src/libcompiler_builtins/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 || SANITIZER_NETBSD || \
  17     SANITIZER_SOLARIS
  18
  19 #include "asan_interceptors.h"
  20 #include "asan_internal.h"
  21 #include "asan_premap_shadow.h"
  22 #include "asan_thread.h"
  23 #include "sanitizer_common/sanitizer_flags.h"
  24 #include "sanitizer_common/sanitizer_freebsd.h"
  25 #include "sanitizer_common/sanitizer_libc.h"
  26 #include "sanitizer_common/sanitizer_procmaps.h"
  27
  28 #include <sys/time.h>
  29 #include <sys/resource.h>
  30 #include <sys/mman.h>
  31 #include <sys/syscall.h>
  32 #include <sys/types.h>
  33 #include <dlfcn.h>
  34 #include <fcntl.h>
  35 #include <pthread.h>
  36 #include <stdio.h>
  37 #include <unistd.h>
  38 #include <unwind.h>
  39
  40 #if SANITIZER_FREEBSD
  41 #include <sys/link_elf.h>
  42 #endif
  43
  44 #if SANITIZER_SOLARIS
  45 #include <link.h>
  46 #endif
  47
  48 #if SANITIZER_ANDROID || SANITIZER_FREEBSD || SANITIZER_SOLARIS
  49 #include <ucontext.h>
  50 extern "C" void* _DYNAMIC;
  51 #elif SANITIZER_NETBSD
  52 #include <link_elf.h>
  53 #include <ucontext.h>
  54 extern Elf_Dyn _DYNAMIC;
  55 #else
  56 #include <sys/ucontext.h>
  57 #include <link.h>
  58 #endif
  59
  60 // x86-64 FreeBSD 9.2 and older define 'ucontext_t' incorrectly in
  61 // 32-bit mode.
  62 #if SANITIZER_FREEBSD && (SANITIZER_WORDSIZE == 32) && \
  63   __FreeBSD_version <= 902001  // v9.2
  64 #define ucontext_t xucontext_t
  65 #endif
  66
  67 typedef enum {
  68   ASAN_RT_VERSION_UNDEFINED = 0,
  69   ASAN_RT_VERSION_DYNAMIC,
  70   ASAN_RT_VERSION_STATIC,
  71 } asan_rt_version_t;
  72
  73 // FIXME: perhaps also store abi version here?
  74 extern "C" {
  75 SANITIZER_INTERFACE_ATTRIBUTE
  76 asan_rt_version_t  __asan_rt_version;
  77 }
  78
  79 namespace __asan {
  80
  81 void InitializePlatformInterceptors() {}
  82 void InitializePlatformExceptionHandlers() {}
  83 bool IsSystemHeapAddress (uptr addr) { return false; }
  84
  85 void *AsanDoesNotSupportStaticLinkage() {
  86   // This will fail to link with -static.
  87   return &_DYNAMIC;  // defined in link.h
  88 }
  89
  90 static void UnmapFromTo(uptr from, uptr to) {
  91   CHECK(to >= from);
  92   if (to == from) return;
  93   uptr res = internal_munmap(reinterpret_cast<void *>(from), to - from);
  94   if (UNLIKELY(internal_iserror(res))) {
  95     Report(
  96         "ERROR: AddresSanitizer failed to unmap 0x%zx (%zd) bytes at address "
  97         "%p\n",
  98         to - from, to - from, from);
  99     CHECK("unable to unmap" && 0);
 100   }
 101 }
 102
 103 #if ASAN_PREMAP_SHADOW
 104 uptr FindPremappedShadowStart() {
 105   uptr granularity = GetMmapGranularity();
 106   uptr shadow_start = reinterpret_cast<uptr>(&__asan_shadow);
 107   uptr premap_shadow_size = PremapShadowSize();
 108   uptr shadow_size = RoundUpTo(kHighShadowEnd, granularity);
 109   // We may have mapped too much. Release extra memory.
 110   UnmapFromTo(shadow_start + shadow_size, shadow_start + premap_shadow_size);
 111   return shadow_start;
 112 }
 113 #endif
 114
 115 uptr FindDynamicShadowStart() {
 116 #if ASAN_PREMAP_SHADOW
 117   if (!PremapShadowFailed())
 118     return FindPremappedShadowStart();
 119 #endif
 120
 121   uptr granularity = GetMmapGranularity();
 122   uptr alignment = granularity * 8;
 123   uptr left_padding = granularity;
 124   uptr shadow_size = RoundUpTo(kHighShadowEnd, granularity);
 125   uptr map_size = shadow_size + left_padding + alignment;
 126
 127   uptr map_start = (uptr)MmapNoAccess(map_size);
 128   CHECK_NE(map_start, ~(uptr)0);
 129
 130   uptr shadow_start = RoundUpTo(map_start + left_padding, alignment);
 131   UnmapFromTo(map_start, shadow_start - left_padding);
 132   UnmapFromTo(shadow_start + shadow_size, map_start + map_size);
 133
 134   return shadow_start;
 135 }
 136
 137 void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
 138   UNIMPLEMENTED();
 139 }
 140
 141 #if SANITIZER_ANDROID
 142 // FIXME: should we do anything for Android?
