summaryrefslogtreecommitdiffstats
path: root/drivers/block/cryptoloop.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/block/cryptoloop.c')
-rw-r--r--drivers/block/cryptoloop.c268
1 files changed, 268 insertions, 0 deletions
diff --git a/drivers/block/cryptoloop.c b/drivers/block/cryptoloop.c
new file mode 100644
index 00000000000..5be6f998d8c
--- /dev/null
+++ b/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);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-17 02:55:21 +0000