aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/clang16-rt/lib/ubsan/ubsan_diag.cpp
blob: 3673e66539d0e103e9ed6bb59f331da97dbc1c57 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
//===-- ubsan_diag.cpp ----------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Diagnostic reporting for the UBSan runtime.
//
//===----------------------------------------------------------------------===//

#include "ubsan_platform.h"
#if CAN_SANITIZE_UB
#include "ubsan_diag.h"
#include "ubsan_init.h"
#include "ubsan_flags.h"
#include "ubsan_monitor.h"
#include "sanitizer_common/sanitizer_placement_new.h"
#include "sanitizer_common/sanitizer_report_decorator.h"
#include "sanitizer_common/sanitizer_stacktrace.h"
#include "sanitizer_common/sanitizer_stacktrace_printer.h"
#include "sanitizer_common/sanitizer_suppressions.h"
#include "sanitizer_common/sanitizer_symbolizer.h"
#include <stdio.h>

using namespace __ubsan;

// UBSan is combined with runtimes that already provide this functionality
// (e.g., ASan) as well as runtimes that lack it (e.g., scudo). Tried to use
// weak linkage to resolve this issue which is not portable and breaks on
// Windows.
// TODO(yln): This is a temporary workaround. GetStackTrace functions will be
// removed in the future.
void ubsan_GetStackTrace(BufferedStackTrace *stack, uptr max_depth, uptr pc,
                         uptr bp, void *context, bool request_fast) {
  uptr top = 0;
  uptr bottom = 0;
  GetThreadStackTopAndBottom(false, &top, &bottom);
  bool fast = StackTrace::WillUseFastUnwind(request_fast);
  stack->Unwind(max_depth, pc, bp, context, top, bottom, fast);
}

static void MaybePrintStackTrace(uptr pc, uptr bp) {
  // We assume that flags are already parsed, as UBSan runtime
  // will definitely be called when we print the first diagnostics message.
  if (!flags()->print_stacktrace)
    return;

  BufferedStackTrace stack;
  ubsan_GetStackTrace(&stack, kStackTraceMax, pc, bp, nullptr,
                common_flags()->fast_unwind_on_fatal);
  stack.Print();
}

static const char *ConvertTypeToString(ErrorType Type) {
  switch (Type) {
#define UBSAN_CHECK(Name, SummaryKind, FSanitizeFlagName)                      \
  case ErrorType::Name:                                                        \
    return SummaryKind;
#include "ubsan_checks.inc"
#undef UBSAN_CHECK
  }
  UNREACHABLE("unknown ErrorType!");
}

static const char *ConvertTypeToFlagName(ErrorType Type) {
  switch (Type) {
#define UBSAN_CHECK(Name, SummaryKind, FSanitizeFlagName)                      \
  case ErrorType::Name:                                                        \
    return FSanitizeFlagName;
#include "ubsan_checks.inc"
#undef UBSAN_CHECK
  }
  UNREACHABLE("unknown ErrorType!");
}

static void MaybeReportErrorSummary(Location Loc, ErrorType Type) {
  if (!common_flags()->print_summary)
    return;
  if (!flags()->report_error_type)
    Type = ErrorType::GenericUB;
  const char *ErrorKind = ConvertTypeToString(Type);
  if (Loc.isSourceLocation()) {
    SourceLocation SLoc = Loc.getSourceLocation();
    if (!SLoc.isInvalid()) {
      AddressInfo AI;
      AI.file = internal_strdup(SLoc.getFilename());
      AI.line = SLoc.getLine();
      AI.column = SLoc.getColumn();
      AI.function = internal_strdup("");  // Avoid printing ?? as function name.
      ReportErrorSummary(ErrorKind, AI, GetSanititizerToolName());
      AI.Clear();
      return;
    }
  } else if (Loc.isSymbolizedStack()) {
    const AddressInfo &AI = Loc.getSymbolizedStack()->info;
    ReportErrorSummary(ErrorKind, AI, GetSanititizerToolName());
    return;
  }
  ReportErrorSummary(ErrorKind, GetSanititizerToolName());
}

namespace {
class Decorator : public SanitizerCommonDecorator {
 public:
  Decorator() : SanitizerCommonDecorator() {}
  const char *Highlight() const { return Green(); }
  const char *Note() const { return Black(); }
};
}

