(2006-08-06) rescue-bootcd

extra/linux-2.6.10/drivers/block/cryptoloop.c

@@ -0,0 +1,268 @@
+/*
+   Linux loop encryption enabling module
+
+   Copyright (C)  2002 Herbert Valerio Riedel <hvr@gnu.org>
+   Copyright (C)  2003 Fruhwirth Clemens <clemens@endorphin.org>
+
+   This module is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This module is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this module; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/crypto.h>
+#include <linux/blkdev.h>
+#include <linux/loop.h>
+#include <asm/semaphore.h>
+#include <asm/uaccess.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI");
+MODULE_AUTHOR("Herbert Valerio Riedel <hvr@gnu.org>");
+
+#define LOOP_IV_SECTOR_BITS 9
+#define LOOP_IV_SECTOR_SIZE (1 << LOOP_IV_SECTOR_BITS)
+
+static int
+cryptoloop_init(struct loop_device *lo, const struct loop_info64 *info)
+{
+	int err = -EINVAL;
+	char cms[LO_NAME_SIZE];			/* cipher-mode string */
+	char *cipher;
+	char *mode;
+	char *cmsp = cms;			/* c-m string pointer */
+	struct crypto_tfm *tfm = NULL;
+
+	/* encryption breaks for non sector aligned offsets */
+
+	if (info->lo_offset % LOOP_IV_SECTOR_SIZE)
+		goto out;
+
+	strncpy(cms, info->lo_crypt_name, LO_NAME_SIZE);
+	cms[LO_NAME_SIZE - 1] = 0;
+	cipher = strsep(&cmsp, "-");
+	mode = strsep(&cmsp, "-");
+
+	if (mode == NULL || strcmp(mode, "cbc") == 0)
+		tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_CBC);
+	else if (strcmp(mode, "ecb") == 0)
+		tfm = crypto_alloc_tfm(cipher, CRYPTO_TFM_MODE_ECB);
+	if (tfm == NULL)
+		return -EINVAL;
+
+	err = tfm->crt_u.cipher.cit_setkey(tfm, info->lo_encrypt_key,
+					   info->lo_encrypt_key_size);
+	
+	if (err != 0)
+		goto out_free_tfm;
+
+	lo->key_data = tfm;
+	return 0;
+
+ out_free_tfm:
+	crypto_free_tfm(tfm);
+
+ out:
+	return err;
+}
+
+
+typedef int (*encdec_ecb_t)(struct crypto_tfm *tfm,
+			struct scatterlist *sg_out,
+			struct scatterlist *sg_in,
+			unsigned int nsg);
+
+
+static int
+cryptoloop_transfer_ecb(struct loop_device *lo, int cmd,
+			struct page *raw_page, unsigned raw_off,
+			struct page *loop_page, unsigned loop_off,
+			int size, sector_t IV)
+{
+	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+	struct scatterlist sg_out = { NULL, };
+	struct scatterlist sg_in = { NULL, };
+
+	encdec_ecb_t encdecfunc;
+	struct page *in_page, *out_page;
+	unsigned in_offs, out_offs;
+
+	if (cmd == READ) {
+		in_page = raw_page;
+		in_offs = raw_off;
+		out_page = loop_page;
+		out_offs = loop_off;
+		encdecfunc = tfm->crt_u.cipher.cit_decrypt;
+	} else {
+		in_page = loop_page;
+		in_offs = loop_off;
+		out_page = raw_page;
+		out_offs = raw_off;
+		encdecfunc = tfm->crt_u.cipher.cit_encrypt;
+	}
+
+	while (size > 0) {
+		const int sz = min(size, LOOP_IV_SECTOR_SIZE);
+
+		sg_in.page = in_page;
+		sg_in.offset = in_offs;
+		sg_in.length = sz;
+
+		sg_out.page = out_page;
+		sg_out.offset = out_offs;
+		sg_out.length = sz;
+
+		encdecfunc(tfm, &sg_out, &sg_in, sz);
+
+		size -= sz;
+		in_offs += sz;
+		out_offs += sz;
+	}
+
+	return 0;
+}
+
+typedef int (*encdec_cbc_t)(struct crypto_tfm *tfm,
+			struct scatterlist *sg_out,
