xfs: don't crash the vfs on a garbage inline symlink
The VFS routine that calls ->get_link blindly copies whatever's returned
into the user's buffer. If we return a NULL pointer, the vfs will
crash on the null pointer. Therefore, return -EFSCORRUPTED instead of
blowing up the kernel.
[dgc: clean up with hch's suggestions]
Reported-by: wen.xu@gatech.edu
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index c3e74f9..f48ffd7 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -471,8 +471,18 @@ xfs_vn_get_link_inline(
struct inode *inode,
struct delayed_call *done)
{
+ char *link;
+
ASSERT(XFS_I(inode)->i_df.if_flags & XFS_IFINLINE);
- return XFS_I(inode)->i_df.if_u1.if_data;
+
+ /*
+ * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED if
+ * if_data is junk.
+ */
+ link = XFS_I(inode)->i_df.if_u1.if_data;
+ if (!link)
+ return ERR_PTR(-EFSCORRUPTED);
+ return link;
}
STATIC int
