501 lines
16 KiB
C++
501 lines
16 KiB
C++
//===-- asan_descriptions.cc ------------------------------------*- C++ -*-===//
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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//
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// ASan functions for getting information about an address and/or printing it.
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//===----------------------------------------------------------------------===//
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#include "asan_descriptions.h"
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#include "asan_mapping.h"
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#include "asan_report.h"
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#include "asan_stack.h"
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#include "sanitizer_common/sanitizer_stackdepot.h"
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namespace __asan {
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AsanThreadIdAndName::AsanThreadIdAndName(AsanThreadContext *t) {
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Init(t->tid, t->name);
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}
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AsanThreadIdAndName::AsanThreadIdAndName(u32 tid) {
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if (tid == kInvalidTid) {
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Init(tid, "");
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} else {
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asanThreadRegistry().CheckLocked();
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AsanThreadContext *t = GetThreadContextByTidLocked(tid);
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Init(tid, t->name);
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}
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}
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void AsanThreadIdAndName::Init(u32 tid, const char *tname) {
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int len = internal_snprintf(name, sizeof(name), "T%d", tid);
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CHECK(((unsigned int)len) < sizeof(name));
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if (tname[0] != '\0')
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internal_snprintf(&name[len], sizeof(name) - len, " (%s)", tname);
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}
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void DescribeThread(AsanThreadContext *context) {
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CHECK(context);
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asanThreadRegistry().CheckLocked();
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// No need to announce the main thread.
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if (context->tid == 0 || context->announced) {
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return;
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}
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context->announced = true;
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InternalScopedString str(1024);
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str.append("Thread %s", AsanThreadIdAndName(context).c_str());
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if (context->parent_tid == kInvalidTid) {
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str.append(" created by unknown thread\n");
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Printf("%s", str.data());
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return;
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}
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str.append(" created by %s here:\n",
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AsanThreadIdAndName(context->parent_tid).c_str());
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Printf("%s", str.data());
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StackDepotGet(context->stack_id).Print();
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// Recursively described parent thread if needed.
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if (flags()->print_full_thread_history) {
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AsanThreadContext *parent_context =
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GetThreadContextByTidLocked(context->parent_tid);
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DescribeThread(parent_context);
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}
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}
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// Shadow descriptions
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static bool GetShadowKind(uptr addr, ShadowKind *shadow_kind) {
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CHECK(!AddrIsInMem(addr));
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if (AddrIsInShadowGap(addr)) {
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*shadow_kind = kShadowKindGap;
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} else if (AddrIsInHighShadow(addr)) {
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*shadow_kind = kShadowKindHigh;
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} else if (AddrIsInLowShadow(addr)) {
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*shadow_kind = kShadowKindLow;
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} else {
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CHECK(0 && "Address is not in memory and not in shadow?");
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return false;
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}
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return true;
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}
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bool DescribeAddressIfShadow(uptr addr) {
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ShadowAddressDescription descr;
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if (!GetShadowAddressInformation(addr, &descr)) return false;
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descr.Print();
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return true;
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}
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bool GetShadowAddressInformation(uptr addr, ShadowAddressDescription *descr) {
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if (AddrIsInMem(addr)) return false;
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ShadowKind shadow_kind;
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if (!GetShadowKind(addr, &shadow_kind)) return false;
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if (shadow_kind != kShadowKindGap) descr->shadow_byte = *(u8 *)addr;
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descr->addr = addr;
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descr->kind = shadow_kind;
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return true;
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}
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// Heap descriptions
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static void GetAccessToHeapChunkInformation(ChunkAccess *descr,
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AsanChunkView chunk, uptr addr,
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uptr access_size) {
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descr->bad_addr = addr;
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if (chunk.AddrIsAtLeft(addr, access_size, &descr->offset)) {
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descr->access_type = kAccessTypeLeft;
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} else if (chunk.AddrIsAtRight(addr, access_size, &descr->offset)) {
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descr->access_type = kAccessTypeRight;
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if (descr->offset < 0) {
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descr->bad_addr -= descr->offset;
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descr->offset = 0;
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}
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} else if (chunk.AddrIsInside(addr, access_size, &descr->offset)) {
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descr->access_type = kAccessTypeInside;
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} else {
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descr->access_type = kAccessTypeUnknown;
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}
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descr->chunk_begin = chunk.Beg();
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descr->chunk_size = chunk.UsedSize();
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descr->user_requested_alignment = chunk.UserRequestedAlignment();
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descr->alloc_type = chunk.GetAllocType();
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}
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static void PrintHeapChunkAccess(uptr addr, const ChunkAccess &descr) {
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Decorator d;
