|
|
|
if (out) {
|
|
for (i = 0; i < 16; i++) {
|
|
out[i] = r->pool[add_ptr];
|
|
add_ptr = (add_ptr - 1) & wordmask;
|
|
}
|
|
}
|
|
|
|
spin_unlock_irqrestore(&r->lock, flags);
|
|
}
|
|
|
|
static inline void add_entropy_words(struct entropy_store *r, const __u32 *in,
|
|
int nwords)
|
|
{
|
|
__add_entropy_words(r, in, nwords, NULL);
|
|
}
|
|
|
|
|
|
/*
|
|
* Credit (or debit) the entropy store with n bits of entropy
|
|
*/
|
|
static void credit_entropy_store(struct entropy_store *r, int nbits)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&r->lock, flags);
|
|
|
|
if (r->entropy_count + nbits < 0) {
|
|
DEBUG_ENT("negative entropy/overflow (%d+%d)\n",
|
|
r->entropy_count, nbits);
|
|
r->entropy_count = 0;
|
|
} else if (r->entropy_count + nbits > r->poolinfo.POOLBITS) {
|
|
r->entropy_count = r->poolinfo.POOLBITS;
|
|
} else {
|
|
r->entropy_count += nbits;
|
|
if (nbits)
|
|
DEBUG_ENT("Added %d entropy credits to %s, now %d\n",
|
|
nbits, r->name, r->entropy_count);
|
|
}
|
|
|
|
spin_unlock_irqrestore(&r->lock, flags);
|
|
}
|
|
|
|
/**********************************************************************
|
|
*
|
|
* Entropy batch input management
|
|
*
|
|
* We batch entropy to be added to avoid increasing interrupt latency
|
|
*
|
|
**********************************************************************/
|
|
|
|
struct sample {
|
|
__u32 data[2];
|
|
int credit;
|
|
};
|
|
|
|
static struct sample *batch_entropy_pool, *batch_entropy_copy;
|
|
static int batch_head, batch_tail;
|
|
static spinlock_t batch_lock = SPIN_LOCK_UNLOCKED;
|
|
|
|
static int batch_max;
|
|
static void batch_entropy_process(void *private_);
|
|
static DECLARE_WORK(batch_work, batch_entropy_process, NULL);
|
|
|
|
/* note: the size must be a power of 2 */
|
|
static int __init batch_entropy_init(int size, struct entropy_store *r)
|
|
{
|
|
batch_entropy_pool = kmalloc(size*sizeof(struct sample), GFP_KERNEL);
|
|
if (!batch_entropy_pool)
|
|
return -1;
|
|
batch_entropy_copy = kmalloc(size*sizeof(struct sample), GFP_KERNEL);
|
|
if (!batch_entropy_copy) {
|
|
kfree(batch_entropy_pool);
|
|
return -1;
|
|
}
|
|
batch_head = batch_tail = 0;
|
|
batch_work.data = r;
|
|
batch_max = size;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Changes to the entropy data is put into a queue rather than being added to
|
|
* the entropy counts directly. This is presumably to avoid doing heavy
|
|
* hashing calculations during an interrupt in add_timer_randomness().
|
|
* Instead, the entropy is only added to the pool by keventd.
|
|
*/
|
|
static void batch_entropy_store(u32 a, u32 b, int num)
|
|
{
|
|
int new;
|
|
unsigned long flags;
|
|
|
|
if (!batch_max)
|
|
return;
|
|
|
|
spin_lock_irqsave(&batch_lock, flags);
|
|
|
|
batch_entropy_pool[batch_head].data[0] = a;
|
|
batch_entropy_pool[batch_head].data[1] = b;
|
|
batch_entropy_pool[batch_head].credit = num;
|
|
|
|
if (((batch_head - batch_tail) & (batch_max-1)) >= (batch_max / 2)) {
|
|
/*
|
|
* Schedule it for the next timer tick:
|
|
*/
|
|
schedule_delayed_work(&batch_work, 1);
|
|
}
|
|
|
|
new = (batch_head+1) & (batch_max-1);
|
|
if (new == batch_tail) {
|
|
DEBUG_ENT("batch entropy buffer full\n");
|
|
} else {
|
|
batch_head = new;
|
|
}
|
|
|
|
spin_unlock_irqrestore(&batch_lock, flags);
|
|
}
|
|
|
|
/*
|
|
* Flush out the accumulated entropy operations, adding entropy to the passed
|
|
* store (normally random_state). If that store has enough entropy, alternate
|
|
* between randomizing the data of the primary and secondary stores.
|
|
*/
|
|
static void batch_entropy_process(void *private_)
|
|
{
|
|
struct entropy_store *r = (struct entropy_store *) private_, *p;
|
|
int max_entropy = r->poolinfo.POOLBITS;
|
|
unsigned head, tail;
|
|
|
|
/* Mixing into the pool is expensive, so copy over the batch
|
|
* data and release the batch lock. The pool is at least half
|
|
* full, so don't worry too much about copying only the used
|
|
* part.
|
|
*/
|
|
spin_lock_irq(&batch_lock);
|
|
|
|
memcpy(batch_entropy_copy, batch_entropy_pool,
|
|
batch_max*sizeof(struct sample));
|
|
|
|
head = batch_head;
|
|
tail = batch_tail;
|
|
batch_tail = batch_head;
|
|
|
|
spin_unlock_irq(&batch_lock);
|
|
|
|
p = r;
|
|
while (head != tail) {
|
|
if (r->entropy_count >= max_entropy) {
|
|
r = (r == sec_random_state) ? random_state :
|
|
sec_random_state;
|
|
max_entropy = r->poolinfo.POOLBITS;
|
|
}
|
|
add_entropy_words(r, batch_entropy_copy[tail].data, 2);
|
|
credit_entropy_store(r, batch_entropy_copy[tail].credit);
|
|
tail = (tail+1) & (batch_max-1);
|
|
}
|
|
if (p->entropy_count >= random_read_wakeup_thresh)
|
|
wake_up_interruptible(&random_read_wait);
|
|
}
|
|
|
|
/*********************************************************************
|
|
*
|
|
* Entropy input management
|
|
*
|
|
*********************************************************************/
|
|
|
|
/* There is one of these per entropy source */
|
|
struct timer_rand_state {
|
|
cycles_t last_time;
|
|
long last_delta,last_delta2;
|
|
unsigned dont_count_entropy:1;
|
|
};
|
|
|
|
static struct timer_rand_state keyboard_timer_state;
|
|
static struct timer_rand_state mouse_timer_state;
|
|
static struct timer_rand_state extract_timer_state;
|
|
static struct timer_rand_state *irq_timer_state[NR_IRQS];
|
|
|
|
/*
|
|
* This function adds entropy to the entropy "pool" by using timing
|
|
* delays. It uses the timer_rand_state structure to make an estimate
|
|
* of how many bits of entropy this call has added to the pool.
|
|
*
|
|
* The number "num" is also added to the pool - it should somehow describe
|
|
* the type of event which just happened. This is currently 0-255 for
|
|
* keyboard scan codes, and 256 upwards for interrupts.
|
|
*
|
|
*/
|
|
static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
|
|
{
|
|
cycles_t time;
|
|
long delta, delta2, delta3;
|
|
int entropy = 0;
|
|
|
|
preempt_disable();
|
|
/* if over the trickle threshold, use only 1 in 4096 samples */
|
|
if ( random_state->entropy_count > trickle_thresh &&
|
|
(__get_cpu_var(trickle_count)++ & 0xfff))
|
|
goto out;
|
|
|
|
/*
|
|
* Use get_cycles() if implemented, otherwise fall back to
|
|
* jiffies.
|
|
*/
|
|
time = get_cycles();
|
|
if (time)
|
|
num ^= (u32)((time >> 31) >> 1);
|
|
else
|
|
time = jiffies;
|
|
|
|
/*
|
|
* Calculate number of bits of randomness we probably added.
|
|
* We take into account the first, second and third-order deltas
|
|
* in order to make our estimate.
|
|
*/
|
|
if (!state->dont_count_entropy) {
|
|
delta = time - state->last_time;
|
|
state->last_time = time;
|
|
|
|
delta2 = delta - state->last_delta;
|
|
state->last_delta = delta;
|
|
|
|
delta3 = delta2 - state->last_delta2;
|
|
state->last_delta2 = delta2;
|
|
|
|
if (delta < 0)
|
|
delta = -delta;
|
|
if (delta2 < 0)
|
|
delta2 = -delta2;
|
|
if (delta3 < 0)
|
|
delta3 = -delta3;
|
|
if (delta > delta2)
|
|
delta = delta2;
|
|
if (delta > delta3)
|
|
delta = delta3;
|
|
|
|
/*
|
|
* delta is now minimum absolute delta.
|
|
* Round down by 1 bit on general principles,
|
|
* and limit entropy entimate to 12 bits.