 143 void AsanCheckDynamicRTPrereqs() {}
 144 void AsanCheckIncompatibleRT() {}
 145 #else
 146 static int FindFirstDSOCallback(struct dl_phdr_info *info, size_t size,
 147                                 void *data) {
 148   VReport(2, "info->dlpi_name = %s\tinfo->dlpi_addr = %p\n",
 149           info->dlpi_name, info->dlpi_addr);
 150
 151   // Continue until the first dynamic library is found
 152   if (!info->dlpi_name || info->dlpi_name[0] == 0)
 153     return 0;
 154
 155   // Ignore vDSO
 156   if (internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0)
 157     return 0;
 158
 159 #if SANITIZER_FREEBSD || SANITIZER_NETBSD
 160   // Ignore first entry (the main program)
 161   char **p = (char **)data;
 162   if (!(*p)) {
 163     *p = (char *)-1;
 164     return 0;
 165   }
 166 #endif
 167
 168 #if SANITIZER_SOLARIS
 169   // Ignore executable on Solaris
 170   if (info->dlpi_addr == 0)
 171     return 0;
 172 #endif
 173
 174   *(const char **)data = info->dlpi_name;
 175   return 1;
 176 }
 177
 178 static bool IsDynamicRTName(const char *libname) {
 179   return internal_strstr(libname, "libclang_rt.asan") ||
 180     internal_strstr(libname, "libasan.so");
 181 }
 182
 183 static void ReportIncompatibleRT() {
 184   Report("Your application is linked against incompatible ASan runtimes.\n");
 185   Die();
 186 }
 187
 188 void AsanCheckDynamicRTPrereqs() {
 189   if (!ASAN_DYNAMIC || !flags()->verify_asan_link_order)
 190     return;
 191
 192   // Ensure that dynamic RT is the first DSO in the list
 193   const char *first_dso_name = nullptr;
 194   dl_iterate_phdr(FindFirstDSOCallback, &first_dso_name);
 195   if (first_dso_name && !IsDynamicRTName(first_dso_name)) {
 196     Report("ASan runtime does not come first in initial library list; "
 197            "you should either link runtime to your application or "
 198            "manually preload it with LD_PRELOAD.\n");
 199     Die();
 200   }
 201 }
 202
 203 void AsanCheckIncompatibleRT() {
 204   if (ASAN_DYNAMIC) {
 205     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
 206       __asan_rt_version = ASAN_RT_VERSION_DYNAMIC;
 207     } else if (__asan_rt_version != ASAN_RT_VERSION_DYNAMIC) {
 208       ReportIncompatibleRT();
 209     }
 210   } else {
 211     if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) {
 212       // Ensure that dynamic runtime is not present. We should detect it
 213       // as early as possible, otherwise ASan interceptors could bind to
 214       // the functions in dynamic ASan runtime instead of the functions in
 215       // system libraries, causing crashes later in ASan initialization.
 216       MemoryMappingLayout proc_maps(/*cache_enabled*/true);
 217       char filename[128];
 218       MemoryMappedSegment segment(filename, sizeof(filename));
 219       while (proc_maps.Next(&segment)) {
 220         if (IsDynamicRTName(segment.filename)) {
 221           Report("Your application is linked against "
 222                  "incompatible ASan runtimes.\n");
 223           Die();
 224         }
 225       }
 226       __asan_rt_version = ASAN_RT_VERSION_STATIC;
 227     } else if (__asan_rt_version != ASAN_RT_VERSION_STATIC) {
 228       ReportIncompatibleRT();
 229     }
 230   }
 231 }
 232 #endif // SANITIZER_ANDROID
 233
 234 #if !SANITIZER_ANDROID
 235 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 236   ucontext_t *ucp = (ucontext_t*)context;
 237   *stack = (uptr)ucp->uc_stack.ss_sp;
 238   *ssize = ucp->uc_stack.ss_size;
 239 }
 240 #else
 241 void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
 242   UNIMPLEMENTED();
 243 }
 244 #endif
 245
 246 void *AsanDlSymNext(const char *sym) {
 247   return dlsym(RTLD_NEXT, sym);
 248 }
 249
 250 } // namespace __asan
 251
 252 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD ||
 253         // SANITIZER_SOLARIS