llvm-project

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// RUN: %clang_safestack -fno-stack-protector -D_FORTIFY_SOURCE=0 -g %s -o %t.nossp
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// RUN: %run %t.nossp 2>&1 | FileCheck --check-prefix=NOSSP %s
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// RUN: %clang_safestack -fstack-protector-all -D_FORTIFY_SOURCE=0 -g %s -o %t.ssp
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// RUN: env LIBC_FATAL_STDERR_=1 not --crash %run %t.ssp 2>&1 | \
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// RUN:     FileCheck -check-prefix=SSP %s
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// Test stack canaries on the unsafe stack.
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// REQUIRES: stable-runtime
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#include <assert.h>
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#include <stdio.h>
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#include <string.h>
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__attribute__((noinline)) void f(unsigned *y) {
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  char x;
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  char *volatile p = &x;
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  char *volatile q = (char *)y;
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  assert(p < q);
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  assert(q - p < 1024); // sanity
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  // This has technically undefined behavior, but we know the actual layout of
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  // the unsafe stack and this should not touch anything important.
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  memset(&x, 0xab, q - p + sizeof(*y));
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}
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int main(int argc, char **argv)
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{
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  unsigned y;
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  // NOSSP: main 1
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  // SSP: main 1
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  fprintf(stderr, "main 1\n");
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  f(&y);
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  // NOSSP: main 2
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  // SSP-NOT: main 2
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  fprintf(stderr, "main 2\n");
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  return 0;
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}
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