|
|
*/
|
|
delta >>= 1;
|
|
delta &= (1 << 12) - 1;
|
|
|
|
entropy = int_ln_12bits(delta);
|
|
}
|
|
batch_entropy_store(num, time, entropy);
|
|
out:
|
|
preempt_enable();
|
|
}
|
|
|
|
void add_keyboard_randomness(unsigned char scancode)
|
|
{
|
|
static unsigned char last_scancode;
|
|
/* ignore autorepeat (multiple key down w/o key up) */
|
|
if (scancode != last_scancode) {
|
|
last_scancode = scancode;
|
|
add_timer_randomness(&keyboard_timer_state, scancode);
|
|
}
|
|
}
|
|
|
|
void add_mouse_randomness(__u32 mouse_data)
|
|
{
|
|
add_timer_randomness(&mouse_timer_state, mouse_data);
|
|
}
|
|
|
|
EXPORT_SYMBOL(add_mouse_randomness);
|
|
|
|
void add_interrupt_randomness(int irq)
|
|
{
|
|
if (irq >= NR_IRQS || irq_timer_state[irq] == 0)
|
|
return;
|
|
|
|
add_timer_randomness(irq_timer_state[irq], 0x100+irq);
|
|
}
|
|
|
|
void add_disk_randomness(struct gendisk *disk)
|
|
{
|
|
if (!disk || !disk->random)
|
|
return;
|
|
/* first major is 1, so we get >= 0x200 here */
|
|
add_timer_randomness(disk->random, 0x100+MKDEV(disk->major, disk->first_minor));
|
|
}
|
|
|
|
EXPORT_SYMBOL(add_disk_randomness);
|
|
|
|
/******************************************************************
|
|
*
|
|
* Hash function definition
|
|
*
|
|
*******************************************************************/
|
|
|
|
/*
|
|
* This chunk of code defines a function
|
|
* void HASH_TRANSFORM(__u32 digest[HASH_BUFFER_SIZE + HASH_EXTRA_SIZE],
|
|
* __u32 const data[16])
|
|
*
|
|
* The function hashes the input data to produce a digest in the first
|
|
* HASH_BUFFER_SIZE words of the digest[] array, and uses HASH_EXTRA_SIZE
|
|
* more words for internal purposes. (This buffer is exported so the
|
|
* caller can wipe it once rather than this code doing it each call,
|
|
* and tacking it onto the end of the digest[] array is the quick and
|
|
* dirty way of doing it.)
|
|
*
|
|
* It so happens that MD5 and SHA share most of the initial vector
|
|
* used to initialize the digest[] array before the first call:
|
|
* 1) 0x67452301
|
|
* 2) 0xefcdab89
|
|
* 3) 0x98badcfe
|
|
* 4) 0x10325476
|
|
* 5) 0xc3d2e1f0 (SHA only)
|
|
*
|
|
* For /dev/random purposes, the length of the data being hashed is
|
|
* fixed in length, so appending a bit count in the usual way is not
|
|
* cryptographically necessary.
|
|
*/
|
|
|
|
#ifdef USE_SHA
|
|
|
|
#define HASH_BUFFER_SIZE 5
|
|
#define HASH_EXTRA_SIZE 80
|
|
#define HASH_TRANSFORM SHATransform
|
|
|
|
/* Various size/speed tradeoffs are available. Choose 0..3. */
|
|
#define SHA_CODE_SIZE 0
|
|
|
|
/*
|
|
* SHA transform algorithm, taken from code written by Peter Gutmann,
|
|
* and placed in the public domain.
|
|
*/
|
|
|
|
/* The SHA f()-functions. */
|
|
|
|
#define f1(x,y,z) ( z ^ (x & (y^z)) ) /* Rounds 0-19: x ? y : z */
|
|
#define f2(x,y,z) (x ^ y ^ z) /* Rounds 20-39: XOR */
|
|
#define f3(x,y,z) ( (x & y) + (z & (x ^ y)) ) /* Rounds 40-59: majority */
|
|
#define f4(x,y,z) (x ^ y ^ z) /* Rounds 60-79: XOR */
|
|
|
|
/* The SHA Mysterious Constants */
|
|
|
|
#define K1 0x5A827999L /* Rounds 0-19: sqrt(2) * 2^30 */
|
|
#define K2 0x6ED9EBA1L /* Rounds 20-39: sqrt(3) * 2^30 */
|
|
#define K3 0x8F1BBCDCL /* Rounds 40-59: sqrt(5) * 2^30 */
|
|
#define K4 0xCA62C1D6L /* Rounds 60-79: sqrt(10) * 2^30 */
|
|
|
|
#define ROTL(n,X) ( ( ( X ) << n ) | ( ( X ) >> ( 32 - n ) ) )
|
|
|
|
#define subRound(a, b, c, d, e, f, k, data) \
|
|
( e += ROTL( 5, a ) + f( b, c, d ) + k + data, b = ROTL( 30, b ) )
|
|
|
|
|
|
static void SHATransform(__u32 digest[85], __u32 const data[16])
|
|
{
|
|
__u32 A, B, C, D, E; /* Local vars */
|
|
__u32 TEMP;
|
|
int i;
|
|
#define W (digest + HASH_BUFFER_SIZE) /* Expanded data array */
|
|
|
|
/*
|
|
* Do the preliminary expansion of 16 to 80 words. Doing it
|
|
* out-of-line line this is faster than doing it in-line on
|
|
* register-starved machines like the x86, and not really any
|
|
* slower on real processors.
|
|
*/
|
|
memcpy(W, data, 16*sizeof(__u32));
|
|
for (i = 0; i < 64; i++) {
|
|
TEMP = W[i] ^ W[i+2] ^ W[i+8] ^ W[i+13];
|
|
W[i+16] = ROTL(1, TEMP);
|
|
}
|
|
|
|
/* Set up first buffer and local data buffer */
|
|
A = digest[ 0 ];
|
|
B = digest[ 1 ];
|
|
C = digest[ 2 ];
|
|
D = digest[ 3 ];
|
|
E = digest[ 4 ];
|
|
|
|
/* Heavy mangling, in 4 sub-rounds of 20 iterations each. */
|
|
#if SHA_CODE_SIZE == 0
|
|
/*
|
|
* Approximately 50% of the speed of the largest version, but
|
|
* takes up 1/16 the space. Saves about 6k on an i386 kernel.
|
|
*/
|
|
for (i = 0; i < 80; i++) {
|
|
if (i < 40) {
|
|
if (i < 20)
|
|
TEMP = f1(B, C, D) + K1;
|
|
else
|
|
TEMP = f2(B, C, D) + K2;
|
|
} else {
|
|
if (i < 60)
|
|
TEMP = f3(B, C, D) + K3;
|
|
else
|
|
TEMP = f4(B, C, D) + K4;
|
|
}
|
|
TEMP += ROTL(5, A) + E + W[i];
|
|
E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
|
|
}
|
|
#elif SHA_CODE_SIZE == 1
|
|
for (i = 0; i < 20; i++) {
|
|
TEMP = f1(B, C, D) + K1 + ROTL(5, A) + E + W[i];
|
|
E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
|
|
}
|
|
for (; i < 40; i++) {
|
|
TEMP = f2(B, C, D) + K2 + ROTL(5, A) + E + W[i];
|
|
E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
|
|
}
|
|
for (; i < 60; i++) {
|
|
TEMP = f3(B, C, D) + K3 + ROTL(5, A) + E + W[i];
|
|
E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
|
|
}
|
|
for (; i < 80; i++) {
|
|
TEMP = f4(B, C, D) + K4 + ROTL(5, A) + E + W[i];
|
|
E = D; D = C; C = ROTL(30, B); B = A; A = TEMP;
|
|
}
|
|
#elif SHA_CODE_SIZE == 2
|
|
for (i = 0; i < 20; i += 5) {
|
|
subRound( A, B, C, D, E, f1, K1, W[ i ] );
|
|
subRound( E, A, B, C, D, f1, K1, W[ i+1 ] );
|
|
subRound( D, E, A, B, C, f1, K1, W[ i+2 ] );
|
|
subRound( C, D, E, A, B, f1, K1, W[ i+3 ] );
|
|
subRound( B, C, D, E, A, f1, K1, W[ i+4 ] );
|
|
}
|
|
for (; i < 40; i += 5) {
|
|
subRound( A, B, C, D, E, f2, K2, W[ i ] );
|
|
subRound( E, A, B, C, D, f2, K2, W[ i+1 ] );
|
|
subRound( D, E, A, B, C, f2, K2, W[ i+2 ] );
