libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cc

   1 //===-- sanitizer_linux_libcdep.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 shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries and implements linux-specific functions from
  10 // sanitizer_libc.h.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_platform.h"
  14 #if SANITIZER_FREEBSD || SANITIZER_LINUX
  15
  16 #include "sanitizer_common.h"
  17 #include "sanitizer_flags.h"
  18 #include "sanitizer_freebsd.h"
  19 #include "sanitizer_linux.h"
  20 #include "sanitizer_placement_new.h"
  21 #include "sanitizer_procmaps.h"
  22 #include "sanitizer_stacktrace.h"
  23 #include "sanitizer_atomic.h"
  24 #include "sanitizer_symbolizer.h"
  25
  26 #if SANITIZER_ANDROID || SANITIZER_FREEBSD
  27 #include <dlfcn.h>  // for dlsym()
  28 #endif
  29
  30 #include <pthread.h>
  31 #include <signal.h>
  32 #include <sys/resource.h>
  33
  34 #if SANITIZER_FREEBSD
  35 #include <pthread_np.h>
  36 #include <osreldate.h>
  37 #define pthread_getattr_np pthread_attr_get_np
  38 #endif
  39
  40 #if SANITIZER_LINUX
  41 #include <sys/prctl.h>
  42 #endif
  43
  44 #if !SANITIZER_ANDROID
  45 #include <elf.h>
  46 #include <link.h>
  47 #include <unistd.h>
  48 #endif
  49
  50 namespace __sanitizer {
  51
  52 // This function is defined elsewhere if we intercepted pthread_attr_getstack.
  53 extern "C" {
  54 SANITIZER_WEAK_ATTRIBUTE int
  55 real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
  56 }  // extern "C"
  57
  58 static int my_pthread_attr_getstack(void *attr, void **addr, size_t *size) {
  59   if (real_pthread_attr_getstack)
  60     return real_pthread_attr_getstack((pthread_attr_t *)attr, addr, size);
  61   return pthread_attr_getstack((pthread_attr_t *)attr, addr, size);
  62 }
  63
  64 SANITIZER_WEAK_ATTRIBUTE int
  65 real_sigaction(int signum, const void *act, void *oldact);
  66
  67 int internal_sigaction(int signum, const void *act, void *oldact) {
  68   if (real_sigaction)
  69     return real_sigaction(signum, act, oldact);
  70   return sigaction(signum, (struct sigaction *)act, (struct sigaction *)oldact);
  71 }
  72
  73 void GetThreadStackTopAndBottom(bool at_initialization, uptr *stack_top,
  74                                 uptr *stack_bottom) {
  75   CHECK(stack_top);
  76   CHECK(stack_bottom);
  77   if (at_initialization) {
  78     // This is the main thread. Libpthread may not be initialized yet.
  79     struct rlimit rl;
  80     CHECK_EQ(getrlimit(RLIMIT_STACK, &rl), 0);
  81
  82     // Find the mapping that contains a stack variable.
  83     MemoryMappingLayout proc_maps(/*cache_enabled*/true);
  84     uptr start, end, offset;
  85     uptr prev_end = 0;
  86     while (proc_maps.Next(&start, &end, &offset, 0, 0, /* protection */0)) {
  87       if ((uptr)&rl < end)
  88         break;
  89       prev_end = end;
  90     }
  91     CHECK((uptr)&rl >= start && (uptr)&rl < end);
  92
  93     // Get stacksize from rlimit, but clip it so that it does not overlap
  94     // with other mappings.
  95     uptr stacksize = rl.rlim_cur;
  96     if (stacksize > end - prev_end)
  97       stacksize = end - prev_end;
  98     // When running with unlimited stack size, we still want to set some limit.
  99     // The unlimited stack size is caused by 'ulimit -s unlimited'.
 100     // Also, for some reason, GNU make spawns subprocesses with unlimited stack.
 101     if (stacksize > kMaxThreadStackSize)
 102       stacksize = kMaxThreadStackSize;
 103     *stack_top = end;
 104     *stack_bottom = end - stacksize;
 105     return;
 106   }
 107   pthread_attr_t attr;
 108   pthread_attr_init(&attr);
 109   CHECK_EQ(pthread_getattr_np(pthread_self(), &attr), 0);
 110   uptr stacksize = 0;
 111   void *stackaddr = 0;
 112   my_pthread_attr_getstack(&attr, &stackaddr, (size_t*)&stacksize);
 113   pthread_attr_destroy(&attr);
