asan_posix.cc revision 302408 
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_posix.h"
25#include "sanitizer_common/sanitizer_procmaps.h"
26
27#include <pthread.h>
28#include <signal.h>
29#include <stdlib.h>
30#include <sys/time.h>
31#include <sys/resource.h>
32#include <unistd.h>
33
34namespace __asan {
35
36void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
37  ScopedDeadlySignal signal_scope(GetCurrentThread());
38  int code = (int)((siginfo_t*)siginfo)->si_code;
39  // Write the first message using the bullet-proof write.
40  if (18 != internal_write(2, "ASAN:DEADLYSIGNAL\n", 18)) Die();
41  SignalContext sig = SignalContext::Create(siginfo, context);
42
43  // Access at a reasonable offset above SP, or slightly below it (to account
44  // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
45  // probably a stack overflow.
46  bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
47
48#if __powerpc__
49  // Large stack frames can be allocated with e.g.
50  //   lis r0,-10000
51  //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
52  // If the store faults then sp will not have been updated, so test above
53  // will not work, becase the fault address will be more than just "slightly"
54  // below sp.
55  if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
56    u32 inst = *(unsigned *)sig.pc;
57    u32 ra = (inst >> 16) & 0x1F;
58    u32 opcd = inst >> 26;
59    u32 xo = (inst >> 1) & 0x3FF;
60    // Check for store-with-update to sp. The instructions we accept are:
61    //   stbu rs,d(ra)          stbux rs,ra,rb
62    //   sthu rs,d(ra)          sthux rs,ra,rb
63    //   stwu rs,d(ra)          stwux rs,ra,rb
64    //   stdu rs,ds(ra)         stdux rs,ra,rb
65    // where ra is r1 (the stack pointer).
66    if (ra == 1 &&
67        (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
68         (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
69      IsStackAccess = true;
70  }
71#endif // __powerpc__
72
73  // We also check si_code to filter out SEGV caused by something else other
74  // then hitting the guard page or unmapped memory, like, for example,
75  // unaligned memory access.
76  if (IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR))
77    ReportStackOverflow(sig);
78  else if (signo == SIGFPE)
79    ReportDeadlySignal("FPE", sig);
80  else if (signo == SIGILL)
81    ReportDeadlySignal("ILL", sig);
82  else
83    ReportDeadlySignal("SEGV", sig);
84}
85
86// ---------------------- TSD ---------------- {{{1
87
88static pthread_key_t tsd_key;
89static bool tsd_key_inited = false;
90void AsanTSDInit(void (*destructor)(void *tsd)) {
91  CHECK(!tsd_key_inited);
92  tsd_key_inited = true;
93  CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
94}
95
96void *AsanTSDGet() {
97  CHECK(tsd_key_inited);
98  return pthread_getspecific(tsd_key);
99}
100
101void AsanTSDSet(void *tsd) {
102  CHECK(tsd_key_inited);
103  pthread_setspecific(tsd_key, tsd);
104}
105
106void PlatformTSDDtor(void *tsd) {
107  AsanThreadContext *context = (AsanThreadContext*)tsd;
108  if (context->destructor_iterations > 1) {
109    context->destructor_iterations--;
110    CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
111    return;
112  }
113  AsanThread::TSDDtor(tsd);
114}
115}  // namespace __asan
116
117#endif  // SANITIZER_POSIX
118