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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