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    Subject[PATCH AUTOSEL 4.20 088/117] dm crypt: use u64 instead of sector_t to store iv_offset
    Date
    From: AliOS system security <alios_sys_security@linux.alibaba.com>

    [ Upstream commit 8d683dcd65c037efc9fb38c696ec9b65b306e573 ]

    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@linux.alibaba.com>
    Tested-and-Reviewed-by: Milan Broz <gmazyland@gmail.com>
    Signed-off-by: Mike Snitzer <snitzer@redhat.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 b8eec515a003..9a4dec0a0f71 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;
    --
    2.19.1
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