From 0440d5c0ca9744b92a07aeb6df0a9a75db6f4280 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Tue, 7 Nov 2017 10:35:57 -0500 Subject: [PATCH] dm crypt: allow unaligned bv_offset MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When slub_debug is enabled kmalloc returns unaligned memory. XFS uses this unaligned memory for its buffers (if an unaligned buffer crosses a page, XFS frees it and allocates a full page instead - see the function xfs_buf_allocate_memory). dm-crypt checks if bv_offset is aligned on page size and these checks fail with slub_debug and XFS. Fix this bug by removing the bv_offset checks. Switch to checking if bv_len is aligned instead of bv_offset (this check should be sufficient to prevent overruns if a bio with too small bv_len is received). Fixes: 8f0009a22517 ("dm crypt: optionally support larger encryption sector size") Cc: stable@vger.kernel.org # v4.12+ Reported-by: Bruno Prémont Tested-by: Bruno Prémont Signed-off-by: Mikulas Patocka Reviewed-by: Milan Broz Signed-off-by: Mike Snitzer --- drivers/md/dm-crypt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 96ab465..9fc12f5 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -1075,7 +1075,7 @@ static int crypt_convert_block_aead(struct crypt_config *cc, BUG_ON(cc->integrity_iv_size && cc->integrity_iv_size != cc->iv_size); /* Reject unexpected unaligned bio. */ - if (unlikely(bv_in.bv_offset & (cc->sector_size - 1))) + if (unlikely(bv_in.bv_len & (cc->sector_size - 1))) return -EIO; dmreq = dmreq_of_req(cc, req); @@ -1168,7 +1168,7 @@ static int crypt_convert_block_skcipher(struct crypt_config *cc, int r = 0; /* Reject unexpected unaligned bio. */ - if (unlikely(bv_in.bv_offset & (cc->sector_size - 1))) + if (unlikely(bv_in.bv_len & (cc->sector_size - 1))) return -EIO; dmreq = dmreq_of_req(cc, req); -- 2.7.4