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InternalScopedString str(4096);
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str.append("%s", d.Location());
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switch (descr.access_type) {
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case kAccessTypeLeft:
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str.append("%p is located %zd bytes to the left of",
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(void *)descr.bad_addr, descr.offset);
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break;
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case kAccessTypeRight:
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str.append("%p is located %zd bytes to the right of",
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(void *)descr.bad_addr, descr.offset);
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break;
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case kAccessTypeInside:
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str.append("%p is located %zd bytes inside of", (void *)descr.bad_addr,
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descr.offset);
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break;
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case kAccessTypeUnknown:
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str.append(
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"%p is located somewhere around (this is AddressSanitizer bug!)",
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(void *)descr.bad_addr);
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}
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str.append(" %zu-byte region [%p,%p)\n", descr.chunk_size,
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(void *)descr.chunk_begin,
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(void *)(descr.chunk_begin + descr.chunk_size));
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str.append("%s", d.Default());
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Printf("%s", str.data());
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}
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bool GetHeapAddressInformation(uptr addr, uptr access_size,
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HeapAddressDescription *descr) {
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AsanChunkView chunk = FindHeapChunkByAddress(addr);
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if (!chunk.IsValid()) {
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return false;
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}
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descr->addr = addr;
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GetAccessToHeapChunkInformation(&descr->chunk_access, chunk, addr,
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access_size);
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CHECK_NE(chunk.AllocTid(), kInvalidTid);
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descr->alloc_tid = chunk.AllocTid();
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descr->alloc_stack_id = chunk.GetAllocStackId();
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descr->free_tid = chunk.FreeTid();
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if (descr->free_tid != kInvalidTid)
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descr->free_stack_id = chunk.GetFreeStackId();
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return true;
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}
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static StackTrace GetStackTraceFromId(u32 id) {
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CHECK(id);
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StackTrace res = StackDepotGet(id);
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CHECK(res.trace);
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return res;
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}
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bool DescribeAddressIfHeap(uptr addr, uptr access_size) {
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HeapAddressDescription descr;
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if (!GetHeapAddressInformation(addr, access_size, &descr)) {
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Printf(
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"AddressSanitizer can not describe address in more detail "
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"(wild memory access suspected).\n");
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return false;
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}
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descr.Print();
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return true;
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}
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// Stack descriptions
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bool GetStackAddressInformation(uptr addr, uptr access_size,
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StackAddressDescription *descr) {
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AsanThread *t = FindThreadByStackAddress(addr);
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if (!t) return false;
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descr->addr = addr;
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descr->tid = t->tid();
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// Try to fetch precise stack frame for this access.
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AsanThread::StackFrameAccess access;
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if (!t->GetStackFrameAccessByAddr(addr, &access)) {
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descr->frame_descr = nullptr;
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return true;
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}
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descr->offset = access.offset;
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descr->access_size = access_size;
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descr->frame_pc = access.frame_pc;
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descr->frame_descr = access.frame_descr;
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#if SANITIZER_PPC64V1
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// On PowerPC64 ELFv1, the address of a function actually points to a
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// three-doubleword data structure with the first field containing
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// the address of the function's code.
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descr->frame_pc = *reinterpret_cast<uptr *>(descr->frame_pc);
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#endif
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descr->frame_pc += 16;
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return true;
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}
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static void PrintAccessAndVarIntersection(const StackVarDescr &var, uptr addr,
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uptr access_size, uptr prev_var_end,
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uptr next_var_beg) {
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uptr var_end = var.beg + var.size;
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uptr addr_end = addr + access_size;
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const char *pos_descr = nullptr;
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// If the variable [var.beg, var_end) is the nearest variable to the
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// current memory access, indicate it in the log.
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if (addr >= var.beg) {
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if (addr_end <= var_end)
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pos_descr = "is inside"; // May happen if this is a use-after-return.
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else if (addr < var_end)
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pos_descr = "partially overflows";
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else if (addr_end <= next_var_beg &&
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next_var_beg - addr_end >= addr - var_end)
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pos_descr = "overflows";
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} else {
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if (addr_end > var.beg)
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pos_descr = "partially underflows";
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else if (addr >= prev_var_end && addr - prev_var_end >= var.beg - addr_end)
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pos_descr = "underflows";
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}
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InternalScopedString str(1024);
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str.append(" [%zd, %zd)", var.beg, var_end);
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// Render variable name.
