1 //===-- tsan_platform_linux.cpp -------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is a part of ThreadSanitizer (TSan), a race detector.
10 //
11 // Linux- and BSD-specific code.
12 //===----------------------------------------------------------------------===//
13 
14 #include "sanitizer_common/sanitizer_platform.h"
15 #if SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD
16 
17 #include "sanitizer_common/sanitizer_common.h"
18 #include "sanitizer_common/sanitizer_libc.h"
19 #include "sanitizer_common/sanitizer_linux.h"
20 #include "sanitizer_common/sanitizer_platform_limits_netbsd.h"
21 #include "sanitizer_common/sanitizer_platform_limits_posix.h"
22 #include "sanitizer_common/sanitizer_posix.h"
23 #include "sanitizer_common/sanitizer_procmaps.h"
24 #include "sanitizer_common/sanitizer_stackdepot.h"
25 #include "sanitizer_common/sanitizer_stoptheworld.h"
26 #include "tsan_flags.h"
27 #include "tsan_platform.h"
28 #include "tsan_rtl.h"
29 
30 #include <fcntl.h>
31 #include <pthread.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <stdarg.h>
37 #include <sys/mman.h>
38 #if SANITIZER_LINUX
39 #include <sys/personality.h>
40 #include <setjmp.h>
41 #endif
42 #include <sys/syscall.h>
43 #include <sys/socket.h>
44 #include <sys/time.h>
45 #include <sys/types.h>
46 #include <sys/resource.h>
47 #include <sys/stat.h>
48 #include <unistd.h>
49 #include <sched.h>
50 #include <dlfcn.h>
51 #if SANITIZER_LINUX
52 #define __need_res_state
53 #include <resolv.h>
54 #endif
55 
56 #ifdef sa_handler
57 # undef sa_handler
58 #endif
59 
60 #ifdef sa_sigaction
61 # undef sa_sigaction
62 #endif
63 
64 #if SANITIZER_FREEBSD
65 extern "C" void *__libc_stack_end;
66 void *__libc_stack_end = 0;
67 #endif
68 
69 #if SANITIZER_LINUX && defined(__aarch64__) && !SANITIZER_GO
70 # define INIT_LONGJMP_XOR_KEY 1
71 #else
72 # define INIT_LONGJMP_XOR_KEY 0
73 #endif
74 
75 #if INIT_LONGJMP_XOR_KEY
76 #include "interception/interception.h"
77 // Must be declared outside of other namespaces.
78 DECLARE_REAL(int, _setjmp, void *env)
79 #endif
80 
81 namespace __tsan {
82 
83 #if INIT_LONGJMP_XOR_KEY
84 static void InitializeLongjmpXorKey();
85 static uptr longjmp_xor_key;
86 #endif
87 
88 // Runtime detected VMA size.
89 uptr vmaSize;
90 
91 enum {
92   MemTotal  = 0,
93   MemShadow = 1,
94   MemMeta   = 2,
95   MemFile   = 3,
96   MemMmap   = 4,
97   MemTrace  = 5,
98   MemHeap   = 6,
99   MemOther  = 7,
100   MemCount  = 8,
101 };
102 
103 void FillProfileCallback(uptr p, uptr rss, bool file,
104                          uptr *mem, uptr stats_size) {
105   mem[MemTotal] += rss;
106   if (p >= ShadowBeg() && p < ShadowEnd())
107     mem[MemShadow] += rss;
108   else if (p >= MetaShadowBeg() && p < MetaShadowEnd())
109     mem[MemMeta] += rss;
110   else if (p >= LoAppMemBeg() && p < LoAppMemEnd())
111     mem[file ? MemFile : MemMmap] += rss;
112   else if (p >= HiAppMemBeg() && p < HiAppMemEnd())
113     mem[file ? MemFile : MemMmap] += rss;
