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1 //===-- asan_report.cc ----------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 //
12 // This file contains error reporting code.
13 //===----------------------------------------------------------------------===//
14 #include "asan_flags.h"
15 #include "asan_internal.h"
16 #include "asan_mapping.h"
17 #include "asan_report.h"
18 #include "asan_stack.h"
19 #include "asan_thread.h"
20 #include "sanitizer_common/sanitizer_common.h"
21 #include "sanitizer_common/sanitizer_flags.h"
22 #include "sanitizer_common/sanitizer_report_decorator.h"
23 #include "sanitizer_common/sanitizer_stackdepot.h"
24 #include "sanitizer_common/sanitizer_symbolizer.h"
25 
26 namespace __asan {
27 
28 // -------------------- User-specified callbacks ----------------- {{{1
29 static void (*error_report_callback)(const char*);
30 static char *error_message_buffer = 0;
31 static uptr error_message_buffer_pos = 0;
32 static uptr error_message_buffer_size = 0;
33 
AppendToErrorMessageBuffer(const char * buffer)34 void AppendToErrorMessageBuffer(const char *buffer) {
35   if (error_message_buffer) {
36     uptr length = internal_strlen(buffer);
37     CHECK_GE(error_message_buffer_size, error_message_buffer_pos);
38     uptr remaining = error_message_buffer_size - error_message_buffer_pos;
39     internal_strncpy(error_message_buffer + error_message_buffer_pos,
40                      buffer, remaining);
41     error_message_buffer[error_message_buffer_size - 1] = '\0';
42     // FIXME: reallocate the buffer instead of truncating the message.
43     error_message_buffer_pos += remaining > length ? length : remaining;
44   }
45 }
46 
47 // ---------------------- Decorator ------------------------------ {{{1
48 class Decorator: public __sanitizer::SanitizerCommonDecorator {
49  public:
Decorator()50   Decorator() : SanitizerCommonDecorator() { }
Access()51   const char *Access()     { return Blue(); }
EndAccess()52   const char *EndAccess()  { return Default(); }
Location()53   const char *Location()   { return Green(); }
EndLocation()54   const char *EndLocation() { return Default(); }
Allocation()55   const char *Allocation()  { return Magenta(); }
EndAllocation()56   const char *EndAllocation()  { return Default(); }
57 
ShadowByte(u8 byte)58   const char *ShadowByte(u8 byte) {
59     switch (byte) {
60       case kAsanHeapLeftRedzoneMagic:
61       case kAsanHeapRightRedzoneMagic:
62         return Red();
63       case kAsanHeapFreeMagic:
64         return Magenta();
65       case kAsanStackLeftRedzoneMagic:
66       case kAsanStackMidRedzoneMagic:
67       case kAsanStackRightRedzoneMagic:
68       case kAsanStackPartialRedzoneMagic:
69         return Red();
70       case kAsanStackAfterReturnMagic:
71         return Magenta();
72       case kAsanInitializationOrderMagic:
73         return Cyan();
74       case kAsanUserPoisonedMemoryMagic:
75       case kAsanContiguousContainerOOBMagic:
76         return Blue();
77       case kAsanStackUseAfterScopeMagic:
78         return Magenta();
79       case kAsanGlobalRedzoneMagic:
80         return Red();
81       case kAsanInternalHeapMagic:
82         return Yellow();
83       default:
84         return Default();
85     }
86   }
EndShadowByte()87   const char *EndShadowByte() { return Default(); }
88 };
89 
90 // ---------------------- Helper functions ----------------------- {{{1
91 
PrintShadowByte(InternalScopedString * str,const char * before,u8 byte,const char * after="\\n")92 static void PrintShadowByte(InternalScopedString *str, const char *before,
93                             u8 byte, const char *after = "\n") {
94   Decorator d;
95   str->append("%s%s%x%x%s%s", before, d.ShadowByte(byte), byte >> 4, byte & 15,
96               d.EndShadowByte(), after);
97 }
98 
PrintShadowBytes(InternalScopedString * str,const char * before,u8 * bytes,u8 * guilty,uptr n)99 static void PrintShadowBytes(InternalScopedString *str, const char *before,
100                              u8 *bytes, u8 *guilty, uptr n) {
101   Decorator d;
102   if (before) str->append("%s%p:", before, bytes);
103   for (uptr i = 0; i < n; i++) {
104     u8 *p = bytes + i;
105     const char *before =
106         p == guilty ? "[" : (p - 1 == guilty && i != 0) ? "" : " ";
107     const char *after = p == guilty ? "]" : "";
108     PrintShadowByte(str, before, *p, after);
109   }
110   str->append("\n");
111 }
112 
PrintLegend(InternalScopedString * str)113 static void PrintLegend(InternalScopedString *str) {
114   str->append(
115       "Shadow byte legend (one shadow byte represents %d "
116       "application bytes):\n",
117       (int)SHADOW_GRANULARITY);
118   PrintShadowByte(str, "  Addressable:           ", 0);
119   str->append("  Partially addressable: ");
120   for (u8 i = 1; i < SHADOW_GRANULARITY; i++) PrintShadowByte(str, "", i, " ");
121   str->append("\n");
122   PrintShadowByte(str, "  Heap left redzone:       ",
123                   kAsanHeapLeftRedzoneMagic);
124   PrintShadowByte(str, "  Heap right redzone:      ",
125                   kAsanHeapRightRedzoneMagic);
126   PrintShadowByte(str, "  Freed heap region:       ", kAsanHeapFreeMagic);
127   PrintShadowByte(str, "  Stack left redzone:      ",
128                   kAsanStackLeftRedzoneMagic);
129   PrintShadowByte(str, "  Stack mid redzone:       ",
130                   kAsanStackMidRedzoneMagic);
