| From | Ben Hutchings <> | Date | Fri, 10 Mar 2017 11:46:10 +0000 | Subject | [PATCH 3.2 017/199] ext4: fix stack memory corruption with 64k block size |
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3.2.87-rc1 review patch. If anyone has any objections, please let me know.
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From: Chandan Rajendra <chandan@linux.vnet.ibm.com>
commit 30a9d7afe70ed6bd9191d3000e2ef1a34fb58493 upstream.
The number of 'counters' elements needed in 'struct sg' is super_block->s_blocksize_bits + 2. Presently we have 16 'counters' elements in the array. This is insufficient for block sizes >= 32k. In such cases the memcpy operation performed in ext4_mb_seq_groups_show() would cause stack memory corruption.
Fixes: c9de560ded61f Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- fs/ext4/mballoc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2134,7 +2134,7 @@ static int ext4_mb_seq_groups_show(struc struct ext4_buddy e4b; struct sg { struct ext4_group_info info; - ext4_grpblk_t counters[16]; + ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2]; } sg; group--;
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