libsanitizer/asan/asan_posix.cc

   1 //===-- asan_posix.cc -----------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Posix-specific details.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #if SANITIZER_POSIX
  15
  16 #include "asan_internal.h"
  17 #include "asan_interceptors.h"
  18 #include "asan_mapping.h"
  19 #include "asan_report.h"
  20 #include "asan_stack.h"
  21 #include "sanitizer_common/sanitizer_libc.h"
  22 #include "sanitizer_common/sanitizer_posix.h"
  23 #include "sanitizer_common/sanitizer_procmaps.h"
  24
  25 #include <pthread.h>
  26 #include <signal.h>
  27 #include <stdlib.h>
  28 #include <sys/time.h>
  29 #include <sys/resource.h>
  30 #include <unistd.h>
  31
  32 namespace __asan {
  33
  34 const char *DescribeSignalOrException(int signo) {
  35   switch (signo) {
  36     case SIGFPE:
  37       return "FPE";
  38     case SIGILL:
  39       return "ILL";
  40     case SIGABRT:
  41       return "ABRT";
  42     default:
  43       return "SEGV";
  44   }
  45 }
  46
  47 void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
  48   ScopedDeadlySignal signal_scope(GetCurrentThread());
  49   int code = (int)((siginfo_t*)siginfo)->si_code;
  50   // Write the first message using fd=2, just in case.
  51   // It may actually fail to write in case stderr is closed.
  52   internal_write(2, "ASAN:DEADLYSIGNAL\n", 18);
  53   SignalContext sig = SignalContext::Create(siginfo, context);
  54
  55   // Access at a reasonable offset above SP, or slightly below it (to account
  56   // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
  57   // probably a stack overflow.
  58 #ifdef __s390__
  59   // On s390, the fault address in siginfo points to start of the page, not
  60   // to the precise word that was accessed.  Mask off the low bits of sp to
  61   // take it into account.
  62   bool IsStackAccess = sig.addr >= (sig.sp & ~0xFFF) &&
  63                        sig.addr < sig.sp + 0xFFFF;
  64 #else
  65   bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
  66 #endif
  67
  68 #if __powerpc__
  69   // Large stack frames can be allocated with e.g.
  70   //   lis r0,-10000
  71   //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
  72   // If the store faults then sp will not have been updated, so test above
  73   // will not work, becase the fault address will be more than just "slightly"
  74   // below sp.
  75   if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
  76     u32 inst = *(unsigned *)sig.pc;
  77     u32 ra = (inst >> 16) & 0x1F;
  78     u32 opcd = inst >> 26;
  79     u32 xo = (inst >> 1) & 0x3FF;
  80     // Check for store-with-update to sp. The instructions we accept are:
  81     //   stbu rs,d(ra)          stbux rs,ra,rb
  82     //   sthu rs,d(ra)          sthux rs,ra,rb
  83     //   stwu rs,d(ra)          stwux rs,ra,rb
  84     //   stdu rs,ds(ra)         stdux rs,ra,rb
  85     // where ra is r1 (the stack pointer).
  86     if (ra == 1 &&
  87         (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
  88          (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
  89       IsStackAccess = true;
  90   }
  91 #endif // __powerpc__
  92
  93   // We also check si_code to filter out SEGV caused by something else other
  94   // then hitting the guard page or unmapped memory, like, for example,
  95   // unaligned memory access.
  96   if (IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR))
  97     ReportStackOverflow(sig);
  98   else
  99     ReportDeadlySignal(signo, sig);
 100 }
 101
 102 // ---------------------- TSD ---------------- {{{1
 103
 104 static pthread_key_t tsd_key;
 105 static bool tsd_key_inited = false;
 106 void AsanTSDInit(void (*destructor)(void *tsd)) {
 107   CHECK(!tsd_key_inited);
 108   tsd_key_inited = true;
 109   CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
 110 }
 111
 112 void *AsanTSDGet() {
 113   CHECK(tsd_key_inited);
 114   return pthread_getspecific(tsd_key);
 115 }
 116
 117 void AsanTSDSet(void *tsd) {
 118   CHECK(tsd_key_inited);
 119   pthread_setspecific(tsd_key, tsd);
 120 }
 121
 122 void PlatformTSDDtor(void *tsd) {
 123   AsanThreadContext *context = (AsanThreadContext*)tsd;
 124   if (context->destructor_iterations > 1) {
 125     context->destructor_iterations--;
 126     CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
 127     return;
 128   }
 129   AsanThread::TSDDtor(tsd);
 130 }
 131 }  // namespace __asan
 132
 133 #endif  // SANITIZER_POSIX