|
|
subRound( C, D, E, A, B, f2, K2, W[ i+3 ] );
|
|
subRound( B, C, D, E, A, f2, K2, W[ i+4 ] );
|
|
}
|
|
for (; i < 60; i += 5) {
|
|
subRound( A, B, C, D, E, f3, K3, W[ i ] );
|
|
subRound( E, A, B, C, D, f3, K3, W[ i+1 ] );
|
|
subRound( D, E, A, B, C, f3, K3, W[ i+2 ] );
|
|
subRound( C, D, E, A, B, f3, K3, W[ i+3 ] );
|
|
subRound( B, C, D, E, A, f3, K3, W[ i+4 ] );
|
|
}
|
|
for (; i < 80; i += 5) {
|
|
subRound( A, B, C, D, E, f4, K4, W[ i ] );
|
|
subRound( E, A, B, C, D, f4, K4, W[ i+1 ] );
|
|
subRound( D, E, A, B, C, f4, K4, W[ i+2 ] );
|
|
subRound( C, D, E, A, B, f4, K4, W[ i+3 ] );
|
|
subRound( B, C, D, E, A, f4, K4, W[ i+4 ] );
|
|
}
|
|
#elif SHA_CODE_SIZE == 3 /* Really large version */
|
|
subRound( A, B, C, D, E, f1, K1, W[ 0 ] );
|
|
subRound( E, A, B, C, D, f1, K1, W[ 1 ] );
|
|
subRound( D, E, A, B, C, f1, K1, W[ 2 ] );
|
|
subRound( C, D, E, A, B, f1, K1, W[ 3 ] );
|
|
subRound( B, C, D, E, A, f1, K1, W[ 4 ] );
|
|
subRound( A, B, C, D, E, f1, K1, W[ 5 ] );
|
|
subRound( E, A, B, C, D, f1, K1, W[ 6 ] );
|
|
subRound( D, E, A, B, C, f1, K1, W[ 7 ] );
|
|
subRound( C, D, E, A, B, f1, K1, W[ 8 ] );
|
|
subRound( B, C, D, E, A, f1, K1, W[ 9 ] );
|
|
subRound( A, B, C, D, E, f1, K1, W[ 10 ] );
|
|
subRound( E, A, B, C, D, f1, K1, W[ 11 ] );
|
|
subRound( D, E, A, B, C, f1, K1, W[ 12 ] );
|
|
subRound( C, D, E, A, B, f1, K1, W[ 13 ] );
|
|
subRound( B, C, D, E, A, f1, K1, W[ 14 ] );
|
|
subRound( A, B, C, D, E, f1, K1, W[ 15 ] );
|
|
subRound( E, A, B, C, D, f1, K1, W[ 16 ] );
|
|
subRound( D, E, A, B, C, f1, K1, W[ 17 ] );
|
|
subRound( C, D, E, A, B, f1, K1, W[ 18 ] );
|
|
subRound( B, C, D, E, A, f1, K1, W[ 19 ] );
|
|
|
|
subRound( A, B, C, D, E, f2, K2, W[ 20 ] );
|
|
subRound( E, A, B, C, D, f2, K2, W[ 21 ] );
|
|
subRound( D, E, A, B, C, f2, K2, W[ 22 ] );
|
|
subRound( C, D, E, A, B, f2, K2, W[ 23 ] );
|
|
subRound( B, C, D, E, A, f2, K2, W[ 24 ] );
|
|
subRound( A, B, C, D, E, f2, K2, W[ 25 ] );
|
|
subRound( E, A, B, C, D, f2, K2, W[ 26 ] );
|
|
subRound( D, E, A, B, C, f2, K2, W[ 27 ] );
|
|
subRound( C, D, E, A, B, f2, K2, W[ 28 ] );
|
|
subRound( B, C, D, E, A, f2, K2, W[ 29 ] );
|
|
subRound( A, B, C, D, E, f2, K2, W[ 30 ] );
|
|
subRound( E, A, B, C, D, f2, K2, W[ 31 ] );
|
|
subRound( D, E, A, B, C, f2, K2, W[ 32 ] );
|
|
subRound( C, D, E, A, B, f2, K2, W[ 33 ] );
|
|
subRound( B, C, D, E, A, f2, K2, W[ 34 ] );
|
|
subRound( A, B, C, D, E, f2, K2, W[ 35 ] );
|
|
subRound( E, A, B, C, D, f2, K2, W[ 36 ] );
|
|
subRound( D, E, A, B, C, f2, K2, W[ 37 ] );
|
|
subRound( C, D, E, A, B, f2, K2, W[ 38 ] );
|
|
subRound( B, C, D, E, A, f2, K2, W[ 39 ] );
|
|
|
|
subRound( A, B, C, D, E, f3, K3, W[ 40 ] );
|
|
subRound( E, A, B, C, D, f3, K3, W[ 41 ] );
|
|
subRound( D, E, A, B, C, f3, K3, W[ 42 ] );
|
|
subRound( C, D, E, A, B, f3, K3, W[ 43 ] );
|
|
subRound( B, C, D, E, A, f3, K3, W[ 44 ] );
|
|
subRound( A, B, C, D, E, f3, K3, W[ 45 ] );
|
|
subRound( E, A, B, C, D, f3, K3, W[ 46 ] );
|
|
subRound( D, E, A, B, C, f3, K3, W[ 47 ] );
|
|
subRound( C, D, E, A, B, f3, K3, W[ 48 ] );
|
|
subRound( B, C, D, E, A, f3, K3, W[ 49 ] );
|
|
subRound( A, B, C, D, E, f3, K3, W[ 50 ] );
|
|
subRound( E, A, B, C, D, f3, K3, W[ 51 ] );
|
|
subRound( D, E, A, B, C, f3, K3, W[ 52 ] );
|
|
subRound( C, D, E, A, B, f3, K3, W[ 53 ] );
|
|
subRound( B, C, D, E, A, f3, K3, W[ 54 ] );
|
|
subRound( A, B, C, D, E, f3, K3, W[ 55 ] );
|
|
subRound( E, A, B, C, D, f3, K3, W[ 56 ] );
|
|
subRound( D, E, A, B, C, f3, K3, W[ 57 ] );
|
|
subRound( C, D, E, A, B, f3, K3, W[ 58 ] );
|
|
subRound( B, C, D, E, A, f3, K3, W[ 59 ] );
|
|
|
|
subRound( A, B, C, D, E, f4, K4, W[ 60 ] );
|
|
subRound( E, A, B, C, D, f4, K4, W[ 61 ] );
|
|
subRound( D, E, A, B, C, f4, K4, W[ 62 ] );
|
|
subRound( C, D, E, A, B, f4, K4, W[ 63 ] );
|
|
subRound( B, C, D, E, A, f4, K4, W[ 64 ] );
|
|
subRound( A, B, C, D, E, f4, K4, W[ 65 ] );
|
|
subRound( E, A, B, C, D, f4, K4, W[ 66 ] );
|
|
subRound( D, E, A, B, C, f4, K4, W[ 67 ] );
|
|
subRound( C, D, E, A, B, f4, K4, W[ 68 ] );
|
|
subRound( B, C, D, E, A, f4, K4, W[ 69 ] );
|
|
subRound( A, B, C, D, E, f4, K4, W[ 70 ] );
|
|
subRound( E, A, B, C, D, f4, K4, W[ 71 ] );
|
|
subRound( D, E, A, B, C, f4, K4, W[ 72 ] );
|
|
subRound( C, D, E, A, B, f4, K4, W[ 73 ] );
|
|
subRound( B, C, D, E, A, f4, K4, W[ 74 ] );
|
|
subRound( A, B, C, D, E, f4, K4, W[ 75 ] );
|
|
subRound( E, A, B, C, D, f4, K4, W[ 76 ] );
|
|
subRound( D, E, A, B, C, f4, K4, W[ 77 ] );
|
|
subRound( C, D, E, A, B, f4, K4, W[ 78 ] );
|
|
subRound( B, C, D, E, A, f4, K4, W[ 79 ] );
|
|
#else
|
|
#error Illegal SHA_CODE_SIZE
|
|
#endif
|
|
|
|
/* Build message digest */
|
|
digest[ 0 ] += A;
|
|
digest[ 1 ] += B;
|
|
digest[ 2 ] += C;
|
|
digest[ 3 ] += D;
|
|
digest[ 4 ] += E;
|
|
|
|
/* W is wiped by the caller */
|
|
#undef W
|
|
}
|
|
|
|
#undef ROTL
|
|
#undef f1
|
|
#undef f2
|
|
#undef f3
|
|
#undef f4
|
|
#undef K1
|
|
#undef K2
|
|
#undef K3
|
|
#undef K4
|
|
#undef subRound
|
|
|
|
#else /* !USE_SHA - Use MD5 */
|
|
|
|
#define HASH_BUFFER_SIZE 4
|
|
#define HASH_EXTRA_SIZE 0
|
|
#define HASH_TRANSFORM MD5Transform
|
|
|
|
/*
|
|
* MD5 transform algorithm, taken from code written by Colin Plumb,
|
|
* and put into the public domain
|
|
*/
|
|
|
|
/* The four core functions - F1 is optimized somewhat */
|
|
|
|
/* #define F1(x, y, z) (x & y | ~x & z) */
|
|
#define F1(x, y, z) (z ^ (x & (y ^ z)))
|
|
#define F2(x, y, z) F1(z, x, y)
|
|
#define F3(x, y, z) (x ^ y ^ z)
|
|
#define F4(x, y, z) (y ^ (x | ~z))
|
|
|
|
/* This is the central step in the MD5 algorithm. */
|
|
#define MD5STEP(f, w, x, y, z, data, s) \
|
|
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
|
|
|
|
/*
|
|
* The core of the MD5 algorithm, this alters an existing MD5 hash to
|
|
* reflect the addition of 16 longwords of new data. MD5Update blocks
|
|
* the data and converts bytes into longwords for this routine.
