Patch "xfs: don't allow di_size with high bit set" has been added to the 4.4-stable tree

Patch "xfs: don't allow di_size with high bit set" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    xfs: don't allow di_size with high bit set

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfs-don-t-allow-di_size-with-high-bit-set.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ef388e2054feedaeb05399ed654bdb06f385d294 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Mon, 5 Dec 2016 12:38:38 +1100
Subject: xfs: don't allow di_size with high bit set

From: Darrick J. Wong <darrick.wong@oracle.com>

commit ef388e2054feedaeb05399ed654bdb06f385d294 upstream.

The on-disk field di_size is used to set i_size, which is a signed
integer of loff_t.  If the high bit of di_size is set, we'll end up with
a negative i_size, which will cause all sorts of problems.  Since the
VFS won't let us create a file with such length, we should catch them
here in the verifier too.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/xfs/libxfs/xfs_inode_buf.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -299,6 +299,14 @@ xfs_dinode_verify(
 	if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
 		return false;
 
+	/* don't allow invalid i_size */
+	if (be64_to_cpu(dip->di_size) & (1ULL << 63))
+		return false;
+
+	/* No zero-length symlinks. */
+	if (S_ISLNK(be16_to_cpu(dip->di_mode)) && dip->di_size == 0)
+		return false;
+
 	/* only version 3 or greater inodes are extensively verified here */
 	if (dip->di_version < 3)
 		return true;


Patches currently in stable-queue which might be from darrick.wong@oracle.com are

queue-4.4/xfs-don-t-allow-di_size-with-high-bit-set.patch