dm-crypt: recheck the integrity tag after a failure

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commit 42e15d1207 upstream.

If a userspace process reads (with O_DIRECT) multiple blocks into the same
buffer, dm-crypt reports an authentication error [1]. The error is
reported in a log and it may cause RAID leg being kicked out of the
array.

This commit fixes dm-crypt, so that if integrity verification fails, the
data is read again into a kernel buffer (where userspace can't modify it)
and the integrity tag is rechecked. If the recheck succeeds, the content
of the kernel buffer is copied into the user buffer; if the recheck fails,
an integrity error is reported.

[1] https://people.redhat.com/~mpatocka/testcases/blk-auth-modify/read2.c

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Mikulas Patocka 2024-02-19 21:31:11 +01:00 • committed by Greg Kroah-Hartman

parent 287abdcb9e

commit 5583552eec

1 changed files with 73 additions and 16 deletions

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drivers/md/dm-crypt.c

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