commit: aeb1e5d69a5be592e86a926be73efb38c55af404 From: Theodore Ts'o <[email protected]> Date: Thu, 29 Nov 2012 21:21:22 -0500 Subject: ext4: fix possible use after free with metadata csum
Commit fa77dcfafeaa introduces block bitmap checksum calculation into ext4_new_inode() in the case that block group was uninitialized. However we brelse() the bitmap buffer before we attempt to checksum it so we have no guarantee that the buffer is still there. Fix this by releasing the buffer after the possible checksum computation. Signed-off-by: Lukas Czerner <[email protected]> Signed-off-by: "Theodore Ts'o" <[email protected]> Acked-by: Darrick J. Wong <[email protected]> Cc: [email protected] --- fs/ext4/ialloc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 3a100e7..c7efa88 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -762,7 +762,6 @@ got: BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap"); err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh); - brelse(block_bitmap_bh); /* recheck and clear flag under lock if we still need to */ ext4_lock_group(sb, group); @@ -775,6 +774,7 @@ got: ext4_group_desc_csum_set(sb, group, gdp); } ext4_unlock_group(sb, group); + brelse(block_bitmap_bh); if (err) goto fail; -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
