The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 08c1af8f1c13bbf210f1760132f4df24d0ed46d6 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka mpatocka@redhat.com Date: Sun, 3 Apr 2022 14:38:22 -0400 Subject: [PATCH] dm integrity: fix memory corruption when tag_size is less than digest size

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

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c index ad2d5faa2ebb..36ae30b73a6e 100644 --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -4399,6 +4399,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv) }

if (ic->internal_hash) { + size_t recalc_tags_size; ic->recalc_wq = alloc_workqueue("dm-integrity-recalc", WQ_MEM_RECLAIM, 1); if (!ic->recalc_wq ) { ti->error = "Cannot allocate workqueue"; @@ -4412,8 +4413,10 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned argc, char **argv) r = -ENOMEM; goto bad; } - ic->recalc_tags = kvmalloc_array(RECALC_SECTORS >> ic->sb->log2_sectors_per_block, - ic->tag_size, GFP_KERNEL); + recalc_tags_size = (RECALC_SECTORS >> ic->sb->log2_sectors_per_block) * ic->tag_size; + if (crypto_shash_digestsize(ic->internal_hash) > ic->tag_size) + recalc_tags_size += crypto_shash_digestsize(ic->internal_hash) - ic->tag_size; + ic->recalc_tags = kvmalloc(recalc_tags_size, GFP_KERNEL); if (!ic->recalc_tags) { ti->error = "Cannot allocate tags for recalculating"; r = -ENOMEM;