|
|
*/
|
|
static void MD5Transform(__u32 buf[HASH_BUFFER_SIZE], __u32 const in[16])
|
|
{
|
|
__u32 a, b, c, d;
|
|
|
|
a = buf[0];
|
|
b = buf[1];
|
|
c = buf[2];
|
|
d = buf[3];
|
|
|
|
MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478, 7);
|
|
MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
|
|
MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
|
|
MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
|
|
MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf, 7);
|
|
MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
|
|
MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
|
|
MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
|
|
MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8, 7);
|
|
MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
|
|
MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
|
|
MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
|
|
MD5STEP(F1, a, b, c, d, in[12]+0x6b901122, 7);
|
|
MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
|
|
MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
|
|
MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);
|
|
|
|
MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562, 5);
|
|
MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340, 9);
|
|
MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
|
|
MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
|
|
MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d, 5);
|
|
MD5STEP(F2, d, a, b, c, in[10]+0x02441453, 9);
|
|
MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
|
|
MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
|
|
MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6, 5);
|
|
MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6, 9);
|
|
MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
|
|
MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
|
|
MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905, 5);
|
|
MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8, 9);
|
|
MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
|
|
MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);
|
|
|
|
MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942, 4);
|
|
MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
|
|
MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
|
|
MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
|
|
MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44, 4);
|
|
MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
|
|
MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
|
|
MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
|
|
MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6, 4);
|
|
MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
|
|
MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
|
|
MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
|
|
MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039, 4);
|
|
MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
|
|
MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
|
|
MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);
|
|
|
|
MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244, 6);
|
|
MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
|
|
MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
|
|
MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
|
|
MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3, 6);
|
|
MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
|
|
MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
|
|
MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
|
|
MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f, 6);
|
|
MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
|
|
MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
|
|
MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
|
|
MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82, 6);
|
|
MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
|
|
MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
|
|
MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);
|
|
|
|
buf[0] += a;
|
|
buf[1] += b;
|
|
buf[2] += c;
|
|
buf[3] += d;
|
|
}
|
|
|
|
#undef F1
|
|
#undef F2
|
|
#undef F3
|
|
#undef F4
|
|
#undef MD5STEP
|
|
|
|
#endif /* !USE_SHA */
|
|
|
|
/*********************************************************************
|
|
*
|
|
* Entropy extraction routines
|
|
*
|
|
*********************************************************************/
|
|
|
|
#define EXTRACT_ENTROPY_USER 1
|
|
#define EXTRACT_ENTROPY_SECONDARY 2
|
|
#define EXTRACT_ENTROPY_LIMIT 4
|
|
#define TMP_BUF_SIZE (HASH_BUFFER_SIZE + HASH_EXTRA_SIZE)
|
|
#define SEC_XFER_SIZE (TMP_BUF_SIZE*4)
|
|
|
|
static ssize_t extract_entropy(struct entropy_store *r, void * buf,
|
|
size_t nbytes, int flags);
|
|
|
|
/*
|
|
* This utility inline function is responsible for transfering entropy
|
|
* from the primary pool to the secondary extraction pool. We make
|
|
* sure we pull enough for a 'catastrophic reseed'.
|
|
*/
|
|
static inline void xfer_secondary_pool(struct entropy_store *r,
|
|
size_t nbytes, __u32 *tmp)
|
|
{
|
|
if (r->entropy_count < nbytes * 8 &&
|
|
r->entropy_count < r->poolinfo.POOLBITS) {
|
|
int bytes = max_t(int, random_read_wakeup_thresh / 8,
|
|
min_t(int, nbytes, TMP_BUF_SIZE));
|
|
|
|
DEBUG_ENT("%04d %04d : going to reseed %s with %d bits "
|
|
"(%d of %d requested)\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count,
|
|
r->name, bytes * 8, nbytes * 8, r->entropy_count);
|
|
|
|
bytes=extract_entropy(random_state, tmp, bytes,
|
|
EXTRACT_ENTROPY_LIMIT);
|
|
add_entropy_words(r, tmp, bytes);
|
|
credit_entropy_store(r, bytes*8);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This function extracts randomness from the "entropy pool", and
|
|
* returns it in a buffer. This function computes how many remaining
|
|
* bits of entropy are left in the pool, but it does not restrict the
|
|
* number of bytes that are actually obtained. If the EXTRACT_ENTROPY_USER
|
|
* flag is given, then the buf pointer is assumed to be in user space.
|
|
*
|
|
* If the EXTRACT_ENTROPY_SECONDARY flag is given, then we are actually
|
|
* extracting entropy from the secondary pool, and can refill from the
|
|
* primary pool if needed.
|
|
*
|
|
* Note: extract_entropy() assumes that .poolwords is a multiple of 16 words.
|
|
*/
|
|
static ssize_t extract_entropy(struct entropy_store *r, void * buf,
|
|
size_t nbytes, int flags)
|
|
{
|
|
ssize_t ret, i;
|
|
__u32 tmp[TMP_BUF_SIZE], data[16];
|
|
__u32 x;
|
|
unsigned long cpuflags;
|
|
|
|
|
|
/* Redundant, but just in case... */
|
|
if (r->entropy_count > r->poolinfo.POOLBITS)
|
|
r->entropy_count = r->poolinfo.POOLBITS;
|
|
|
|
if (flags & EXTRACT_ENTROPY_SECONDARY)
|
|
xfer_secondary_pool(r, nbytes, tmp);
|
|
|
|
/* Hold lock while accounting */
|
|
spin_lock_irqsave(&r->lock, cpuflags);
|
|
|
|
DEBUG_ENT("%04d %04d : trying to extract %d bits from %s\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count,
|
|
nbytes * 8, r->name);
|
|
|
|
if (flags & EXTRACT_ENTROPY_LIMIT && nbytes >= r->entropy_count / 8)
|
|
nbytes = r->entropy_count / 8;
|
|
|
|
if (r->entropy_count / 8 >= nbytes)
|
|
r->entropy_count -= nbytes*8;
|
|
else
|
|
r->entropy_count = 0;
|
|
|
|
if (r->entropy_count < random_write_wakeup_thresh)
|
|
wake_up_interruptible(&random_write_wait);
|
|
|
|
DEBUG_ENT("Debiting %d entropy credits from %s%s\n",
|
|
nbytes * 8, r->name,
|
|
flags & EXTRACT_ENTROPY_LIMIT ? "" : " (unlimited)");
|
|
|
|
spin_unlock_irqrestore(&r->lock, cpuflags);
|
|
|
|
ret = 0;
|
|
while (nbytes) {
|
|
/*
|
|
* Check if we need to break out or reschedule....
|
|
*/
|
|
if ((flags & EXTRACT_ENTROPY_USER) && need_resched()) {
|
|
if (signal_pending(current)) {
|
|
if (ret == 0)
|
|
ret = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
|
|
DEBUG_ENT("%04d %04d : extract feeling sleepy (%d bytes left)\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count, nbytes);
|
|
|
|
schedule();
|
|
|
|
DEBUG_ENT("%04d %04d : extract woke up\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count);
|
|
}
|
|
|
|
/* Hash the pool to get the output */
|
|
tmp[0] = 0x67452301;
|
|
tmp[1] = 0xefcdab89;
|
|
tmp[2] = 0x98badcfe;
|
|
tmp[3] = 0x10325476;
|
|
#ifdef USE_SHA
|
|
tmp[4] = 0xc3d2e1f0;
|
|
#endif
|
|
/*
|
|
* As we hash the pool, we mix intermediate values of
|
|
* the hash back into the pool. This eliminates
|
|
* backtracking attacks (where the attacker knows
|
|
* the state of the pool plus the current outputs, and
|
|
* attempts to find previous ouputs), unless the hash
|
|
* function can be inverted.
|
|
*/
|
|
for (i = 0, x = 0; i < r->poolinfo.poolwords; i += 16, x+=2) {
|
|
HASH_TRANSFORM(tmp, r->pool+i);
|
|
add_entropy_words(r, &tmp[x%HASH_BUFFER_SIZE], 1);
|
|
}
|
|
|
|
/*
|
|
* To avoid duplicates, we atomically extract a
|
|
* portion of the pool while mixing, and hash one
|
|
* final time.
|
|
*/
|
|
__add_entropy_words(r, &tmp[x%HASH_BUFFER_SIZE], 1, data);
|
|
HASH_TRANSFORM(tmp, data);
|
|
|
|
/*
|
|
* In case the hash function has some recognizable
|
|
* output pattern, we fold it in half.
|
|
*/
|
|
for (i = 0; i < HASH_BUFFER_SIZE/2; i++)
|
|
tmp[i] ^= tmp[i + (HASH_BUFFER_SIZE+1)/2];
|
|
#if HASH_BUFFER_SIZE & 1 /* There's a middle word to deal with */
|
|
x = tmp[HASH_BUFFER_SIZE/2];
|
|
x ^= (x >> 16); /* Fold it in half */
|
|
((__u16 *)tmp)[HASH_BUFFER_SIZE-1] = (__u16)x;
|
|
#endif
|
|
|
|
/* Copy data to destination buffer */
|
|
i = min(nbytes, HASH_BUFFER_SIZE*sizeof(__u32)/2);
|
|
if (flags & EXTRACT_ENTROPY_USER) {
|
|
i -= copy_to_user(buf, (__u8 const *)tmp, i);
|
|
if (!i) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
} else
|
|
memcpy(buf, (__u8 const *)tmp, i);
|
|
nbytes -= i;
|
|
buf += i;
|
|
ret += i;
|
|
}
|
|
|
|
/* Wipe data just returned from memory */
|
|
memset(tmp, 0, sizeof(tmp));
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This function is the exported kernel interface. It returns some
|
|
* number of good random numbers, suitable for seeding TCP sequence
|
|
* numbers, etc.
|
|
*/
|
|
void get_random_bytes(void *buf, int nbytes)
|
|
{
|
|
struct entropy_store *r = urandom_state;
|
|
int flags = EXTRACT_ENTROPY_SECONDARY;
|
|
|
|
if (!r)
|
|
r = sec_random_state;
|
|
if (!r) {
|
|
r = random_state;
|
|
flags = 0;
|
|
}
|
|
if (!r) {
|
|
printk(KERN_NOTICE "get_random_bytes called before "
|
|
"random driver initialization\n");
|
|
return;
|
|
}
|
|
extract_entropy(r, (char *) buf, nbytes, flags);
|
|
}
|
|
|
|
EXPORT_SYMBOL(get_random_bytes);
|
|
|
|
/*********************************************************************
|
|
*
|
|
* Functions to interface with Linux
|
|
*
|
|
*********************************************************************/
|
|
|
|
/*
|
|
* Initialize the random pool with standard stuff.
|
|
*
|
|
* NOTE: This is an OS-dependent function.