114   else if (p >= HeapMemBeg() && p < HeapMemEnd())
115     mem[MemHeap] += rss;
116   else if (p >= TraceMemBeg() && p < TraceMemEnd())
117     mem[MemTrace] += rss;
118   else
119     mem[MemOther] += rss;
120 }
121 
122 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
123   uptr mem[MemCount];
124   internal_memset(mem, 0, sizeof(mem[0]) * MemCount);
125   __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
126   StackDepotStats *stacks = StackDepotGetStats();
127   internal_snprintf(buf, buf_size,
128       "RSS %zd MB: shadow:%zd meta:%zd file:%zd mmap:%zd"
129       " trace:%zd heap:%zd other:%zd stacks=%zd[%zd] nthr=%zd/%zd\n",
130       mem[MemTotal] >> 20, mem[MemShadow] >> 20, mem[MemMeta] >> 20,
131       mem[MemFile] >> 20, mem[MemMmap] >> 20, mem[MemTrace] >> 20,
132       mem[MemHeap] >> 20, mem[MemOther] >> 20,
133       stacks->allocated >> 20, stacks->n_uniq_ids,
134       nlive, nthread);
135 }
136 
137 #if SANITIZER_LINUX
138 void FlushShadowMemoryCallback(
139     const SuspendedThreadsList &suspended_threads_list,
140     void *argument) {
141   ReleaseMemoryPagesToOS(ShadowBeg(), ShadowEnd());
142 }
143 #endif
144 
145 void FlushShadowMemory() {
146 #if SANITIZER_LINUX
147   StopTheWorld(FlushShadowMemoryCallback, 0);
148 #endif
149 }
150 
151 #if !SANITIZER_GO
152 // Mark shadow for .rodata sections with the special kShadowRodata marker.
153 // Accesses to .rodata can't race, so this saves time, memory and trace space.
154 static void MapRodata() {
155   // First create temp file.
156   const char *tmpdir = GetEnv("TMPDIR");
157   if (tmpdir == 0)
158     tmpdir = GetEnv("TEST_TMPDIR");
159 #ifdef P_tmpdir
160   if (tmpdir == 0)
161     tmpdir = P_tmpdir;
162 #endif
163   if (tmpdir == 0)
164     return;
165   char name[256];
166   internal_snprintf(name, sizeof(name), "%s/tsan.rodata.%d",
167                     tmpdir, (int)internal_getpid());
168   uptr openrv = internal_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
169   if (internal_iserror(openrv))
170     return;
171   internal_unlink(name);  // Unlink it now, so that we can reuse the buffer.
172   fd_t fd = openrv;
173   // Fill the file with kShadowRodata.
174   const uptr kMarkerSize = 512 * 1024 / sizeof(u64);
175   InternalMmapVector<u64> marker(kMarkerSize);
176   // volatile to prevent insertion of memset
177   for (volatile u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++)
178     *p = kShadowRodata;
179   internal_write(fd, marker.data(), marker.size() * sizeof(u64));
180   // Map the file into memory.
181   uptr page = internal_mmap(0, GetPageSizeCached(), PROT_READ | PROT_WRITE,
182                             MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
183   if (internal_iserror(page)) {
184     internal_close(fd);
185     return;
186   }
187   // Map the file into shadow of .rodata sections.
188   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
189   // Reusing the buffer 'name'.
