diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp index a9533d6fc04ca..b3edcb77d13b4 100644 --- a/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp +++ b/compiler-rt/lib/sanitizer_common/sanitizer_procmaps_mac.cpp @@ -42,7 +42,6 @@ struct MemoryMappedSegmentData { const char *current_load_cmd_addr; u32 lc_type; uptr base_virt_addr; - uptr addr_mask; }; template @@ -51,12 +50,58 @@ static void NextSectionLoad(LoadedModule *module, MemoryMappedSegmentData *data, const Section *sc = (const Section *)data->current_load_cmd_addr; data->current_load_cmd_addr += sizeof(Section); - uptr sec_start = (sc->addr & data->addr_mask) + data->base_virt_addr; + uptr sec_start = sc->addr + data->base_virt_addr; uptr sec_end = sec_start + sc->size; module->addAddressRange(sec_start, sec_end, /*executable=*/false, isWritable, sc->sectname); } +static bool VerifyMemoryMapping(MemoryMappingLayout* mapping) { + InternalMmapVector modules; + modules.reserve(128); // matches DumpProcessMap + mapping->DumpListOfModules(&modules); + + InternalMmapVector segments; + for (uptr i = 0; i < modules.size(); ++i) { + for (auto& range : modules[i].ranges()) { + segments.push_back(range); + } + } + + // Verify that none of the segments overlap: + // 1. Sort the segments by the start address + // 2. Check that every segment starts after the previous one ends. + Sort(segments.data(), segments.size(), + [](LoadedModule::AddressRange& a, LoadedModule::AddressRange& b) { + return a.beg < b.beg; + }); + + // To avoid spam, we only print the report message once-per-process. + static bool invalid_module_map_reported = false; + bool well_formed = true; + + for (size_t i = 1; i < segments.size(); i++) { + uptr cur_start = segments[i].beg; + uptr prev_end = segments[i - 1].end; + if (cur_start < prev_end) { + well_formed = false; + VReport(2, "Overlapping mappings: %s start = %p, %s end = %p\n", + segments[i].name, (void*)cur_start, segments[i - 1].name, + (void*)prev_end); + if (!invalid_module_map_reported) { + Report( + "WARN: Invalid dyld module map detected. This is most likely a bug " + "in the sanitizer.\n"); + Report("WARN: Backtraces may be unreliable.\n"); + invalid_module_map_reported = true; + } + } + } + + mapping->Reset(); + return well_formed; +} + void MemoryMappedSegment::AddAddressRanges(LoadedModule *module) { // Don't iterate over sections when the caller hasn't set up the // data pointer, when there are no sections, or when the segment @@ -82,6 +127,7 @@ void MemoryMappedSegment::AddAddressRanges(LoadedModule *module) { MemoryMappingLayout::MemoryMappingLayout(bool cache_enabled) { Reset(); + VerifyMemoryMapping(this); } MemoryMappingLayout::~MemoryMappingLayout() { @@ -187,6 +233,7 @@ typedef struct dyld_shared_cache_dylib_text_info extern bool _dyld_get_shared_cache_uuid(uuid_t uuid); extern const void *_dyld_get_shared_cache_range(size_t *length); +extern intptr_t _dyld_get_image_slide(const struct mach_header* mh); extern int dyld_shared_cache_iterate_text( const uuid_t cacheUuid, void (^callback)(const dyld_shared_cache_dylib_text_info *info)); @@ -255,23 +302,21 @@ static bool NextSegmentLoad(MemoryMappedSegment *segment, layout_data->current_load_cmd_count--; if (((const load_command *)lc)->cmd == kLCSegment) { const SegmentCommand* sc = (const SegmentCommand *)lc; - uptr base_virt_addr, addr_mask; - if (layout_data->current_image == kDyldImageIdx) { - base_virt_addr = (uptr)get_dyld_hdr(); - // vmaddr is masked with 0xfffff because on macOS versions < 10.12, - // it contains an absolute address rather than an offset for dyld. - // To make matters even more complicated, this absolute address - // isn't actually the absolute segment address, but the offset portion - // of the address is accurate when combined with the dyld base address, - // and the mask will give just this offset. - addr_mask = 0xfffff; - } else { + if (strncmp(sc->segname, "__LINKEDIT", sizeof("__LINKEDIT")) == 0) { + // The LINKEDIT sections are for internal linker use, and may alias + // with the LINKEDIT section for other modules. (If we included them, + // our memory map would contain overlappping sections.) + return false; + } + + uptr base_virt_addr; + if (layout_data->current_image == kDyldImageIdx) + base_virt_addr = (uptr)_dyld_get_image_slide(get_dyld_hdr()); + else base_virt_addr = (uptr)_dyld_get_image_vmaddr_slide(layout_data->current_image); - addr_mask = ~0; - } - segment->start = (sc->vmaddr & addr_mask) + base_virt_addr; + segment->start = sc->vmaddr + base_virt_addr; segment->end = segment->start + sc->vmsize; // Most callers don't need section information, so only fill this struct // when required. @@ -281,7 +326,6 @@ static bool NextSegmentLoad(MemoryMappedSegment *segment, (const char *)lc + sizeof(SegmentCommand); seg_data->lc_type = kLCSegment; seg_data->base_virt_addr = base_virt_addr; - seg_data->addr_mask = addr_mask; internal_strncpy(seg_data->name, sc->segname, ARRAY_SIZE(seg_data->name)); } diff --git a/compiler-rt/test/asan/TestCases/Darwin/asan-verify-module-map.cpp b/compiler-rt/test/asan/TestCases/Darwin/asan-verify-module-map.cpp new file mode 100644 index 0000000000000..7660841c72877 --- /dev/null +++ b/compiler-rt/test/asan/TestCases/Darwin/asan-verify-module-map.cpp @@ -0,0 +1,25 @@ +// This test simply checks that the "Invalid dyld module map" warning is not printed +// in the output of a backtrace. + +// RUN: %clangxx_asan -DSHARED_LIB -g %s -dynamiclib -o %t.dylib +// RUN: %clangxx_asan -O0 -g %s %t.dylib -o %t.executable +// RUN: %env_asan_opts="print_module_map=2" not %run %t.executable 2>&1 | FileCheck %s -DDYLIB=%t.dylib + +// CHECK-NOT: WARN: Invalid dyld module map +// CHECK-DAG: 0x{{.*}}-0x{{.*}} [[DYLIB]] +// CHECK-DAG: 0x{{.*}}-0x{{.*}} {{.*}}libsystem + +#ifdef SHARED_LIB +extern "C" void foo(int *a) { *a = 5; } +#else +# include + +extern "C" void foo(int *a); + +int main() { + int *a = (int *)malloc(sizeof(int)); + free(a); + foo(a); + return 0; +} +#endif \ No newline at end of file