3.16.42-rc1 review patch. If anyone has any objections, please let me know.
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From: Chandan Rajendra <chandan@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2252,7 +2252,7 @@ static int ext4_mb_seq_groups_show(struc
struct ext4_group_info *grinfo;
struct sg {
struct ext4_group_info info;
- ext4_grpblk_t counters[16];
+ ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];
} sg;
group--;