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str.append(" '");
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for (uptr i = 0; i < var.name_len; ++i) {
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str.append("%c", var.name_pos[i]);
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}
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str.append("'");
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if (var.line > 0) {
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str.append(" (line %d)", var.line);
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}
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if (pos_descr) {
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Decorator d;
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// FIXME: we may want to also print the size of the access here,
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// but in case of accesses generated by memset it may be confusing.
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str.append("%s <== Memory access at offset %zd %s this variable%s\n",
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d.Location(), addr, pos_descr, d.Default());
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} else {
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str.append("\n");
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}
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Printf("%s", str.data());
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}
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bool DescribeAddressIfStack(uptr addr, uptr access_size) {
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StackAddressDescription descr;
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if (!GetStackAddressInformation(addr, access_size, &descr)) return false;
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descr.Print();
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return true;
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}
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// Global descriptions
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static void DescribeAddressRelativeToGlobal(uptr addr, uptr access_size,
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const __asan_global &g) {
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InternalScopedString str(4096);
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Decorator d;
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str.append("%s", d.Location());
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if (addr < g.beg) {
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str.append("%p is located %zd bytes to the left", (void *)addr,
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g.beg - addr);
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} else if (addr + access_size > g.beg + g.size) {
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if (addr < g.beg + g.size) addr = g.beg + g.size;
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str.append("%p is located %zd bytes to the right", (void *)addr,
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addr - (g.beg + g.size));
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} else {
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// Can it happen?
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str.append("%p is located %zd bytes inside", (void *)addr, addr - g.beg);
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}
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str.append(" of global variable '%s' defined in '",
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MaybeDemangleGlobalName(g.name));
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PrintGlobalLocation(&str, g);
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str.append("' (0x%zx) of size %zu\n", g.beg, g.size);
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str.append("%s", d.Default());
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PrintGlobalNameIfASCII(&str, g);
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Printf("%s", str.data());
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}
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bool GetGlobalAddressInformation(uptr addr, uptr access_size,
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GlobalAddressDescription *descr) {
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descr->addr = addr;
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int globals_num = GetGlobalsForAddress(addr, descr->globals, descr->reg_sites,
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ARRAY_SIZE(descr->globals));
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descr->size = globals_num;
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descr->access_size = access_size;
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return globals_num != 0;
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}
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bool DescribeAddressIfGlobal(uptr addr, uptr access_size,
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const char *bug_type) {
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GlobalAddressDescription descr;
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if (!GetGlobalAddressInformation(addr, access_size, &descr)) return false;
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descr.Print(bug_type);
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return true;
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}
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void ShadowAddressDescription::Print() const {
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Printf("Address %p is located in the %s area.\n", addr, ShadowNames[kind]);
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}
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void GlobalAddressDescription::Print(const char *bug_type) const {
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for (int i = 0; i < size; i++) {
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DescribeAddressRelativeToGlobal(addr, access_size, globals[i]);
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if (bug_type &&
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0 == internal_strcmp(bug_type, "initialization-order-fiasco") &&
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reg_sites[i]) {
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Printf(" registered at:\n");
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StackDepotGet(reg_sites[i]).Print();
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}
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}
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}
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bool GlobalAddressDescription::PointsInsideTheSameVariable(
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const GlobalAddressDescription &other) const {
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if (size == 0 || other.size == 0) return false;
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for (uptr i = 0; i < size; i++) {
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const __asan_global &a = globals[i];
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for (uptr j = 0; j < other.size; j++) {
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const __asan_global &b = other.globals[j];
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if (a.beg == b.beg &&
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a.beg <= addr &&
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b.beg <= other.addr &&
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(addr + access_size) < (a.beg + a.size) &&
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(other.addr + other.access_size) < (b.beg + b.size))
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return true;
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}
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}
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return false;
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}
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void StackAddressDescription::Print() const {
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Decorator d;
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Printf("%s", d.Location());
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Printf("Address %p is located in stack of thread %s", addr,
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AsanThreadIdAndName(tid).c_str());
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if (!frame_descr) {
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Printf("%s\n", d.Default());
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return;
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}
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Printf(" at offset %zu in frame%s\n", offset, d.Default());
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// Now we print the frame where the alloca has happened.
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// We print this frame as a stack trace with one element.
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// The symbolizer may print more than one frame if inlining was involved.
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// The frame numbers may be different than those in the stack trace printed
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// previously. That's unfortunate, but I have no better solution,
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// especially given that the alloca may be from entirely different place
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// (e.g. use-after-scope, or different thread's stack).
