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_procmaps.h"
30 #include <sys/resource.h>
35 SignalContext SignalContext::Create(void *siginfo, void *context) {
36 uptr addr = (uptr)((siginfo_t*)siginfo)->si_addr;
38 GetPcSpBp(context, &pc, &sp, &bp);
39 return SignalContext(context, addr, pc, sp, bp);
42 void 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);
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;
55 // Large stack frames can be allocated with e.g.
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"
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).
73 (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
74 (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
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);
85 ReportSIGSEGV("SEGV", sig);
88 // ---------------------- TSD ---------------- {{{1
90 static pthread_key_t tsd_key;
91 static bool tsd_key_inited = false;
92 void 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));
99 CHECK(tsd_key_inited);
100 return pthread_getspecific(tsd_key);
103 void AsanTSDSet(void *tsd) {
104 CHECK(tsd_key_inited);
105 pthread_setspecific(tsd_key, tsd);
108 void 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));
115 AsanThread::TSDDtor(tsd);
117 } // namespace __asan
119 #endif // SANITIZER_POSIX