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 50namespace __sanitizer { 51 52// This function is defined elsewhere if we intercepted pthread_attr_getstack. 53extern "C" { 54SANITIZER_WEAK_ATTRIBUTE int 55real_pthread_attr_getstack(void *attr, void **addr, size_t *size); 56} // extern "C" 57 58static 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 64SANITIZER_WEAK_ATTRIBUTE int 65real_sigaction(int signum, const void *act, void *oldact); 66 67int 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 73void 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 120bool 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 131bool 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 139bool 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 153static 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 162void 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. 180static atomic_uintptr_t kThreadDescriptorSize; 181 182uptr 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. 220const uptr kThreadSelfOffset = FIRST_32_SECOND_64(8, 16); 221 222uptr ThreadSelfOffset() { 223 return kThreadSelfOffset; 224} 225 226uptr 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 240static 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 254uptr ThreadSelf() { 255 return (uptr)ThreadSelfSegbase()[2]; 256} 257#endif // SANITIZER_FREEBSD 258 259static 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 288uptr 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 298void 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 318void 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 344uptr 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 351typedef 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 358struct DlIteratePhdrData { 359 LoadedModule *modules; 360 uptr current_n; 361 bool first; 362 uptr max_n; 363 string_predicate_t filter; 364}; 365 366static 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 399uptr 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 408uptr indirect_call_wrapper; 409 410void SetIndirectCallWrapper(uptr wrapper) { 411 CHECK(!indirect_call_wrapper); 412 CHECK(wrapper); 413 indirect_call_wrapper = wrapper; 414} 415 416void 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 432