131   PrintShadowByte(str, "  Stack right redzone:     ",
132                   kAsanStackRightRedzoneMagic);
133   PrintShadowByte(str, "  Stack partial redzone:   ",
134                   kAsanStackPartialRedzoneMagic);
135   PrintShadowByte(str, "  Stack after return:      ",
136                   kAsanStackAfterReturnMagic);
137   PrintShadowByte(str, "  Stack use after scope:   ",
138                   kAsanStackUseAfterScopeMagic);
139   PrintShadowByte(str, "  Global redzone:          ", kAsanGlobalRedzoneMagic);
140   PrintShadowByte(str, "  Global init order:       ",
141                   kAsanInitializationOrderMagic);
142   PrintShadowByte(str, "  Poisoned by user:        ",
143                   kAsanUserPoisonedMemoryMagic);
144   PrintShadowByte(str, "  Container overflow:      ",
145                   kAsanContiguousContainerOOBMagic);
146   PrintShadowByte(str, "  ASan internal:           ", kAsanInternalHeapMagic);
147 }
148 
PrintShadowMemoryForAddress(uptr addr)149 static void PrintShadowMemoryForAddress(uptr addr) {
150   if (!AddrIsInMem(addr)) return;
151   uptr shadow_addr = MemToShadow(addr);
152   const uptr n_bytes_per_row = 16;
153   uptr aligned_shadow = shadow_addr & ~(n_bytes_per_row - 1);
154   InternalScopedString str(4096 * 8);
155   str.append("Shadow bytes around the buggy address:\n");
156   for (int i = -5; i <= 5; i++) {
157     const char *prefix = (i == 0) ? "=>" : "  ";
158     PrintShadowBytes(&str, prefix, (u8 *)(aligned_shadow + i * n_bytes_per_row),
159                      (u8 *)shadow_addr, n_bytes_per_row);
160   }
161   if (flags()->print_legend) PrintLegend(&str);
162   Printf("%s", str.data());
163 }
164 
PrintZoneForPointer(uptr ptr,uptr zone_ptr,const char * zone_name)165 static void PrintZoneForPointer(uptr ptr, uptr zone_ptr,
166                                 const char *zone_name) {
167   if (zone_ptr) {
168     if (zone_name) {
169       Printf("malloc_zone_from_ptr(%p) = %p, which is %s\n",
170                  ptr, zone_ptr, zone_name);
171     } else {
172       Printf("malloc_zone_from_ptr(%p) = %p, which doesn't have a name\n",
173                  ptr, zone_ptr);
174     }
175   } else {
176     Printf("malloc_zone_from_ptr(%p) = 0\n", ptr);
177   }
178 }
179 
DescribeThread(AsanThread * t)180 static void DescribeThread(AsanThread *t) {
181   if (t)
182     DescribeThread(t->context());
183 }
184 
185 // ---------------------- Address Descriptions ------------------- {{{1
186 
IsASCII(unsigned char c)187 static bool IsASCII(unsigned char c) {
188   return /*0x00 <= c &&*/ c <= 0x7F;
189 }
190 
MaybeDemangleGlobalName(const char * name)191 static const char *MaybeDemangleGlobalName(const char *name) {
192   // We can spoil names of globals with C linkage, so use an heuristic
193   // approach to check if the name should be demangled.
194   bool should_demangle = false;
195   if (name[0] == '_' && name[1] == 'Z')
196     should_demangle = true;
197   else if (SANITIZER_WINDOWS && name[0] == '\01' && name[1] == '?')
198     should_demangle = true;
199 
200   return should_demangle ? Symbolizer::Get()->Demangle(name) : name;
201 }
202 
203 // Check if the global is a zero-terminated ASCII string. If so, print it.
PrintGlobalNameIfASCII(InternalScopedString * str,const __asan_global & g)204 static void PrintGlobalNameIfASCII(InternalScopedString *str,
205                                    const __asan_global &g) {
206   for (uptr p = g.beg; p < g.beg + g.size - 1; p++) {
207     unsigned char c = *(unsigned char*)p;
208     if (c == '\0' || !IsASCII(c)) return;
209   }
210   if (*(char*)(g.beg + g.size - 1) != '\0') return;
211   str->append("  '%s' is ascii string '%s'\n", MaybeDemangleGlobalName(g.name),
212               (char *)g.beg);
213 }
214 
GlobalFilename(const __asan_global & g)215 static const char *GlobalFilename(const __asan_global &g) {
216   const char *res = g.module_name;
217   // Prefer the filename from source location, if is available.
218   if (g.location)
219     res = g.location->filename;
220   CHECK(res);
221   return res;
222 }
223 
PrintGlobalLocation(InternalScopedString * str,const __asan_global & g)224 static void PrintGlobalLocation(InternalScopedString *str,
225                                 const __asan_global &g) {
226   str->append("%s", GlobalFilename(g));
227   if (!g.location)
228     return;
229   if (g.location->line_no)
230     str->append(":%d", g.location->line_no);
231   if (g.location->column_no)
232     str->append(":%d", g.location->column_no);
233 }
234 
DescribeAddressRelativeToGlobal(uptr addr,uptr size,const __asan_global & g)235 bool DescribeAddressRelativeToGlobal(uptr addr, uptr size,
236                                      const __asan_global &g) {
237   static const uptr kMinimalDistanceFromAnotherGlobal = 64;
238   if (addr <= g.beg - kMinimalDistanceFromAnotherGlobal) return false;
239   if (addr >= g.beg + g.size_with_redzone) return false;
240   InternalScopedString str(4096);
241   Decorator d;
242   str.append("%s", d.Location());
243   if (addr < g.beg) {
244     str.append("%p is located %zd bytes to the left", (void *)addr,
245                g.beg - addr);
246   } else if (addr + size > g.beg + g.size) {
247     if (addr < g.beg + g.size)
248       addr = g.beg + g.size;
249     str.append("%p is located %zd bytes to the right", (void *)addr,
250                addr - (g.beg + g.size));
251   } else {
252     // Can it happen?
