openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
new file mode 100644
index 000000000..bebbb77a8
--- /dev/null
+++ b/include/drm/drm_blend.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#ifndef __DRM_BLEND_H__
+#define __DRM_BLEND_H__
+
+#include <linux/list.h>
+#include <linux/ctype.h>
+#include <drm/drm_mode.h>
+
+#define DRM_MODE_BLEND_PREMULTI		0
+#define DRM_MODE_BLEND_COVERAGE		1
+#define DRM_MODE_BLEND_PIXEL_NONE	2
+
+struct drm_atomic_commit;
+struct drm_crtc;
+struct drm_device;
+struct drm_plane;
+
+static inline bool drm_rotation_90_or_270(unsigned int rotation)
+{
+	return rotation & (DRM_MODE_ROTATE_90 | DRM_MODE_ROTATE_270);
+}
+
+#define DRM_BLEND_ALPHA_OPAQUE		0xffff
+
+int drm_plane_create_alpha_property(struct drm_plane *plane);
+int drm_plane_create_rotation_property(struct drm_plane *plane,
+				       unsigned int rotation,
+				       unsigned int supported_rotations);
+unsigned int drm_rotation_simplify(unsigned int rotation,
+				   unsigned int supported_rotations);
+
+int drm_plane_create_zpos_property(struct drm_plane *plane,
+				   unsigned int zpos,
+				   unsigned int min, unsigned int max);
+int drm_plane_create_zpos_immutable_property(struct drm_plane *plane,
+					     unsigned int zpos);
+int drm_atomic_normalize_zpos(struct drm_device *dev,
+			      struct drm_atomic_commit *state);
+int drm_plane_create_blend_mode_property(struct drm_plane *plane,
+					 unsigned int supported_modes);
+void drm_crtc_attach_background_color_property(struct drm_crtc *crtc);
+#endif