190   MemoryMappedSegment segment(name, ARRAY_SIZE(name));
191   while (proc_maps.Next(&segment)) {
192     if (segment.filename[0] != 0 && segment.filename[0] != '[' &&
193         segment.IsReadable() && segment.IsExecutable() &&
194         !segment.IsWritable() && IsAppMem(segment.start)) {
195       // Assume it's .rodata
196       char *shadow_start = (char *)MemToShadow(segment.start);
197       char *shadow_end = (char *)MemToShadow(segment.end);
198       for (char *p = shadow_start; p < shadow_end;
199            p += marker.size() * sizeof(u64)) {
200         internal_mmap(p, Min<uptr>(marker.size() * sizeof(u64), shadow_end - p),
201                       PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0);
202       }
203     }
204   }
205   internal_close(fd);
206 }
207 
208 void InitializeShadowMemoryPlatform() {
209   MapRodata();
210 }
211 
212 #endif  // #if !SANITIZER_GO
213 
214 void InitializePlatformEarly() {
215   vmaSize =
216     (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1);
217 #if defined(__aarch64__)
218 # if !SANITIZER_GO
219   if (vmaSize != 39 && vmaSize != 42 && vmaSize != 48) {
220     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
221     Printf("FATAL: Found %zd - Supported 39, 42 and 48\n", vmaSize);
222     Die();
223   }
224 #else
225   if (vmaSize != 48) {
226     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
227     Printf("FATAL: Found %zd - Supported 48\n", vmaSize);
228     Die();
229   }
230 #endif
231 #elif defined(__powerpc64__)
232 # if !SANITIZER_GO
233   if (vmaSize != 44 && vmaSize != 46 && vmaSize != 47) {
234     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
235     Printf("FATAL: Found %zd - Supported 44, 46, and 47\n", vmaSize);
236     Die();
237   }
238 # else
239   if (vmaSize != 46 && vmaSize != 47) {
240     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
241     Printf("FATAL: Found %zd - Supported 46, and 47\n", vmaSize);
242     Die();
243   }
244 # endif
245 #elif defined(__mips64)
246 # if !SANITIZER_GO
247   if (vmaSize != 40) {
248     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
249     Printf("FATAL: Found %zd - Supported 40\n", vmaSize);
250     Die();
251   }
252 # else
253   if (vmaSize != 47) {
254     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
255     Printf("FATAL: Found %zd - Supported 47\n", vmaSize);
256     Die();
257   }
258 # endif
259 #endif
260 }
261 
262 void InitializePlatform() {
263   DisableCoreDumperIfNecessary();
264 
265   // Go maps shadow memory lazily and works fine with limited address space.
266   // Unlimited stack is not a problem as well, because the executable
267   // is not compiled with -pie.
268 #if !SANITIZER_GO
269   {
270     bool reexec = false;
271     // TSan doesn't play well with unlimited stack size (as stack
272     // overlaps with shadow memory). If we detect unlimited stack size,
273     // we re-exec the program with limited stack size as a best effort.
274     if (StackSizeIsUnlimited()) {
275       const uptr kMaxStackSize = 32 * 1024 * 1024;
276       VReport(1, "Program is run with unlimited stack size, which wouldn't "
277                  "work with ThreadSanitizer.\n"
278                  "Re-execing with stack size limited to %zd bytes.\n",
279               kMaxStackSize);
280       SetStackSizeLimitInBytes(kMaxStackSize);
281       reexec = true;
282     }
283 
284     if (!AddressSpaceIsUnlimited()) {
285       Report("WARNING: Program is run with limited virtual address space,"
286              " which wouldn't work with ThreadSanitizer.\n");
287       Report("Re-execing with unlimited virtual address space.\n");
288       SetAddressSpaceUnlimited();
289       reexec = true;
290     }
291 #if SANITIZER_LINUX && defined(__aarch64__)
292     // After patch "arm64: mm: support ARCH_MMAP_RND_BITS." is introduced in
293     // linux kernel, the random gap between stack and mapped area is increased
294     // from 128M to 36G on 39-bit aarch64. As it is almost impossible to cover
295     // this big range, we should disable randomized virtual space on aarch64.
296     int old_personality = personality(0xffffffff);
297     if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
298       VReport(1, "WARNING: Program is run with randomized virtual address "
299               "space, which wouldn't work with ThreadSanitizer.\n"
300               "Re-execing with fixed virtual address space.\n");
301       CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
302       reexec = true;
303     }
304     // Initialize the xor key used in {sig}{set,long}jump.
305     InitializeLongjmpXorKey();
306 #endif
307     if (reexec)
308       ReExec();
309   }
310 
311   CheckAndProtect();
312   InitTlsSize();
313 #endif  // !SANITIZER_GO
314 }
315 
316 #if !SANITIZER_GO
317 // Extract file descriptors passed to glibc internal __res_iclose function.
318 // This is required to properly "close" the fds, because we do not see internal
319 // closes within glibc. The code is a pure hack.
320 int ExtractResolvFDs(void *state, int *fds, int nfd) {
321 #if SANITIZER_LINUX && !SANITIZER_ANDROID
322   int cnt = 0;
323   struct __res_state *statp = (struct __res_state*)state;
324   for (int i = 0; i < MAXNS && cnt < nfd; i++) {
325     if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
326       fds[cnt++] = statp->_u._ext.nssocks[i];
327   }
328   return cnt;
329 #else
330   return 0;
331 #endif
332 }
333 
334 // Extract file descriptors passed via UNIX domain sockets.
