> 2.5.75
Good!
> getting patches in is going to be a lot harder
Let me try nevertheless
There seem to be no objections against the patch below.
Andrew [2 Jul 2003]: Please don't let me stand in the way of #3.
[util-linux is waiting for this; when 2.6 comes out, or the
first mount/losetup comes out that uses struct loop_info64,
whichever comes first, struct loop_info64 must be considered
frozen: a stable kernel must not change API and user space
ABI must remain constant. This means that if cryptoloop is
added later, some backwards compatibility is lost.]
Andries
[similar things hold for some dev_t related ioctl changes:
it would be best to do them before 2.6, if indeed one
intends to do these dev_t changes at all]
diff -u --recursive --new-file -X /linux/dontdiff a/drivers/block/Kconfig b/drivers/block/Kconfig
--- a/drivers/block/Kconfig Thu May 22 13:16:20 2003
+++ b/drivers/block/Kconfig Fri Jul 11 00:46:23 2003
@@ -237,29 +237,20 @@
root file system inside a DOS FAT file using this loop device
driver.
- The loop device driver can also be used to "hide" a file system in a
- disk partition, floppy, or regular file, either using encryption
+ To use the loop device, you need the losetup utility, found in the
+ util-linux package, see
+ <ftp://ftp.kernel.org/pub/linux/utils/util-linux/>.
+
+ The loop device driver can also be used to "hide" a file system in
+ a disk partition, floppy, or regular file, either using encryption
(scrambling the data) or steganography (hiding the data in the low
bits of, say, a sound file). This is also safe if the file resides
- on a remote file server. If you want to do this, you will first have
- to acquire and install a kernel patch from
- <ftp://ftp.kerneli.org/pub/kerneli/>, and then you need to
- say Y to this option.
-
- Note that alternative ways to use encrypted file systems are
- provided by the cfs package, which can be gotten from
- <ftp://ftp.kerneli.org/pub/kerneli/net-source/>, and the newer tcfs
- package, available at <http://tcfs.dia.unisa.it/>. You do not need
- to say Y here if you want to use one of these. However, using cfs
- requires saying Y to "NFS file system support" below while using
- tcfs requires applying a kernel patch. An alternative steganography
- solution is provided by StegFS, also available from
- <ftp://ftp.kerneli.org/pub/kerneli/net-source/>.
-
- To use the loop device, you need the losetup utility and a recent
- version of the mount program, both contained in the util-linux
- package. The location and current version number of util-linux is
- contained in the file <file:Documentation/Changes>.
+ on a remote file server.
+
+ There are several ways of doing this. Some of these require kernel
+ patches. The vanilla kernel offers the cryptoloop option. If you
+ want to use that, say Y to both LOOP and CRYPTOLOOP, and make sure
+ you have a recent (version 2.12 or later) version of util-linux.
Note that this loop device has nothing to do with the loopback
device used for network connections from the machine to itself.
@@ -271,6 +262,14 @@
Most users will answer N here.
+config BLK_DEV_CRYPTOLOOP
+ tristate "Cryptoloop Support"
+ depends on BLK_DEV_LOOP
+ ---help---
+ Say Y here if you want to be able to use the ciphers that are
+ provided by the CryptoAPI as loop transformation. This might be
+ used as hard disk encryption.
+
config BLK_DEV_NBD
tristate "Network block device support"
depends on NET
diff -u --recursive --new-file -X /linux/dontdiff a/drivers/block/Makefile b/drivers/block/Makefile
--- a/drivers/block/Makefile Fri Jul 11 00:35:23 2003
+++ b/drivers/block/Makefile Fri Jul 11 00:46:23 2003
@@ -36,3 +36,4 @@
obj-$(CONFIG_BLK_DEV_UMEM) += umem.o
obj-$(CONFIG_BLK_DEV_NBD) += nbd.o
+obj-$(CONFIG_BLK_DEV_CRYPTOLOOP) += cryptoloop.o
diff -u --recursive --new-file -X /linux/dontdiff a/drivers/block/cryptoloop.c b/drivers/block/cryptoloop.c
--- a/drivers/block/cryptoloop.c Thu Jan 1 01:00:00 1970
+++ b/drivers/block/cryptoloop.c Fri Jul 11 00:46:23 2003
@@ -0,0 +1,182 @@
+/*
+ Linux loop encryption enabling module
+
+ Copyright (C) 2002 Herbert Valerio Riedel <[email protected]>
+ Copyright (C) 2003 Fruhwirth Clemens <[email protected]>
+
+ 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 <linux/blk.h>
+#include <asm/semaphore.h>
+#include <asm/uaccess.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("loop blockdevice transferfunction adaptor / CryptoAPI");
