// RUN: %clang_safestack -fno-stack-protector -D_FORTIFY_SOURCE=0 -g %s -o %t.nossp // RUN: %run %t.nossp 2>&1 | FileCheck --check-prefix=NOSSP %s // RUN: %clang_safestack -fstack-protector-all -D_FORTIFY_SOURCE=0 -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; }