335 // This is requried to properly handle "open" of these fds.
336 // see 'man recvmsg' and 'man 3 cmsg'.
337 int ExtractRecvmsgFDs(void *msgp, int *fds, int nfd) {
338   int res = 0;
339   msghdr *msg = (msghdr*)msgp;
340   struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
341   for (; cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
342     if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
343       continue;
344     int n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(fds[0]);
345     for (int i = 0; i < n; i++) {
346       fds[res++] = ((int*)CMSG_DATA(cmsg))[i];
347       if (res == nfd)
348         return res;
349     }
350   }
351   return res;
352 }
353 
354 // Reverse operation of libc stack pointer mangling
355 static uptr UnmangleLongJmpSp(uptr mangled_sp) {
356 #if defined(__x86_64__)
357 # if SANITIZER_LINUX
358   // Reverse of:
359   //   xor  %fs:0x30, %rsi
360   //   rol  $0x11, %rsi
361   uptr sp;
362   asm("ror  $0x11,     %0 \n"
363       "xor  %%fs:0x30, %0 \n"
364       : "=r" (sp)
365       : "0" (mangled_sp));
366   return sp;
367 # else
368   return mangled_sp;
369 # endif
370 #elif defined(__aarch64__)
371 # if SANITIZER_LINUX
372   return mangled_sp ^ longjmp_xor_key;
373 # else
374   return mangled_sp;
375 # endif
376 #elif defined(__powerpc64__)
377   // Reverse of:
378   //   ld   r4, -28696(r13)
379   //   xor  r4, r3, r4
380   uptr xor_key;
381   asm("ld  %0, -28696(%%r13)" : "=r" (xor_key));
382   return mangled_sp ^ xor_key;
383 #elif defined(__mips__)
384   return mangled_sp;
385 #elif defined(__s390x__)
386   // tcbhead_t.stack_guard
387   uptr xor_key = ((uptr *)__builtin_thread_pointer())[5];
388   return mangled_sp ^ xor_key;
389 #else
390   #error "Unknown platform"
391 #endif
392 }
393 
394 #if SANITIZER_NETBSD
395 # ifdef __x86_64__
396 #  define LONG_JMP_SP_ENV_SLOT 6
397 # else
398 #  error unsupported
399 # endif
400 #elif defined(__powerpc__)
401 # define LONG_JMP_SP_ENV_SLOT 0
402 #elif SANITIZER_FREEBSD
403 # define LONG_JMP_SP_ENV_SLOT 2
404 #elif SANITIZER_LINUX
405 # ifdef __aarch64__
406 #  define LONG_JMP_SP_ENV_SLOT 13
407 # elif defined(__mips64)
408 #  define LONG_JMP_SP_ENV_SLOT 1
409 # elif defined(__s390x__)
410 #  define LONG_JMP_SP_ENV_SLOT 9
411 # else
412 #  define LONG_JMP_SP_ENV_SLOT 6
413 # endif
414 #endif
415 
416 uptr ExtractLongJmpSp(uptr *env) {
417   uptr mangled_sp = env[LONG_JMP_SP_ENV_SLOT];
418   return UnmangleLongJmpSp(mangled_sp);
419 }
420 
421 #if INIT_LONGJMP_XOR_KEY
422 // GLIBC mangles the function pointers in jmp_buf (used in {set,long}*jmp
423 // functions) by XORing them with a random key.  For AArch64 it is a global
424 // variable rather than a TCB one (as for x86_64/powerpc).  We obtain the key by
425 // issuing a setjmp and XORing the SP pointer values to derive the key.
426 static void InitializeLongjmpXorKey() {
427   // 1. Call REAL(setjmp), which stores the mangled SP in env.
428   jmp_buf env;
429   REAL(_setjmp)(env);
430 
431   // 2. Retrieve vanilla/mangled SP.
432   uptr sp;
433   asm("mov  %0, sp" : "=r" (sp));
434   uptr mangled_sp = ((uptr *)&env)[LONG_JMP_SP_ENV_SLOT];
435 
436   // 3. xor SPs to obtain key.
