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, 43 insertions, 0 deletions

diff --git a/include/sound/sof/debug.h b/include/sound/sof/debug.h
new file mode 100644
index 000000000..8b308d7e5
--- /dev/null
+++ b/include/sound/sof/debug.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ * redistributing this file, you may do so under either license.
+ *
+ * Copyright(c) 2020 Intel Corporation
+ *
+ * Author: Karol Trzcinski <karolx.trzcinski@linux.intel.com>
+ */
+
+#ifndef __INCLUDE_SOUND_SOF_DEBUG_H__
+#define __INCLUDE_SOUND_SOF_DEBUG_H__
+
+#include <sound/sof/header.h>
+
+/** ABI3.18 */
+enum sof_ipc_dbg_mem_zone {
+	SOF_IPC_MEM_ZONE_SYS		= 0,	/**< System zone */
+	SOF_IPC_MEM_ZONE_SYS_RUNTIME	= 1,	/**< System-runtime zone */
+	SOF_IPC_MEM_ZONE_RUNTIME	= 2,	/**< Runtime zone */
+	SOF_IPC_MEM_ZONE_BUFFER		= 3,	/**< Buffer zone */
+	SOF_IPC_MEM_ZONE_RUNTIME_SHARED	= 4,	/**< System runtime zone */
+	SOF_IPC_MEM_ZONE_SYS_SHARED	= 5,	/**< System shared zone */
+};
+
+/** ABI3.18 */
+struct sof_ipc_dbg_mem_usage_elem {
+	uint32_t zone;		/**< see sof_ipc_dbg_mem_zone */
+	uint32_t id;		/**< heap index within zone */
+	uint32_t used;		/**< number of bytes used in zone */
+	uint32_t free;		/**< number of bytes free to use within zone */
+	uint32_t reserved;	/**< for future use */
+} __packed;
+
+/** ABI3.18 */
+struct sof_ipc_dbg_mem_usage {
+	struct sof_ipc_reply rhdr;			/**< generic IPC reply header */
+	uint32_t reserved[4];				/**< reserved for future use */
+	uint32_t num_elems;				/**< elems[] counter */
+	struct sof_ipc_dbg_mem_usage_elem elems[];	/**< memory usage information */
+} __packed;
+
+#endif