+			struct scatterlist *sg_in,
+			unsigned int nsg, u8 *iv);
+
+static int
+cryptoloop_transfer_cbc(struct loop_device *lo, int cmd,
+			struct page *raw_page, unsigned raw_off,
+			struct page *loop_page, unsigned loop_off,
+			int size, sector_t IV)
+{
+	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+	struct scatterlist sg_out = { NULL, };
+	struct scatterlist sg_in = { NULL, };
+
+	encdec_cbc_t encdecfunc;
+	struct page *in_page, *out_page;
+	unsigned in_offs, out_offs;
+
+	if (cmd == READ) {
+		in_page = raw_page;
+		in_offs = raw_off;
+		out_page = loop_page;
+		out_offs = loop_off;
+		encdecfunc = tfm->crt_u.cipher.cit_decrypt_iv;
+	} else {
+		in_page = loop_page;
+		in_offs = loop_off;
+		out_page = raw_page;
+		out_offs = raw_off;
+		encdecfunc = tfm->crt_u.cipher.cit_encrypt_iv;
+	}
+
+	while (size > 0) {
+		const int sz = min(size, LOOP_IV_SECTOR_SIZE);
+		u32 iv[4] = { 0, };
+		iv[0] = cpu_to_le32(IV & 0xffffffff);
+
+		sg_in.page = in_page;
+		sg_in.offset = in_offs;
+		sg_in.length = sz;
+
+		sg_out.page = out_page;
+		sg_out.offset = out_offs;
+		sg_out.length = sz;
+
+		encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);
+
+		IV++;
+		size -= sz;
+		in_offs += sz;
+		out_offs += sz;
+	}
+
+	return 0;
+}
+
+static int
+cryptoloop_transfer(struct loop_device *lo, int cmd,
+		    struct page *raw_page, unsigned raw_off,
+		    struct page *loop_page, unsigned loop_off,
+		    int size, sector_t IV)
+{
+	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_ECB)
+	{
+		lo->transfer = cryptoloop_transfer_ecb;
+		return cryptoloop_transfer_ecb(lo, cmd, raw_page, raw_off,
+					       loop_page, loop_off, size, IV);
+	}	
+	if(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_CBC)
+	{	
+		lo->transfer = cryptoloop_transfer_cbc;
+		return cryptoloop_transfer_cbc(lo, cmd, raw_page, raw_off,
+					       loop_page, loop_off, size, IV);
+	}
+	
+	/*  This is not supposed to happen */
+
+	printk( KERN_ERR "cryptoloop: unsupported cipher mode in cryptoloop_transfer!\n");
+	return -EINVAL;
+}
+
+static int
+cryptoloop_ioctl(struct loop_device *lo, int cmd, unsigned long arg)
+{
+	return -EINVAL;
+}
+
+static int
+cryptoloop_release(struct loop_device *lo)
+{
+	struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+	if (tfm != NULL) {
+		crypto_free_tfm(tfm);
+		lo->key_data = NULL;
+		return 0;
+	}
+	printk(KERN_ERR "cryptoloop_release(): tfm == NULL?\n");
+	return -EINVAL;
+}
+
+static struct loop_func_table cryptoloop_funcs = {
+	.number = LO_CRYPT_CRYPTOAPI,
+	.init = cryptoloop_init,
+	.ioctl = cryptoloop_ioctl,
+	.transfer = cryptoloop_transfer,
+	.release = cryptoloop_release,
+	.owner = THIS_MODULE
+};
+
+static int __init
+init_cryptoloop(void)
+{
+	int rc = loop_register_transfer(&cryptoloop_funcs);
+
+	if (rc)
+		printk(KERN_ERR "cryptoloop: loop_register_transfer failed\n");
+	return rc;
+}
+
+static void __exit
+cleanup_cryptoloop(void)
+{
+	if (loop_unregister_transfer(LO_CRYPT_CRYPTOAPI))
+		printk(KERN_ERR
+			"cryptoloop: loop_unregister_transfer failed\n");
+}
+
+module_init(init_cryptoloop);
+module_exit(cleanup_cryptoloop);