 114
 115   CHECK_LE(stacksize, kMaxThreadStackSize);  // Sanity check.
 116   *stack_top = (uptr)stackaddr + stacksize;
 117   *stack_bottom = (uptr)stackaddr;
 118 }
 119
 120 bool SetEnv(const char *name, const char *value) {
 121   void *f = dlsym(RTLD_NEXT, "setenv");
 122   if (f == 0)
 123     return false;
 124   typedef int(*setenv_ft)(const char *name, const char *value, int overwrite);
 125   setenv_ft setenv_f;
 126   CHECK_EQ(sizeof(setenv_f), sizeof(f));
 127   internal_memcpy(&setenv_f, &f, sizeof(f));
 128   return IndirectExternCall(setenv_f)(name, value, 1) == 0;
 129 }
 130
 131 bool SanitizerSetThreadName(const char *name) {
 132 #ifdef PR_SET_NAME
 133   return 0 == prctl(PR_SET_NAME, (unsigned long)name, 0, 0, 0);  // NOLINT
 134 #else
 135   return false;
 136 #endif
 137 }
 138
 139 bool SanitizerGetThreadName(char *name, int max_len) {
 140 #ifdef PR_GET_NAME
 141   char buff[17];
 142   if (prctl(PR_GET_NAME, (unsigned long)buff, 0, 0, 0))  // NOLINT
 143     return false;
 144   internal_strncpy(name, buff, max_len);
 145   name[max_len] = 0;
 146   return true;
 147 #else
 148   return false;
 149 #endif
 150 }
 151
 152 #if !SANITIZER_FREEBSD
 153 static uptr g_tls_size;
 154 #endif
 155
 156 #ifdef __i386__
 157 # define DL_INTERNAL_FUNCTION __attribute__((regparm(3), stdcall))
 158 #else
 159 # define DL_INTERNAL_FUNCTION
 160 #endif
 161
 162 void InitTlsSize() {
 163 #if !SANITIZER_FREEBSD && !SANITIZER_ANDROID
 164   typedef void (*get_tls_func)(size_t*, size_t*) DL_INTERNAL_FUNCTION;
 165   get_tls_func get_tls;
 166   void *get_tls_static_info_ptr = dlsym(RTLD_NEXT, "_dl_get_tls_static_info");
 167   CHECK_EQ(sizeof(get_tls), sizeof(get_tls_static_info_ptr));
 168   internal_memcpy(&get_tls, &get_tls_static_info_ptr,
 169                   sizeof(get_tls_static_info_ptr));
 170   CHECK_NE(get_tls, 0);
 171   size_t tls_size = 0;
 172   size_t tls_align = 0;
 173   IndirectExternCall(get_tls)(&tls_size, &tls_align);
 174   g_tls_size = tls_size;
 175 #endif  // !SANITIZER_FREEBSD && !SANITIZER_ANDROID
 176 }
 177
 178 #if (defined(__x86_64__) || defined(__i386__)) && SANITIZER_LINUX
 179 // sizeof(struct thread) from glibc.
 180 static atomic_uintptr_t kThreadDescriptorSize;
 181
 182 uptr ThreadDescriptorSize() {
 183   uptr val = atomic_load(&kThreadDescriptorSize, memory_order_relaxed);
 184   if (val)
 185     return val;
 186 #ifdef _CS_GNU_LIBC_VERSION
 187   char buf[64];
 188   uptr len = confstr(_CS_GNU_LIBC_VERSION, buf, sizeof(buf));
 189   if (len < sizeof(buf) && internal_strncmp(buf, "glibc 2.", 8) == 0) {
 190     char *end;
 191     int minor = internal_simple_strtoll(buf + 8, &end, 10);
 192     if (end != buf + 8 && (*end == '\0' || *end == '.')) {
 193       /* sizeof(struct thread) values from various glibc versions.  */
 194       if (SANITIZER_X32)
 195         val = 1728;  // Assume only one particular version for x32.
 196       else if (minor <= 3)
 197         val = FIRST_32_SECOND_64(1104, 1696);
 198       else if (minor == 4)
 199         val = FIRST_32_SECOND_64(1120, 1728);
 200       else if (minor == 5)
 201         val = FIRST_32_SECOND_64(1136, 1728);
 202       else if (minor <= 9)
 203         val = FIRST_32_SECOND_64(1136, 1712);
 204       else if (minor == 10)
 205         val = FIRST_32_SECOND_64(1168, 1776);
 206       else if (minor <= 12)
 207         val = FIRST_32_SECOND_64(1168, 2288);
 208       else
 209         val = FIRST_32_SECOND_64(1216, 2304);
 210     }
 211     if (val)
 212       atomic_store(&kThreadDescriptorSize, val, memory_order_relaxed);
 213     return val;
 214   }
 215 #endif
 216   return 0;
 217 }
 218
 219 // The offset at which pointer to self is located in the thread descriptor.
