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

    xfs: underflow bug in xfs_attrlist_by_handle()

to the 3.12-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-underflow-bug-in-xfs_attrlist_by_handle.patch
and it can be found in the queue-3.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 31978b5cc66b8ba8a7e8eef60b12395d41b7b890 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <[email protected]>
Date: Thu, 31 Oct 2013 21:00:10 +0300
Subject: xfs: underflow bug in xfs_attrlist_by_handle()

From: Dan Carpenter <[email protected]>

commit 31978b5cc66b8ba8a7e8eef60b12395d41b7b890 upstream.

If we allocate less than sizeof(struct attrlist) then we end up
corrupting memory or doing a ZERO_PTR_SIZE dereference.

This can only be triggered with CAP_SYS_ADMIN.

Reported-by: Nico Golde <[email protected]>
Reported-by: Fabian Yamaguchi <[email protected]>
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Dave Chinner <[email protected]>
Signed-off-by: Ben Myers <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 fs/xfs/xfs_ioctl.c   |    3 ++-
 fs/xfs/xfs_ioctl32.c |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -443,7 +443,8 @@ xfs_attrlist_by_handle(
                return -XFS_ERROR(EPERM);
        if (copy_from_user(&al_hreq, arg, 
sizeof(xfs_fsop_attrlist_handlereq_t)))
                return -XFS_ERROR(EFAULT);
-       if (al_hreq.buflen > XATTR_LIST_MAX)
+       if (al_hreq.buflen < sizeof(struct attrlist) ||
+           al_hreq.buflen > XATTR_LIST_MAX)
                return -XFS_ERROR(EINVAL);
 
        /*
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -357,7 +357,8 @@ xfs_compat_attrlist_by_handle(
        if (copy_from_user(&al_hreq, arg,
                           sizeof(compat_xfs_fsop_attrlist_handlereq_t)))
                return -XFS_ERROR(EFAULT);
-       if (al_hreq.buflen > XATTR_LIST_MAX)
+       if (al_hreq.buflen < sizeof(struct attrlist) ||
+           al_hreq.buflen > XATTR_LIST_MAX)
                return -XFS_ERROR(EINVAL);
 
        /*


Patches currently in stable-queue which might be from [email protected] 
are

queue-3.12/hwmon-prevent-some-divide-by-zeros-in-fan_to_reg.patch
queue-3.12/xfs-underflow-bug-in-xfs_attrlist_by_handle.patch
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