dm integrity: fix memory corruption when tag_size is less than digest size

stable inclusion
from stable-v5.10.112
commit cd02b2687d66f0a8e716384de4b9a0671331f1dc
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5HL0X

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cd02b2687d66f0a8e716384de4b9a0671331f1dc



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commit 08c1af8f upstream.

It is possible to set up dm-integrity in such a way that the
"tag_size" parameter is less than the actual digest size. In this
situation, a part of the digest beyond tag_size is ignored.

In this case, dm-integrity would write beyond the end of the
ic->recalc_tags array and corrupt memory. The corruption happened in
integrity_recalc->integrity_sector_checksum->crypto_shash_final.

Fix this corruption by increasing the tags array so that it has enough
padding at the end to accomodate the loop in integrity_recalc() being
able to write a full digest size for the last member of the tags
array.

Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>