crashpad/util/file/string_file_writer.cc
Mark Mentovai 6e720f1421 Fix StringFileWriter::Seek().
The final range check needs to check that the value fits in a size_t,
because that’s what StringFileWriter uses for its offset_.

TEST=util_test StringFileWriter.SeekInvalid
R=rsesek@chromium.org

Review URL: https://codereview.chromium.org/434103003
2014-08-01 13:30:27 -04:00

138 lines
3.4 KiB
C++

// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "util/file/string_file_writer.h"
#include <string.h>
#include "base/logging.h"
#include "base/numerics/safe_math.h"
#include "util/numeric/safe_assignment.h"
namespace crashpad {
StringFileWriter::StringFileWriter() : string_(), offset_(0) {
}
StringFileWriter::~StringFileWriter() {
}
void StringFileWriter::Reset() {
string_.clear();
offset_ = 0;
}
bool StringFileWriter::Write(const void* data, size_t size) {
DCHECK(offset_.IsValid());
const size_t offset = offset_.ValueOrDie();
if (offset > string_.size()) {
string_.resize(offset);
}
base::CheckedNumeric<ssize_t> new_offset = offset_;
new_offset += size;
if (!new_offset.IsValid()) {
LOG(ERROR) << "Write(): file too large";
return false;
}
string_.replace(offset, size, reinterpret_cast<const char*>(data), size);
offset_ = new_offset;
return true;
}
bool StringFileWriter::WriteIoVec(std::vector<WritableIoVec>* iovecs) {
DCHECK(offset_.IsValid());
if (iovecs->empty()) {
LOG(ERROR) << "WriteIoVec(): no iovecs";
return false;
}
// Avoid writing anything at all if it would cause an overflow.
base::CheckedNumeric<ssize_t> new_offset = offset_;
for (const WritableIoVec& iov : *iovecs) {
new_offset += iov.iov_len;
if (!new_offset.IsValid()) {
LOG(ERROR) << "WriteIoVec(): file too large";
return false;
}
}
for (const WritableIoVec& iov : *iovecs) {
if (!Write(iov.iov_base, iov.iov_len)) {
return false;
}
}
#ifndef NDEBUG
// The interface says that |iovecs| is not sacred, so scramble it to make sure
// that nobody depends on it.
memset(&(*iovecs)[0], 0xa5, sizeof((*iovecs)[0]) * iovecs->size());
#endif
return true;
}
off_t StringFileWriter::Seek(off_t offset, int whence) {
DCHECK(offset_.IsValid());
size_t base_offset;
switch (whence) {
case SEEK_SET:
base_offset = 0;
break;
case SEEK_CUR:
base_offset = offset_.ValueOrDie();
break;
case SEEK_END:
base_offset = string_.size();
break;
default:
LOG(ERROR) << "Seek(): invalid whence " << whence;
return -1;
}
off_t base_offset_offt;
if (!AssignIfInRange(&base_offset_offt, base_offset)) {
LOG(ERROR) << "Seek(): base_offset " << base_offset << " invalid for off_t";
return -1;
}
base::CheckedNumeric<off_t> new_offset(base_offset_offt);
new_offset += offset;
if (!new_offset.IsValid()) {
LOG(ERROR) << "Seek(): new_offset invalid";
return -1;
}
off_t new_offset_offt = new_offset.ValueOrDie();
size_t new_offset_sizet;
if (!AssignIfInRange(&new_offset_sizet, new_offset_offt)) {
LOG(ERROR) << "Seek(): new_offset " << new_offset_offt
<< " invalid for size_t";
return -1;
}
offset_ = new_offset_sizet;
return offset_.ValueOrDie();
}
} // namespace crashpad