xfs: underflow bug in xfs_attrlist_by_handle()
authorDan Carpenter <dan.carpenter@oracle.com>
Thu, 31 Oct 2013 18:00:10 +0000 (21:00 +0300)
committerBen Myers <bpm@sgi.com>
Wed, 4 Dec 2013 20:23:46 +0000 (14:23 -0600)
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 <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
fs/xfs/xfs_ioctl.c
fs/xfs/xfs_ioctl32.c

index 4d613401a5e056a08dd2f8b21b77833bfe14cbc6..33ad9a77791f7ebbf3f8762e0c9df1af637c5328 100644 (file)
@@ -442,7 +442,8 @@ 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);
 
        /*
index e8fb1231db8124dc08b2ffbcc551d6bfa1bc21f5..a7992f8de9d3fa53a63ab2d3250f0c4933caded9 100644 (file)
@@ -356,7 +356,8 @@ 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);
 
        /*