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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "sandbox/mac/seatbelt_exec.h"
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <limits>
#include <vector>
#include "base/posix/eintr_wrapper.h" //nogncheck
#include "sandbox/mac/sandbox_logging.h"
#include "sandbox/mac/sandbox_serializer.h"
#include "sandbox/mac/seatbelt.h"
namespace sandbox {
namespace {
struct ReadTraits {
using BufferType = uint8_t*;
static constexpr char kNameString[] = "read";
static ssize_t Operate(int fd, BufferType buffer, size_t size) {
return read(fd, buffer, size);
}
};
constexpr char ReadTraits::kNameString[];
struct WriteTraits {
using BufferType = const uint8_t*;
static constexpr char kNameString[] = "write";
static ssize_t Operate(int fd, BufferType buffer, size_t size) {
return write(fd, buffer, size);
}
};
constexpr char WriteTraits::kNameString[];
template <typename Traits>
bool ReadOrWrite(int fd,
const typename Traits::BufferType buffer,
const size_t size,
const char* operation_description) {
if (size > std::numeric_limits<ssize_t>::max()) {
logging::Error("request size is greater than ssize_t::max");
return false;
}
ssize_t bytes_to_transact = static_cast<ssize_t>(size);
while (bytes_to_transact > 0) {
ssize_t offset = size - bytes_to_transact;
ssize_t transacted_bytes =
HANDLE_EINTR(Traits::Operate(fd, buffer + offset, bytes_to_transact));
if (transacted_bytes < 0) {
logging::PError("SeatbeltExec: %s %s failed", operation_description,
Traits::kNameString);
return false;
} else if (transacted_bytes == 0) {
// A short read from the sender, perhaps the sender process died.
logging::Error("SeatbeltExec: %s %s failed", operation_description,
Traits::kNameString);
return false;
}
bytes_to_transact -= transacted_bytes;
}
return true;
}
} // namespace
namespace switches {
const char kSeatbeltClient[] = "--seatbelt-client=";
const char kSeatbeltClientName[] = "seatbelt-client";
} // namespace switches
SeatbeltExecClient::SeatbeltExecClient() {
if (pipe(pipe_) != 0)
logging::PFatal("SeatbeltExecClient: pipe failed");
}
SeatbeltExecClient::~SeatbeltExecClient() {
if (pipe_[0] != -1)
IGNORE_EINTR(close(pipe_[0]));
if (pipe_[1] != -1)
IGNORE_EINTR(close(pipe_[1]));
}
int SeatbeltExecClient::GetReadFD() {
return pipe_[0];
}
bool SeatbeltExecClient::SendPolicy(const std::string& serialized_policy) {
IGNORE_EINTR(close(pipe_[0]));
pipe_[0] = -1;
if (!WriteString(serialized_policy)) {
return false;
}
IGNORE_EINTR(close(pipe_[1]));
pipe_[1] = -1;
return true;
}
bool SeatbeltExecClient::WriteString(const std::string& str) {
uint64_t str_len = static_cast<uint64_t>(str.size());
if (!ReadOrWrite<WriteTraits>(pipe_[1], reinterpret_cast<uint8_t*>(&str_len),
sizeof(str_len), "buffer length")) {
return false;
}
if (!ReadOrWrite<WriteTraits>(pipe_[1],
reinterpret_cast<const uint8_t*>(&str[0]),
str_len, "buffer")) {
return false;
}
return true;
}
SeatbeltExecServer::SeatbeltExecServer(int fd) : fd_(fd) {}
SeatbeltExecServer::~SeatbeltExecServer() {
close(fd_);
}
sandbox::SeatbeltExecServer::CreateFromArgumentsResult::
CreateFromArgumentsResult() = default;
sandbox::SeatbeltExecServer::CreateFromArgumentsResult::
CreateFromArgumentsResult(CreateFromArgumentsResult&&) = default;
sandbox::SeatbeltExecServer::CreateFromArgumentsResult::
~CreateFromArgumentsResult() = default;
// static
sandbox::SeatbeltExecServer::CreateFromArgumentsResult
SeatbeltExecServer::CreateFromArguments(const char* executable_path,
int argc,
const char* const* argv) {
CreateFromArgumentsResult result;
int seatbelt_client_fd = -1;
for (int i = 1; i < argc; ++i) {
if (strncmp(argv[i], switches::kSeatbeltClient,
strlen(switches::kSeatbeltClient)) == 0) {
result.sandbox_required = true;
std::string arg(argv[i]);
std::string fd_string = arg.substr(strlen(switches::kSeatbeltClient));
seatbelt_client_fd = std::stoi(fd_string);
}
}
if (!result.sandbox_required)
return result;
if (seatbelt_client_fd < 0) {
logging::Error("Must pass a valid file descriptor to %s",
switches::kSeatbeltClient);
return result;
}
result.server.reset(new SeatbeltExecServer(seatbelt_client_fd));
return result;
}
bool SeatbeltExecServer::InitializeSandbox() {
std::string policy_string;
if (!ReadString(&policy_string))
return false;
return SandboxSerializer::ApplySerializedPolicy(policy_string);
}
bool SeatbeltExecServer::ReadString(std::string* str) {
uint64_t buf_len = 0;
if (!ReadOrWrite<ReadTraits>(fd_, reinterpret_cast<uint8_t*>(&buf_len),
sizeof(buf_len), "buffer length")) {
return false;
}
str->resize(buf_len);
if (!ReadOrWrite<ReadTraits>(fd_, reinterpret_cast<uint8_t*>(&(*str)[0]),
buf_len, "buffer")) {
return false;
}
return true;
}
} // namespace sandbox
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