+MODULE_AUTHOR("Herbert Valerio Riedel <[email protected]>");
+
+#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_t)(struct crypto_tfm *tfm,
+ struct scatterlist *sg_out,
+ struct scatterlist *sg_in,
+ unsigned int nsg, u8 *iv);
+
+static int
+cryptoloop_transfer(struct loop_device *lo, int cmd, char *raw_buf,
+ char *loop_buf, int size, sector_t IV)
+{
+ struct crypto_tfm *tfm = (struct crypto_tfm *) lo->key_data;
+ struct scatterlist sg_out = { 0, };
+ struct scatterlist sg_in = { 0, };
+
+ encdec_t encdecfunc;
+ char const *in;
+ char *out;
+
+ if (cmd == READ) {
+ in = raw_buf;
+ out = loop_buf;
+ encdecfunc = tfm->crt_u.cipher.cit_decrypt_iv;
+ } else {
+ in = loop_buf;
+ out = raw_buf;
+ 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 = virt_to_page(in);
+ sg_in.offset = (unsigned long)in & ~PAGE_MASK;
+ sg_in.length = sz;
+
+ sg_out.page = virt_to_page(out);
+ sg_out.offset = (unsigned long)out & ~PAGE_MASK;
+ sg_out.length = sz;
+
+ encdecfunc(tfm, &sg_out, &sg_in, sz, (u8 *)iv);
+
+ IV++;
+ size -= sz;
+ in += sz;
+ out += 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_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);
diff -u --recursive --new-file -X /linux/dontdiff a/drivers/block/loop.c b/drivers/block/loop.c
--- a/drivers/block/loop.c Thu Jul 3 09:26:43 2003
+++ b/drivers/block/loop.c Fri Jul 11 00:46:23 2003
@@ -840,7 +840,8 @@
lo->lo_flags = 0;
lo->lo_queue.queuedata = NULL;
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
- memset(lo->lo_name, 0, LO_NAME_SIZE);
+ memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
+ memset(lo->lo_file_name, 0, LO_NAME_SIZE);
invalidate_bdev(bdev, 0);
set_capacity(disks[lo->lo_number], 0);
filp->f_dentry->d_inode->i_mapping->gfp_mask = gfp;
@@ -892,7 +893,10 @@
return -EFBIG;
}
- strlcpy(lo->lo_name, info->lo_name, LO_NAME_SIZE);
+ memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
+ memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
+ lo->lo_file_name[LO_NAME_SIZE-1] = 0;
+ lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
if (!xfer)
xfer = &none_funcs;
@@ -931,7 +935,8 @@
info->lo_offset = lo->lo_offset;
info->lo_sizelimit = lo->lo_sizelimit;
info->lo_flags = lo->lo_flags;
- strlcpy(info->lo_name, lo->lo_name, LO_NAME_SIZE);
+ memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
+ memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
info->lo_encrypt_type =
lo->lo_encryption ? lo->lo_encryption->number : 0;
if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
@@ -957,7 +962,10 @@
info64->lo_flags = info->lo_flags;
info64->lo_init[0] = info->lo_init[0];
info64->lo_init[1] = info->lo_init[1];
- memcpy(info64->lo_name, info->lo_name, LO_NAME_SIZE);
+ if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
+ memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
+ else
+ memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
}
@@ -975,8 +983,11 @@
info->lo_flags = info64->lo_flags;
info->lo_init[0] = info64->lo_init[0];
info->lo_init[1] = info64->lo_init[1];
- memcpy(info->lo_name, info64->lo_name, LO_NAME_SIZE);
- memcpy(info->lo_encrypt_key,info64->lo_encrypt_key,LO_KEY_SIZE);
+ if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
+ memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
+ else
+ memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
+ memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
/* error in case values were truncated */
if (info->lo_device != info64->lo_device ||
diff -u --recursive --new-file -X /linux/dontdiff a/include/linux/loop.h b/include/linux/loop.h
--- a/include/linux/loop.h Thu Jul 3 09:26:47 2003
+++ b/include/linux/loop.h Fri Jul 11 00:46:23 2003
@@ -36,7 +36,8 @@
int (*transfer)(struct loop_device *, int cmd,
char *raw_buf, char *loop_buf, int size,
sector_t real_block);
- char lo_name[LO_NAME_SIZE];
+ char lo_file_name[LO_NAME_SIZE];
+ char lo_crypt_name[LO_NAME_SIZE];
char lo_encrypt_key[LO_KEY_SIZE];
int lo_encrypt_key_size;
struct loop_func_table *lo_encryption;
@@ -49,7 +50,6 @@
struct block_device *lo_device;
unsigned lo_blocksize;
void *key_data;
- char key_reserved[48]; /* for use by the filter modules */
int old_gfp_mask;
@@ -102,7 +102,8 @@
__u32 lo_encrypt_type;
__u32 lo_encrypt_key_size; /* ioctl w/o */
__u32 lo_flags; /* ioctl r/o */
- __u8 lo_name[LO_NAME_SIZE];
+ __u8 lo_file_name[LO_NAME_SIZE];
+ __u8 lo_crypt_name[LO_NAME_SIZE];
__u8 lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
__u64 lo_init[2];
};