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, 206 insertions, 0 deletions

diff --git a/include/trace/events/rtc.h b/include/trace/events/rtc.h
new file mode 100644
index 000000000..621333f1c
--- /dev/null
+++ b/include/trace/events/rtc.h
@@ -0,0 +1,206 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rtc
+
+#if !defined(_TRACE_RTC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RTC_H
+
+#include <linux/rtc.h>
+#include <linux/tracepoint.h>
+
+DECLARE_EVENT_CLASS(rtc_time_alarm_class,
+
+	TP_PROTO(time64_t secs, int err),
+
+	TP_ARGS(secs, err),
+
+	TP_STRUCT__entry(
+		__field(time64_t, secs)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->secs = secs;
+		__entry->err = err;
+	),
+
+	TP_printk("UTC (%lld) (%d)",
+		  __entry->secs, __entry->err
+	)
+);
+
+DEFINE_EVENT(rtc_time_alarm_class, rtc_set_time,
+
+	TP_PROTO(time64_t secs, int err),
+
+	TP_ARGS(secs, err)
+);
+
+DEFINE_EVENT(rtc_time_alarm_class, rtc_read_time,
+
+	TP_PROTO(time64_t secs, int err),
+
+	TP_ARGS(secs, err)
+);
+
+DEFINE_EVENT(rtc_time_alarm_class, rtc_set_alarm,
+
+	TP_PROTO(time64_t secs, int err),
+
+	TP_ARGS(secs, err)
+);
+
+DEFINE_EVENT(rtc_time_alarm_class, rtc_read_alarm,
+
+	TP_PROTO(time64_t secs, int err),
+
+	TP_ARGS(secs, err)
+);
+
+TRACE_EVENT(rtc_irq_set_freq,
+
+	TP_PROTO(int freq, int err),
+
+	TP_ARGS(freq, err),
+
+	TP_STRUCT__entry(
+		__field(int, freq)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->freq = freq;
+		__entry->err = err;
+	),
+
+	TP_printk("set RTC periodic IRQ frequency:%u (%d)",
+		  __entry->freq, __entry->err
+	)
+);
+
+TRACE_EVENT(rtc_irq_set_state,
+
+	TP_PROTO(int enabled, int err),
+
+	TP_ARGS(enabled, err),
+
+	TP_STRUCT__entry(
+		__field(int, enabled)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->enabled = enabled;
+		__entry->err = err;
+	),
+
+	TP_printk("%s RTC 2^N Hz periodic IRQs (%d)",
+		  __entry->enabled ? "enable" : "disable",
+		  __entry->err
+	)
+);
+
+TRACE_EVENT(rtc_alarm_irq_enable,
+
+	TP_PROTO(unsigned int enabled, int err),
+
+	TP_ARGS(enabled, err),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, enabled)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->enabled = enabled;
+		__entry->err = err;
+	),
+
+	TP_printk("%s RTC alarm IRQ (%d)",
+		  __entry->enabled ? "enable" : "disable",
+		  __entry->err
+	)
+);
+
+DECLARE_EVENT_CLASS(rtc_offset_class,
+
+	TP_PROTO(long offset, int err),
+
+	TP_ARGS(offset, err),
+
+	TP_STRUCT__entry(
+		__field(long, offset)
+		__field(int, err)
+	),
+
+	TP_fast_assign(
+		__entry->offset = offset;
+		__entry->err = err;
+	),
+
+	TP_printk("RTC offset: %ld (%d)",
+		  __entry->offset, __entry->err
+	)
+);
+
+DEFINE_EVENT(rtc_offset_class, rtc_set_offset,
+
+	TP_PROTO(long offset, int err),
+
+	TP_ARGS(offset, err)
+);
+
+DEFINE_EVENT(rtc_offset_class, rtc_read_offset,
+
+	TP_PROTO(long offset, int err),
+
+	TP_ARGS(offset, err)
+);
+
+DECLARE_EVENT_CLASS(rtc_timer_class,
+
+	TP_PROTO(struct rtc_timer *timer),
+
+	TP_ARGS(timer),
+
+	TP_STRUCT__entry(
+		__field(struct rtc_timer *, timer)
+		__field(ktime_t, expires)
+		__field(ktime_t, period)
+	),
+
+	TP_fast_assign(
+		__entry->timer = timer;
+		__entry->expires = timer->node.expires;
+		__entry->period = timer->period;
+	),
+
+	TP_printk("RTC timer:(%p) expires:%lld period:%lld",
+		  __entry->timer, __entry->expires, __entry->period
+	)
+);
+
+DEFINE_EVENT(rtc_timer_class, rtc_timer_enqueue,
+
+	TP_PROTO(struct rtc_timer *timer),
+
+	TP_ARGS(timer)
+);
+
+DEFINE_EVENT(rtc_timer_class, rtc_timer_dequeue,
+
+	TP_PROTO(struct rtc_timer *timer),
+
+	TP_ARGS(timer)
+);
+
+DEFINE_EVENT(rtc_timer_class, rtc_timer_fired,
+
+	TP_PROTO(struct rtc_timer *timer),
+
+	TP_ARGS(timer)
+);
+
+#endif /* _TRACE_RTC_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>