|
|
*/
|
|
static void init_std_data(struct entropy_store *r)
|
|
{
|
|
struct timeval tv;
|
|
__u32 words[2];
|
|
char *p;
|
|
int i;
|
|
|
|
do_gettimeofday(&tv);
|
|
words[0] = tv.tv_sec;
|
|
words[1] = tv.tv_usec;
|
|
add_entropy_words(r, words, 2);
|
|
|
|
/*
|
|
* This doesn't lock system.utsname. However, we are generating
|
|
* entropy so a race with a name set here is fine.
|
|
*/
|
|
p = (char *) &system_utsname;
|
|
for (i = sizeof(system_utsname) / sizeof(words); i; i--) {
|
|
memcpy(words, p, sizeof(words));
|
|
add_entropy_words(r, words, sizeof(words)/4);
|
|
p += sizeof(words);
|
|
}
|
|
}
|
|
|
|
static int __init rand_initialize(void)
|
|
{
|
|
int i;
|
|
|
|
if (create_entropy_store(DEFAULT_POOL_SIZE, "primary", &random_state))
|
|
goto err;
|
|
if (batch_entropy_init(BATCH_ENTROPY_SIZE, random_state))
|
|
goto err;
|
|
if (create_entropy_store(SECONDARY_POOL_SIZE, "secondary",
|
|
&sec_random_state))
|
|
goto err;
|
|
if (create_entropy_store(SECONDARY_POOL_SIZE, "urandom",
|
|
&urandom_state))
|
|
goto err;
|
|
clear_entropy_store(random_state);
|
|
clear_entropy_store(sec_random_state);
|
|
clear_entropy_store(urandom_state);
|
|
init_std_data(random_state);
|
|
init_std_data(sec_random_state);
|
|
init_std_data(urandom_state);
|
|
#ifdef CONFIG_SYSCTL
|
|
sysctl_init_random(random_state);
|
|
#endif
|
|
for (i = 0; i < NR_IRQS; i++)
|
|
irq_timer_state[i] = NULL;
|
|
memset(&keyboard_timer_state, 0, sizeof(struct timer_rand_state));
|
|
memset(&mouse_timer_state, 0, sizeof(struct timer_rand_state));
|
|
memset(&extract_timer_state, 0, sizeof(struct timer_rand_state));
|
|
extract_timer_state.dont_count_entropy = 1;
|
|
return 0;
|
|
err:
|
|
return -1;
|
|
}
|
|
module_init(rand_initialize);
|
|
|
|
void rand_initialize_irq(int irq)
|
|
{
|
|
struct timer_rand_state *state;
|
|
|
|
if (irq >= NR_IRQS || irq_timer_state[irq])
|
|
return;
|
|
|
|
/*
|
|
* If kmalloc returns null, we just won't use that entropy
|
|
* source.
|
|
*/
|
|
state = kmalloc(sizeof(struct timer_rand_state), GFP_KERNEL);
|
|
if (state) {
|
|
memset(state, 0, sizeof(struct timer_rand_state));
|
|
irq_timer_state[irq] = state;
|
|
}
|
|
}
|
|
|
|
void rand_initialize_disk(struct gendisk *disk)
|
|
{
|
|
struct timer_rand_state *state;
|
|
|
|
/*
|
|
* If kmalloc returns null, we just won't use that entropy
|
|
* source.
|
|
*/
|
|
state = kmalloc(sizeof(struct timer_rand_state), GFP_KERNEL);
|
|
if (state) {
|
|
memset(state, 0, sizeof(struct timer_rand_state));
|
|
disk->random = state;
|
|
}
|
|
}
|
|
|
|
static ssize_t
|
|
random_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
|
|
{
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
ssize_t n, retval = 0, count = 0;
|
|
|
|
if (nbytes == 0)
|
|
return 0;
|
|
|
|
while (nbytes > 0) {
|
|
n = nbytes;
|
|
if (n > SEC_XFER_SIZE)
|
|
n = SEC_XFER_SIZE;
|
|
|
|
DEBUG_ENT("%04d %04d : reading %d bits, p: %d s: %d\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count,
|
|
n*8, random_state->entropy_count,
|
|
sec_random_state->entropy_count);
|
|
|
|
n = extract_entropy(sec_random_state, buf, n,
|
|
EXTRACT_ENTROPY_USER |
|
|
EXTRACT_ENTROPY_LIMIT |
|
|
EXTRACT_ENTROPY_SECONDARY);
|
|
|
|
DEBUG_ENT("%04d %04d : read got %d bits (%d still needed)\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count,
|
|
n*8, (nbytes-n)*8);
|
|
|
|
if (n == 0) {
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
retval = -EAGAIN;
|
|
break;
|
|
}
|
|
if (signal_pending(current)) {
|
|
retval = -ERESTARTSYS;
|
|
break;
|
|
}
|
|
|
|
DEBUG_ENT("%04d %04d : sleeping?\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count);
|
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
add_wait_queue(&random_read_wait, &wait);
|
|
|
|
if (sec_random_state->entropy_count / 8 == 0)
|
|
schedule();
|
|
|
|
set_current_state(TASK_RUNNING);
|
|
remove_wait_queue(&random_read_wait, &wait);
|
|
|
|
DEBUG_ENT("%04d %04d : waking up\n",
|
|
random_state->entropy_count,
|
|
sec_random_state->entropy_count);
|
|
|
|
continue;
|
|
}
|
|
|
|
if (n < 0) {
|
|
retval = n;
|
|
break;
|
|
}
|
|
count += n;
|
|
buf += n;
|
|
nbytes -= n;
|
|
break; /* This break makes the device work */
|
|
/* like a named pipe */
|
|
}
|
|
|
|
/*
|
|
* If we gave the user some bytes, update the access time.
|
|
*/
|
|
if (count)
|
|
file_accessed(file);
|
|
|
|
return (count ? count : retval);
|
|
}
|
|
|
|
static ssize_t
|
|
urandom_read(struct file * file, char __user * buf,
|
|
size_t nbytes, loff_t *ppos)
|
|
{
|
|
int flags = EXTRACT_ENTROPY_USER;
|
|
unsigned long cpuflags;
|
|
|
|
spin_lock_irqsave(&random_state->lock, cpuflags);
|
|
if (random_state->entropy_count > random_state->poolinfo.POOLBITS)
|
|
flags |= EXTRACT_ENTROPY_SECONDARY;
|
|
spin_unlock_irqrestore(&random_state->lock, cpuflags);
|
|
|
|
return extract_entropy(urandom_state, buf, nbytes, flags);
|
|
}
|
|
|
|
static unsigned int
|
|
random_poll(struct file *file, poll_table * wait)
|
|
{
|
|
unsigned int mask;
|
|
|
|
poll_wait(file, &random_read_wait, wait);
|
|
poll_wait(file, &random_write_wait, wait);
|
|
mask = 0;
|
|
if (random_state->entropy_count >= random_read_wakeup_thresh)
|
|
mask |= POLLIN | POLLRDNORM;
|
|
if (random_state->entropy_count < random_write_wakeup_thresh)
|
|
mask |= POLLOUT | POLLWRNORM;
|
|
return mask;
|
|
}
|
|
|
|
static ssize_t
|
|
random_write(struct file * file, const char __user * buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
int ret = 0;
|
|
size_t bytes;
|
|
__u32 buf[16];
|
|
const char __user *p = buffer;
|
|
size_t c = count;
|
|
|
|
while (c > 0) {
|
|
bytes = min(c, sizeof(buf));
|
|
|
|
bytes -= copy_from_user(&buf, p, bytes);
|
|
if (!bytes) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
c -= bytes;
|
|
p += bytes;
|
|
|
|
add_entropy_words(random_state, buf, (bytes + 3) / 4);
|
|
}
|
|
if (p == buffer) {
|
|
return (ssize_t)ret;
|
|
} else {
|
|
file->f_dentry->d_inode->i_mtime = CURRENT_TIME;
|
|
mark_inode_dirty(file->f_dentry->d_inode);
|
|
return (ssize_t)(p - buffer);
|
|
}
|
|
}
|
|
|
|
static int
|
|
random_ioctl(struct inode * inode, struct file * file,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
int size, ent_count;
|
|
int __user *p = (int __user *)arg;
|
|
int retval;
|
|
|
|
switch (cmd) {
|
|
case RNDGETENTCNT:
|
|
ent_count = random_state->entropy_count;
|
|
if (put_user(ent_count, p))
|
|
return -EFAULT;
|
|
return 0;
|
|
case RNDADDTOENTCNT:
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
if (get_user(ent_count, p))
|
|
return -EFAULT;
|
|
credit_entropy_store(random_state, ent_count);
|
|
/*
|
|
* Wake up waiting processes if we have enough
|
|
* entropy.
|
|
*/
|
|
if (random_state->entropy_count >= random_read_wakeup_thresh)
|
|
wake_up_interruptible(&random_read_wait);
|
|
return 0;
|
|
case RNDADDENTROPY:
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
if (get_user(ent_count, p++))
|
|
return -EFAULT;
|
|
if (ent_count < 0)
|
|
return -EINVAL;
|
|
if (get_user(size, p++))
|
|
return -EFAULT;
|
|
retval = random_write(file, (const char __user *) p,
|
|
size, &file->f_pos);
|
|
if (retval < 0)
|
|
return retval;
|
|
credit_entropy_store(random_state, ent_count);
|
|
/*
|
|
* Wake up waiting processes if we have enough
|
|
* entropy.
