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, 55 insertions, 0 deletions

diff --git a/net/mac80211/trace_msg.h b/net/mac80211/trace_msg.h
new file mode 100644
index 000000000..aea4ce55c
--- /dev/null
+++ b/net/mac80211/trace_msg.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Portions of this file
+ * Copyright (C) 2019 Intel Corporation
+ */
+
+#ifdef CONFIG_MAC80211_MESSAGE_TRACING
+
+#if !defined(__MAC80211_MSG_DRIVER_TRACE) || defined(TRACE_HEADER_MULTI_READ)
+#define __MAC80211_MSG_DRIVER_TRACE
+
+#include <linux/tracepoint.h>
+#include <net/mac80211.h>
+#include "ieee80211_i.h"
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM mac80211_msg
+
+DECLARE_EVENT_CLASS(mac80211_msg_event,
+	TP_PROTO(struct va_format *vaf),
+
+	TP_ARGS(vaf),
+
+	TP_STRUCT__entry(
+		__vstring(msg, vaf->fmt, vaf->va)
+	),
+
+	TP_fast_assign(
+		__assign_vstr(msg, vaf->fmt, vaf->va);
+	),
+
+	TP_printk("%s", __get_str(msg))
+);
+
+DEFINE_EVENT(mac80211_msg_event, mac80211_info,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+DEFINE_EVENT(mac80211_msg_event, mac80211_dbg,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+DEFINE_EVENT(mac80211_msg_event, mac80211_err,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+#endif /* !__MAC80211_MSG_DRIVER_TRACE || TRACE_HEADER_MULTI_READ */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace_msg
+#include <trace/define_trace.h>
+
+#endif