The iv_offset in the mapping table of crypt target is a 64bit number when
IV algorithm is plain64, plain64be, essiv or benbi. It will be assigned to
iv_offset of struct crypt_config, cc_sector of struct convert_context and
iv_sector of struct dm_crypt_request. These structures members are defined
as a sector_t. But sector_t is 32bit when CONFIG_LBDAF is not set in 32bit
kernel. In this situation sector_t is not big enough to store the 64bit
iv_offset.
Here is a reproducer.
Prepare test image and device (loop is automatically allocated by cryptsetup):
# dd if=/dev/zero of=tst.img bs=1M count=1
# echo "tst"|cryptsetup open --type plain -c aes-xts-plain64 \
--skip 500000000000000000 tst.img test
On 32bit system (use IV offset value that overflows to 64bit; CONFIG_LBDAF if off)
and device checksum is wrong:
# dmsetup table test --showkeys
0 2048 crypt aes-xts-plain64 dfa7cfe3c481f2239155739c42e539ae8f2d38f304dcc89d20b26f69daaf0933 3551657984 7:0 0
# sha256sum /dev/mapper/test
533e25c09176632b3794f35303488c4a8f3f965dffffa6ec2df347c168cb6c19 /dev/mapper/test
On 64bit system (and on 32bit system with the patch), table and checksum is now correct:
# dmsetup table test --showkeys
0 2048 crypt aes-xts-plain64 dfa7cfe3c481f2239155739c42e539ae8f2d38f304dcc89d20b26f69daaf0933 500000000000000000 7:0 0
# sha256sum /dev/mapper/test
5d16160f9d5f8c33d8051e65fdb4f003cc31cd652b5abb08f03aa6fce0df75fc /dev/mapper/test
Signed-off-by: AliOS system security <alios_sys_security@xxxxxxxxxxxxxxxxx>
Tested-and-Reviewed-by: Milan Broz <gmazyland@xxxxxxxxx>
---
Changes since v2:
* add all IV algorithms that are affected in commit message
* add reproducer in commit message
* use u64 instead of unsigned long long
---
drivers/md/dm-crypt.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index b8eec51..9a4dec0 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -49,7 +49,7 @@ struct convert_context {
struct bio *bio_out;
struct bvec_iter iter_in;
struct bvec_iter iter_out;
- sector_t cc_sector;
+ u64 cc_sector;
atomic_t cc_pending;
union {
struct skcipher_request *req;
@@ -81,7 +81,7 @@ struct dm_crypt_request {
struct convert_context *ctx;
struct scatterlist sg_in[4];
struct scatterlist sg_out[4];
- sector_t iv_sector;
+ u64 iv_sector;
};
struct crypt_config;
@@ -160,7 +160,7 @@ struct crypt_config {
struct iv_lmk_private lmk;
struct iv_tcw_private tcw;
} iv_gen_private;
- sector_t iv_offset;
+ u64 iv_offset;
unsigned int iv_size;
unsigned short int sector_size;
unsigned char sector_shift;
--
2.7.4
--
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