SymbolizedStack *__ubsan::getSymbolizedLocation(uptr PC) {
  InitAsStandaloneIfNecessary();
  return Symbolizer::GetOrInit()->SymbolizePC(PC);
}

Diag &Diag::operator<<(const TypeDescriptor &V) {
  return AddArg(V.getTypeName());
}

Diag &Diag::operator<<(const Value &V) {
  if (V.getType().isSignedIntegerTy())
    AddArg(V.getSIntValue());
  else if (V.getType().isUnsignedIntegerTy())
    AddArg(V.getUIntValue());
  else if (V.getType().isFloatTy())
    AddArg(V.getFloatValue());
  else
    AddArg("<unknown>");
  return *this;
}

/// Hexadecimal printing for numbers too large for Printf to handle directly.
static void RenderHex(InternalScopedString *Buffer, UIntMax Val) {
#if HAVE_INT128_T
  Buffer->append("0x%08x%08x%08x%08x", (unsigned int)(Val >> 96),
                 (unsigned int)(Val >> 64), (unsigned int)(Val >> 32),
                 (unsigned int)(Val));
#else
  UNREACHABLE("long long smaller than 64 bits?");
#endif
}

static void RenderLocation(InternalScopedString *Buffer, Location Loc) {
  switch (Loc.getKind()) {
  case Location::LK_Source: {
    SourceLocation SLoc = Loc.getSourceLocation();
    if (SLoc.isInvalid())
      Buffer->append("<unknown>");
    else
      RenderSourceLocation(Buffer, SLoc.getFilename(), SLoc.getLine(),
                           SLoc.getColumn(), common_flags()->symbolize_vs_style,
                           common_flags()->strip_path_prefix);
    return;
  }
  case Location::LK_Memory:
    Buffer->append("%p", reinterpret_cast<void *>(Loc.getMemoryLocation()));
    return;
  case Location::LK_Symbolized: {
    const AddressInfo &Info = Loc.getSymbolizedStack()->info;
    if (Info.file)
      RenderSourceLocation(Buffer, Info.file, Info.line, Info.column,
                           common_flags()->symbolize_vs_style,
                           common_flags()->strip_path_prefix);
    else if (Info.module)
      RenderModuleLocation(Buffer, Info.module, Info.module_offset,
                           Info.module_arch, common_flags()->strip_path_prefix);
    else
      Buffer->append("%p", reinterpret_cast<void *>(Info.address));
    return;
  }
  case Location::LK_Null:
    Buffer->append("<unknown>");
    return;
  }
}

static void RenderText(InternalScopedString *Buffer, const char *Message,
                       const Diag::Arg *Args) {
  for (const char *Msg = Message; *Msg; ++Msg) {
    if (*Msg != '%') {
      Buffer->append("%c", *Msg);
      continue;
    }
    const Diag::Arg &A = Args[*++Msg - '0'];
    switch (A.Kind) {
    case Diag::AK_String:
      Buffer->append("%s", A.String);
      break;
    case Diag::AK_TypeName: {
      if (SANITIZER_WINDOWS)
        // The Windows implementation demangles names early.
        Buffer->append("'%s'", A.String);
      else
        Buffer->append("'%s'", Symbolizer::GetOrInit()->Demangle(A.String));
      break;
    }
    case Diag::AK_SInt:
      // 'long long' is guaranteed to be at least 64 bits wide.
      if (A.SInt >= INT64_MIN && A.SInt <= INT64_MAX)
        Buffer->append("%lld", (long long)A.SInt);
      else
        RenderHex(Buffer, A.SInt);
      break;
    case Diag::AK_UInt:
      if (A.UInt <= UINT64_MAX)
        Buffer->append("%llu", (unsigned long long)A.UInt);
      else
        RenderHex(Buffer, A.UInt);
      break;
    case Diag::AK_Float: {
      // FIXME: Support floating-point formatting in sanitizer_common's
      //        printf, and stop using snprintf here.
      char FloatBuffer[32];
#if SANITIZER_WINDOWS
      sprintf_s(FloatBuffer, sizeof(FloatBuffer), "%Lg", (long double)A.Float);
#else
      snprintf(FloatBuffer, sizeof(FloatBuffer), "%Lg", (long double)A.Float);
#endif
      Buffer->append("%s", FloatBuffer);
      break;
    }
    case Diag::AK_Pointer:
      Buffer->append("%p", A.Pointer);
      break;
    }
  }
}