253     str.append("%p is located %zd bytes inside", (void *)addr, addr - g.beg);
254   }
255   str.append(" of global variable '%s' defined in '",
256              MaybeDemangleGlobalName(g.name));
257   PrintGlobalLocation(&str, g);
258   str.append("' (0x%zx) of size %zu\n", g.beg, g.size);
259   str.append("%s", d.EndLocation());
260   PrintGlobalNameIfASCII(&str, g);
261   Printf("%s", str.data());
262   return true;
263 }
264 
DescribeAddressIfShadow(uptr addr)265 bool DescribeAddressIfShadow(uptr addr) {
266   if (AddrIsInMem(addr))
267     return false;
268   static const char kAddrInShadowReport[] =
269       "Address %p is located in the %s.\n";
270   if (AddrIsInShadowGap(addr)) {
271     Printf(kAddrInShadowReport, addr, "shadow gap area");
272     return true;
273   }
274   if (AddrIsInHighShadow(addr)) {
275     Printf(kAddrInShadowReport, addr, "high shadow area");
276     return true;
277   }
278   if (AddrIsInLowShadow(addr)) {
279     Printf(kAddrInShadowReport, addr, "low shadow area");
280     return true;
281   }
282   CHECK(0 && "Address is not in memory and not in shadow?");
283   return false;
284 }
285 
286 // Return " (thread_name) " or an empty string if the name is empty.
ThreadNameWithParenthesis(AsanThreadContext * t,char buff[],uptr buff_len)287 const char *ThreadNameWithParenthesis(AsanThreadContext *t, char buff[],
288                                       uptr buff_len) {
289   const char *name = t->name;
290   if (name[0] == '\0') return "";
291   buff[0] = 0;
292   internal_strncat(buff, " (", 3);
293   internal_strncat(buff, name, buff_len - 4);
294   internal_strncat(buff, ")", 2);
295   return buff;
296 }
297 
ThreadNameWithParenthesis(u32 tid,char buff[],uptr buff_len)298 const char *ThreadNameWithParenthesis(u32 tid, char buff[],
299                                       uptr buff_len) {
300   if (tid == kInvalidTid) return "";
301   asanThreadRegistry().CheckLocked();
302   AsanThreadContext *t = GetThreadContextByTidLocked(tid);
303   return ThreadNameWithParenthesis(t, buff, buff_len);
304 }
305 
PrintAccessAndVarIntersection(const char * var_name,uptr var_beg,uptr var_size,uptr addr,uptr access_size,uptr prev_var_end,uptr next_var_beg)306 void PrintAccessAndVarIntersection(const char *var_name,
307                                    uptr var_beg, uptr var_size,
308                                    uptr addr, uptr access_size,
309                                    uptr prev_var_end, uptr next_var_beg) {
310   uptr var_end = var_beg + var_size;
311   uptr addr_end = addr + access_size;
312   const char *pos_descr = 0;
313   // If the variable [var_beg, var_end) is the nearest variable to the
314   // current memory access, indicate it in the log.
315   if (addr >= var_beg) {
316     if (addr_end <= var_end)
317       pos_descr = "is inside";  // May happen if this is a use-after-return.
318     else if (addr < var_end)
319       pos_descr = "partially overflows";
320     else if (addr_end <= next_var_beg &&
321              next_var_beg - addr_end >= addr - var_end)
322       pos_descr = "overflows";
323   } else {
324     if (addr_end > var_beg)
325       pos_descr = "partially underflows";
326     else if (addr >= prev_var_end &&
327              addr - prev_var_end >= var_beg - addr_end)
328       pos_descr = "underflows";
329   }
330   InternalScopedString str(1024);
331   str.append("    [%zd, %zd) '%s'", var_beg, var_beg + var_size, var_name);
332   if (pos_descr) {
333     Decorator d;
334     // FIXME: we may want to also print the size of the access here,
335     // but in case of accesses generated by memset it may be confusing.
336     str.append("%s <== Memory access at offset %zd %s this variable%s\n",
337                d.Location(), addr, pos_descr, d.EndLocation());
338   } else {
339     str.append("\n");
340   }
341   Printf("%s", str.data());
342 }
343 
344 struct StackVarDescr {
345   uptr beg;
346   uptr size;
347   const char *name_pos;
348   uptr name_len;
349 };
350 
DescribeAddressIfStack(uptr addr,uptr access_size)351 bool DescribeAddressIfStack(uptr addr, uptr access_size) {
352   AsanThread *t = FindThreadByStackAddress(addr);
353   if (!t) return false;
354   const uptr kBufSize = 4095;
355   char buf[kBufSize];
356   uptr offset = 0;
357   uptr frame_pc = 0;
358   char tname[128];
359   const char *frame_descr = t->GetFrameNameByAddr(addr, &offset, &frame_pc);
360 
361 #ifdef __powerpc64__
362   // On PowerPC64, the address of a function actually points to a
363   // three-doubleword data structure with the first field containing
364   // the address of the function's code.
365   frame_pc = *reinterpret_cast<uptr *>(frame_pc);
366 #endif
367 
368   // This string is created by the compiler and has the following form:
369   // "n alloc_1 alloc_2 ... alloc_n"
370   // where alloc_i looks like "offset size len ObjectName ".
