Mark Brown broonie@kernel.org writes:
diff --git a/tools/testing/selftests/arm64/signal/testcases/gcs_exception_fault.c b/tools/testing/selftests/arm64/signal/testcases/gcs_exception_fault.c new file mode 100644 index 000000000000..532d533592a1 --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/gcs_exception_fault.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- Copyright (C) 2023 ARM Limited
- */
+#include <errno.h> +#include <signal.h> +#include <unistd.h>
+#include <sys/mman.h> +#include <sys/prctl.h>
+#include "test_signals_utils.h" +#include "testcases.h"
+/* This should be includable from some standard header, but which? */ +#ifndef SEGV_CPERR +#define SEGV_CPERR 10 +#endif
One suggestion is include/uapi/asm-generic/siginfo.h. It already has SEGV_MTEAERR and SEGV_MTESERR, as well as si_codes specific to other arches.
From there, it should find its way to glibc's sysdeps/unix/sysv/linux/bits/siginfo-consts.h.
+static int gcs_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc) +{
- size_t offset;
- struct _aarch64_ctx *head = GET_BUF_RESV_HEAD(context);
- struct gcs_context *gcs;
- unsigned long expected, gcspr;
- int ret;
- ret = prctl(PR_GET_SHADOW_STACK_STATUS, &expected, 0, 0, 0);
- if (ret != 0) {
fprintf(stderr, "Unable to query GCS status\n");return 1;- }
- /* We expect a cap to be added to the GCS in the signal frame */
- gcspr = get_gcspr_el0();
- gcspr -= 8;
- fprintf(stderr, "Expecting GCSPR_EL0 %lx\n", gcspr);
- if (!get_current_context(td, &context.uc, sizeof(context))) {
fprintf(stderr, "Failed getting context\n");return 1;- }
At this point, before any function call is made, can the test check that *(gcspr + 8) == 0? This would detect the issue I mentioned in patch 24 of gcs_restore_signal() not zeroing the location of the cap.
- fprintf(stderr, "Got context\n");
- head = get_header(head, GCS_MAGIC, GET_BUF_RESV_SIZE(context),
&offset);- if (!head) {
fprintf(stderr, "No GCS context\n");return 1;- }
- gcs = (struct gcs_context *)head;
- /* Basic size validation is done in get_current_context() */
- if (gcs->features_enabled != expected) {
fprintf(stderr, "Features enabled %llx but expected %lx\n",gcs->features_enabled, expected);return 1;- }
- if (gcs->gcspr != gcspr) {
fprintf(stderr, "Got GCSPR %llx but expected %lx\n",gcs->gcspr, gcspr);return 1;- }
I suggest adding a new check here to ensure that gcs->reserved == 0.
- fprintf(stderr, "GCS context validated\n");
- td->pass = 1;
- return 0;
+}
+struct tdescr tde = {
- .name = "GCS basics",
- .descr = "Validate a GCS signal context",
- .feats_required = FEAT_GCS,
- .timeout = 3,
- .run = gcs_regs,
+}; diff --git a/tools/testing/selftests/arm64/signal/testcases/gcs_write_fault.c b/tools/testing/selftests/arm64/signal/testcases/gcs_write_fault.c new file mode 100644 index 000000000000..126b1a294a29 --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/gcs_write_fault.c @@ -0,0 +1,67 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- Copyright (C) 2023 ARM Limited
- */
+#include <errno.h> +#include <signal.h> +#include <unistd.h>
+#include <sys/mman.h> +#include <sys/prctl.h>
+#include "test_signals_utils.h" +#include "testcases.h"
+static uint64_t *gcs_page;
+#ifndef __NR_map_shadow_stack +#define __NR_map_shadow_stack 452 +#endif
+static bool alloc_gcs(struct tdescr *td) +{
- long page_size = sysconf(_SC_PAGE_SIZE);
- gcs_page = (void *)syscall(__NR_map_shadow_stack, 0,
page_size, 0);- if (gcs_page == MAP_FAILED) {
fprintf(stderr, "Failed to map %ld byte GCS: %d\n",page_size, errno);
This call is failing with EINVAL for me:
# timeout set to 45 # selftests: arm64/signal: gcs_write_fault # # GCS write fault :: Normal writes to a GCS segfault # Registered handlers for all signals. # Detected MINSTKSIGSZ:4720 # Required Features: [ GCS ] supported # Incompatible Features: [] absent # Failed to map 4096 byte GCS: 22 # FAILED Testcase initialization. # ==>> completed. FAIL(0) not ok 11 selftests: arm64/signal: gcs_write_fault # exit=1
return false;- }
- return true;
+}