From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall 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 Signed-off-by: Stafford Horne --- tools/perf/tests/mem.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 tools/perf/tests/mem.c (limited to 'tools/perf/tests/mem.c') diff --git a/tools/perf/tests/mem.c b/tools/perf/tests/mem.c new file mode 100644 index 000000000..cb3d749e1 --- /dev/null +++ b/tools/perf/tests/mem.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "util/map_symbol.h" +#include "util/mem-events.h" +#include "util/mem-info.h" +#include "util/symbol.h" +#include "linux/perf_event.h" +#include "util/debug.h" +#include "tests.h" +#include + +static int check(union perf_mem_data_src data_src, + const char *string) +{ + char out[100]; + char failure[100]; + struct mem_info *mi = mem_info__new(); + int n; + + TEST_ASSERT_VAL("Memory allocation failed", mi); + *mem_info__data_src(mi) = data_src; + n = perf_mem__snp_scnprintf(out, sizeof out, mi); + n += perf_mem__lvl_scnprintf(out + n, sizeof out - n, mi); + mem_info__put(mi); + scnprintf(failure, sizeof failure, "unexpected %s", out); + TEST_ASSERT_VAL(failure, !strcmp(string, out)); + return 0; +} + +static int test__mem(struct test_suite *text __maybe_unused, int subtest __maybe_unused) +{ + int ret = 0; + union perf_mem_data_src src; + + memset(&src, 0, sizeof(src)); + + src.mem_lvl = PERF_MEM_LVL_HIT; + src.mem_lvl_num = 4; + + ret |= check(src, "N/AL4 hit"); + + src.mem_remote = 1; + + ret |= check(src, "N/ARemote L4 hit"); + + src.mem_lvl = PERF_MEM_LVL_MISS; + src.mem_lvl_num = PERF_MEM_LVLNUM_PMEM; + src.mem_remote = 0; + + ret |= check(src, "N/APMEM miss"); + + src.mem_remote = 1; + + ret |= check(src, "N/ARemote PMEM miss"); + + src.mem_snoopx = PERF_MEM_SNOOPX_FWD; + src.mem_lvl_num = PERF_MEM_LVLNUM_RAM; + + ret |= check(src , "FwdRemote RAM miss"); + + return ret; +} + +DEFINE_SUITE("Test data source output", mem); -- cgit v1.3.1