From 3a3675b7f23f83ca8c67c9c2b6edf707fd28d1ba Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Mon, 14 Feb 2011 13:45:28 +0000 Subject: [PATCH 1/2] xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1 The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to xfs_fs_geometry() with a version number of 3. This code path does not fill in the logsunit member of the passed xfs_fsop_geom_t, leading to the leaking of four bytes of uninitialized stack data to potentially unprivileged callers. v2 switches to memset() to avoid future issues if structure members change, on suggestion of Dave Chinner. Signed-off-by: Dan Rosenberg Reviewed-by: Eugene Teo Signed-off-by: Alex Elder --- fs/xfs/xfs_fsops.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index cec89dd5d7d28..85668efb3e3e0 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -53,6 +53,9 @@ xfs_fs_geometry( xfs_fsop_geom_t *geo, int new_version) { + + memset(geo, 0, sizeof(*geo)); + geo->blocksize = mp->m_sb.sb_blocksize; geo->rtextsize = mp->m_sb.sb_rextsize; geo->agblocks = mp->m_sb.sb_agblocks; From be715140b5c3baf8ab6708060cfab80bef279d18 Mon Sep 17 00:00:00 2001 From: Lukas Czerner Date: Tue, 15 Feb 2011 17:07:36 +0000 Subject: [PATCH 2/2] xfs: check if device support discard in xfs_ioc_trim() Right now we, are relying on the fact that when we attempt to actually do the discard, blkdev_issue_discar() returns -EOPNOTSUPP and the user is informed that the device does not support discard. However, in the case where the we do not hit any suitable free extent to trim in FITRIM code, it will finish without any error. This is very confusing, because it seems that FITRIM was successful even though the device does not actually supports discard. Solution: Check for the discard support before attempt to search for free extents. Signed-off-by: Lukas Czerner Signed-off-by: Alex Elder --- fs/xfs/linux-2.6/xfs_discard.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/xfs/linux-2.6/xfs_discard.c b/fs/xfs/linux-2.6/xfs_discard.c index 05201ae719e5f..d61611c88012c 100644 --- a/fs/xfs/linux-2.6/xfs_discard.c +++ b/fs/xfs/linux-2.6/xfs_discard.c @@ -152,6 +152,8 @@ xfs_ioc_trim( if (!capable(CAP_SYS_ADMIN)) return -XFS_ERROR(EPERM); + if (!blk_queue_discard(q)) + return -XFS_ERROR(EOPNOTSUPP); if (copy_from_user(&range, urange, sizeof(range))) return -XFS_ERROR(EFAULT);