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https://github.com/chromium/crashpad.git
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a02ba24006
Follows https://codereview.chromium.org/1911823002/ but fixes includes that were messed up there. Change-Id: Ic4bad7d095ee6f5a1c9f8ca2d11ac9e67d55a626 Reviewed-on: https://chromium-review.googlesource.com/340497 Reviewed-by: Robert Sesek <rsesek@chromium.org>
294 lines
12 KiB
C++
294 lines
12 KiB
C++
// Copyright 2014 The Crashpad Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "snapshot/mac/mach_o_image_symbol_table_reader.h"
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#include <mach-o/loader.h>
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#include <mach-o/nlist.h>
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#include <sys/types.h>
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#include <memory>
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#include <utility>
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#include "base/strings/stringprintf.h"
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#include "util/mac/checked_mach_address_range.h"
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#include "util/mach/task_memory.h"
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namespace crashpad {
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namespace internal {
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//! \brief The internal implementation for MachOImageSymbolTableReader.
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//!
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//! Initialization is broken into more than one function that needs to share
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//! data, so member variables are used. However, much of this data is irrelevant
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//! after initialization is completed, so rather than doing it in
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//! MachOImageSymbolTableReader, it’s handled by this class, which is a “friend”
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//! of MachOImageSymbolTableReader.
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class MachOImageSymbolTableReaderInitializer {
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public:
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MachOImageSymbolTableReaderInitializer(
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ProcessReader* process_reader,
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const MachOImageSegmentReader* linkedit_segment,
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const std::string& module_info)
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: module_info_(module_info),
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linkedit_range_(),
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process_reader_(process_reader),
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linkedit_segment_(linkedit_segment) {
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linkedit_range_.SetRange(process_reader_->Is64Bit(),
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linkedit_segment->Address(),
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linkedit_segment->Size());
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DCHECK(linkedit_range_.IsValid());
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}
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~MachOImageSymbolTableReaderInitializer() {}
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//! \brief Reads the symbol table from another process.
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//!
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//! \sa MachOImageSymbolTableReader::Initialize()
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bool Initialize(const process_types::symtab_command* symtab_command,
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const process_types::dysymtab_command* dysymtab_command,
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MachOImageSymbolTableReader::SymbolInformationMap*
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external_defined_symbols) {
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mach_vm_address_t symtab_address =
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AddressForLinkEditComponent(symtab_command->symoff);
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uint32_t symbol_count = symtab_command->nsyms;
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size_t nlist_size = process_types::nlist::ExpectedSize(process_reader_);
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mach_vm_size_t symtab_size = symbol_count * nlist_size;
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if (!IsInLinkEditSegment(symtab_address, symtab_size, "symtab")) {
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return false;
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}
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// If a dysymtab is present, use it to filter the symtab for just the
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// portion used for extdefsym. If no dysymtab is present, the entire symtab
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// will need to be consulted.
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uint32_t skip_count = 0;
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if (dysymtab_command) {
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if (dysymtab_command->iextdefsym >= symtab_command->nsyms ||
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dysymtab_command->iextdefsym + dysymtab_command->nextdefsym >
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symtab_command->nsyms) {
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LOG(WARNING) << base::StringPrintf(
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"dysymtab extdefsym %u + %u > symtab nsyms %u",
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dysymtab_command->iextdefsym,
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dysymtab_command->nextdefsym,
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symtab_command->nsyms) << module_info_;
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return false;
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}
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skip_count = dysymtab_command->iextdefsym;
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mach_vm_size_t skip_size = skip_count * nlist_size;
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symtab_address += skip_size;
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symtab_size -= skip_size;
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symbol_count = dysymtab_command->nextdefsym;
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}
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mach_vm_address_t strtab_address =
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AddressForLinkEditComponent(symtab_command->stroff);
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mach_vm_size_t strtab_size = symtab_command->strsize;
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if (!IsInLinkEditSegment(strtab_address, strtab_size, "strtab")) {
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return false;
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}
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std::unique_ptr<process_types::nlist[]> symbols(
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new process_types::nlist[symtab_command->nsyms]);
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if (!process_types::nlist::ReadArrayInto(
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process_reader_, symtab_address, symbol_count, &symbols[0])) {
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LOG(WARNING) << "could not read symbol table" << module_info_;
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return false;
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}
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std::unique_ptr<TaskMemory::MappedMemory> string_table;
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for (size_t symbol_index = 0; symbol_index < symbol_count; ++symbol_index) {
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const process_types::nlist& symbol = symbols[symbol_index];
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std::string symbol_info = base::StringPrintf(", symbol index %zu%s",
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skip_count + symbol_index,
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module_info_.c_str());
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bool valid_symbol = true;
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if ((symbol.n_type & N_STAB) == 0 && (symbol.n_type & N_PEXT) == 0 &&
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(symbol.n_type & N_EXT)) {
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uint8_t symbol_type = symbol.n_type & N_TYPE;
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if (symbol_type == N_ABS || symbol_type == N_SECT) {
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if (symbol.n_strx >= strtab_size) {
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LOG(WARNING) << base::StringPrintf(
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"string at 0x%x out of bounds (0x%llx)",
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symbol.n_strx,
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strtab_size) << symbol_info;
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return false;
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}
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if (!string_table) {
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string_table = process_reader_->Memory()->ReadMapped(
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strtab_address, strtab_size);
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if (!string_table) {
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LOG(WARNING) << "could not read string table" << module_info_;
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return false;
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}
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}
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std::string name;
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if (!string_table->ReadCString(symbol.n_strx, &name)) {
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LOG(WARNING) << "could not read string" << symbol_info;
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return false;
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}
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if (symbol_type == N_ABS && symbol.n_sect != NO_SECT) {
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LOG(WARNING) << base::StringPrintf("N_ABS symbol %s in section %u",
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name.c_str(),
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symbol.n_sect) << symbol_info;
