| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "ipc/ipc_channel_posix.h" |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <stddef.h> |
| #include <sys/socket.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <sys/un.h> |
| #include <unistd.h> |
| |
| #if defined(OS_OPENBSD) |
| #include <sys/uio.h> |
| #endif |
| |
| #include <map> |
| #include <string> |
| |
| #include "base/command_line.h" |
| #include "base/file_util.h" |
| #include "base/files/file_path.h" |
| #include "base/location.h" |
| #include "base/logging.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/memory/singleton.h" |
| #include "base/posix/eintr_wrapper.h" |
| #include "base/posix/global_descriptors.h" |
| #include "base/process/process_handle.h" |
| #include "base/rand_util.h" |
| #include "base/stl_util.h" |
| #include "base/strings/string_util.h" |
| #include "base/synchronization/lock.h" |
| #include "ipc/file_descriptor_set_posix.h" |
| #include "ipc/ipc_descriptors.h" |
| #include "ipc/ipc_listener.h" |
| #include "ipc/ipc_logging.h" |
| #include "ipc/ipc_message_utils.h" |
| #include "ipc/ipc_switches.h" |
| #include "ipc/unix_domain_socket_util.h" |
| |
| namespace IPC { |
| |
| // IPC channels on Windows use named pipes (CreateNamedPipe()) with |
| // channel ids as the pipe names. Channels on POSIX use sockets as |
| // pipes These don't quite line up. |
| // |
| // When creating a child subprocess we use a socket pair and the parent side of |
| // the fork arranges it such that the initial control channel ends up on the |
| // magic file descriptor kPrimaryIPCChannel in the child. Future |
| // connections (file descriptors) can then be passed via that |
| // connection via sendmsg(). |
| // |
| // A POSIX IPC channel can also be set up as a server for a bound UNIX domain |
| // socket, and will handle multiple connect and disconnect sequences. Currently |
| // it is limited to one connection at a time. |
| |
| //------------------------------------------------------------------------------ |
| namespace { |
| |
| // The PipeMap class works around this quirk related to unit tests: |
| // |
| // When running as a server, we install the client socket in a |
| // specific file descriptor number (@kPrimaryIPCChannel). However, we |
| // also have to support the case where we are running unittests in the |
| // same process. (We do not support forking without execing.) |
| // |
| // Case 1: normal running |
| // The IPC server object will install a mapping in PipeMap from the |
| // name which it was given to the client pipe. When forking the client, the |
| // GetClientFileDescriptorMapping will ensure that the socket is installed in |
| // the magic slot (@kPrimaryIPCChannel). The client will search for the |
| // mapping, but it won't find any since we are in a new process. Thus the |
| // magic fd number is returned. Once the client connects, the server will |
| // close its copy of the client socket and remove the mapping. |
| // |
| // Case 2: unittests - client and server in the same process |
| // The IPC server will install a mapping as before. The client will search |
| // for a mapping and find out. It duplicates the file descriptor and |
| // connects. Once the client connects, the server will close the original |
| // copy of the client socket and remove the mapping. Thus, when the client |
| // object closes, it will close the only remaining copy of the client socket |
| // in the fd table and the server will see EOF on its side. |
| // |
| // TODO(port): a client process cannot connect to multiple IPC channels with |
| // this scheme. |
| |
| class PipeMap { |
| public: |
| static PipeMap* GetInstance() { |
| return Singleton<PipeMap>::get(); |
| } |
| |
| ~PipeMap() { |
| // Shouldn't have left over pipes. |
| DCHECK(map_.empty()); |
| } |
| |
| // Lookup a given channel id. Return -1 if not found. |
| int Lookup(const std::string& channel_id) { |
| base::AutoLock locked(lock_); |
| |
| ChannelToFDMap::const_iterator i = map_.find(channel_id); |
| if (i == map_.end()) |
| return -1; |
| return i->second; |
| } |
| |
| // Remove the mapping for the given channel id. No error is signaled if the |
| // channel_id doesn't exist |
| void Remove(const std::string& channel_id) { |
| base::AutoLock locked(lock_); |
| map_.erase(channel_id); |
| } |
| |
| // Insert a mapping from @channel_id to @fd. It's a fatal error to insert a |
| // mapping if one already exists for the given channel_id |
| void Insert(const std::string& channel_id, int fd) { |
