diff mbox series

[CVE-2018-13094,X/A/B/C,SRU] xfs: don't call xfs_da_shrink_inode with NULL bp

Message ID 20180716044449.18302-3-po-hsu.lin@canonical.com
State New
Headers show
Series [CVE-2018-13094,X/A/B/C,SRU] xfs: don't call xfs_da_shrink_inode with NULL bp | expand

Commit Message

Po-Hsu Lin July 16, 2018, 4:44 a.m. UTC 
From: Eric Sandeen <sandeen@sandeen.net>

CVE-2018-13094

xfs_attr3_leaf_create may have errored out before instantiating a buffer,
for example if the blkno is out of range.  In that case there is no work
to do to remove it, and in fact xfs_da_shrink_inode will lead to an oops
if we try.

This also seems to fix a flaw where the original error from
xfs_attr3_leaf_create gets overwritten in the cleanup case, and it
removes a pointless assignment to bp which isn't used after this.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=199969
Reported-by: Xu, Wen <wen.xu@gatech.edu>
Tested-by: Xu, Wen <wen.xu@gatech.edu>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
(cherry picked from commit bb3d48dcf86a97dc25fe9fc2c11938e19cb4399a)
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
---
 fs/xfs/libxfs/xfs_attr_leaf.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 601eaa3..9fe3a3e 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -784,9 +784,8 @@  xfs_attr_shortform_to_leaf(
 	ASSERT(blkno == 0);
 	error = xfs_attr3_leaf_create(args, blkno, &bp);
 	if (error) {
-		error = xfs_da_shrink_inode(args, 0, bp);
-		bp = NULL;
-		if (error)
+		/* xfs_attr3_leaf_create may not have instantiated a block */
+		if (bp && (xfs_da_shrink_inode(args, 0, bp) != 0))
 			goto out;
 		xfs_idata_realloc(dp, size, XFS_ATTR_FORK);	/* try to put */
 		memcpy(ifp->if_u1.if_data, tmpbuffer, size);	/* it back */