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, 77 insertions, 0 deletions

diff --git a/net/mac80211/trace.c b/net/mac80211/trace.c
new file mode 100644
index 000000000..837857261
--- /dev/null
+++ b/net/mac80211/trace.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0
+/* bug in tracepoint.h, it should include this */
+#include <linux/module.h>
+
+/* sparse isn't too happy with all macros... */
+#ifndef __CHECKER__
+#include <net/cfg80211.h>
+#include "driver-ops.h"
+#include "debug.h"
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+#include "trace_msg.h"
+
+#ifdef CONFIG_MAC80211_MESSAGE_TRACING
+void __sdata_info(const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	pr_info("%pV", &vaf);
+	trace_mac80211_info(&vaf);
+	va_end(args);
+}
+
+void __sdata_dbg(bool print, const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	if (print)
+		pr_debug("%pV", &vaf);
+	trace_mac80211_dbg(&vaf);
+	va_end(args);
+}
+
+void __sdata_err(const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	pr_err("%pV", &vaf);
+	trace_mac80211_err(&vaf);
+	va_end(args);
+}
+
+void __wiphy_dbg(struct wiphy *wiphy, bool print, const char *fmt, ...)
+{
+	struct va_format vaf = {
+		.fmt = fmt,
+	};
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	if (print)
+		wiphy_dbg(wiphy, "%pV", &vaf);
+	trace_mac80211_dbg(&vaf);
+	va_end(args);
+}
+#endif
+#endif