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, 32 insertions, 0 deletions

diff --git a/tools/perf/bench/Build b/tools/perf/bench/Build
new file mode 100644
index 000000000..67b76fe20
--- /dev/null
+++ b/tools/perf/bench/Build
@@ -0,0 +1,32 @@
+perf-bench-y += sched-messaging.o
+perf-bench-y += sched-pipe.o
+perf-bench-y += sched-seccomp-notify.o
+perf-bench-y += syscall.o
+perf-bench-y += mem-functions.o
+perf-bench-y += futex.o
+perf-bench-y += futex-hash.o
+perf-bench-y += futex-wake.o
+perf-bench-y += futex-wake-parallel.o
+perf-bench-y += futex-requeue.o
+perf-bench-y += futex-lock-pi.o
+perf-bench-y += epoll-wait.o
+perf-bench-y += epoll-ctl.o
+perf-bench-y += synthesize.o
+perf-bench-y += kallsyms-parse.o
+perf-bench-y += find-bit-bench.o
+perf-bench-y += inject-buildid.o
+perf-bench-y += evlist-open-close.o
+perf-bench-y += breakpoint.o
+perf-bench-y += pmu-scan.o
+perf-bench-y += uprobe.o
+
+perf-bench-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o
+perf-bench-$(CONFIG_X86_64) += mem-memset-x86-64-asm.o
+
+perf-bench-$(CONFIG_NUMA) += numa.o
+
+ifeq ($(CONFIG_PERF_BPF_SKEL),y)
+include $(srctree)/tools/perf/bpf_skel.mak
+
+$(OUTPUT)bench/uprobe.o: $(SKEL_OUT)/bench_uprobe.skel.h
+endif