|
|
*/
|
|
if (random_state->entropy_count >= random_read_wakeup_thresh)
|
|
wake_up_interruptible(&random_read_wait);
|
|
return 0;
|
|
case RNDZAPENTCNT:
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
random_state->entropy_count = 0;
|
|
return 0;
|
|
case RNDCLEARPOOL:
|
|
/* Clear the entropy pool and associated counters. */
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
clear_entropy_store(random_state);
|
|
init_std_data(random_state);
|
|
return 0;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
struct file_operations random_fops = {
|
|
.read = random_read,
|
|
.write = random_write,
|
|
.poll = random_poll,
|
|
.ioctl = random_ioctl,
|
|
};
|
|
|
|
struct file_operations urandom_fops = {
|
|
.read = urandom_read,
|
|
.write = random_write,
|
|
.ioctl = random_ioctl,
|
|
};
|
|
|
|
/***************************************************************
|
|
* Random UUID interface
|
|
*
|
|
* Used here for a Boot ID, but can be useful for other kernel
|
|
* drivers.
|
|
***************************************************************/
|
|
|
|
/*
|
|
* Generate random UUID
|
|
*/
|
|
void generate_random_uuid(unsigned char uuid_out[16])
|
|
{
|
|
get_random_bytes(uuid_out, 16);
|
|
/* Set UUID version to 4 --- truely random generation */
|
|
uuid_out[6] = (uuid_out[6] & 0x0F) | 0x40;
|
|
/* Set the UUID variant to DCE */
|
|
uuid_out[8] = (uuid_out[8] & 0x3F) | 0x80;
|
|
}
|
|
|
|
EXPORT_SYMBOL(generate_random_uuid);
|
|
|
|
/********************************************************************
|
|
*
|
|
* Sysctl interface
|
|
*
|
|
********************************************************************/
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
|
|
#include <linux/sysctl.h>
|
|
|
|
static int sysctl_poolsize;
|
|
static int min_read_thresh, max_read_thresh;
|
|
static int min_write_thresh, max_write_thresh;
|
|
static char sysctl_bootid[16];
|
|
|
|
/*
|
|
* This function handles a request from the user to change the pool size
|
|
* of the primary entropy store.
|
|
*/
|
|
static int change_poolsize(int poolsize)
|
|
{
|
|
struct entropy_store *new_store, *old_store;
|
|
int ret;
|
|
|
|
if ((ret = create_entropy_store(poolsize, random_state->name,
|
|
&new_store)))
|
|
return ret;
|
|
|
|
add_entropy_words(new_store, random_state->pool,
|
|
random_state->poolinfo.poolwords);
|
|
credit_entropy_store(new_store, random_state->entropy_count);
|
|
|
|
sysctl_init_random(new_store);
|
|
old_store = random_state;
|
|
random_state = batch_work.data = new_store;
|
|
free_entropy_store(old_store);
|
|
return 0;
|
|
}
|
|
|
|
static int proc_do_poolsize(ctl_table *table, int write, struct file *filp,
|
|
void __user *buffer, size_t *lenp, loff_t *ppos)
|
|
{
|
|
int ret;
|
|
|
|
sysctl_poolsize = random_state->poolinfo.POOLBYTES;
|
|
|
|
ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
|
|
if (ret || !write ||
|
|
(sysctl_poolsize == random_state->poolinfo.POOLBYTES))
|
|
return ret;
|
|
|
|
return change_poolsize(sysctl_poolsize);
|
|
}
|
|
|
|
static int poolsize_strategy(ctl_table *table, int __user *name, int nlen,
|
|
void __user *oldval, size_t __user *oldlenp,
|
|
void __user *newval, size_t newlen, void **context)
|
|
{
|
|
int len;
|
|
|
|
sysctl_poolsize = random_state->poolinfo.POOLBYTES;
|
|
|
|
/*
|
|
* We only handle the write case, since the read case gets
|
|
* handled by the default handler (and we don't care if the
|
|
* write case happens twice; it's harmless).
|
|
*/
|
|
if (newval && newlen) {
|
|
len = newlen;
|
|
if (len > table->maxlen)
|
|
len = table->maxlen;
|
|
if (copy_from_user(table->data, newval, len))
|
|
return -EFAULT;
|
|
}
|
|
|
|
if (sysctl_poolsize != random_state->poolinfo.POOLBYTES)
|
|
return change_poolsize(sysctl_poolsize);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* These functions is used to return both the bootid UUID, and random
|
|
* UUID. The difference is in whether table->data is NULL; if it is,
|
|
* then a new UUID is generated and returned to the user.
|
|
*
|
|
* If the user accesses this via the proc interface, it will be returned
|
|
* as an ASCII string in the standard UUID format. If accesses via the
|
|
* sysctl system call, it is returned as 16 bytes of binary data.
|
|
*/
|
|
static int proc_do_uuid(ctl_table *table, int write, struct file *filp,
|
|
void __user *buffer, size_t *lenp, loff_t *ppos)
|
|
{
|
|
ctl_table fake_table;
|
|
unsigned char buf[64], tmp_uuid[16], *uuid;
|
|
|
|
uuid = table->data;
|
|
if (!uuid) {
|
|
uuid = tmp_uuid;
|
|
uuid[8] = 0;
|
|
}
|
|
if (uuid[8] == 0)
|
|
generate_random_uuid(uuid);
|
|
|
|
sprintf(buf, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-"
|
|
"%02x%02x%02x%02x%02x%02x",
|
|
uuid[0], uuid[1], uuid[2], uuid[3],
|
|
uuid[4], uuid[5], uuid[6], uuid[7],
|
|
uuid[8], uuid[9], uuid[10], uuid[11],
|
|
uuid[12], uuid[13], uuid[14], uuid[15]);
|
|
fake_table.data = buf;
|
|
fake_table.maxlen = sizeof(buf);
|
|
|
|
return proc_dostring(&fake_table, write, filp, buffer, lenp, ppos);
|
|
}
|
|
|
|
static int uuid_strategy(ctl_table *table, int __user *name, int nlen,
|
|
void __user *oldval, size_t __user *oldlenp,
|
|
void __user *newval, size_t newlen, void **context)
|
|
{
|
|
unsigned char tmp_uuid[16], *uuid;
|
|
unsigned int len;
|
|
|
|
if (!oldval || !oldlenp)
|
|
return 1;
|
|
|
|
uuid = table->data;
|
|
if (!uuid) {
|
|
uuid = tmp_uuid;
|
|
uuid[8] = 0;
|
|
}
|
|
if (uuid[8] == 0)
|
|
generate_random_uuid(uuid);
|
|
|
|
if (get_user(len, oldlenp))
|
|
return -EFAULT;
|
|
if (len) {
|
|
if (len > 16)
|
|
len = 16;
|
|
if (copy_to_user(oldval, uuid, len) ||
|
|
put_user(len, oldlenp))
|
|
return -EFAULT;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
ctl_table random_table[] = {
|
|
{
|
|
.ctl_name = RANDOM_POOLSIZE,
|
|
.procname = "poolsize",
|
|
.data = &sysctl_poolsize,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_do_poolsize,
|
|
.strategy = &poolsize_strategy,
|
|
},
|
|
{
|
|
.ctl_name = RANDOM_ENTROPY_COUNT,
|
|
.procname = "entropy_avail",
|
|
.maxlen = sizeof(int),
|
|
.mode = 0444,
|
|
.proc_handler = &proc_dointvec,
|
|
},
|
|
{
|
|
.ctl_name = RANDOM_READ_THRESH,
|
|
.procname = "read_wakeup_threshold",
|
|
.data = &random_read_wakeup_thresh,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.strategy = &sysctl_intvec,
|
|
.extra1 = &min_read_thresh,
|
|
.extra2 = &max_read_thresh,
|
|
},
|
|
{
|
|
.ctl_name = RANDOM_WRITE_THRESH,
|
|
.procname = "write_wakeup_threshold",
|
|
.data = &random_write_wakeup_thresh,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.strategy = &sysctl_intvec,
|
|
.extra1 = &min_write_thresh,
|
|
.extra2 = &max_write_thresh,
|
|
},
|
|
{
|
|
.ctl_name = RANDOM_BOOT_ID,
|
|
.procname = "boot_id",
|
|
.data = &sysctl_bootid,
|
|
.maxlen = 16,
|
|
.mode = 0444,
|
|
.proc_handler = &proc_do_uuid,
|
|
.strategy = &uuid_strategy,
|
|
},
|
|
{
|
|
.ctl_name = RANDOM_UUID,
|
|
.procname = "uuid",
|
|
.maxlen = 16,
|
|
.mode = 0444,
|
|
.proc_handler = &proc_do_uuid,
|
|
.strategy = &uuid_strategy,
|
|
},
|
|
{ .ctl_name = 0 }
|
|
};
|
|
|
|
static void sysctl_init_random(struct entropy_store *random_state)
|
|
{
|
|
min_read_thresh = 8;
|
|
min_write_thresh = 0;
|
|
max_read_thresh = max_write_thresh = random_state->poolinfo.POOLBITS;
|
|
random_table[1].data = &random_state->entropy_count;
|
|
}
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
/********************************************************************
|
|
*
|
|
* Random funtions for networking
|
|
*
|
|
********************************************************************/
|
|
|
|
#ifdef CONFIG_INET
|
|
/*
|
|
* TCP initial sequence number picking. This uses the random number
|
|
* generator to pick an initial secret value. This value is hashed
|
|
* along with the TCP endpoint information to provide a unique
|
|
* starting point for each pair of TCP endpoints. This defeats
|
|
* attacks which rely on guessing the initial TCP sequence number.
