From ae29478766f4c8e16edca6fe1e25d73c47991ebe Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Sat, 29 Sep 2018 13:40:40 +1000 Subject: [PATCH] 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 Reviewed-by: Allison Henderson Signed-off-by: Dave Chinner --- fs/xfs/xfs_iops.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) 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 -- 2.7.4