 220 const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16);
 221
 222 uptr ThreadSelfOffset() {
 223   return kThreadSelfOffset;
 224 }
 225
 226 uptr ThreadSelf() {
 227   uptr descr_addr;
 228 # if defined(__i386__)
 229   asm("mov %%gs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
 230 # elif defined(__x86_64__)
 231   asm("mov %%fs:%c1,%0" : "=r"(descr_addr) : "i"(kThreadSelfOffset));
 232 # else
 233 #  error "unsupported CPU arch"
 234 # endif
 235   return descr_addr;
 236 }
 237 #endif  // (defined(__x86_64__) || defined(__i386__)) && SANITIZER_LINUX
 238
 239 #if SANITIZER_FREEBSD
 240 static void **ThreadSelfSegbase() {
 241   void **segbase = 0;
 242 # if defined(__i386__)
 243   // sysarch(I386_GET_GSBASE, segbase);
 244   __asm __volatile("mov %%gs:0, %0" : "=r" (segbase));
 245 # elif defined(__x86_64__)
 246   // sysarch(AMD64_GET_FSBASE, segbase);
 247   __asm __volatile("movq %%fs:0, %0" : "=r" (segbase));
 248 # else
 249 #  error "unsupported CPU arch for FreeBSD platform"
 250 # endif
 251   return segbase;
 252 }
 253
 254 uptr ThreadSelf() {
 255   return (uptr)ThreadSelfSegbase()[2];
 256 }
 257 #endif  // SANITIZER_FREEBSD
 258
 259 static void GetTls(uptr *addr, uptr *size) {
 260 #if SANITIZER_LINUX
 261 # if defined(__x86_64__) || defined(__i386__)
 262   *addr = ThreadSelf();
 263   *size = GetTlsSize();
 264   *addr -= *size;
 265   *addr += ThreadDescriptorSize();
 266 # else
 267   *addr = 0;
 268   *size = 0;
 269 # endif
 270 #elif SANITIZER_FREEBSD
 271   void** segbase = ThreadSelfSegbase();
 272   *addr = 0;
 273   *size = 0;
 274   if (segbase != 0) {
 275     // tcbalign = 16
 276     // tls_size = round(tls_static_space, tcbalign);
 277     // dtv = segbase[1];
 278     // dtv[2] = segbase - tls_static_space;
 279     void **dtv = (void**) segbase[1];
 280     *addr = (uptr) dtv[2];
 281     *size = (*addr == 0) ? 0 : ((uptr) segbase[0] - (uptr) dtv[2]);
 282   }
 283 #else
 284 # error "Unknown OS"
 285 #endif
 286 }
 287
 288 uptr GetTlsSize() {
 289 #if SANITIZER_FREEBSD
 290   uptr addr, size;
 291   GetTls(&addr, &size);
 292   return size;
 293 #else
 294   return g_tls_size;
 295 #endif
 296 }
 297
 298 void GetThreadStackAndTls(bool main, uptr *stk_addr, uptr *stk_size,
 299                           uptr *tls_addr, uptr *tls_size) {
 300   GetTls(tls_addr, tls_size);
 301
 302   uptr stack_top, stack_bottom;
 303   GetThreadStackTopAndBottom(main, &stack_top, &stack_bottom);
 304   *stk_addr = stack_bottom;
 305   *stk_size = stack_top - stack_bottom;
 306
 307   if (!main) {
 308     // If stack and tls intersect, make them non-intersecting.
 309     if (*tls_addr > *stk_addr && *tls_addr < *stk_addr + *stk_size) {
 310       CHECK_GT(*tls_addr + *tls_size, *stk_addr);
 311       CHECK_LE(*tls_addr + *tls_size, *stk_addr + *stk_size);
 312       *stk_size -= *tls_size;
 313       *tls_addr = *stk_addr + *stk_size;
 314     }
 315   }
 316 }
 317
 318 void AdjustStackSize(void *attr_) {
 319   pthread_attr_t *attr = (pthread_attr_t *)attr_;
 320   uptr stackaddr = 0;
 321   size_t stacksize = 0;
 322   my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
 323   // GLibC will return (0 - stacksize) as the stack address in the case when
 324   // stacksize is set, but stackaddr is not.
 325   bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
 326   // We place a lot of tool data into TLS, account for that.