|
|
* This algorithm was suggested by Steve Bellovin.
|
|
*
|
|
* Using a very strong hash was taking an appreciable amount of the total
|
|
* TCP connection establishment time, so this is a weaker hash,
|
|
* compensated for by changing the secret periodically.
|
|
*/
|
|
|
|
/* F, G and H are basic MD4 functions: selection, majority, parity */
|
|
#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
|
|
#define G(x, y, z) (((x) & (y)) + (((x) ^ (y)) & (z)))
|
|
#define H(x, y, z) ((x) ^ (y) ^ (z))
|
|
|
|
/*
|
|
* The generic round function. The application is so specific that
|
|
* we don't bother protecting all the arguments with parens, as is generally
|
|
* good macro practice, in favor of extra legibility.
|
|
* Rotation is separate from addition to prevent recomputation
|
|
*/
|
|
#define ROUND(f, a, b, c, d, x, s) \
|
|
(a += f(b, c, d) + x, a = (a << s) | (a >> (32-s)))
|
|
#define K1 0
|
|
#define K2 013240474631UL
|
|
#define K3 015666365641UL
|
|
|
|
/*
|
|
* Basic cut-down MD4 transform. Returns only 32 bits of result.
|
|
*/
|
|
static __u32 halfMD4Transform (__u32 const buf[4], __u32 const in[8])
|
|
{
|
|
__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
|
|
|
|
/* Round 1 */
|
|
ROUND(F, a, b, c, d, in[0] + K1, 3);
|
|
ROUND(F, d, a, b, c, in[1] + K1, 7);
|
|
ROUND(F, c, d, a, b, in[2] + K1, 11);
|
|
ROUND(F, b, c, d, a, in[3] + K1, 19);
|
|
ROUND(F, a, b, c, d, in[4] + K1, 3);
|
|
ROUND(F, d, a, b, c, in[5] + K1, 7);
|
|
ROUND(F, c, d, a, b, in[6] + K1, 11);
|
|
ROUND(F, b, c, d, a, in[7] + K1, 19);
|
|
|
|
/* Round 2 */
|
|
ROUND(G, a, b, c, d, in[1] + K2, 3);
|
|
ROUND(G, d, a, b, c, in[3] + K2, 5);
|
|
ROUND(G, c, d, a, b, in[5] + K2, 9);
|
|
ROUND(G, b, c, d, a, in[7] + K2, 13);
|
|
ROUND(G, a, b, c, d, in[0] + K2, 3);
|
|
ROUND(G, d, a, b, c, in[2] + K2, 5);
|
|
ROUND(G, c, d, a, b, in[4] + K2, 9);
|
|
ROUND(G, b, c, d, a, in[6] + K2, 13);
|
|
|
|
/* Round 3 */
|
|
ROUND(H, a, b, c, d, in[3] + K3, 3);
|
|
ROUND(H, d, a, b, c, in[7] + K3, 9);
|
|
ROUND(H, c, d, a, b, in[2] + K3, 11);
|
|
ROUND(H, b, c, d, a, in[6] + K3, 15);
|
|
ROUND(H, a, b, c, d, in[1] + K3, 3);
|
|
ROUND(H, d, a, b, c, in[5] + K3, 9);
|
|
ROUND(H, c, d, a, b, in[0] + K3, 11);
|
|
ROUND(H, b, c, d, a, in[4] + K3, 15);
|
|
|
|
return buf[1] + b; /* "most hashed" word */
|
|
/* Alternative: return sum of all words? */
|
|
}
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
|
|
|
static __u32 twothirdsMD4Transform (__u32 const buf[4], __u32 const in[12])
|
|
{
|
|
__u32 a = buf[0], b = buf[1], c = buf[2], d = buf[3];
|
|
|
|
/* Round 1 */
|
|
ROUND(F, a, b, c, d, in[ 0] + K1, 3);
|
|
ROUND(F, d, a, b, c, in[ 1] + K1, 7);
|
|
ROUND(F, c, d, a, b, in[ 2] + K1, 11);
|
|
ROUND(F, b, c, d, a, in[ 3] + K1, 19);
|
|
ROUND(F, a, b, c, d, in[ 4] + K1, 3);
|
|
ROUND(F, d, a, b, c, in[ 5] + K1, 7);
|
|
ROUND(F, c, d, a, b, in[ 6] + K1, 11);
|
|
ROUND(F, b, c, d, a, in[ 7] + K1, 19);
|
|
ROUND(F, a, b, c, d, in[ 8] + K1, 3);
|
|
ROUND(F, d, a, b, c, in[ 9] + K1, 7);
|
|
ROUND(F, c, d, a, b, in[10] + K1, 11);
|
|
ROUND(F, b, c, d, a, in[11] + K1, 19);
|
|
|
|
/* Round 2 */
|
|
ROUND(G, a, b, c, d, in[ 1] + K2, 3);
|
|
ROUND(G, d, a, b, c, in[ 3] + K2, 5);
|
|
ROUND(G, c, d, a, b, in[ 5] + K2, 9);
|
|
ROUND(G, b, c, d, a, in[ 7] + K2, 13);
|
|
ROUND(G, a, b, c, d, in[ 9] + K2, 3);
|
|
ROUND(G, d, a, b, c, in[11] + K2, 5);
|
|
ROUND(G, c, d, a, b, in[ 0] + K2, 9);
|
|
ROUND(G, b, c, d, a, in[ 2] + K2, 13);
|
|
ROUND(G, a, b, c, d, in[ 4] + K2, 3);
|
|
ROUND(G, d, a, b, c, in[ 6] + K2, 5);
|
|
ROUND(G, c, d, a, b, in[ 8] + K2, 9);
|
|
ROUND(G, b, c, d, a, in[10] + K2, 13);
|
|
|
|
/* Round 3 */
|
|
ROUND(H, a, b, c, d, in[ 3] + K3, 3);
|
|
ROUND(H, d, a, b, c, in[ 7] + K3, 9);
|
|
ROUND(H, c, d, a, b, in[11] + K3, 11);
|
|
ROUND(H, b, c, d, a, in[ 2] + K3, 15);
|
|
ROUND(H, a, b, c, d, in[ 6] + K3, 3);
|
|
ROUND(H, d, a, b, c, in[10] + K3, 9);
|
|
ROUND(H, c, d, a, b, in[ 1] + K3, 11);
|
|
ROUND(H, b, c, d, a, in[ 5] + K3, 15);
|
|
ROUND(H, a, b, c, d, in[ 9] + K3, 3);
|
|
ROUND(H, d, a, b, c, in[ 0] + K3, 9);
|
|
ROUND(H, c, d, a, b, in[ 4] + K3, 11);
|
|
ROUND(H, b, c, d, a, in[ 8] + K3, 15);
|
|
|
|
return buf[1] + b; /* "most hashed" word */
|
|
/* Alternative: return sum of all words? */
|
|
}
|
|
#endif
|
|
|
|
#undef ROUND
|
|
#undef F
|
|
#undef G
|
|
#undef H
|
|
#undef K1
|
|
#undef K2
|
|
#undef K3
|
|
|
|
/* This should not be decreased so low that ISNs wrap too fast. */
|
|
#define REKEY_INTERVAL (300*HZ)
|
|
/*
|
|
* Bit layout of the tcp sequence numbers (before adding current time):
|
|
* bit 24-31: increased after every key exchange
|
|
* bit 0-23: hash(source,dest)
|
|
*
|
|
* The implementation is similar to the algorithm described
|
|
* in the Appendix of RFC 1185, except that
|
|
* - it uses a 1 MHz clock instead of a 250 kHz clock
|
|
* - it performs a rekey every 5 minutes, which is equivalent
|
|
* to a (source,dest) tulple dependent forward jump of the
|
|
* clock by 0..2^(HASH_BITS+1)
|
|
*
|
|
* Thus the average ISN wraparound time is 68 minutes instead of
|
|
* 4.55 hours.
|
|
*
|
|
* SMP cleanup and lock avoidance with poor man's RCU.
|
|
* Manfred Spraul <manfred@colorfullife.com>
|
|
*
|
|
*/
|
|
#define COUNT_BITS 8
|
|
#define COUNT_MASK ( (1<<COUNT_BITS)-1)
|
|
#define HASH_BITS 24
|
|
#define HASH_MASK ( (1<<HASH_BITS)-1 )
|
|
|
|
static struct keydata {
|
|
__u32 count; // already shifted to the final position
|
|
__u32 secret[12];
|
|
} ____cacheline_aligned ip_keydata[2];
|
|
|
|
static unsigned int ip_cnt;
|
|
|
|
static void rekey_seq_generator(void *private_);
|
|
|
|
static DECLARE_WORK(rekey_work, rekey_seq_generator, NULL);
|
|
|
|
/*
|
|
* Lock avoidance:
|
|
* The ISN generation runs lockless - it's just a hash over random data.
|
|
* State changes happen every 5 minutes when the random key is replaced.
|
|
* Synchronization is performed by having two copies of the hash function
|
|
* state and rekey_seq_generator always updates the inactive copy.
|
|
* The copy is then activated by updating ip_cnt.
|
|
* The implementation breaks down if someone blocks the thread
|
|
* that processes SYN requests for more than 5 minutes. Should never
|
|
* happen, and even if that happens only a not perfectly compliant
|
|
* ISN is generated, nothing fatal.
