e26b25f8b1
Summary: Refactor the current global header iteration to be callback-based, and add a feature that reports the size of the global variable during reporting. This allows binaries without symbols to still report the size of the global variable, which is always available in the HWASan globals PT_NOTE metadata. Reviewers: eugenis, pcc Reviewed By: pcc Subscribers: mgorny, llvm-commits, #sanitizers Tags: #sanitizers, #llvm Differential Revision: https://reviews.llvm.org/D80599
92 lines
3.0 KiB
C++
92 lines
3.0 KiB
C++
//===-- hwasan_globals.cpp ------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of HWAddressSanitizer.
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//
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// HWAddressSanitizer globals-specific runtime.
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//===----------------------------------------------------------------------===//
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#include "hwasan_globals.h"
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namespace __hwasan {
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enum { NT_LLVM_HWASAN_GLOBALS = 3 };
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struct hwasan_global_note {
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s32 begin_relptr;
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s32 end_relptr;
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};
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// Check that the given library meets the code model requirements for tagged
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// globals. These properties are not checked at link time so they need to be
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// checked at runtime.
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static void CheckCodeModel(ElfW(Addr) base, const ElfW(Phdr) * phdr,
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ElfW(Half) phnum) {
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ElfW(Addr) min_addr = -1ull, max_addr = 0;
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for (unsigned i = 0; i != phnum; ++i) {
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if (phdr[i].p_type != PT_LOAD)
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continue;
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ElfW(Addr) lo = base + phdr[i].p_vaddr, hi = lo + phdr[i].p_memsz;
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if (min_addr > lo)
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min_addr = lo;
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if (max_addr < hi)
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max_addr = hi;
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}
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if (max_addr - min_addr > 1ull << 32) {
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Report("FATAL: HWAddressSanitizer: library size exceeds 2^32\n");
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Die();
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}
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if (max_addr > 1ull << 48) {
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Report("FATAL: HWAddressSanitizer: library loaded above address 2^48\n");
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Die();
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}
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}
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ArrayRef<const hwasan_global> HwasanGlobalsFor(ElfW(Addr) base,
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const ElfW(Phdr) * phdr,
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ElfW(Half) phnum) {
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// Read the phdrs from this DSO.
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for (unsigned i = 0; i != phnum; ++i) {
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if (phdr[i].p_type != PT_NOTE)
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continue;
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const char *note = reinterpret_cast<const char *>(base + phdr[i].p_vaddr);
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const char *nend = note + phdr[i].p_memsz;
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// Traverse all the notes until we find a HWASan note.
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while (note < nend) {
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auto *nhdr = reinterpret_cast<const ElfW(Nhdr) *>(note);
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const char *name = note + sizeof(ElfW(Nhdr));
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const char *desc = name + RoundUpTo(nhdr->n_namesz, 4);
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// Discard non-HWASan-Globals notes.
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if (nhdr->n_type != NT_LLVM_HWASAN_GLOBALS ||
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internal_strcmp(name, "LLVM") != 0) {
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note = desc + RoundUpTo(nhdr->n_descsz, 4);
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continue;
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}
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// Only libraries with instrumented globals need to be checked against the
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// code model since they use relocations that aren't checked at link time.
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CheckCodeModel(base, phdr, phnum);
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auto *global_note = reinterpret_cast<const hwasan_global_note *>(desc);
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auto *globals_begin = reinterpret_cast<const hwasan_global *>(
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note + global_note->begin_relptr);
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auto *globals_end = reinterpret_cast<const hwasan_global *>(
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note + global_note->end_relptr);
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return {globals_begin, globals_end};
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}
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}
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return {};
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}
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} // namespace __hwasan
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