src/libcompiler_builtins/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 #include <assert.h>
  16 #include <dlfcn.h>
  17 #include <stdio.h>
  18 #include <stdint.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <sys/mman.h>
  22
  23 struct A {
  24   virtual void f();
  25 };
  26
  27 #ifdef SHARED_LIB
  28
  29 void A::f() {}
  30
  31 extern "C" A *create_A() { return new A(); }
  32
  33 #else
  34
  35 constexpr unsigned kShadowGranularity = 12;
  36
  37 namespace __cfi {
  38 uintptr_t GetShadow();
  39 }
  40
  41 void write_shadow(void *ptr) {
  42   uintptr_t base = __cfi::GetShadow();
  43   uint16_t *s =
  44       (uint16_t *)(base + (((uintptr_t)ptr >> kShadowGranularity) << 1));
  45   fprintf(stderr, "going to crash\n");
  46   // CHECK: going to crash
  47   *s = 42;
  48   fprintf(stderr, "did not crash\n");
  49   // CHECK-NOT: did not crash
  50   exit(1);
  51 }
  52
  53 int main(int argc, char *argv[]) {
  54   assert(argc > 1);
  55   const bool test_mmap = strcmp(argv[1], "mmap") == 0;
  56   const bool test_start = strcmp(argv[1], "start") == 0;
  57   const bool test_dlopen = strcmp(argv[1], "dlopen") == 0;
  58   const bool test_dlclose = strcmp(argv[1], "dlclose") == 0;
  59   const char *lib = argc > 2 ? argv[2] : nullptr;
  60
  61   if (test_start)
  62     write_shadow((void *)&main);
  63
  64   if (test_mmap) {
  65     void *p = mmap(nullptr, 1 << 20, PROT_READ | PROT_WRITE | PROT_EXEC,
  66                    MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
  67     assert(p != MAP_FAILED);
  68     write_shadow((char *)p + 100);
  69   } else {
  70     void *handle = dlopen(lib, RTLD_NOW);
  71     assert(handle);
  72     void *create_A = dlsym(handle, "create_A");
  73     assert(create_A);
  74
  75     if (test_dlopen)
  76       write_shadow(create_A);
  77
  78     int res = dlclose(handle);
  79     assert(res == 0);
  80
  81     if (test_dlclose)
  82       write_shadow(create_A);
  83   }
  84 }
  85 #endif