371   CHECK(frame_descr);
372   Decorator d;
373   Printf("%s", d.Location());
374   Printf("Address %p is located in stack of thread T%d%s "
375          "at offset %zu in frame\n",
376          addr, t->tid(),
377          ThreadNameWithParenthesis(t->tid(), tname, sizeof(tname)),
378          offset);
379   // Now we print the frame where the alloca has happened.
380   // We print this frame as a stack trace with one element.
381   // The symbolizer may print more than one frame if inlining was involved.
382   // The frame numbers may be different than those in the stack trace printed
383   // previously. That's unfortunate, but I have no better solution,
384   // especially given that the alloca may be from entirely different place
385   // (e.g. use-after-scope, or different thread's stack).
386   StackTrace alloca_stack;
387   alloca_stack.trace[0] = frame_pc + 16;
388   alloca_stack.size = 1;
389   Printf("%s", d.EndLocation());
390   alloca_stack.Print();
391   // Report the number of stack objects.
392   char *p;
393   uptr n_objects = (uptr)internal_simple_strtoll(frame_descr, &p, 10);
394   CHECK_GT(n_objects, 0);
395   Printf("  This frame has %zu object(s):\n", n_objects);
396 
397   // Report all objects in this frame.
398   InternalScopedBuffer<StackVarDescr> vars(n_objects);
399   for (uptr i = 0; i < n_objects; i++) {
400     uptr beg, size;
401     uptr len;
402     beg  = (uptr)internal_simple_strtoll(p, &p, 10);
403     size = (uptr)internal_simple_strtoll(p, &p, 10);
404     len  = (uptr)internal_simple_strtoll(p, &p, 10);
405     if (beg == 0 || size == 0 || *p != ' ') {
406       Printf("AddressSanitizer can't parse the stack frame "
407                  "descriptor: |%s|\n", frame_descr);
408       break;
409     }
410     p++;
411     vars[i].beg = beg;
412     vars[i].size = size;
413     vars[i].name_pos = p;
414     vars[i].name_len = len;
415     p += len;
416   }
417   for (uptr i = 0; i < n_objects; i++) {
418     buf[0] = 0;
419     internal_strncat(buf, vars[i].name_pos,
420                      static_cast<uptr>(Min(kBufSize, vars[i].name_len)));
421     uptr prev_var_end = i ? vars[i - 1].beg + vars[i - 1].size : 0;
422     uptr next_var_beg = i + 1 < n_objects ? vars[i + 1].beg : ~(0UL);
423     PrintAccessAndVarIntersection(buf, vars[i].beg, vars[i].size,
424                                   offset, access_size,
425                                   prev_var_end, next_var_beg);
426   }
427   Printf("HINT: this may be a false positive if your program uses "
428              "some custom stack unwind mechanism or swapcontext\n"
429              "      (longjmp and C++ exceptions *are* supported)\n");
430   DescribeThread(t);
431   return true;
432 }
433 
DescribeAccessToHeapChunk(AsanChunkView chunk,uptr addr,uptr access_size)434 static void DescribeAccessToHeapChunk(AsanChunkView chunk, uptr addr,
435                                       uptr access_size) {
436   sptr offset;
437   Decorator d;
438   InternalScopedString str(4096);
439   str.append("%s", d.Location());
440   if (chunk.AddrIsAtLeft(addr, access_size, &offset)) {
441     str.append("%p is located %zd bytes to the left of", (void *)addr, offset);
442   } else if (chunk.AddrIsAtRight(addr, access_size, &offset)) {
443     if (offset < 0) {
444       addr -= offset;
445       offset = 0;
446     }
447     str.append("%p is located %zd bytes to the right of", (void *)addr, offset);
448   } else if (chunk.AddrIsInside(addr, access_size, &offset)) {
449     str.append("%p is located %zd bytes inside of", (void*)addr, offset);
450   } else {
451     str.append("%p is located somewhere around (this is AddressSanitizer bug!)",
452                (void *)addr);
453   }
454   str.append(" %zu-byte region [%p,%p)\n", chunk.UsedSize(),
455              (void *)(chunk.Beg()), (void *)(chunk.End()));
456   str.append("%s", d.EndLocation());
457   Printf("%s", str.data());
458 }
459 
DescribeHeapAddress(uptr addr,uptr access_size)460 void DescribeHeapAddress(uptr addr, uptr access_size) {
461   AsanChunkView chunk = FindHeapChunkByAddress(addr);
462   if (!chunk.IsValid()) {
463     Printf("AddressSanitizer can not describe address in more detail "
464            "(wild memory access suspected).\n");
465     return;
466   }
467   DescribeAccessToHeapChunk(chunk, addr, access_size);
468   CHECK(chunk.AllocTid() != kInvalidTid);
469   asanThreadRegistry().CheckLocked();
470   AsanThreadContext *alloc_thread =
471       GetThreadContextByTidLocked(chunk.AllocTid());
472   StackTrace alloc_stack;
473   chunk.GetAllocStack(&alloc_stack);
474   char tname[128];
475   Decorator d;
476   AsanThreadContext *free_thread = 0;
477   if (chunk.FreeTid() != kInvalidTid) {
478     free_thread = GetThreadContextByTidLocked(chunk.FreeTid());
479     Printf("%sfreed by thread T%d%s here:%s\n", d.Allocation(),
480            free_thread->tid,
481            ThreadNameWithParenthesis(free_thread, tname, sizeof(tname)),
482            d.EndAllocation());
483     StackTrace free_stack;
484     chunk.GetFreeStack(&free_stack);
485     free_stack.Print();
486     Printf("%spreviously allocated by thread T%d%s here:%s\n",
487            d.Allocation(), alloc_thread->tid,
488            ThreadNameWithParenthesis(alloc_thread, tname, sizeof(tname)),
489            d.EndAllocation());
490   } else {
491     Printf("%sallocated by thread T%d%s here:%s\n", d.Allocation(),
492            alloc_thread->tid,
493            ThreadNameWithParenthesis(alloc_thread, tname, sizeof(tname)),
494            d.EndAllocation());
495   }
496   alloc_stack.Print();
497   DescribeThread(GetCurrentThread());
498   if (free_thread)
499     DescribeThread(free_thread);
500   DescribeThread(alloc_thread);
501 }
502 
DescribeAddress(uptr addr,uptr access_size)503 void DescribeAddress(uptr addr, uptr access_size) {
504   // Check if this is shadow or shadow gap.