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Printf("%s", d.Default());
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StackTrace alloca_stack(&frame_pc, 1);
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alloca_stack.Print();
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InternalMmapVector<StackVarDescr> vars;
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vars.reserve(16);
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if (!ParseFrameDescription(frame_descr, &vars)) {
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Printf(
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"AddressSanitizer can't parse the stack frame "
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"descriptor: |%s|\n",
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frame_descr);
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// 'addr' is a stack address, so return true even if we can't parse frame
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return;
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}
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uptr n_objects = vars.size();
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// Report the number of stack objects.
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Printf(" This frame has %zu object(s):\n", n_objects);
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// Report all objects in this frame.
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for (uptr i = 0; i < n_objects; i++) {
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uptr prev_var_end = i ? vars[i - 1].beg + vars[i - 1].size : 0;
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uptr next_var_beg = i + 1 < n_objects ? vars[i + 1].beg : ~(0UL);
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PrintAccessAndVarIntersection(vars[i], offset, access_size, prev_var_end,
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next_var_beg);
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}
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Printf(
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"HINT: this may be a false positive if your program uses "
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"some custom stack unwind mechanism, swapcontext or vfork\n");
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if (SANITIZER_WINDOWS)
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Printf(" (longjmp, SEH and C++ exceptions *are* supported)\n");
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else
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Printf(" (longjmp and C++ exceptions *are* supported)\n");
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DescribeThread(GetThreadContextByTidLocked(tid));
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}
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void HeapAddressDescription::Print() const {
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PrintHeapChunkAccess(addr, chunk_access);
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asanThreadRegistry().CheckLocked();
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AsanThreadContext *alloc_thread = GetThreadContextByTidLocked(alloc_tid);
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StackTrace alloc_stack = GetStackTraceFromId(alloc_stack_id);
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Decorator d;
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AsanThreadContext *free_thread = nullptr;
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if (free_tid != kInvalidTid) {
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free_thread = GetThreadContextByTidLocked(free_tid);
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Printf("%sfreed by thread %s here:%s\n", d.Allocation(),
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AsanThreadIdAndName(free_thread).c_str(), d.Default());
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StackTrace free_stack = GetStackTraceFromId(free_stack_id);
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free_stack.Print();
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Printf("%spreviously allocated by thread %s here:%s\n", d.Allocation(),
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AsanThreadIdAndName(alloc_thread).c_str(), d.Default());
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} else {
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Printf("%sallocated by thread %s here:%s\n", d.Allocation(),
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AsanThreadIdAndName(alloc_thread).c_str(), d.Default());
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}
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alloc_stack.Print();
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DescribeThread(GetCurrentThread());
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if (free_thread) DescribeThread(free_thread);
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DescribeThread(alloc_thread);
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}
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AddressDescription::AddressDescription(uptr addr, uptr access_size,
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bool shouldLockThreadRegistry) {
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if (GetShadowAddressInformation(addr, &data.shadow)) {
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data.kind = kAddressKindShadow;
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return;
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}
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if (GetHeapAddressInformation(addr, access_size, &data.heap)) {
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data.kind = kAddressKindHeap;
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return;
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}
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bool isStackMemory = false;
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if (shouldLockThreadRegistry) {
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ThreadRegistryLock l(&asanThreadRegistry());
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isStackMemory = GetStackAddressInformation(addr, access_size, &data.stack);
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} else {
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isStackMemory = GetStackAddressInformation(addr, access_size, &data.stack);
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}
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if (isStackMemory) {
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data.kind = kAddressKindStack;
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return;
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}
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if (GetGlobalAddressInformation(addr, access_size, &data.global)) {
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data.kind = kAddressKindGlobal;
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return;
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}
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data.kind = kAddressKindWild;
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addr = 0;
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}
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void PrintAddressDescription(uptr addr, uptr access_size,
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const char *bug_type) {
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ShadowAddressDescription shadow_descr;
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if (GetShadowAddressInformation(addr, &shadow_descr)) {
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shadow_descr.Print();
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return;
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}
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GlobalAddressDescription global_descr;
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if (GetGlobalAddressInformation(addr, access_size, &global_descr)) {
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global_descr.Print(bug_type);
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return;
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}
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StackAddressDescription stack_descr;
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if (GetStackAddressInformation(addr, access_size, &stack_descr)) {
|
|
stack_descr.Print();
|
|
return;
|
|
}
|
|
|
|
HeapAddressDescription heap_descr;
|
|
if (GetHeapAddressInformation(addr, access_size, &heap_descr)) {
|
|
heap_descr.Print();
|
|
return;
|
|
}
|
|
|
|
// We exhausted our possibilities. Bail out.
|
|
Printf(
|
|
"AddressSanitizer can not describe address in more detail "
|
|
"(wild memory access suspected).\n");
|
|
}
|
|
} // namespace __asan
|