 327   const uptr minstacksize = GetTlsSize() + 128*1024;
 328   if (stacksize < minstacksize) {
 329     if (!stack_set) {
 330       if (stacksize != 0) {
 331         VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
 332                 minstacksize);
 333         pthread_attr_setstacksize(attr, minstacksize);
 334       }
 335     } else {
 336       Printf("Sanitizer: pre-allocated stack size is insufficient: "
 337              "%zu < %zu\n", stacksize, minstacksize);
 338       Printf("Sanitizer: pthread_create is likely to fail.\n");
 339     }
 340   }
 341 }
 342
 343 #if SANITIZER_ANDROID
 344 uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
 345                       string_predicate_t filter) {
 346   MemoryMappingLayout memory_mapping(false);
 347   return memory_mapping.DumpListOfModules(modules, max_modules, filter);
 348 }
 349 #else  // SANITIZER_ANDROID
 350 # if !SANITIZER_FREEBSD
 351 typedef ElfW(Phdr) Elf_Phdr;
 352 # elif SANITIZER_WORDSIZE == 32 && __FreeBSD_version <= 902001  // v9.2
 353 #  define Elf_Phdr XElf32_Phdr
 354 #  define dl_phdr_info xdl_phdr_info
 355 #  define dl_iterate_phdr(c, b) xdl_iterate_phdr((c), (b))
 356 # endif
 357
 358 struct DlIteratePhdrData {
 359   LoadedModule *modules;
 360   uptr current_n;
 361   bool first;
 362   uptr max_n;
 363   string_predicate_t filter;
 364 };
 365
 366 static int dl_iterate_phdr_cb(dl_phdr_info *info, size_t size, void *arg) {
 367   DlIteratePhdrData *data = (DlIteratePhdrData*)arg;
 368   if (data->current_n == data->max_n)
 369     return 0;
 370   InternalScopedBuffer<char> module_name(kMaxPathLength);
 371   module_name.data()[0] = '\0';
 372   if (data->first) {
 373     data->first = false;
 374     // First module is the binary itself.
 375     ReadBinaryName(module_name.data(), module_name.size());
 376   } else if (info->dlpi_name) {
 377     internal_strncpy(module_name.data(), info->dlpi_name, module_name.size());
 378   }
 379   if (module_name.data()[0] == '\0')
 380     return 0;
 381   if (data->filter && !data->filter(module_name.data()))
 382     return 0;
 383   void *mem = &data->modules[data->current_n];
 384   LoadedModule *cur_module = new(mem) LoadedModule(module_name.data(),
 385                                                    info->dlpi_addr);
 386   data->current_n++;
 387   for (int i = 0; i < info->dlpi_phnum; i++) {
 388     const Elf_Phdr *phdr = &info->dlpi_phdr[i];
 389     if (phdr->p_type == PT_LOAD) {
 390       uptr cur_beg = info->dlpi_addr + phdr->p_vaddr;
 391       uptr cur_end = cur_beg + phdr->p_memsz;
 392       bool executable = phdr->p_flags & PF_X;
 393       cur_module->addAddressRange(cur_beg, cur_end, executable);
 394     }
 395   }
 396   return 0;
 397 }
 398
 399 uptr GetListOfModules(LoadedModule *modules, uptr max_modules,
 400                       string_predicate_t filter) {
 401   CHECK(modules);
 402   DlIteratePhdrData data = {modules, 0, true, max_modules, filter};
 403   dl_iterate_phdr(dl_iterate_phdr_cb, &data);
 404   return data.current_n;
 405 }
 406 #endif  // SANITIZER_ANDROID
 407
 408 uptr indirect_call_wrapper;
 409
 410 void SetIndirectCallWrapper(uptr wrapper) {
 411   CHECK(!indirect_call_wrapper);
 412   CHECK(wrapper);
 413   indirect_call_wrapper = wrapper;
 414 }
 415
 416 void PrepareForSandboxing(__sanitizer_sandbox_arguments *args) {
 417   // Some kinds of sandboxes may forbid filesystem access, so we won't be able
 418   // to read the file mappings from /proc/self/maps. Luckily, neither the
 419   // process will be able to load additional libraries, so it's fine to use the
 420   // cached mappings.
 421   MemoryMappingLayout::CacheMemoryMappings();
 422   // Same for /proc/self/exe in the symbolizer.
 423 #if !SANITIZER_GO
 424   Symbolizer::GetOrInit()->PrepareForSandboxing();
 425   CovPrepareForSandboxing(args);
 426 #endif
 427 }
 428
 429 }  // namespace __sanitizer
 430
 431 #endif  // SANITIZER_FREEBSD || SANITIZER_LINUX