437   longjmp_xor_key = mangled_sp ^ sp;
438 }
439 #endif
440 
441 void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
442   // Check that the thr object is in tls;
443   const uptr thr_beg = (uptr)thr;
444   const uptr thr_end = (uptr)thr + sizeof(*thr);
445   CHECK_GE(thr_beg, tls_addr);
446   CHECK_LE(thr_beg, tls_addr + tls_size);
447   CHECK_GE(thr_end, tls_addr);
448   CHECK_LE(thr_end, tls_addr + tls_size);
449   // Since the thr object is huge, skip it.
450   MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr, thr_beg - tls_addr);
451   MemoryRangeImitateWrite(thr, /*pc=*/2, thr_end,
452                           tls_addr + tls_size - thr_end);
453 }
454 
455 // Note: this function runs with async signals enabled,
456 // so it must not touch any tsan state.
457 int call_pthread_cancel_with_cleanup(int (*fn)(void *arg),
458                                      void (*cleanup)(void *arg), void *arg) {
459   // pthread_cleanup_push/pop are hardcore macros mess.
460   // We can't intercept nor call them w/o including pthread.h.
461   int res;
462   pthread_cleanup_push(cleanup, arg);
463   res = fn(arg);
464   pthread_cleanup_pop(0);
465   return res;
466 }
467 #endif  // !SANITIZER_GO
468 
469 #if !SANITIZER_GO
470 void ReplaceSystemMalloc() { }
471 #endif
472 
473 #if !SANITIZER_GO
474 #if SANITIZER_ANDROID
475 // On Android, one thread can call intercepted functions after
476 // DestroyThreadState(), so add a fake thread state for "dead" threads.
477 static ThreadState *dead_thread_state = nullptr;
478 
479 ThreadState *cur_thread() {
480   ThreadState* thr = reinterpret_cast<ThreadState*>(*get_android_tls_ptr());
481   if (thr == nullptr) {
482     __sanitizer_sigset_t emptyset;
483     internal_sigfillset(&emptyset);
484     __sanitizer_sigset_t oldset;
485     CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &emptyset, &oldset));
486     thr = reinterpret_cast<ThreadState*>(*get_android_tls_ptr());
487     if (thr == nullptr) {
488       thr = reinterpret_cast<ThreadState*>(MmapOrDie(sizeof(ThreadState),
489                                                      "ThreadState"));
490       *get_android_tls_ptr() = reinterpret_cast<uptr>(thr);
491       if (dead_thread_state == nullptr) {
492         dead_thread_state = reinterpret_cast<ThreadState*>(
493             MmapOrDie(sizeof(ThreadState), "ThreadState"));
494         dead_thread_state->fast_state.SetIgnoreBit();
495         dead_thread_state->ignore_interceptors = 1;
496         dead_thread_state->is_dead = true;
497         *const_cast<u32*>(&dead_thread_state->tid) = -1;
498         CHECK_EQ(0, internal_mprotect(dead_thread_state, sizeof(ThreadState),
499                                       PROT_READ));
500       }
501     }
502     CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &oldset, nullptr));
503   }
504   return thr;
505 }
506 
507 void set_cur_thread(ThreadState *thr) {
508   *get_android_tls_ptr() = reinterpret_cast<uptr>(thr);
509 }
510 
511 void cur_thread_finalize() {
512   __sanitizer_sigset_t emptyset;
513   internal_sigfillset(&emptyset);
514   __sanitizer_sigset_t oldset;
515   CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &emptyset, &oldset));
516   ThreadState* thr = reinterpret_cast<ThreadState*>(*get_android_tls_ptr());
517   if (thr != dead_thread_state) {
518     *get_android_tls_ptr() = reinterpret_cast<uptr>(dead_thread_state);
519     UnmapOrDie(thr, sizeof(ThreadState));
520   }
521   CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &oldset, nullptr));
522 }
523 #endif  // SANITIZER_ANDROID
524 #endif  // if !SANITIZER_GO
525 
526 }  // namespace __tsan
527 
528 #endif  // SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD
529