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@xxxxxxxxxxxxxxx> know about it.
>From ef388e2054feedaeb05399ed654bdb06f385d294 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
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@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Nikolay Borisov <n.borisov.lkml@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxx are
queue-4.4/xfs-don-t-allow-di_size-with-high-bit-set.patch