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 fd=2, just in case.
40  // It may actually fail to write in case stderr is closed.
41  internal_write(2, "ASAN:DEADLYSIGNAL\n", 18);
42  SignalContext sig = SignalContext::Create(siginfo, context);
43
44  // Access at a reasonable offset above SP, or slightly below it (to account
45  // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
46  // probably a stack overflow.
47#ifdef __s390__
48  // On s390, the fault address in siginfo points to start of the page, not
49  // to the precise word that was accessed.  Mask off the low bits of sp to
50  // take it into account.
51  bool IsStackAccess = sig.addr >= (sig.sp & ~0xFFF) &&
52                       sig.addr < sig.sp + 0xFFFF;
53#else
54  bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
55#endif
56
57#if __powerpc__
58  // Large stack frames can be allocated with e.g.
59  //   lis r0,-10000
60  //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
61  // If the store faults then sp will not have been updated, so test above
62  // will not work, becase the fault address will be more than just "slightly"
63  // below sp.
64  if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
65    u32 inst = *(unsigned *)sig.pc;
66    u32 ra = (inst >> 16) & 0x1F;
67    u32 opcd = inst >> 26;
68    u32 xo = (inst >> 1) & 0x3FF;
69    // Check for store-with-update to sp. The instructions we accept are:
70    //   stbu rs,d(ra)          stbux rs,ra,rb
71    //   sthu rs,d(ra)          sthux rs,ra,rb
72    //   stwu rs,d(ra)          stwux rs,ra,rb
73    //   stdu rs,ds(ra)         stdux rs,ra,rb
74    // where ra is r1 (the stack pointer).
75    if (ra == 1 &&
76        (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
77         (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
78      IsStackAccess = true;
79  }
80#endif // __powerpc__
81
82  // We also check si_code to filter out SEGV caused by something else other
83  // then hitting the guard page or unmapped memory, like, for example,
84  // unaligned memory access.
85  if (IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR))
86    ReportStackOverflow(sig);
87  else if (signo == SIGFPE)
88    ReportDeadlySignal("FPE", sig);
89  else if (signo == SIGILL)
90    ReportDeadlySignal("ILL", sig);
91  else
92    ReportDeadlySignal("SEGV", sig);
93}
94
95// ---------------------- TSD ---------------- {{{1
96
97static pthread_key_t tsd_key;
98static bool tsd_key_inited = false;
99void AsanTSDInit(void (*destructor)(void *tsd)) {
100  CHECK(!tsd_key_inited);
101  tsd_key_inited = true;
102  CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
103}
104
105void *AsanTSDGet() {
106  CHECK(tsd_key_inited);
107  return pthread_getspecific(tsd_key);
108}
109
110void AsanTSDSet(void *tsd) {
111  CHECK(tsd_key_inited);
112  pthread_setspecific(tsd_key, tsd);
113}
114
115void PlatformTSDDtor(void *tsd) {
116  AsanThreadContext *context = (AsanThreadContext*)tsd;
117  if (context->destructor_iterations > 1) {
118    context->destructor_iterations--;
119    CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
120    return;
121  }
122  AsanThread::TSDDtor(tsd);
123}
124}  // namespace __asan
125
126#endif  // SANITIZER_POSIX
127