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, 197 insertions, 0 deletions

diff --git a/include/drm/drm_debugfs.h b/include/drm/drm_debugfs.h
new file mode 100644
index 000000000..ea8cba942
--- /dev/null
+++ b/include/drm/drm_debugfs.h
@@ -0,0 +1,197 @@
+/*
+ * Internal Header for the Direct Rendering Manager
+ *
+ * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
+ * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
+ * Copyright (c) 2009-2010, Code Aurora Forum.
+ * All rights reserved.
+ *
+ * Author: Rickard E. (Rik) Faith <faith@valinux.com>
+ * Author: Gareth Hughes <gareth@valinux.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _DRM_DEBUGFS_H_
+#define _DRM_DEBUGFS_H_
+
+#include <linux/types.h>
+#include <linux/seq_file.h>
+
+#include <drm/drm_gpuvm.h>
+
+/**
+ * DRM_DEBUGFS_GPUVA_INFO - &drm_info_list entry to dump a GPU VA space
+ * @show: the &drm_info_list's show callback
+ * @data: driver private data
+ *
+ * Drivers should use this macro to define a &drm_info_list entry to provide a
+ * debugfs file for dumping the GPU VA space regions and mappings.
+ *
+ * For each DRM GPU VA space drivers should call drm_debugfs_gpuva_info() from
+ * their @show callback.
+ */
+#define DRM_DEBUGFS_GPUVA_INFO(show, data) {"gpuvas", show, DRIVER_GEM_GPUVA, data}
+
+/**
+ * struct drm_info_list - debugfs info list entry
+ *
+ * This structure represents a debugfs file to be created by the drm
+ * core.
+ */
+struct drm_info_list {
+	/** @name: file name */
+	const char *name;
+	/**
+	 * @show:
+	 *
+	 * Show callback. &seq_file->private will be set to the &struct
+	 * drm_info_node corresponding to the instance of this info on a given
+	 * &struct drm_minor.
+	 */
+	int (*show)(struct seq_file*, void*);
+	/** @driver_features: Required driver features for this entry */
+	u32 driver_features;
+	/** @data: Driver-private data, should not be device-specific. */
+	void *data;
+};
+
+/**
+ * struct drm_info_node - Per-minor debugfs node structure
+ *
+ * This structure represents a debugfs file, as an instantiation of a &struct
+ * drm_info_list on a &struct drm_minor.
+ *
+ * FIXME:
+ *
+ * No it doesn't make a hole lot of sense that we duplicate debugfs entries for
+ * both the render and the primary nodes, but that's how this has organically
+ * grown. It should probably be fixed, with a compatibility link, if needed.
+ */
+struct drm_info_node {
+	/** @minor: &struct drm_minor for this node. */
+	struct drm_minor *minor;
+	/** @info_ent: template for this node. */
+	const struct drm_info_list *info_ent;
+	/* private: */
+	struct list_head list;
+	struct dentry *dent;
+};
+
+/**
+ * struct drm_debugfs_info - debugfs info list entry
+ *
+ * This structure represents a debugfs file to be created by the drm
+ * core.
+ */
+struct drm_debugfs_info {
+	/** @name: File name */
+	const char *name;
+
+	/**
+	 * @show:
+	 *
+	 * Show callback. &seq_file->private will be set to the &struct
+	 * drm_debugfs_entry corresponding to the instance of this info
+	 * on a given &struct drm_device.
+	 */
+	int (*show)(struct seq_file*, void*);
+
+	/** @driver_features: Required driver features for this entry. */
+	u32 driver_features;
+
+	/** @data: Driver-private data, should not be device-specific. */
+	void *data;
+};
+
+/**
+ * struct drm_debugfs_entry - Per-device debugfs node structure
+ *
+ * This structure represents a debugfs file, as an instantiation of a &struct
+ * drm_debugfs_info on a &struct drm_device.
+ */
+struct drm_debugfs_entry {
+	/** @dev: &struct drm_device for this node. */
+	struct drm_device *dev;
+
+	/** @file: Template for this node. */
+	struct drm_debugfs_info file;
+
+	/** @list: Linked list of all device nodes. */
+	struct list_head list;
+};
+
+#if defined(CONFIG_DEBUG_FS)
+void drm_debugfs_create_files(const struct drm_info_list *files,
+			      int count, struct dentry *root,
+			      struct drm_minor *minor);
+int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
+			     struct dentry *root, struct drm_minor *minor);
+
+void drm_debugfs_add_file(struct drm_device *dev, const char *name,
+			  int (*show)(struct seq_file*, void*), void *data);
+
+void drm_debugfs_add_files(struct drm_device *dev,
+			   const struct drm_debugfs_info *files, int count);
+
+int drm_debugfs_gpuva_info(struct seq_file *m,
+			   struct drm_gpuvm *gpuvm);
+
+void drm_debugfs_clients_add(struct drm_file *file);
+void drm_debugfs_clients_remove(struct drm_file *file);
+#else
+static inline void drm_debugfs_create_files(const struct drm_info_list *files,
+					    int count, struct dentry *root,
+					    struct drm_minor *minor)
+{}
+
+static inline int drm_debugfs_remove_files(const struct drm_info_list *files,
+					   int count, struct dentry *root,
+					   struct drm_minor *minor)
+{
+	return 0;
+}
+
+static inline void drm_debugfs_add_file(struct drm_device *dev, const char *name,
+					int (*show)(struct seq_file*, void*),
+					void *data)
+{}
+
+static inline void drm_debugfs_add_files(struct drm_device *dev,
+					 const struct drm_debugfs_info *files,
+					 int count)
+{}
+
+static inline int drm_debugfs_gpuva_info(struct seq_file *m,
+					 struct drm_gpuvm *gpuvm)
+{
+	return 0;
+}
+
+static inline void drm_debugfs_clients_add(struct drm_file *file)
+{
+}
+
+static inline void drm_debugfs_clients_remove(struct drm_file *file)
+{
+}
+#endif
+
+#endif /* _DRM_DEBUGFS_H_ */