/// Find the earliest-starting range in Ranges which ends after Loc.
static Range *upperBound(MemoryLocation Loc, Range *Ranges,
                         unsigned NumRanges) {
  Range *Best = 0;
  for (unsigned I = 0; I != NumRanges; ++I)
    if (Ranges[I].getEnd().getMemoryLocation() > Loc &&
        (!Best ||
         Best->getStart().getMemoryLocation() >
         Ranges[I].getStart().getMemoryLocation()))
      Best = &Ranges[I];
  return Best;
}

static inline uptr subtractNoOverflow(uptr LHS, uptr RHS) {
  return (LHS < RHS) ? 0 : LHS - RHS;
}

static inline uptr addNoOverflow(uptr LHS, uptr RHS) {
  const uptr Limit = (uptr)-1;
  return (LHS > Limit - RHS) ? Limit : LHS + RHS;
}

/// Render a snippet of the address space near a location.
static void PrintMemorySnippet(const Decorator &Decor, MemoryLocation Loc,
                               Range *Ranges, unsigned NumRanges,
                               const Diag::Arg *Args) {
  // Show at least the 8 bytes surrounding Loc.
  const unsigned MinBytesNearLoc = 4;
  MemoryLocation Min = subtractNoOverflow(Loc, MinBytesNearLoc);
  MemoryLocation Max = addNoOverflow(Loc, MinBytesNearLoc);
  MemoryLocation OrigMin = Min;
  for (unsigned I = 0; I < NumRanges; ++I) {
    Min = __sanitizer::Min(Ranges[I].getStart().getMemoryLocation(), Min);
    Max = __sanitizer::Max(Ranges[I].getEnd().getMemoryLocation(), Max);
  }

  // If we have too many interesting bytes, prefer to show bytes after Loc.
  const unsigned BytesToShow = 32;
  if (Max - Min > BytesToShow)
    Min = __sanitizer::Min(Max - BytesToShow, OrigMin);
  Max = addNoOverflow(Min, BytesToShow);

  if (!IsAccessibleMemoryRange(Min, Max - Min)) {
    Printf("<memory cannot be printed>\n");
    return;
  }

  // Emit data.
  InternalScopedString Buffer;
  for (uptr P = Min; P != Max; ++P) {
    unsigned char C = *reinterpret_cast<const unsigned char*>(P);
    Buffer.append("%s%02x", (P % 8 == 0) ? "  " : " ", C);
  }
  Buffer.append("\n");

  // Emit highlights.
  Buffer.append("%s", Decor.Highlight());
  Range *InRange = upperBound(Min, Ranges, NumRanges);
  for (uptr P = Min; P != Max; ++P) {
    char Pad = ' ', Byte = ' ';
    if (InRange && InRange->getEnd().getMemoryLocation() == P)
      InRange = upperBound(P, Ranges, NumRanges);
    if (!InRange && P > Loc)
      break;
    if (InRange && InRange->getStart().getMemoryLocation() < P)
      Pad = '~';
    if (InRange && InRange->getStart().getMemoryLocation() <= P)
      Byte = '~';
    if (P % 8 == 0)
      Buffer.append("%c", Pad);
    Buffer.append("%c", Pad);
    Buffer.append("%c", P == Loc ? '^' : Byte);
    Buffer.append("%c", Byte);
  }
  Buffer.append("%s\n", Decor.Default());

  // Go over the line again, and print names for the ranges.
  InRange = 0;
  unsigned Spaces = 0;
  for (uptr P = Min; P != Max; ++P) {
    if (!InRange || InRange->getEnd().getMemoryLocation() == P)
      InRange = upperBound(P, Ranges, NumRanges);
    if (!InRange)
      break;

    Spaces += (P % 8) == 0 ? 2 : 1;

    if (InRange && InRange->getStart().getMemoryLocation() == P) {
      while (Spaces--)
        Buffer.append(" ");
      RenderText(&Buffer, InRange->getText(), Args);
      Buffer.append("\n");
      // FIXME: We only support naming one range for now!
      break;
    }

