1 files changed, 37 insertions, 0 deletions
diff --git a/test/safestack/canary.c b/test/safestack/canary.c
new file mode 100644
index 000000000..b316aa240
--- /dev/null
+++ b/test/safestack/canary.c
@@ -0,0 +1,37 @@
+// RUN: %clang_safestack -g %s -o %t.nossp
+// RUN: %run %t.nossp 2>&1 | FileCheck --check-prefix=NOSSP %s
+
+// RUN: %clang_safestack -fstack-protector-all -g %s -o %t.ssp
+// RUN: not --crash %run %t.ssp 2>&1 | FileCheck -check-prefix=SSP %s
+
+// Test stack canaries on the unsafe stack.
+
+// REQUIRES: stable-runtime
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+__attribute__((noinline)) void f(unsigned *y) {
+  char x;
+  char *volatile p = &x;
+  char *volatile q = (char *)y;
+  assert(p < q);
+  assert(q - p < 1024); // sanity
+  // This has technically undefined behavior, but we know the actual layout of
+  // the unsafe stack and this should not touch anything important.
+  memset(&x, 0xab, q - p + sizeof(*y));
+}
+
+int main(int argc, char **argv)
+{
+  unsigned y;
+  // NOSSP: main 1
+  // SSP: main 1
+  fprintf(stderr, "main 1\n");
+  f(&y);
+  // NOSSP: main 2
+  // SSP-NOT: main 2
+  fprintf(stderr, "main 2\n");
+  return 0;
+}