libsanitizer/asan/asan_linux.cc

   1 //===-- asan_linux.cc -----------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Linux-specific details.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #if SANITIZER_FREEBSD || SANITIZER_LINUX
  15
  16 #include "asan_interceptors.h"
  17 #include "asan_internal.h"
  18 #include "asan_thread.h"
  19 #include "sanitizer_common/sanitizer_flags.h"
  20 #include "sanitizer_common/sanitizer_freebsd.h"
  21 #include "sanitizer_common/sanitizer_libc.h"
  22 #include "sanitizer_common/sanitizer_procmaps.h"
  23
  24 #include <sys/time.h>
  25 #include <sys/resource.h>
  26 #include <sys/mman.h>
  27 #include <sys/syscall.h>
  28 #include <sys/types.h>
  29 #include <dlfcn.h>
  30 #include <fcntl.h>
  31 #include <pthread.h>
  32 #include <stdio.h>
  33 #include <unistd.h>
  34 #include <unwind.h>
  35
  36 #if SANITIZER_FREEBSD
  37 #include <sys/link_elf.h>
  38 #endif
  39
  40 #if SANITIZER_ANDROID || SANITIZER_FREEBSD
  41 #include <ucontext.h>
  42 extern "C" void* _DYNAMIC;
  43 #else
  44 #include <sys/ucontext.h>
  45 #include <link.h>
  46 #endif
  47
  48 // x86-64 FreeBSD 9.2 and older define 'ucontext_t' incorrectly in
  49 // 32-bit mode.
  50 #if SANITIZER_FREEBSD && (SANITIZER_WORDSIZE == 32) && \
  51   __FreeBSD_version <= 902001  // v9.2
  52 #define ucontext_t xucontext_t
  53 #endif
  54
  55 typedef enum {
  56   ASAN_RT_VERSION_UNDEFINED = 0,
  57   ASAN_RT_VERSION_DYNAMIC,
  58   ASAN_RT_VERSION_STATIC,
  59 } asan_rt_version_t;
  60
  61 // FIXME: perhaps also store abi version here?
  62 extern "C" {
  63 SANITIZER_INTERFACE_ATTRIBUTE
  64 asan_rt_version_t  __asan_rt_version;
  65 }
  66
  67 namespace __asan {
  68
  69 void InitializePlatformInterceptors() {}
  70
  71 void DisableReexec() {
  72   // No need to re-exec on Linux.
  73 }
  74
  75 void MaybeReexec() {
  76   // No need to re-exec on Linux.
  77 }
  78
  79 void *AsanDoesNotSupportStaticLinkage() {
  80   // This will fail to link with -static.
  81   return &_DYNAMIC;  // defined in link.h
  82 }
  83
  84 #if SANITIZER_ANDROID
  85 // FIXME: should we do anything for Android?
  86 void AsanCheckDynamicRTPrereqs() {}
  87 void AsanCheckIncompatibleRT() {}
  88 #else
  89 static int FindFirstDSOCallback(struct dl_phdr_info *info, size_t size,
  90                                 void *data) {
  91   // Continue until the first dynamic library is found
  92   if (!info->dlpi_name || info->dlpi_name[0] == 0)
  93     return 0;
  94
  95   // Ignore vDSO
  96   if (internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0)
  97     return 0;
  98
  99   *(const char **)data = info->dlpi_name;
 100   return 1;
 101 }
 102
 103 static bool IsDynamicRTName(const char *libname) {
 104   return internal_strstr(libname, "libclang_rt.asan") ||
 105     internal_strstr(libname, "libasan.so");
 106 }
 107
 108 static void ReportIncompatibleRT() {
 109   Report("Your application is linked against incompatible ASan runtimes.\n");
 110   Die();
 111 }
 112
 113 void AsanCheckDynamicRTPrereqs() {
 114   if (!ASAN_DYNAMIC)
 115     return;
 116
 117   // Ensure that dynamic RT is the first DSO in the list
 118   const char *first_dso_name = nullptr;
 119   dl_iterate_phdr(FindFirstDSOCallback, &first_dso_name);
 120   if (first_dso_name && !IsDynamicRTName(first_dso_name)) {
 121     Report("ASan runtime does not come first in initial library list; "
 122            "you should either link runtime to your application or "
 123            "manually preload it with LD_PRELOAD.\n");
 124     Die();
 125   }
 126 }
 127
 128 void AsanCheckIncompatibleRT() {
 129   if (ASAN_DYNAMIC) {
 130     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
 131       __asan_rt_version = ASAN_RT_VERSION_DYNAMIC;
 132     } else if (__asan_rt_version != ASAN_RT_VERSION_DYNAMIC) {
 133       ReportIncompatibleRT();
 134     }
 135   } else {
 136     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
 137       // Ensure that dynamic runtime is not present. We should detect it
 138       // as early as possible, otherwise ASan interceptors could bind to
 139       // the functions in dynamic ASan runtime instead of the functions in
 140       // system libraries, causing crashes later in ASan initialization.
 141       MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 142       char filename[128];
 143       while (proc_maps.Next(nullptr, nullptr, nullptr, filename,
 144                             sizeof(filename), nullptr)) {
 145         if (IsDynamicRTName(filename)) {
 146           Report("Your application is linked against "
 147                  "incompatible ASan runtimes.\n");
 148           Die();
 149         }
 150       }
 151       __asan_rt_version = ASAN_RT_VERSION_STATIC;
 152     } else if (__asan_rt_version != ASAN_RT_VERSION_STATIC) {
 153       ReportIncompatibleRT();
 154     }
 155   }
 156 }
 157 #endif // SANITIZER_ANDROID
 158
 159 #if !SANITIZER_ANDROID
 160 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 161   ucontext_t *ucp = (ucontext_t*)context;
 162   *stack = (uptr)ucp->uc_stack.ss_sp;
 163   *ssize = ucp->uc_stack.ss_size;
 164 }
 165 #else
 166 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 167   UNIMPLEMENTED();
 168 }
 169 #endif
 170
 171 void *AsanDlSymNext(const char *sym) {
 172   return dlsym(RTLD_NEXT, sym);
 173 }
 174
 175 } // namespace __asan
 176
 177 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX