From 7b115360756c00867dfeb633daaf092c0a3996ba Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Thu, 21 Nov 2013 15:41:06 +1100 Subject: xfs: growfs overruns AGFL buffer on V4 filesystems commit f94c44573e7c22860e2c3dfe349c45f72ba35ad3 upstream. This loop in xfs_growfs_data_private() is incorrect for V4 superblocks filesystems: for (bucket = 0; bucket < XFS_AGFL_SIZE(mp); bucket++) agfl->agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK); For V4 filesystems, we don't have a agfl header structure, and so XFS_AGFL_SIZE() returns an entire sector's worth of entries, which we then index from an offset into the sector. Hence: buffer overrun. This problem was introduced in 3.10 by commit 77c95bba ("xfs: add CRC checks to the AGFL") which changed the AGFL structure but failed to update the growfs code to handle the different structures. Fix it by using the correct offset into the buffer for both V4 and V5 filesystems. Signed-off-by: Dave Chinner Reviewed-by: Jie Liu Signed-off-by: Ben Myers Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_fsops.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index e64ee5288b8..c888040a1e9 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -217,6 +217,8 @@ xfs_growfs_data_private( */ nfree = 0; for (agno = nagcount - 1; agno >= oagcount; agno--, new -= agsize) { + __be32 *agfl_bno; + /* * AG freespace header block */ @@ -276,8 +278,10 @@ xfs_growfs_data_private( agfl->agfl_seqno = cpu_to_be32(agno); uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_uuid); } + + agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp); for (bucket = 0; bucket < XFS_AGFL_SIZE(mp); bucket++) - agfl->agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK); + agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK); error = xfs_bwrite(bp); xfs_buf_relse(bp); -- cgit v1.2.3-18-g5258