|
|
*/
|
|
static void rekey_seq_generator(void *private_)
|
|
{
|
|
struct keydata *keyptr = &ip_keydata[1^(ip_cnt&1)];
|
|
|
|
get_random_bytes(keyptr->secret, sizeof(keyptr->secret));
|
|
keyptr->count = (ip_cnt&COUNT_MASK)<<HASH_BITS;
|
|
smp_wmb();
|
|
ip_cnt++;
|
|
schedule_delayed_work(&rekey_work, REKEY_INTERVAL);
|
|
}
|
|
|
|
static inline struct keydata *get_keyptr(void)
|
|
{
|
|
struct keydata *keyptr = &ip_keydata[ip_cnt&1];
|
|
|
|
smp_rmb();
|
|
|
|
return keyptr;
|
|
}
|
|
|
|
static __init int seqgen_init(void)
|
|
{
|
|
rekey_seq_generator(NULL);
|
|
return 0;
|
|
}
|
|
late_initcall(seqgen_init);
|
|
|
|
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
|
|
__u32 secure_tcpv6_sequence_number(__u32 *saddr, __u32 *daddr,
|
|
__u16 sport, __u16 dport)
|
|
{
|
|
struct timeval tv;
|
|
__u32 seq;
|
|
__u32 hash[12];
|
|
struct keydata *keyptr = get_keyptr();
|
|
|
|
/* The procedure is the same as for IPv4, but addresses are longer.
|
|
* Thus we must use twothirdsMD4Transform.
|
|
*/
|
|
|
|
|
|
memcpy(hash, saddr, 16);
|
|
hash[4]=(sport << 16) + dport;
|
|
memcpy(&hash[5],keyptr->secret,sizeof(__u32)*7);
|
|
|
|
seq = twothirdsMD4Transform(daddr, hash) & HASH_MASK;
|
|
seq += keyptr->count;
|
|
|
|
do_gettimeofday(&tv);
|
|
seq += tv.tv_usec + tv.tv_sec*1000000;
|
|
|
|
return seq;
|
|
}
|
|
EXPORT_SYMBOL(secure_tcpv6_sequence_number);
|
|
#endif
|
|
|
|
__u32 secure_tcp_sequence_number(__u32 saddr, __u32 daddr,
|
|
__u16 sport, __u16 dport)
|
|
{
|
|
struct timeval tv;
|
|
__u32 seq;
|
|
__u32 hash[4];
|
|
struct keydata *keyptr = get_keyptr();
|
|
|
|
/*
|
|
* Pick a unique starting offset for each TCP connection endpoints
|
|
* (saddr, daddr, sport, dport).
|
|
* Note that the words are placed into the starting vector, which is
|
|
* then mixed with a partial MD4 over random data.
|
|
*/
|
|
hash[0]=saddr;
|
|
hash[1]=daddr;
|
|
hash[2]=(sport << 16) + dport;
|
|
hash[3]=keyptr->secret[11];
|
|
|
|
seq = halfMD4Transform(hash, keyptr->secret) & HASH_MASK;
|
|
seq += keyptr->count;
|
|
/*
|
|
* As close as possible to RFC 793, which
|
|
* suggests using a 250 kHz clock.
|
|
* Further reading shows this assumes 2 Mb/s networks.
|
|
* For 10 Mb/s Ethernet, a 1 MHz clock is appropriate.
|
|
* That's funny, Linux has one built in! Use it!
|
|
* (Networks are faster now - should this be increased?)
|
|
*/
|
|
do_gettimeofday(&tv);
|
|
seq += tv.tv_usec + tv.tv_sec*1000000;
|
|
#if 0
|
|
printk("init_seq(%lx, %lx, %d, %d) = %d\n",
|
|
saddr, daddr, sport, dport, seq);
|
|
#endif
|
|
return seq;
|
|
}
|
|
|
|
EXPORT_SYMBOL(secure_tcp_sequence_number);
|
|
|
|
/* The code below is shamelessly stolen from secure_tcp_sequence_number().
|
|
* All blames to Andrey V. Savochkin <saw@msu.ru>.
|
|
*/
|
|
__u32 secure_ip_id(__u32 daddr)
|
|
{
|
|
struct keydata *keyptr;
|
|
__u32 hash[4];
|
|
|
|
keyptr = get_keyptr();
|
|
|
|
/*
|
|
* Pick a unique starting offset for each IP destination.
|
|
* The dest ip address is placed in the starting vector,
|
|
* which is then hashed with random data.
|
|
*/
|
|
hash[0] = daddr;
|
|
hash[1] = keyptr->secret[9];
|
|
hash[2] = keyptr->secret[10];
|
|
hash[3] = keyptr->secret[11];
|
|
|
|
return halfMD4Transform(hash, keyptr->secret);
|
|
}
|
|
|
|
#ifdef CONFIG_SYN_COOKIES
|
|
/*
|
|
* Secure SYN cookie computation. This is the algorithm worked out by
|
|
* Dan Bernstein and Eric Schenk.
|
|
*
|
|
* For linux I implement the 1 minute counter by looking at the jiffies clock.
|
|
* The count is passed in as a parameter, so this code doesn't much care.
|
|
*/
|
|
|
|
#define COOKIEBITS 24 /* Upper bits store count */
|
|
#define COOKIEMASK (((__u32)1 << COOKIEBITS) - 1)
|
|
|
|
static int syncookie_init;
|
|
static __u32 syncookie_secret[2][16-3+HASH_BUFFER_SIZE];
|
|
|
|
__u32 secure_tcp_syn_cookie(__u32 saddr, __u32 daddr, __u16 sport,
|
|
__u16 dport, __u32 sseq, __u32 count, __u32 data)
|
|
{
|
|
__u32 tmp[16 + HASH_BUFFER_SIZE + HASH_EXTRA_SIZE];
|
|
__u32 seq;
|
|
|
|
/*
|
|
* Pick two random secrets the first time we need a cookie.
|
|
*/
|
|
if (syncookie_init == 0) {
|
|
get_random_bytes(syncookie_secret, sizeof(syncookie_secret));
|
|
syncookie_init = 1;
|
|
}
|
|
|
|
/*
|
|
* Compute the secure sequence number.
|
|
* The output should be:
|
|
* HASH(sec1,saddr,sport,daddr,dport,sec1) + sseq + (count * 2^24)
|
|
* + (HASH(sec2,saddr,sport,daddr,dport,count,sec2) % 2^24).
|
|
* Where sseq is their sequence number and count increases every
|
|
* minute by 1.
|
|
* As an extra hack, we add a small "data" value that encodes the
|
|
* MSS into the second hash value.
|
|
*/
|
|
|
|
memcpy(tmp+3, syncookie_secret[0], sizeof(syncookie_secret[0]));
|
|
tmp[0]=saddr;
|
|
tmp[1]=daddr;
|
|
tmp[2]=(sport << 16) + dport;
|
|
HASH_TRANSFORM(tmp+16, tmp);
|
|
seq = tmp[17] + sseq + (count << COOKIEBITS);
|
|
|
|
memcpy(tmp+3, syncookie_secret[1], sizeof(syncookie_secret[1]));
|
|
tmp[0]=saddr;
|
|
tmp[1]=daddr;
|
|
tmp[2]=(sport << 16) + dport;
|
|
tmp[3] = count; /* minute counter */
|
|
HASH_TRANSFORM(tmp+16, tmp);
|
|
|
|
/* Add in the second hash and the data */
|
|
return seq + ((tmp[17] + data) & COOKIEMASK);
|
|
}
|
|
|
|
/*
|
|
* This retrieves the small "data" value from the syncookie.
|
|
* If the syncookie is bad, the data returned will be out of
|
|
* range. This must be checked by the caller.
|
|
*
|
|
* The count value used to generate the cookie must be within
|
|
* "maxdiff" if the current (passed-in) "count". The return value
|
|
* is (__u32)-1 if this test fails.
|
|
*/
|
|
__u32 check_tcp_syn_cookie(__u32 cookie, __u32 saddr, __u32 daddr, __u16 sport,
|
|
__u16 dport, __u32 sseq, __u32 count, __u32 maxdiff)
|
|
{
|
|
__u32 tmp[16 + HASH_BUFFER_SIZE + HASH_EXTRA_SIZE];
|
|
__u32 diff;
|
|
|
|
if (syncookie_init == 0)
|
|
return (__u32)-1; /* Well, duh! */
|
|
|
|
/* Strip away the layers from the cookie */
|
|
memcpy(tmp+3, syncookie_secret[0], sizeof(syncookie_secret[0]));
|
|
tmp[0]=saddr;
|
|
tmp[1]=daddr;
|
|
tmp[2]=(sport << 16) + dport;
|
|
HASH_TRANSFORM(tmp+16, tmp);
|
|
cookie -= tmp[17] + sseq;
|
|
/* Cookie is now reduced to (count * 2^24) ^ (hash % 2^24) */
|
|
|
|
diff = (count - (cookie >> COOKIEBITS)) & ((__u32)-1 >> COOKIEBITS);
|
|
if (diff >= maxdiff)
|
|
return (__u32)-1;
|
|
|
|
memcpy(tmp+3, syncookie_secret[1], sizeof(syncookie_secret[1]));
|
|
tmp[0] = saddr;
|
|
tmp[1] = daddr;
|
|
tmp[2] = (sport << 16) + dport;
|
|
tmp[3] = count - diff; /* minute counter */
|
|
HASH_TRANSFORM(tmp+16, tmp);
|
|
|
|
return (cookie - tmp[17]) & COOKIEMASK; /* Leaving the data behind */
|
|
}
|
|
#endif
|
|
#endif /* CONFIG_INET */
|