1 //===-- asan_posix.cc -----------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file is a part of AddressSanitizer, an address sanity checker.
12 // Posix-specific details.
13 //===----------------------------------------------------------------------===//
15 #include "sanitizer_common/sanitizer_platform.h"
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"
31 #include <sys/resource.h>
36 const char *DescribeSignalOrException(int signo) {
49 void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
50 ScopedDeadlySignal signal_scope(GetCurrentThread());
51 int code = (int)((siginfo_t*)siginfo)->si_code;
52 // Write the first message using fd=2, just in case.
53 // It may actually fail to write in case stderr is closed.
54 internal_write(2, "ASAN:DEADLYSIGNAL\n", 18);
55 SignalContext sig = SignalContext::Create(siginfo, context);
57 // Access at a reasonable offset above SP, or slightly below it (to account
58 // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
59 // probably a stack overflow.
61 // On s390, the fault address in siginfo points to start of the page, not
62 // to the precise word that was accessed. Mask off the low bits of sp to
63 // take it into account.
64 bool IsStackAccess = sig.addr >= (sig.sp & ~0xFFF) &&
65 sig.addr < sig.sp + 0xFFFF;
67 bool IsStackAccess = sig.addr + 512 > sig.sp && sig.addr < sig.sp + 0xFFFF;
71 // Large stack frames can be allocated with e.g.
73 // stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
74 // If the store faults then sp will not have been updated, so test above
75 // will not work, becase the fault address will be more than just "slightly"
77 if (!IsStackAccess && IsAccessibleMemoryRange(sig.pc, 4)) {
78 u32 inst = *(unsigned *)sig.pc;
79 u32 ra = (inst >> 16) & 0x1F;
80 u32 opcd = inst >> 26;
81 u32 xo = (inst >> 1) & 0x3FF;
82 // Check for store-with-update to sp. The instructions we accept are:
83 // stbu rs,d(ra) stbux rs,ra,rb
84 // sthu rs,d(ra) sthux rs,ra,rb
85 // stwu rs,d(ra) stwux rs,ra,rb
86 // stdu rs,ds(ra) stdux rs,ra,rb
87 // where ra is r1 (the stack pointer).
89 (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
90 (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
95 // We also check si_code to filter out SEGV caused by something else other
96 // then hitting the guard page or unmapped memory, like, for example,
97 // unaligned memory access.
98 if (IsStackAccess && (code == si_SEGV_MAPERR || code == si_SEGV_ACCERR))
99 ReportStackOverflow(sig);
101 ReportDeadlySignal(signo, sig);
104 // ---------------------- TSD ---------------- {{{1
106 static pthread_key_t tsd_key;
107 static bool tsd_key_inited = false;
108 void AsanTSDInit(void (*destructor)(void *tsd)) {
109 CHECK(!tsd_key_inited);
110 tsd_key_inited = true;
111 CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
115 CHECK(tsd_key_inited);
116 return pthread_getspecific(tsd_key);
119 void AsanTSDSet(void *tsd) {
120 CHECK(tsd_key_inited);
121 pthread_setspecific(tsd_key, tsd);
124 void PlatformTSDDtor(void *tsd) {
125 AsanThreadContext *context = (AsanThreadContext*)tsd;
126 if (context->destructor_iterations > 1) {
127 context->destructor_iterations--;
128 CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
131 AsanThread::TSDDtor(tsd);
133 } // namespace __asan
135 #endif // SANITIZER_POSIX