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-rw-r--r--lib/hwasan/hwasan.cpp155
1 files changed, 136 insertions, 19 deletions
diff --git a/lib/hwasan/hwasan.cpp b/lib/hwasan/hwasan.cpp
index 6f2246552164..7b5c6c694be9 100644
--- a/lib/hwasan/hwasan.cpp
+++ b/lib/hwasan/hwasan.cpp
@@ -193,27 +193,12 @@ void UpdateMemoryUsage() {
void UpdateMemoryUsage() {}
#endif
-// Prepare to run instrumented code on the main thread.
-void InitInstrumentation() {
- if (hwasan_instrumentation_inited) return;
-
- if (!InitShadow()) {
- Printf("FATAL: HWAddressSanitizer cannot mmap the shadow memory.\n");
- DumpProcessMap();
- Die();
- }
-
- InitThreads();
- hwasanThreadList().CreateCurrentThread();
-
- hwasan_instrumentation_inited = 1;
-}
-
} // namespace __hwasan
+using namespace __hwasan;
+
void __sanitizer::BufferedStackTrace::UnwindImpl(
uptr pc, uptr bp, void *context, bool request_fast, u32 max_depth) {
- using namespace __hwasan;
Thread *t = GetCurrentThread();
if (!t) {
// the thread is still being created.
@@ -231,9 +216,117 @@ void __sanitizer::BufferedStackTrace::UnwindImpl(
Unwind(max_depth, pc, 0, context, 0, 0, false);
}
-// Interface.
+struct hwasan_global {
+ s32 gv_relptr;
+ u32 info;
+};
+
+static void InitGlobals(const hwasan_global *begin, const hwasan_global *end) {
+ for (auto *desc = begin; desc != end; ++desc) {
+ uptr gv = reinterpret_cast<uptr>(desc) + desc->gv_relptr;
+ uptr size = desc->info & 0xffffff;
+ uptr full_granule_size = RoundDownTo(size, 16);
+ u8 tag = desc->info >> 24;
+ TagMemoryAligned(gv, full_granule_size, tag);
+ if (size % 16)
+ TagMemoryAligned(gv + full_granule_size, 16, size % 16);
+ }
+}
-using namespace __hwasan;
+enum { NT_LLVM_HWASAN_GLOBALS = 3 };
+
+struct hwasan_global_note {
+ s32 begin_relptr;
+ s32 end_relptr;
+};
+
+// Check that the given library meets the code model requirements for tagged
+// globals. These properties are not checked at link time so they need to be
+// checked at runtime.
+static void CheckCodeModel(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+ ElfW(Half) phnum) {
+ ElfW(Addr) min_addr = -1ull, max_addr = 0;
+ for (unsigned i = 0; i != phnum; ++i) {
+ if (phdr[i].p_type != PT_LOAD)
+ continue;
+ ElfW(Addr) lo = base + phdr[i].p_vaddr, hi = lo + phdr[i].p_memsz;
+ if (min_addr > lo)
+ min_addr = lo;
+ if (max_addr < hi)
+ max_addr = hi;
+ }
+
+ if (max_addr - min_addr > 1ull << 32) {
+ Report("FATAL: HWAddressSanitizer: library size exceeds 2^32\n");
+ Die();
+ }
+ if (max_addr > 1ull << 48) {
+ Report("FATAL: HWAddressSanitizer: library loaded above address 2^48\n");
+ Die();
+ }
+}
+
+static void InitGlobalsFromPhdrs(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+ ElfW(Half) phnum) {
+ for (unsigned i = 0; i != phnum; ++i) {
+ if (phdr[i].p_type != PT_NOTE)
+ continue;
+ const char *note = reinterpret_cast<const char *>(base + phdr[i].p_vaddr);
+ const char *nend = note + phdr[i].p_memsz;
+ while (note < nend) {
+ auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(note);
+ const char *name = note + sizeof(ElfW(Nhdr));
+ const char *desc = name + RoundUpTo(nhdr->n_namesz, 4);
+ if (nhdr->n_type != NT_LLVM_HWASAN_GLOBALS ||
+ internal_strcmp(name, "LLVM") != 0) {
+ note = desc + RoundUpTo(nhdr->n_descsz, 4);
+ continue;
+ }
+
+ // Only libraries with instrumented globals need to be checked against the
+ // code model since they use relocations that aren't checked at link time.
+ CheckCodeModel(base, phdr, phnum);
+
+ auto *global_note = reinterpret_cast<const hwasan_global_note *>(desc);
+ auto *global_begin = reinterpret_cast<const hwasan_global *>(
+ note + global_note->begin_relptr);
+ auto *global_end = reinterpret_cast<const hwasan_global *>(
+ note + global_note->end_relptr);
+ InitGlobals(global_begin, global_end);
+ return;
+ }
+ }
+}
+
+static void InitLoadedGlobals() {
+ dl_iterate_phdr(
+ [](dl_phdr_info *info, size_t size, void *data) {
+ InitGlobalsFromPhdrs(info->dlpi_addr, info->dlpi_phdr,
+ info->dlpi_phnum);
+ return 0;
+ },
+ nullptr);
+}
+
+// Prepare to run instrumented code on the main thread.
+static void InitInstrumentation() {
+ if (hwasan_instrumentation_inited) return;
+
+ InitPrctl();
+
+ if (!InitShadow()) {
+ Printf("FATAL: HWAddressSanitizer cannot mmap the shadow memory.\n");
+ DumpProcessMap();
+ Die();
+ }
+
+ InitThreads();
+ hwasanThreadList().CreateCurrentThread();
+
+ hwasan_instrumentation_inited = 1;
+}
+
+// Interface.
uptr __hwasan_shadow_memory_dynamic_address; // Global interface symbol.
@@ -244,6 +337,17 @@ void __hwasan_init_frames(uptr beg, uptr end) {}
void __hwasan_init_static() {
InitShadowGOT();
InitInstrumentation();
+
+ // In the non-static code path we call dl_iterate_phdr here. But at this point
+ // libc might not have been initialized enough for dl_iterate_phdr to work.
+ // Fortunately, since this is a statically linked executable we can use the
+ // linker-defined symbol __ehdr_start to find the only relevant set of phdrs.
+ extern ElfW(Ehdr) __ehdr_start;
+ InitGlobalsFromPhdrs(
+ 0,
+ reinterpret_cast<const ElfW(Phdr) *>(
+ reinterpret_cast<const char *>(&__ehdr_start) + __ehdr_start.e_phoff),
+ __ehdr_start.e_phnum);
}
void __hwasan_init() {
@@ -267,6 +371,7 @@ void __hwasan_init() {
DisableCoreDumperIfNecessary();
InitInstrumentation();
+ InitLoadedGlobals();
// Needs to be called here because flags()->random_tags might not have been
// initialized when InitInstrumentation() was called.
@@ -301,6 +406,18 @@ void __hwasan_init() {
hwasan_inited = 1;
}
+void __hwasan_library_loaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+ ElfW(Half) phnum) {
+ InitGlobalsFromPhdrs(base, phdr, phnum);
+}
+
+void __hwasan_library_unloaded(ElfW(Addr) base, const ElfW(Phdr) * phdr,
+ ElfW(Half) phnum) {
+ for (; phnum != 0; ++phdr, --phnum)
+ if (phdr->p_type == PT_LOAD)
+ TagMemory(base + phdr->p_vaddr, phdr->p_memsz, 0);
+}
+
void __hwasan_print_shadow(const void *p, uptr sz) {
uptr ptr_raw = UntagAddr(reinterpret_cast<uptr>(p));
uptr shadow_first = MemToShadow(ptr_raw);