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, 34 insertions, 0 deletions

diff --git a/tools/perf/ui/progress.h b/tools/perf/ui/progress.h
new file mode 100644
index 000000000..4f52c37b2
--- /dev/null
+++ b/tools/perf/ui/progress.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PERF_UI_PROGRESS_H_
+#define _PERF_UI_PROGRESS_H_ 1
+
+#include <linux/types.h>
+
+void ui_progress__finish(void);
+
+struct ui_progress {
+	const char *title;
+	u64 curr, next, step, total;
+	bool size;
+};
+
+void __ui_progress__init(struct ui_progress *p, u64 total,
+			 const char *title, bool size);
+
+#define ui_progress__init(p, total, title) \
+	__ui_progress__init(p, total, title, false)
+
+#define ui_progress__init_size(p, total, title) \
+	__ui_progress__init(p, total, title, true)
+
+void ui_progress__update(struct ui_progress *p, u64 adv);
+
+struct ui_progress_ops {
+	void (*init)(struct ui_progress *p);
+	void (*update)(struct ui_progress *p);
+	void (*finish)(void);
+};
+
+extern struct ui_progress_ops *ui_progress__ops;
+
+#endif