505   if (DescribeAddressIfShadow(addr))
506     return;
507   CHECK(AddrIsInMem(addr));
508   if (DescribeAddressIfGlobal(addr, access_size))
509     return;
510   if (DescribeAddressIfStack(addr, access_size))
511     return;
512   // Assume it is a heap address.
513   DescribeHeapAddress(addr, access_size);
514 }
515 
516 // ------------------- Thread description -------------------- {{{1
517 
DescribeThread(AsanThreadContext * context)518 void DescribeThread(AsanThreadContext *context) {
519   CHECK(context);
520   asanThreadRegistry().CheckLocked();
521   // No need to announce the main thread.
522   if (context->tid == 0 || context->announced) {
523     return;
524   }
525   context->announced = true;
526   char tname[128];
527   InternalScopedString str(1024);
528   str.append("Thread T%d%s", context->tid,
529              ThreadNameWithParenthesis(context->tid, tname, sizeof(tname)));
530   str.append(
531       " created by T%d%s here:\n", context->parent_tid,
532       ThreadNameWithParenthesis(context->parent_tid, tname, sizeof(tname)));
533   Printf("%s", str.data());
534   uptr stack_size;
535   const uptr *stack_trace = StackDepotGet(context->stack_id, &stack_size);
536   StackTrace::PrintStack(stack_trace, stack_size);
537   // Recursively described parent thread if needed.
538   if (flags()->print_full_thread_history) {
539     AsanThreadContext *parent_context =
540         GetThreadContextByTidLocked(context->parent_tid);
541     DescribeThread(parent_context);
542   }
543 }
544 
545 // -------------------- Different kinds of reports ----------------- {{{1
546 
547 // Use ScopedInErrorReport to run common actions just before and
548 // immediately after printing error report.
549 class ScopedInErrorReport {
550  public:
ScopedInErrorReport()551   ScopedInErrorReport() {
552     static atomic_uint32_t num_calls;
553     static u32 reporting_thread_tid;
554     if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
555       // Do not print more than one report, otherwise they will mix up.
556       // Error reporting functions shouldn't return at this situation, as
557       // they are defined as no-return.
558       Report("AddressSanitizer: while reporting a bug found another one."
559                  "Ignoring.\n");
560       u32 current_tid = GetCurrentTidOrInvalid();
561       if (current_tid != reporting_thread_tid) {
562         // ASan found two bugs in different threads simultaneously. Sleep
563         // long enough to make sure that the thread which started to print
564         // an error report will finish doing it.
565         SleepForSeconds(Max(100, flags()->sleep_before_dying + 1));
566       }
567       // If we're still not dead for some reason, use raw _exit() instead of
568       // Die() to bypass any additional checks.
569       internal__exit(flags()->exitcode);
570     }
571     ASAN_ON_ERROR();
572     // Make sure the registry and sanitizer report mutexes are locked while
573     // we're printing an error report.
574     // We can lock them only here to avoid self-deadlock in case of
575     // recursive reports.
576     asanThreadRegistry().Lock();
577     CommonSanitizerReportMutex.Lock();
578     reporting_thread_tid = GetCurrentTidOrInvalid();
579     Printf("===================================================="
580            "=============\n");
581   }
582   // Destructor is NORETURN, as functions that report errors are.
~ScopedInErrorReport()583   NORETURN ~ScopedInErrorReport() {
584     // Make sure the current thread is announced.
585     DescribeThread(GetCurrentThread());
586     // We may want to grab this lock again when printing stats.
587     asanThreadRegistry().Unlock();
588     // Print memory stats.
589     if (flags()->print_stats)
590       __asan_print_accumulated_stats();
591     if (error_report_callback) {
592       error_report_callback(error_message_buffer);
593     }
594     Report("ABORTING\n");
595     Die();
596   }
597 };
598 
ReportStackOverflow(uptr pc,uptr sp,uptr bp,void * context,uptr addr)599 void ReportStackOverflow(uptr pc, uptr sp, uptr bp, void *context, uptr addr) {
600   ScopedInErrorReport in_report;
601   Decorator d;
602   Printf("%s", d.Warning());
603   Report(
604       "ERROR: AddressSanitizer: stack-overflow on address %p"
605       " (pc %p sp %p bp %p T%d)\n",
606       (void *)addr, (void *)pc, (void *)sp, (void *)bp,
607       GetCurrentTidOrInvalid());
608   Printf("%s", d.EndWarning());
609   GET_STACK_TRACE_SIGNAL(pc, bp, context);
610   stack.Print();
611   ReportErrorSummary("stack-overflow", &stack);
612 }
613 
ReportSIGSEGV(uptr pc,uptr sp,uptr bp,void * context,uptr addr)614 void ReportSIGSEGV(uptr pc, uptr sp, uptr bp, void *context, uptr addr) {
615   ScopedInErrorReport in_report;
616   Decorator d;
617   Printf("%s", d.Warning());
618   Report(
619       "ERROR: AddressSanitizer: SEGV on unknown address %p"
620       " (pc %p sp %p bp %p T%d)\n",
621       (void *)addr, (void *)pc, (void *)sp, (void *)bp,
622       GetCurrentTidOrInvalid());
623   Printf("%s", d.EndWarning());
624   GET_STACK_TRACE_SIGNAL(pc, bp, context);
625   stack.Print();
626   Printf("AddressSanitizer can not provide additional info.\n");
627   ReportErrorSummary("SEGV", &stack);
628 }
629 
ReportDoubleFree(uptr addr,StackTrace * free_stack)630 void ReportDoubleFree(uptr addr, StackTrace *free_stack) {
631   ScopedInErrorReport in_report;
632   Decorator d;
633   Printf("%s", d.Warning());
634   char tname[128];
635   u32 curr_tid = GetCurrentTidOrInvalid();
636   Report("ERROR: AddressSanitizer: attempting double-free on %p in "
637          "thread T%d%s:\n",
638          addr, curr_tid,
639          ThreadNameWithParenthesis(curr_tid, tname, sizeof(tname)));
640   Printf("%s", d.EndWarning());
641   CHECK_GT(free_stack->size, 0);
642   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
643   stack.Print();
644   DescribeHeapAddress(addr, 1);
645   ReportErrorSummary("double-free", &stack);
646 }
647 
ReportFreeNotMalloced(uptr addr,StackTrace * free_stack)648 void ReportFreeNotMalloced(uptr addr, StackTrace *free_stack) {
649   ScopedInErrorReport in_report;
650   Decorator d;
651   Printf("%s", d.Warning());
652   char tname[128];
653   u32 curr_tid = GetCurrentTidOrInvalid();
654   Report("ERROR: AddressSanitizer: attempting free on address "
655              "which was not malloc()-ed: %p in thread T%d%s\n", addr,
656          curr_tid, ThreadNameWithParenthesis(curr_tid, tname, sizeof(tname)));
657   Printf("%s", d.EndWarning());
658   CHECK_GT(free_stack->size, 0);
659   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
660   stack.Print();
661   DescribeHeapAddress(addr, 1);
662   ReportErrorSummary("bad-free", &stack);
663 }
664 
ReportAllocTypeMismatch(uptr addr,StackTrace * free_stack,AllocType alloc_type,AllocType dealloc_type)665 void ReportAllocTypeMismatch(uptr addr, StackTrace *free_stack,
666                              AllocType alloc_type,
667                              AllocType dealloc_type) {
668   static const char *alloc_names[] =
669     {"INVALID", "malloc", "operator new", "operator new []"};
670   static const char *dealloc_names[] =
671     {"INVALID", "free", "operator delete", "operator delete []"};
672   CHECK_NE(alloc_type, dealloc_type);
673   ScopedInErrorReport in_report;
674   Decorator d;
675   Printf("%s", d.Warning());
676   Report("ERROR: AddressSanitizer: alloc-dealloc-mismatch (%s vs %s) on %p\n",
677         alloc_names[alloc_type], dealloc_names[dealloc_type], addr);
678   Printf("%s", d.EndWarning());
679   CHECK_GT(free_stack->size, 0);
680   GET_STACK_TRACE_FATAL(free_stack->trace[0], free_stack->top_frame_bp);
681   stack.Print();
682   DescribeHeapAddress(addr, 1);
683   ReportErrorSummary("alloc-dealloc-mismatch", &stack);
684   Report("HINT: if you don't care about these warnings you may set "
685          "ASAN_OPTIONS=alloc_dealloc_mismatch=0\n");
686 }
687 
ReportMallocUsableSizeNotOwned(uptr addr,StackTrace * stack)688 void ReportMallocUsableSizeNotOwned(uptr addr, StackTrace *stack) {
689   ScopedInErrorReport in_report;
690   Decorator d;
691   Printf("%s", d.Warning());
692   Report("ERROR: AddressSanitizer: attempting to call "
693              "malloc_usable_size() for pointer which is "
694              "not owned: %p\n", addr);
695   Printf("%s", d.EndWarning());
696   stack->Print();
697   DescribeHeapAddress(addr, 1);
698   ReportErrorSummary("bad-malloc_usable_size", stack);
699 }
700 
ReportSanitizerGetAllocatedSizeNotOwned(uptr addr,StackTrace * stack)701 void ReportSanitizerGetAllocatedSizeNotOwned(uptr addr, StackTrace *stack) {
702   ScopedInErrorReport in_report;
703   Decorator d;
704   Printf("%s", d.Warning());
705   Report("ERROR: AddressSanitizer: attempting to call "
706              "__sanitizer_get_allocated_size() for pointer which is "
707              "not owned: %p\n", addr);
708   Printf("%s", d.EndWarning());
709   stack->Print();
710   DescribeHeapAddress(addr, 1);
711   ReportErrorSummary("bad-__sanitizer_get_allocated_size", stack);
712 }
713 
ReportStringFunctionMemoryRangesOverlap(const char * function,const char * offset1,uptr length1,const char * offset2,uptr length2,StackTrace * stack)714 void ReportStringFunctionMemoryRangesOverlap(
715     const char *function, const char *offset1, uptr length1,
716     const char *offset2, uptr length2, StackTrace *stack) {
717   ScopedInErrorReport in_report;
718   Decorator d;
719   char bug_type[100];
720   internal_snprintf(bug_type, sizeof(bug_type), "%s-param-overlap", function);
721   Printf("%s", d.Warning());
722   Report("ERROR: AddressSanitizer: %s: "
723              "memory ranges [%p,%p) and [%p, %p) overlap\n", \
724              bug_type, offset1, offset1 + length1, offset2, offset2 + length2);
725   Printf("%s", d.EndWarning());
726   stack->Print();
727   DescribeAddress((uptr)offset1, length1);
728   DescribeAddress((uptr)offset2, length2);
729   ReportErrorSummary(bug_type, stack);
730 }
731 
ReportStringFunctionSizeOverflow(uptr offset,uptr size,StackTrace * stack)732 void ReportStringFunctionSizeOverflow(uptr offset, uptr size,
733                                       StackTrace *stack) {
734   ScopedInErrorReport in_report;
735   Decorator d;
736   const char *bug_type = "negative-size-param";
737   Printf("%s", d.Warning());
738   Report("ERROR: AddressSanitizer: %s: (size=%zd)\n", bug_type, size);
739   Printf("%s", d.EndWarning());
740   stack->Print();
741   DescribeAddress(offset, size);
742   ReportErrorSummary(bug_type, stack);
743 }
744 
ReportBadParamsToAnnotateContiguousContainer(uptr beg,uptr end,uptr old_mid,uptr new_mid,StackTrace * stack)745 void ReportBadParamsToAnnotateContiguousContainer(uptr beg, uptr end,
746                                                   uptr old_mid, uptr new_mid,
747                                                   StackTrace *stack) {
748   ScopedInErrorReport in_report;
749   Report("ERROR: AddressSanitizer: bad parameters to "
750          "__sanitizer_annotate_contiguous_container:\n"
751          "      beg     : %p\n"
752          "      end     : %p\n"
753          "      old_mid : %p\n"
754          "      new_mid : %p\n",
755          beg, end, old_mid, new_mid);
756   stack->Print();
757   ReportErrorSummary("bad-__sanitizer_annotate_contiguous_container", stack);
758 }
759 
ReportODRViolation(const __asan_global * g1,u32 stack_id1,const __asan_global * g2,u32 stack_id2)760 void ReportODRViolation(const __asan_global *g1, u32 stack_id1,
761                         const __asan_global *g2, u32 stack_id2) {
762   ScopedInErrorReport in_report;
763   Decorator d;
764   Printf("%s", d.Warning());
765   Report("ERROR: AddressSanitizer: odr-violation (%p):\n", g1->beg);
766   Printf("%s", d.EndWarning());
767   InternalScopedString g1_loc(256), g2_loc(256);
768   PrintGlobalLocation(&g1_loc, *g1);
769   PrintGlobalLocation(&g2_loc, *g2);
770   Printf("  [1] size=%zd %s %s\n", g1->size, g1->name, g1_loc.data());
771   Printf("  [2] size=%zd %s %s\n", g2->size, g2->name, g2_loc.data());
772   if (stack_id1 && stack_id2) {
773     Printf("These globals were registered at these points:\n");
774     Printf("  [1]:\n");
775     uptr stack_size;
776     const uptr *stack_trace = StackDepotGet(stack_id1, &stack_size);
777     StackTrace::PrintStack(stack_trace, stack_size);
778     Printf("  [2]:\n");
779     stack_trace = StackDepotGet(stack_id2, &stack_size);
780     StackTrace::PrintStack(stack_trace, stack_size);
781   }
782   Report("HINT: if you don't care about these warnings you may set "
783          "ASAN_OPTIONS=detect_odr_violation=0\n");
784   ReportErrorSummary("odr-violation", g1_loc.data(), 0, g1->name);
785 }
786 
787 // ----------------------- CheckForInvalidPointerPair ----------- {{{1
788 static NOINLINE void
ReportInvalidPointerPair(uptr pc,uptr bp,uptr sp,uptr a1,uptr a2)789 ReportInvalidPointerPair(uptr pc, uptr bp, uptr sp, uptr a1, uptr a2) {
790   ScopedInErrorReport in_report;
791   Decorator d;
792   Printf("%s", d.Warning());
793   Report("ERROR: AddressSanitizer: invalid-pointer-pair: %p %p\n", a1, a2);
794   Printf("%s", d.EndWarning());
795   GET_STACK_TRACE_FATAL(pc, bp);
796   stack.Print();
797   DescribeAddress(a1, 1);
798   DescribeAddress(a2, 1);
799   ReportErrorSummary("invalid-pointer-pair", &stack);
800 }
801 
CheckForInvalidPointerPair(void * p1,void * p2)802 static INLINE void CheckForInvalidPointerPair(void *p1, void *p2) {
803   if (!flags()->detect_invalid_pointer_pairs) return;
804   uptr a1 = reinterpret_cast<uptr>(p1);
805   uptr a2 = reinterpret_cast<uptr>(p2);
806   AsanChunkView chunk1 = FindHeapChunkByAddress(a1);
807   AsanChunkView chunk2 = FindHeapChunkByAddress(a2);
808   bool valid1 = chunk1.IsValid();
809   bool valid2 = chunk2.IsValid();
810   if ((valid1 != valid2) || (valid1 && valid2 && !chunk1.Eq(chunk2))) {
811     GET_CALLER_PC_BP_SP;                                              \
812     return ReportInvalidPointerPair(pc, bp, sp, a1, a2);
813   }
814 }
815 // ----------------------- Mac-specific reports ----------------- {{{1
816 
WarnMacFreeUnallocated(uptr addr,uptr zone_ptr,const char * zone_name,StackTrace * stack)817 void WarnMacFreeUnallocated(
818     uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack) {
819   // Just print a warning here.
820   Printf("free_common(%p) -- attempting to free unallocated memory.\n"
821              "AddressSanitizer is ignoring this error on Mac OS now.\n",
822              addr);
823   PrintZoneForPointer(addr, zone_ptr, zone_name);
824   stack->Print();
825   DescribeHeapAddress(addr, 1);
826 }
827 
ReportMacMzReallocUnknown(uptr addr,uptr zone_ptr,const char * zone_name,StackTrace * stack)828 void ReportMacMzReallocUnknown(
829     uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack) {
830   ScopedInErrorReport in_report;
831   Printf("mz_realloc(%p) -- attempting to realloc unallocated memory.\n"
832              "This is an unrecoverable problem, exiting now.\n",
833              addr);
834   PrintZoneForPointer(addr, zone_ptr, zone_name);
835   stack->Print();
836   DescribeHeapAddress(addr, 1);
837 }
838 
ReportMacCfReallocUnknown(uptr addr,uptr zone_ptr,const char * zone_name,StackTrace * stack)839 void ReportMacCfReallocUnknown(
840     uptr addr, uptr zone_ptr, const char *zone_name, StackTrace *stack) {
841   ScopedInErrorReport in_report;
842   Printf("cf_realloc(%p) -- attempting to realloc unallocated memory.\n"
843              "This is an unrecoverable problem, exiting now.\n",
844              addr);
845   PrintZoneForPointer(addr, zone_ptr, zone_name);
846   stack->Print();
847   DescribeHeapAddress(addr, 1);
848 }
849 
850 }  // namespace __asan
851 
852 // --------------------------- Interface --------------------- {{{1
853 using namespace __asan;  // NOLINT
854 
__asan_report_error(uptr pc,uptr bp,uptr sp,uptr addr,int is_write,uptr access_size)855 void __asan_report_error(uptr pc, uptr bp, uptr sp, uptr addr, int is_write,
856                          uptr access_size) {
857   ScopedInErrorReport in_report;
858 
859   // Determine the error type.
860   const char *bug_descr = "unknown-crash";
861   if (AddrIsInMem(addr)) {
862     u8 *shadow_addr = (u8*)MemToShadow(addr);
863     // If we are accessing 16 bytes, look at the second shadow byte.
864     if (*shadow_addr == 0 && access_size > SHADOW_GRANULARITY)
865       shadow_addr++;
866     // If we are in the partial right redzone, look at the next shadow byte.
867     if (*shadow_addr > 0 && *shadow_addr < 128)
868       shadow_addr++;
869     switch (*shadow_addr) {
870       case kAsanHeapLeftRedzoneMagic:
871       case kAsanHeapRightRedzoneMagic:
872         bug_descr = "heap-buffer-overflow";
873         break;
874       case kAsanHeapFreeMagic:
875         bug_descr = "heap-use-after-free";
876         break;
877       case kAsanStackLeftRedzoneMagic:
878         bug_descr = "stack-buffer-underflow";
879         break;
880       case kAsanInitializationOrderMagic:
881         bug_descr = "initialization-order-fiasco";
882         break;
883       case kAsanStackMidRedzoneMagic:
884       case kAsanStackRightRedzoneMagic:
885       case kAsanStackPartialRedzoneMagic:
886         bug_descr = "stack-buffer-overflow";
887         break;
888       case kAsanStackAfterReturnMagic:
889         bug_descr = "stack-use-after-return";
890         break;
891       case kAsanUserPoisonedMemoryMagic:
892         bug_descr = "use-after-poison";
893         break;
894       case kAsanContiguousContainerOOBMagic:
895         bug_descr = "container-overflow";
896         break;
897       case kAsanStackUseAfterScopeMagic:
898         bug_descr = "stack-use-after-scope";
899         break;
900       case kAsanGlobalRedzoneMagic:
901         bug_descr = "global-buffer-overflow";
902         break;
903     }
904   }
905   Decorator d;
906   Printf("%s", d.Warning());
907   Report("ERROR: AddressSanitizer: %s on address "
908              "%p at pc 0x%zx bp 0x%zx sp 0x%zx\n",
909              bug_descr, (void*)addr, pc, bp, sp);
910   Printf("%s", d.EndWarning());
911 
912   u32 curr_tid = GetCurrentTidOrInvalid();
913   char tname[128];
914   Printf("%s%s of size %zu at %p thread T%d%s%s\n",
915          d.Access(),
916          access_size ? (is_write ? "WRITE" : "READ") : "ACCESS",
917          access_size, (void*)addr, curr_tid,
918          ThreadNameWithParenthesis(curr_tid, tname, sizeof(tname)),
919          d.EndAccess());
920 
921   GET_STACK_TRACE_FATAL(pc, bp);
922   stack.Print();
923 
924   DescribeAddress(addr, access_size);
925   ReportErrorSummary(bug_descr, &stack);
926   PrintShadowMemoryForAddress(addr);
927 }
928 
__asan_set_error_report_callback(void (* callback)(const char *))929 void NOINLINE __asan_set_error_report_callback(void (*callback)(const char*)) {
930   error_report_callback = callback;
931   if (callback) {
932     error_message_buffer_size = 1 << 16;
933     error_message_buffer =
934         (char*)MmapOrDie(error_message_buffer_size, __func__);
935     error_message_buffer_pos = 0;
936   }
937 }
938 
__asan_describe_address(uptr addr)939 void __asan_describe_address(uptr addr) {
940   DescribeAddress(addr, 1);
941 }
942 
943 extern "C" {
944 SANITIZER_INTERFACE_ATTRIBUTE
__sanitizer_ptr_sub(void * a,void * b)945 void __sanitizer_ptr_sub(void *a, void *b) {
946   CheckForInvalidPointerPair(a, b);
947 }
948 SANITIZER_INTERFACE_ATTRIBUTE
__sanitizer_ptr_cmp(void * a,void * b)949 void __sanitizer_ptr_cmp(void *a, void *b) {
950   CheckForInvalidPointerPair(a, b);
951 }
952 }  // extern "C"
953 
954 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
955 // Provide default implementation of __asan_on_error that does nothing
956 // and may be overriden by user.
957 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE NOINLINE
__asan_on_error()958 void __asan_on_error() {}
959 #endif
960