asan_posix.cc revision 276851 
1//===-- asan_posix.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// Posix-specific details.
13//===----------------------------------------------------------------------===//
14
15#include "sanitizer_common/sanitizer_platform.h"
16#if SANITIZER_POSIX
17
18#include "asan_internal.h"
19#include "asan_interceptors.h"
20#include "asan_mapping.h"
21#include "asan_report.h"
22#include "asan_stack.h"
23#include "sanitizer_common/sanitizer_libc.h"
24#include "sanitizer_common/sanitizer_procmaps.h"
25
26#include <pthread.h>
27#include <signal.h>
28#include <stdlib.h>
29#include <sys/time.h>
30#include <sys/resource.h>
31#include <unistd.h>
32
33namespace __asan {
34
35SignalContext SignalContext::Create(void *siginfo, void *context) {
36  uptr addr = (uptr)((siginfo_t*)siginfo)->si_addr;
37  uptr pc, sp, bp;
38  GetPcSpBp(context, &pc, &sp, &bp);
39  return SignalContext(context, addr, pc, sp, bp);
40}
41
42void AsanOnSIGSEGV(int, void *siginfo, void *context) {
43  ScopedDeadlySignal signal_scope(GetCurrentThread());
44  int code = (int)((siginfo_t*)siginfo)->si_code;
45  // Write the first message using the bullet-proof write.
46  if (13 != internal_write(2, "ASAN:SIGSEGV\n", 13)) Die();
47  SignalContext sig = SignalContext::Create(siginfo, context);
48
49  // Access at a reasonable offset above SP, or slightly below it (to account
50  // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
51  // probably a stack overflow.
52  bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
53
54#if __powerpc__
55  // Large stack frames can be allocated with e.g.
56  //   lis r0,-10000
57  //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
58  // If the store faults then sp will not have been updated, so test above
59  // will not work, becase the fault address will be more than just "slightly"
60  // below sp.
61  if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
62    u32 inst = *(unsigned *)sig.pc;
63    u32 ra = (inst >> 16) & 0x1F;
64    u32 opcd = inst >> 26;
65    u32 xo = (inst >> 1) & 0x3FF;
66    // Check for store-with-update to sp. The instructions we accept are:
67    //   stbu rs,d(ra)          stbux rs,ra,rb
68    //   sthu rs,d(ra)          sthux rs,ra,rb
69    //   stwu rs,d(ra)          stwux rs,ra,rb
70    //   stdu rs,ds(ra)         stdux rs,ra,rb
71    // where ra is r1 (the stack pointer).
72    if (ra == 1 &&
73        (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
74         (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
75      IsStackAccess = true;
76  }
77#endif // __powerpc__
78
79  // We also check si_code to filter out SEGV caused by something else other
80  // then hitting the guard page or unmapped memory, like, for example,
81  // unaligned memory access.
82  if (IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR))
83    ReportStackOverflow(sig);
84  else
85    ReportSIGSEGV("SEGV", sig);
86}
87
88// ---------------------- TSD ---------------- {{{1
89
90static pthread_key_t tsd_key;
91static bool tsd_key_inited = false;
92void AsanTSDInit(void (*destructor)(void *tsd)) {
93  CHECK(!tsd_key_inited);
94  tsd_key_inited = true;
95  CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
96}
97
98void *AsanTSDGet() {
99  CHECK(tsd_key_inited);
100  return pthread_getspecific(tsd_key);
101}
102
103void AsanTSDSet(void *tsd) {
104  CHECK(tsd_key_inited);
105  pthread_setspecific(tsd_key, tsd);
106}
107
108void PlatformTSDDtor(void *tsd) {
109  AsanThreadContext *context = (AsanThreadContext*)tsd;
110  if (context->destructor_iterations > 1) {
111    context->destructor_iterations--;
112    CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
113    return;
114  }
115  AsanThread::TSDDtor(tsd);
116}
117}  // namespace __asan
118
119#endif  // SANITIZER_POSIX
120