    Spaces += 2;
  }

  Printf("%s", Buffer.data());
  // FIXME: Print names for anything we can identify within the line:
  //
  //  * If we can identify the memory itself as belonging to a particular
  //    global, stack variable, or dynamic allocation, then do so.
  //
  //  * If we have a pointer-size, pointer-aligned range highlighted,
  //    determine whether the value of that range is a pointer to an
  //    entity which we can name, and if so, print that name.
  //
  // This needs an external symbolizer, or (preferably) ASan instrumentation.
}

Diag::~Diag() {
  // All diagnostics should be printed under report mutex.
  ScopedReport::CheckLocked();
  Decorator Decor;
  InternalScopedString Buffer;

  // Prepare a report that a monitor process can inspect.
  if (Level == DL_Error) {
    RenderText(&Buffer, Message, Args);
    UndefinedBehaviorReport UBR{ConvertTypeToString(ET), Loc, Buffer};
    Buffer.clear();
  }

  Buffer.append("%s", Decor.Bold());
  RenderLocation(&Buffer, Loc);
  Buffer.append(":");

  switch (Level) {
  case DL_Error:
    Buffer.append("%s runtime error: %s%s", Decor.Warning(), Decor.Default(),
                  Decor.Bold());
    break;

  case DL_Note:
    Buffer.append("%s note: %s", Decor.Note(), Decor.Default());
    break;
  }

  RenderText(&Buffer, Message, Args);

  Buffer.append("%s\n", Decor.Default());
  Printf("%s", Buffer.data());

  if (Loc.isMemoryLocation())
    PrintMemorySnippet(Decor, Loc.getMemoryLocation(), Ranges, NumRanges, Args);
}

ScopedReport::Initializer::Initializer() { InitAsStandaloneIfNecessary(); }

ScopedReport::ScopedReport(ReportOptions Opts, Location SummaryLoc,
                           ErrorType Type)
    : Opts(Opts), SummaryLoc(SummaryLoc), Type(Type) {}

ScopedReport::~ScopedReport() {
  MaybePrintStackTrace(Opts.pc, Opts.bp);
  MaybeReportErrorSummary(SummaryLoc, Type);

  if (common_flags()->print_module_map >= 2)
    DumpProcessMap();

  if (flags()->halt_on_error)
    Die();
}

ALIGNED(64) static char suppression_placeholder[sizeof(SuppressionContext)];
static SuppressionContext *suppression_ctx = nullptr;
static const char kVptrCheck[] = "vptr_check";
static const char *kSuppressionTypes[] = {
#define UBSAN_CHECK(Name, SummaryKind, FSanitizeFlagName) FSanitizeFlagName,
#include "ubsan_checks.inc"
#undef UBSAN_CHECK
    kVptrCheck,
};

void __ubsan::InitializeSuppressions() {
  CHECK_EQ(nullptr, suppression_ctx);
  suppression_ctx = new (suppression_placeholder)
      SuppressionContext(kSuppressionTypes, ARRAY_SIZE(kSuppressionTypes));
  suppression_ctx->ParseFromFile(flags()->suppressions);
}

bool __ubsan::IsVptrCheckSuppressed(const char *TypeName) {
  InitAsStandaloneIfNecessary();
  CHECK(suppression_ctx);
  Suppression *s;
  return suppression_ctx->Match(TypeName, kVptrCheck, &s);
}

bool __ubsan::IsPCSuppressed(ErrorType ET, uptr PC, const char *Filename) {
  InitAsStandaloneIfNecessary();
  CHECK(suppression_ctx);
  const char *SuppType = ConvertTypeToFlagName(ET);
  // Fast path: don't symbolize PC if there is no suppressions for given UB
  // type.
  if (!suppression_ctx->HasSuppressionType(SuppType))
    return false;
  Suppression *s = nullptr;
  // Suppress by file name known to runtime.
  if (Filename != nullptr && suppression_ctx->Match(Filename, SuppType, &s))
    return true;
  // Suppress by module name.
  if (const char *Module = Symbolizer::GetOrInit()->GetModuleNameForPc(PC)) {
    if (suppression_ctx->Match(Module, SuppType, &s))
      return true;
  }
  // Suppress by function or source file name from debug info.
  SymbolizedStackHolder Stack(Symbolizer::GetOrInit()->SymbolizePC(PC));
  const AddressInfo &AI = Stack.get()->info;
  return suppression_ctx->Match(AI.function, SuppType, &s) ||
         suppression_ctx->Match(AI.file, SuppType, &s);
}

#endif  // CAN_SANITIZE_UB