src/compiler-rt/lib/asan/asan_linux.cc

   1 //===-- asan_linux.cc -----------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is a part of AddressSanitizer, an address sanity checker.
  11 //
  12 // Linux-specific details.
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "sanitizer_common/sanitizer_platform.h"
  16 #if SANITIZER_FREEBSD || SANITIZER_LINUX
  17
  18 #include "asan_interceptors.h"
  19 #include "asan_internal.h"
  20 #include "asan_thread.h"
  21 #include "sanitizer_common/sanitizer_flags.h"
  22 #include "sanitizer_common/sanitizer_freebsd.h"
  23 #include "sanitizer_common/sanitizer_libc.h"
  24 #include "sanitizer_common/sanitizer_procmaps.h"
  25
  26 #include <sys/time.h>
  27 #include <sys/resource.h>
  28 #include <sys/mman.h>
  29 #include <sys/syscall.h>
  30 #include <sys/types.h>
  31 #include <dlfcn.h>
  32 #include <fcntl.h>
  33 #include <pthread.h>
  34 #include <stdio.h>
  35 #include <unistd.h>
  36 #include <unwind.h>
  37
  38 #if SANITIZER_FREEBSD
  39 #include <sys/link_elf.h>
  40 #endif
  41
  42 #if SANITIZER_ANDROID || SANITIZER_FREEBSD
  43 #include <ucontext.h>
  44 extern "C" void* _DYNAMIC;
  45 #else
  46 #include <sys/ucontext.h>
  47 #include <link.h>
  48 #endif
  49
  50 // x86-64 FreeBSD 9.2 and older define 'ucontext_t' incorrectly in
  51 // 32-bit mode.
  52 #if SANITIZER_FREEBSD && (SANITIZER_WORDSIZE == 32) && \
  53   __FreeBSD_version <= 902001  // v9.2
  54 #define ucontext_t xucontext_t
  55 #endif
  56
  57 typedef enum {
  58   ASAN_RT_VERSION_UNDEFINED = 0,
  59   ASAN_RT_VERSION_DYNAMIC,
  60   ASAN_RT_VERSION_STATIC,
  61 } asan_rt_version_t;
  62
  63 // FIXME: perhaps also store abi version here?
  64 extern "C" {
  65 SANITIZER_INTERFACE_ATTRIBUTE
  66 asan_rt_version_t  __asan_rt_version;
  67 }
  68
  69 namespace __asan {
  70
  71 void InitializePlatformInterceptors() {}
  72 void InitializePlatformExceptionHandlers() {}
  73
  74 void *AsanDoesNotSupportStaticLinkage() {
  75   // This will fail to link with -static.
  76   return &_DYNAMIC;  // defined in link.h
  77 }
  78
  79 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
  80   UNIMPLEMENTED();
  81 }
  82
  83 #if SANITIZER_ANDROID
  84 // FIXME: should we do anything for Android?
  85 void AsanCheckDynamicRTPrereqs() {}
  86 void AsanCheckIncompatibleRT() {}
  87 #else
  88 static int FindFirstDSOCallback(struct dl_phdr_info *info, size_t size,
  89                                 void *data) {
  90   // Continue until the first dynamic library is found
  91   if (!info->dlpi_name || info->dlpi_name[0] == 0)
  92     return 0;
  93
  94   // Ignore vDSO
  95   if (internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0)
  96     return 0;
  97
  98   *(const char **)data = info->dlpi_name;
  99   return 1;
 100 }
 101
 102 static bool IsDynamicRTName(const char *libname) {
 103   return internal_strstr(libname, "libclang_rt.asan") ||
 104     internal_strstr(libname, "libasan.so");
 105 }
 106
 107 static void ReportIncompatibleRT() {
 108   Report("Your application is linked against incompatible ASan runtimes.\n");
 109   Die();
 110 }
 111
 112 void AsanCheckDynamicRTPrereqs() {
 113   if (!ASAN_DYNAMIC)
 114     return;
 115
 116   // Ensure that dynamic RT is the first DSO in the list
 117   const char *first_dso_name = nullptr;
 118   dl_iterate_phdr(FindFirstDSOCallback, &first_dso_name);
 119   if (first_dso_name && !IsDynamicRTName(first_dso_name)) {
 120     Report("ASan runtime does not come first in initial library list; "
 121            "you should either link runtime to your application or "
 122            "manually preload it with LD_PRELOAD.\n");
 123     Die();
 124   }
 125 }
 126
 127 void AsanCheckIncompatibleRT() {
 128   if (ASAN_DYNAMIC) {
 129     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
 130       __asan_rt_version = ASAN_RT_VERSION_DYNAMIC;
 131     } else if (__asan_rt_version != ASAN_RT_VERSION_DYNAMIC) {
 132       ReportIncompatibleRT();
 133     }
 134   } else {
 135     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
 136       // Ensure that dynamic runtime is not present. We should detect it
 137       // as early as possible, otherwise ASan interceptors could bind to
 138       // the functions in dynamic ASan runtime instead of the functions in
 139       // system libraries, causing crashes later in ASan initialization.
 140       MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 141       char filename[128];
 142       while (proc_maps.Next(nullptr, nullptr, nullptr, filename,
 143                             sizeof(filename), nullptr)) {
 144         if (IsDynamicRTName(filename)) {
 145           Report("Your application is linked against "
 146                  "incompatible ASan runtimes.\n");
 147           Die();
 148         }
 149       }
 150       __asan_rt_version = ASAN_RT_VERSION_STATIC;
 151     } else if (__asan_rt_version != ASAN_RT_VERSION_STATIC) {
 152       ReportIncompatibleRT();
 153     }
 154   }
 155 }
 156 #endif // SANITIZER_ANDROID
 157
 158 #if !SANITIZER_ANDROID
 159 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 160   ucontext_t *ucp = (ucontext_t*)context;
 161   *stack = (uptr)ucp->uc_stack.ss_sp;
 162   *ssize = ucp->uc_stack.ss_size;
 163 }
 164 #else
 165 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 166   UNIMPLEMENTED();
 167 }
 168 #endif
 169
 170 void *AsanDlSymNext(const char *sym) {
 171   return dlsym(RTLD_NEXT, sym);
 172 }
 173
 174 } // namespace __asan
 175
 176 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX