1 //===-- sanitizer_posix.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 shared between AddressSanitizer and ThreadSanitizer
10 // run-time libraries and implements POSIX-specific functions from
11 // sanitizer_posix.h.
12 //===----------------------------------------------------------------------===//
13 
14 #include "sanitizer_platform.h"
15 
16 #if SANITIZER_POSIX
17 
18 #include "sanitizer_common.h"
19 #include "sanitizer_file.h"
20 #include "sanitizer_flags.h"
21 #include "sanitizer_libc.h"
22 #include "sanitizer_posix.h"
23 #include "sanitizer_procmaps.h"
24 
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <signal.h>
28 #include <sys/mman.h>
29 
30 #if SANITIZER_FREEBSD
31 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
32 // that, it was never implemented.  So just define it to zero.
33 #undef  MAP_NORESERVE
34 #define MAP_NORESERVE 0
35 #endif
36 
37 namespace __sanitizer {
38 
39 // ------------- sanitizer_common.h
40 uptr GetMmapGranularity() {
41   return GetPageSize();
42 }
43 
44 bool ErrorIsOOM(error_t err) { return err == ENOMEM; }
45 
46 void *MmapOrDie(uptr size, const char *mem_type, bool raw_report) {
47   size = RoundUpTo(size, GetPageSizeCached());
48   uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
49                        MAP_PRIVATE | MAP_ANON, mem_type);
50   int reserrno;
51   if (UNLIKELY(internal_iserror(res, &reserrno)))
52     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno, raw_report);
53   IncreaseTotalMmap(size);
54   return (void *)res;
55 }
56 
57 void UnmapOrDie(void *addr, uptr size) {
58   if (!addr || !size) return;
59   uptr res = internal_munmap(addr, size);
60   if (UNLIKELY(internal_iserror(res))) {
61     Report("ERROR: %s failed to deallocate 0x%zx (%zd) bytes at address %p\n",
62            SanitizerToolName, size, size, addr);
63     CHECK("unable to unmap" && 0);
64   }
65   DecreaseTotalMmap(size);
66 }
67 
68 void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
69   size = RoundUpTo(size, GetPageSizeCached());
70   uptr res = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
71                        MAP_PRIVATE | MAP_ANON, mem_type);
72   int reserrno;
73   if (UNLIKELY(internal_iserror(res, &reserrno))) {
74     if (reserrno == ENOMEM)
75       return nullptr;
76     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
77   }
78   IncreaseTotalMmap(size);
79   return (void *)res;
80 }
81 
82 // We want to map a chunk of address space aligned to 'alignment'.
83 // We do it by mapping a bit more and then unmapping redundant pieces.
84 // We probably can do it with fewer syscalls in some OS-dependent way.
85 void *MmapAlignedOrDieOnFatalError(uptr size, uptr alignment,
86                                    const char *mem_type) {
87   CHECK(IsPowerOfTwo(size));
88   CHECK(IsPowerOfTwo(alignment));
89   uptr map_size = size + alignment;
90   uptr map_res = (uptr)MmapOrDieOnFatalError(map_size, mem_type);
91   if (UNLIKELY(!map_res))
92     return nullptr;
93   uptr map_end = map_res + map_size;
94   uptr res = map_res;
95   if (!IsAligned(res, alignment)) {
96     res = (map_res + alignment - 1) & ~(alignment - 1);
97     UnmapOrDie((void*)map_res, res - map_res);
98   }
99   uptr end = res + size;
100   end = RoundUpTo(end, GetPageSizeCached());
101   if (end != map_end)
102     UnmapOrDie((void*)end, map_end - end);
103   return (void*)res;
104 }
105 
106 void *MmapNoReserveOrDie(uptr size, const char *mem_type) {
107   size = RoundUpTo(size, GetPageSizeCached());
108   uptr p = MmapNamed(nullptr, size, PROT_READ | PROT_WRITE,
109                      MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, mem_type);
110   int reserrno;
111   if (UNLIKELY(internal_iserror(p, &reserrno)))
112     ReportMmapFailureAndDie(size, mem_type, "allocate noreserve", reserrno);
113   IncreaseTotalMmap(size);
114   return (void *)p;
115 }
116 
117 static void *MmapFixedImpl(uptr fixed_addr, uptr size, bool tolerate_enomem,
118                            const char *name) {
119   size = RoundUpTo(size, GetPageSizeCached());
120   fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
121   uptr p = MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
122                      MAP_PRIVATE | MAP_ANON | MAP_FIXED, name);
123   int reserrno;
124   if (UNLIKELY(internal_iserror(p, &reserrno))) {
125     if (tolerate_enomem && reserrno == ENOMEM)
126       return nullptr;
127     char mem_type[40];
128     internal_snprintf(mem_type, sizeof(mem_type), "memory at address 0x%zx",
129                       fixed_addr);
130     ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
131   }
132   IncreaseTotalMmap(size);
133   return (void *)p;
134 }
135 
136 void *MmapFixedOrDie(uptr fixed_addr, uptr size, const char *name) {
137   return MmapFixedImpl(fixed_addr, size, false /*tolerate_enomem*/, name);
138 }
139 
140 void *MmapFixedOrDieOnFatalError(uptr fixed_addr, uptr size, const char *name) {
141   return MmapFixedImpl(fixed_addr, size, true /*tolerate_enomem*/, name);
142 }
143 
144 bool MprotectNoAccess(uptr addr, uptr size) {
145   return 0 == internal_mprotect((void*)addr, size, PROT_NONE);
146 }
147 
148 bool MprotectReadOnly(uptr addr, uptr size) {
149   return 0 == internal_mprotect((void *)addr, size, PROT_READ);
150 }
151 
152 #if !SANITIZER_APPLE
153 void MprotectMallocZones(void *addr, int prot) {}
154 #endif
155 
156 fd_t OpenFile(const char *filename, FileAccessMode mode, error_t *errno_p) {
157   if (ShouldMockFailureToOpen(filename))
158     return kInvalidFd;
159   int flags;
160   switch (mode) {
161     case RdOnly: flags = O_RDONLY; break;
162     case WrOnly: flags = O_WRONLY | O_CREAT | O_TRUNC; break;
163     case RdWr: flags = O_RDWR | O_CREAT; break;
164   }
165   fd_t res = internal_open(filename, flags, 0660);
166   if (internal_iserror(res, errno_p))
167     return kInvalidFd;
168   return ReserveStandardFds(res);
169 }
170 
171 void CloseFile(fd_t fd) {
172   internal_close(fd);
173 }
174 
175 bool ReadFromFile(fd_t fd, void *buff, uptr buff_size, uptr *bytes_read,
176                   error_t *error_p) {
177   uptr res = internal_read(fd, buff, buff_size);
178   if (internal_iserror(res, error_p))
179     return false;
180   if (bytes_read)
181     *bytes_read = res;
182   return true;
183 }
184 
185 bool WriteToFile(fd_t fd, const void *buff, uptr buff_size, uptr *bytes_written,
186                  error_t *error_p) {
187   uptr res = internal_write(fd, buff, buff_size);
188   if (internal_iserror(res, error_p))
189     return false;
190   if (bytes_written)
191     *bytes_written = res;
192   return true;
193 }
194 
195 void *MapFileToMemory(const char *file_name, uptr *buff_size) {
196   fd_t fd = OpenFile(file_name, RdOnly);
197   CHECK(fd != kInvalidFd);
198   uptr fsize = internal_filesize(fd);
199   CHECK_NE(fsize, (uptr)-1);
200   CHECK_GT(fsize, 0);
201   *buff_size = RoundUpTo(fsize, GetPageSizeCached());
202   uptr map = internal_mmap(nullptr, *buff_size, PROT_READ, MAP_PRIVATE, fd, 0);
203   return internal_iserror(map) ? nullptr : (void *)map;
204 }
205 
206 void *MapWritableFileToMemory(void *addr, uptr size, fd_t fd, OFF_T offset) {
207   uptr flags = MAP_SHARED;
208   if (addr) flags |= MAP_FIXED;
209   uptr p = internal_mmap(addr, size, PROT_READ | PROT_WRITE, flags, fd, offset);
210   int mmap_errno = 0;
211   if (internal_iserror(p, &mmap_errno)) {
212     Printf("could not map writable file (%d, %lld, %zu): %zd, errno: %d\n",
213            fd, (long long)offset, size, p, mmap_errno);
214     return nullptr;
215   }
216   return (void *)p;
217 }
218 
219 static inline bool IntervalsAreSeparate(uptr start1, uptr end1,
220                                         uptr start2, uptr end2) {
221   CHECK(start1 <= end1);
222   CHECK(start2 <= end2);
223   return (end1 < start2) || (end2 < start1);
224 }
225 
226 // FIXME: this is thread-unsafe, but should not cause problems most of the time.
227 // When the shadow is mapped only a single thread usually exists (plus maybe
228 // several worker threads on Mac, which aren't expected to map big chunks of
229 // memory).
230 bool MemoryRangeIsAvailable(uptr range_start, uptr range_end) {
231   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
232   if (proc_maps.Error())
233     return true; // and hope for the best
234   MemoryMappedSegment segment;
235   while (proc_maps.Next(&segment)) {
236     if (segment.start == segment.end) continue;  // Empty range.
237     CHECK_NE(0, segment.end);
238     if (!IntervalsAreSeparate(segment.start, segment.end - 1, range_start,
239                               range_end))
240       return false;
241   }
242   return true;
243 }
244 
245 #if !SANITIZER_APPLE
246 void DumpProcessMap() {
247   MemoryMappingLayout proc_maps(/*cache_enabled*/true);
248   const sptr kBufSize = 4095;
249   char *filename = (char*)MmapOrDie(kBufSize, __func__);
250   MemoryMappedSegment segment(filename, kBufSize);
251   Report("Process memory map follows:\n");
252   while (proc_maps.Next(&segment)) {
253     Printf("\t%p-%p\t%s\n", (void *)segment.start, (void *)segment.end,
254            segment.filename);
255   }
256   Report("End of process memory map.\n");
257   UnmapOrDie(filename, kBufSize);
258 }
259 #endif
260 
261 const char *GetPwd() {
262   return GetEnv("PWD");
263 }
264 
265 bool IsPathSeparator(const char c) {
266   return c == '/';
267 }
268 
269 bool IsAbsolutePath(const char *path) {
270   return path != nullptr && IsPathSeparator(path[0]);
271 }
272 
273 void ReportFile::Write(const char *buffer, uptr length) {
274   SpinMutexLock l(mu);
275   ReopenIfNecessary();
276   internal_write(fd, buffer, length);
277 }
278 
279 bool GetCodeRangeForFile(const char *module, uptr *start, uptr *end) {
280   MemoryMappingLayout proc_maps(/*cache_enabled*/false);
281   InternalMmapVector<char> buff(kMaxPathLength);
282   MemoryMappedSegment segment(buff.data(), buff.size());
283   while (proc_maps.Next(&segment)) {
284     if (segment.IsExecutable() &&
285         internal_strcmp(module, segment.filename) == 0) {
286       *start = segment.start;
287       *end = segment.end;
288       return true;
289     }
290   }
291   return false;
292 }
293 
294 uptr SignalContext::GetAddress() const {
295   auto si = static_cast<const siginfo_t *>(siginfo);
296   return (uptr)si->si_addr;
297 }
298 
299 bool SignalContext::IsMemoryAccess() const {
300   auto si = static_cast<const siginfo_t *>(siginfo);
301   return si->si_signo == SIGSEGV || si->si_signo == SIGBUS;
302 }
303 
304 int SignalContext::GetType() const {
305   return static_cast<const siginfo_t *>(siginfo)->si_signo;
306 }
307 
308 const char *SignalContext::Describe() const {
309   switch (GetType()) {
310     case SIGFPE:
311       return "FPE";
312     case SIGILL:
313       return "ILL";
314     case SIGABRT:
315       return "ABRT";
316     case SIGSEGV:
317       return "SEGV";
318     case SIGBUS:
319       return "BUS";
320     case SIGTRAP:
321       return "TRAP";
322   }
323   return "UNKNOWN SIGNAL";
324 }
325 
326 fd_t ReserveStandardFds(fd_t fd) {
327   CHECK_GE(fd, 0);
328   if (fd > 2)
329     return fd;
330   bool used[3];
331   internal_memset(used, 0, sizeof(used));
332   while (fd <= 2) {
333     used[fd] = true;
334     fd = internal_dup(fd);
335   }
336   for (int i = 0; i <= 2; ++i)
337     if (used[i])
338       internal_close(i);
339   return fd;
340 }
341 
342 bool ShouldMockFailureToOpen(const char *path) {
343   return common_flags()->test_only_emulate_no_memorymap &&
344          internal_strncmp(path, "/proc/", 6) == 0;
345 }
346 
347 #if SANITIZER_LINUX && !SANITIZER_ANDROID && !SANITIZER_GO
348 int GetNamedMappingFd(const char *name, uptr size, int *flags) {
349   if (!common_flags()->decorate_proc_maps || !name)
350     return -1;
351   char shmname[200];
352   CHECK(internal_strlen(name) < sizeof(shmname) - 10);
353   internal_snprintf(shmname, sizeof(shmname), "/dev/shm/%zu [%s]",
354                     internal_getpid(), name);
355   int o_cloexec = 0;
356 #if defined(O_CLOEXEC)
357   o_cloexec = O_CLOEXEC;
358 #endif
359   int fd = ReserveStandardFds(
360       internal_open(shmname, O_RDWR | O_CREAT | O_TRUNC | o_cloexec, S_IRWXU));
361   CHECK_GE(fd, 0);
362   int res = internal_ftruncate(fd, size);
363 #if !defined(O_CLOEXEC)
364   res = fcntl(fd, F_SETFD, FD_CLOEXEC);
365   CHECK_EQ(0, res);
366 #endif
367   CHECK_EQ(0, res);
368   res = internal_unlink(shmname);
369   CHECK_EQ(0, res);
370   *flags &= ~(MAP_ANON | MAP_ANONYMOUS);
371   return fd;
372 }
373 #else
374 int GetNamedMappingFd(const char *name, uptr size, int *flags) {
375   return -1;
376 }
377 #endif
378 
379 #if SANITIZER_ANDROID
380 #define PR_SET_VMA 0x53564d41
381 #define PR_SET_VMA_ANON_NAME 0
382 void DecorateMapping(uptr addr, uptr size, const char *name) {
383   if (!common_flags()->decorate_proc_maps || !name)
384     return;
385   internal_prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, addr, size, (uptr)name);
386 }
387 #else
388 void DecorateMapping(uptr addr, uptr size, const char *name) {
389 }
390 #endif
391 
392 uptr MmapNamed(void *addr, uptr length, int prot, int flags, const char *name) {
393   int fd = GetNamedMappingFd(name, length, &flags);
394   uptr res = internal_mmap(addr, length, prot, flags, fd, 0);
395   if (!internal_iserror(res))
396     DecorateMapping(res, length, name);
397   return res;
398 }
399 
400 
401 } // namespace __sanitizer
402 
403 #endif // SANITIZER_POSIX
404