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, 48 insertions, 0 deletions

diff --git a/drivers/soc/qcom/trace-aoss.h b/drivers/soc/qcom/trace-aoss.h
new file mode 100644
index 000000000..fb5b0470c
--- /dev/null
+++ b/drivers/soc/qcom/trace-aoss.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM qcom_aoss
+
+#if !defined(_TRACE_QCOM_AOSS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_QCOM_AOSS_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(aoss_send,
+	TP_PROTO(const char *msg),
+	TP_ARGS(msg),
+	TP_STRUCT__entry(
+		__string(msg, msg)
+	),
+	TP_fast_assign(
+		__assign_str(msg);
+	),
+	TP_printk("%s", __get_str(msg))
+);
+
+TRACE_EVENT(aoss_send_done,
+	TP_PROTO(const char *msg, int ret),
+	TP_ARGS(msg, ret),
+	TP_STRUCT__entry(
+		__string(msg, msg)
+		__field(int, ret)
+	),
+	TP_fast_assign(
+		__assign_str(msg);
+		__entry->ret = ret;
+	),
+	TP_printk("%s: %d", __get_str(msg), __entry->ret)
+);
+
+#endif /* _TRACE_QCOM_AOSS_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace-aoss
+
+#include <trace/define_trace.h>