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return false;
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}
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if (symbol_type == N_SECT && symbol.n_sect == NO_SECT) {
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LOG(WARNING) << base::StringPrintf(
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"N_SECT symbol %s in section NO_SECT",
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name.c_str()) << symbol_info;
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return false;
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}
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MachOImageSymbolTableReader::SymbolInformation this_symbol_info;
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this_symbol_info.value = symbol.n_value;
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this_symbol_info.section = symbol.n_sect;
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if (!external_defined_symbols->insert(
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std::make_pair(name, this_symbol_info)).second) {
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LOG(WARNING) << "duplicate symbol " << name << symbol_info;
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return false;
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}
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} else {
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// External indirect symbols may be found in the portion of the symbol
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// table used for external symbols as opposed to indirect symbols when
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// the indirect symbols are also external. These can be produced by
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// Xcode 5.1 ld64-236.3/src/ld/LinkEditClassic.hpp
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// ld::tool::SymbolTableAtom<>::addGlobal(). Indirect symbols are not
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// currently supported by this symbol table reader, so ignore them
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// without failing or logging a message when encountering them. See
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// https://groups.google.com/a/chromium.org/d/topic/crashpad-dev/k7QkLwO71Zo
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valid_symbol = symbol_type == N_INDR;
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}
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} else {
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valid_symbol = false;
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}
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if (!valid_symbol && dysymtab_command) {
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LOG(WARNING) << "non-external symbol with type " << symbol.n_type
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<< " in extdefsym" << symbol_info;
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return false;
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}
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}
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return true;
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}
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private:
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//! \brief Computes the address for data in the `__LINKEDIT` segment
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//! identified by its file offset in a Mach-O image.
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//!
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//! \param[in] fileoff The file offset relative to the beginning of an image’s
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//! `mach_header` or `mach_header_64` of the data in the `__LINKEDIT`
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//! segment.
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//!
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//! \return The address, in the remote process’ address space, of the
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//! requested data.
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mach_vm_address_t AddressForLinkEditComponent(uint32_t fileoff) const {
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return linkedit_range_.Base() + fileoff - linkedit_segment_->fileoff();
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}
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//! \brief Determines whether an address range is located within the
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//! `__LINKEDIT` segment.
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//!
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//! \param[in] address The base address of the range to check.
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//! \param[in] size The size of the range to check.
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//! \param[in] tag A string that identifies the range being checked. This is
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//! used only for logging.
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//!
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//! \return `true` if the range identified by \a address + \a size lies
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//! entirely within the `__LINKEDIT` segment. `false` if that range is
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//! invalid, or if that range is not contained by the `__LINKEDIT`
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//! segment, with an appropriate message logged.
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bool IsInLinkEditSegment(mach_vm_address_t address,
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mach_vm_size_t size,
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const char* tag) const {
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CheckedMachAddressRange subrange(process_reader_->Is64Bit(), address, size);
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if (!subrange.IsValid()) {
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LOG(WARNING) << base::StringPrintf("invalid %s range (0x%llx + 0x%llx)",
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tag,
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address,
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size) << module_info_;
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return false;
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}
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if (!linkedit_range_.ContainsRange(subrange)) {
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LOG(WARNING) << base::StringPrintf(
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"%s at 0x%llx + 0x%llx outside of " SEG_LINKEDIT
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" segment at 0x%llx + 0x%llx",
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tag,
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address,
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size,
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linkedit_range_.Base(),
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linkedit_range_.Size()) << module_info_;
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return false;
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}
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return true;
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}
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std::string module_info_;
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CheckedMachAddressRange linkedit_range_;
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ProcessReader* process_reader_; // weak
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const MachOImageSegmentReader* linkedit_segment_; // weak
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DISALLOW_COPY_AND_ASSIGN(MachOImageSymbolTableReaderInitializer);
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};
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} // namespace internal
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MachOImageSymbolTableReader::MachOImageSymbolTableReader()
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: external_defined_symbols_(), initialized_() {
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}
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MachOImageSymbolTableReader::~MachOImageSymbolTableReader() {
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}
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bool MachOImageSymbolTableReader::Initialize(
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ProcessReader* process_reader,
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const process_types::symtab_command* symtab_command,
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const process_types::dysymtab_command* dysymtab_command,
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const MachOImageSegmentReader* linkedit_segment,
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const std::string& module_info) {
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INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
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internal::MachOImageSymbolTableReaderInitializer initializer(process_reader,
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linkedit_segment,
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module_info);
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if (!initializer.Initialize(
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symtab_command, dysymtab_command, &external_defined_symbols_)) {
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return false;
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}
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INITIALIZATION_STATE_SET_VALID(initialized_);
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return true;
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}
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const MachOImageSymbolTableReader::SymbolInformation*
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MachOImageSymbolTableReader::LookUpExternalDefinedSymbol(
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const std::string& name) const {
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INITIALIZATION_STATE_DCHECK_VALID(initialized_);
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const auto& iterator = external_defined_symbols_.find(name);
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if (iterator == external_defined_symbols_.end()) {
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return nullptr;
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}
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return &iterator->second;
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}
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} // namespace crashpad
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