--- /dev/null
+/*
+ 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/scatterlist.h>
+#include <asm/uaccess.h>
+#include "loop.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;
+ int cipher_len;
+ int mode_len;
+ char cms[LO_NAME_SIZE]; /* cipher-mode string */
+ char *cipher;
+ char *mode;
+ char *cmsp = cms; /* c-m string pointer */
+ struct crypto_blkcipher *tfm;
+
+ /* 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 = cmsp;
+ cipher_len = strcspn(cmsp, "-");
+
+ mode = cmsp + cipher_len;
+ mode_len = 0;
+ if (*mode) {
+ mode++;
+ mode_len = strcspn(mode, "-");
+ }
+
+ if (!mode_len) {
+ mode = "cbc";
+ mode_len = 3;
+ }
+
+ if (cipher_len + mode_len + 3 > LO_NAME_SIZE)
+ return -EINVAL;
+
+ memmove(cms, mode, mode_len);
+ cmsp = cms + mode_len;
+ *cmsp++ = '(';
+ memcpy(cmsp, info->lo_crypt_name, cipher_len);
+ cmsp += cipher_len;
+ *cmsp++ = ')';
+ *cmsp = 0;
+
+ tfm = crypto_alloc_blkcipher(cms, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm))
+ return PTR_ERR(tfm);
+
+ err = crypto_blkcipher_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_blkcipher(tfm);
+
+ out:
+ return err;
+}
+
+
+typedef int (*encdec_cbc_t)(struct blkcipher_desc *desc,
+ struct scatterlist *sg_out,
+ struct scatterlist *sg_in,
+ unsigned int nsg);
+
+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_blkcipher *tfm = lo->key_data;
+ struct blkcipher_desc desc = {
+ .tfm = tfm,
+ .flags = CRYPTO_TFM_REQ_MAY_SLEEP,
+ };
+ struct scatterlist sg_out;
+ struct scatterlist sg_in;
+
+ encdec_cbc_t encdecfunc;
+ struct page *in_page, *out_page;
+ unsigned in_offs, out_offs;
+ int err;
+
+ sg_init_table(&sg_out, 1);
+ sg_init_table(&sg_in, 1);
+
+ if (cmd == READ) {
+ in_page = raw_page;
+ in_offs = raw_off;
+ out_page = loop_page;
+ out_offs = loop_off;
+ encdecfunc = crypto_blkcipher_crt(tfm)->decrypt;
+ } else {
+ in_page = loop_page;
+ in_offs = loop_off;
+ out_page = raw_page;
+ out_offs = raw_off;
+ encdecfunc = crypto_blkcipher_crt(tfm)->encrypt;
+ }
+
+ while (size > 0) {
+ const int sz = min(size, LOOP_IV_SECTOR_SIZE);
+ u32 iv[4] = { 0, };
+ iv[0] = cpu_to_le32(IV & 0xffffffff);
+
+ sg_set_page(&sg_in, in_page, sz, in_offs);
+ sg_set_page(&sg_out, out_page, sz, out_offs);
+
+ desc.info = iv;
+ err = encdecfunc(&desc, &sg_out, &sg_in, sz);
+ if (err)
+ return err;
+
+ IV++;
+ size -= sz;
+ in_offs += sz;
+ out_offs += sz;
+ }
+
+ return 0;
+}
+
+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_blkcipher *tfm = lo->key_data;
+ if (tfm != NULL) {
+ crypto_free_blkcipher(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);
Code Review / kvmfornfv.git / blobdiff