compiler-rt/test/cfi/cross-dso/shadow_is_read_only.cpp

   1 // RUN: %clangxx_cfi_dso -std=c++11 -g -DSHARED_LIB %s -fPIC -shared -o %t-cfi-so.so
   2 // RUN: %clangxx -std=c++11 -g -DSHARED_LIB %s -fPIC -shared -o %t-nocfi-so.so
   3 // RUN: %clangxx_cfi_dso -std=c++11 -g %s -o %t
   4
   5 // RUN: %expect_crash %t start 2>&1 | FileCheck %s
   6 // RUN: %expect_crash %t mmap 2>&1 | FileCheck %s
   7 // RUN: %expect_crash %t dlopen %t-cfi-so.so 2>&1 | FileCheck %s
   8 // RUN: %expect_crash %t dlclose %t-cfi-so.so 2>&1 | FileCheck %s
   9 // RUN: %expect_crash %t dlopen %t-nocfi-so.so 2>&1 | FileCheck %s
  10 // RUN: %expect_crash %t dlclose %t-nocfi-so.so 2>&1 | FileCheck %s
  11
  12 // Tests that shadow is read-only most of the time.
  13 // REQUIRES: cxxabi
  14
  15 // Uses private API that is not available on Android.
  16 // UNSUPPORTED: android
  17
  18 #include <assert.h>
  19 #include <dlfcn.h>
  20 #include <stdio.h>
  21 #include <stdint.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/mman.h>
  25
  26 struct A {
  27   virtual void f();
  28 };
  29
  30 #ifdef SHARED_LIB
  31
  32 void A::f() {}
  33
  34 extern "C" A *create_A() { return new A(); }
  35
  36 #else
  37
  38 constexpr unsigned kShadowGranularity = 12;
  39
  40 namespace __cfi {
  41 uintptr_t GetShadow();
  42 }
  43
  44 void write_shadow(void *ptr) {
  45   uintptr_t base = __cfi::GetShadow();
  46   uint16_t *s =
  47       (uint16_t *)(base + (((uintptr_t)ptr >> kShadowGranularity) << 1));
  48   fprintf(stderr, "going to crash\n");
  49   // CHECK: going to crash
  50   *s = 42;
  51   fprintf(stderr, "did not crash\n");
  52   // CHECK-NOT: did not crash
  53   exit(1);
  54 }
  55
  56 int main(int argc, char *argv[]) {
  57   assert(argc > 1);
  58   const bool test_mmap = strcmp(argv[1], "mmap") == 0;
  59   const bool test_start = strcmp(argv[1], "start") == 0;
  60   const bool test_dlopen = strcmp(argv[1], "dlopen") == 0;
  61   const bool test_dlclose = strcmp(argv[1], "dlclose") == 0;
  62   const char *lib = argc > 2 ? argv[2] : nullptr;
  63
  64   if (test_start)
  65     write_shadow((void *)&main);
  66
  67   if (test_mmap) {
  68     void *p = mmap(nullptr, 1 << 20, PROT_READ | PROT_WRITE | PROT_EXEC,
  69                    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
  70     assert(p != MAP_FAILED);
  71     write_shadow((char *)p + 100);
  72   } else {
  73     void *handle = dlopen(lib, RTLD_NOW);
  74     assert(handle);
  75     void *create_A = dlsym(handle, "create_A");
  76     assert(create_A);
  77
  78     if (test_dlopen)
  79       write_shadow(create_A);
  80
  81     int res = dlclose(handle);
  82     assert(res == 0);
  83
  84     if (test_dlclose)
  85       write_shadow(create_A);
  86   }
  87 }
  88 #endif