3.5.7.28 -stable review patch.  If anyone has any objections, please let me 
know.

------------------

From: Dan Carpenter <dan.carpen...@oracle.com>

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 <n...@ngolde.de>
Reported-by: Fabian Yamaguchi <f...@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
Reviewed-by: Dave Chinner <dchin...@redhat.com>
Signed-off-by: Ben Myers <b...@sgi.com>
Cc: Josh Boyer <jwbo...@fedoraproject.org>
Cc: Kees Cook <keesc...@google.com>
Signed-off-by: Luis Henriques <luis.henriq...@canonical.com>
---
 fs/xfs/xfs_ioctl.c   | 3 ++-
 fs/xfs/xfs_ioctl32.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 3a05a41..c03f47d 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -398,7 +398,8 @@ 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);
 
        /*
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index c4f2da0..2859665 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -359,7 +359,8 @@ 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);
 
        /*
-- 
1.8.3.2

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