dm crypt: allow unaligned bv_offset

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commit 0440d5c0ca upstream.

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: 8f0009a225 ("dm crypt: optionally support larger encryption sector size")
Reported-by: Bruno Prémont <bonbons@sysophe.eu>
Tested-by: Bruno Prémont <bonbons@sysophe.eu>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Mikulas Patocka 2017-11-07 10:35:57 -05:00 • committed by Greg Kroah-Hartman

parent ec544ec956

commit 8f71f493f4

1 changed files with 2 additions and 2 deletions

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drivers/md/dm-crypt.c

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