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