| base::AutoLock locked(lock_); |
| DCHECK_NE(-1, fd); |
| |
| ChannelToFDMap::const_iterator i = map_.find(channel_id); |
| CHECK(i == map_.end()) << "Creating second IPC server (fd " << fd << ") " |
| << "for '" << channel_id << "' while first " |
| << "(fd " << i->second << ") still exists"; |
| map_[channel_id] = fd; |
| } |
| |
| private: |
| base::Lock lock_; |
| typedef std::map<std::string, int> ChannelToFDMap; |
| ChannelToFDMap map_; |
| |
| friend struct DefaultSingletonTraits<PipeMap>; |
| }; |
| |
| //------------------------------------------------------------------------------ |
| |
| bool SocketWriteErrorIsRecoverable() { |
| #if defined(OS_MACOSX) |
| // On OS X if sendmsg() is trying to send fds between processes and there |
| // isn't enough room in the output buffer to send the fd structure over |
| // atomically then EMSGSIZE is returned. |
| // |
| // EMSGSIZE presents a problem since the system APIs can only call us when |
| // there's room in the socket buffer and not when there is "enough" room. |
| // |
| // The current behavior is to return to the event loop when EMSGSIZE is |
| // received and hopefull service another FD. This is however still |
| // technically a busy wait since the event loop will call us right back until |
| // the receiver has read enough data to allow passing the FD over atomically. |
| return errno == EAGAIN || errno == EMSGSIZE; |
| #else |
| return errno == EAGAIN; |
| #endif // OS_MACOSX |
| } |
| |
| } // namespace |
| //------------------------------------------------------------------------------ |
| |
| #if defined(OS_LINUX) |
| int Channel::ChannelImpl::global_pid_ = 0; |
| #endif // OS_LINUX |
| |
| Channel::ChannelImpl::ChannelImpl(const IPC::ChannelHandle& channel_handle, |
| Mode mode, Listener* listener) |
| : ChannelReader(listener), |
| mode_(mode), |
| peer_pid_(base::kNullProcessId), |
| is_blocked_on_write_(false), |
| waiting_connect_(true), |
| message_send_bytes_written_(0), |
| server_listen_pipe_(-1), |
| pipe_(-1), |
| client_pipe_(-1), |
| #if defined(IPC_USES_READWRITE) |
| fd_pipe_(-1), |
| remote_fd_pipe_(-1), |
| #endif // IPC_USES_READWRITE |
| pipe_name_(channel_handle.name), |
| must_unlink_(false) { |
| memset(input_cmsg_buf_, 0, sizeof(input_cmsg_buf_)); |
| if (!CreatePipe(channel_handle)) { |
| // The pipe may have been closed already. |
| const char *modestr = (mode_ & MODE_SERVER_FLAG) ? "server" : "client"; |
| LOG(WARNING) << "Unable to create pipe named \"" << channel_handle.name |
| << "\" in " << modestr << " mode"; |
| } |
| } |
| |
| Channel::ChannelImpl::~ChannelImpl() { |
| Close(); |
| } |
| |
| bool SocketPair(int* fd1, int* fd2) { |
| int pipe_fds[2]; |
| if (socketpair(AF_UNIX, SOCK_STREAM, 0, pipe_fds) != 0) { |
| PLOG(ERROR) << "socketpair()"; |
| return false; |
| } |
| |
| // Set both ends to be non-blocking. |
| if (fcntl(pipe_fds[0], F_SETFL, O_NONBLOCK) == -1 || |
| fcntl(pipe_fds[1], F_SETFL, O_NONBLOCK) == -1) { |
| PLOG(ERROR) << "fcntl(O_NONBLOCK)"; |
| if (HANDLE_EINTR(close(pipe_fds[0])) < 0) |
| PLOG(ERROR) << "close"; |
| if (HANDLE_EINTR(close(pipe_fds[1])) < 0) |
| PLOG(ERROR) << "close"; |
| return false; |
| } |
| |
| *fd1 = pipe_fds[0]; |
| *fd2 = pipe_fds[1]; |
| |
| return true; |
| } |
| |
| bool Channel::ChannelImpl::CreatePipe( |
| const IPC::ChannelHandle& channel_handle) { |
| DCHECK(server_listen_pipe_ == -1 && pipe_ == -1); |
| |
| // Four possible cases: |
| // 1) It's a channel wrapping a pipe that is given to us. |
| // 2) It's for a named channel, so we create it. |
| // 3) It's for a client that we implement ourself. This is used |
| // in unittesting. |
| // 4) It's the initial IPC channel: |
| // 4a) Client side: Pull the pipe out of the GlobalDescriptors set. |
| // 4b) Server side: create the pipe. |
| |
| int local_pipe = -1; |
| if (channel_handle.socket.fd != -1) { |
| // Case 1 from comment above. |
| local_pipe = channel_handle.socket.fd; |
| #if defined(IPC_USES_READWRITE) |
| // Test the socket passed into us to make sure it is nonblocking. |
| // We don't want to call read/write on a blocking socket. |
| int value = fcntl(local_pipe, F_GETFL); |
| if (value == -1) { |
| PLOG(ERROR) << "fcntl(F_GETFL) " << pipe_name_; |
| return false; |
| } |
| if (!(value & O_NONBLOCK)) { |
| LOG(ERROR) << "Socket " << pipe_name_ << " must be O_NONBLOCK"; |
| return false; |
| } |
| #endif // IPC_USES_READWRITE |
| } else if (mode_ & MODE_NAMED_FLAG) { |
| // Case 2 from comment above. |
| if (mode_ & MODE_SERVER_FLAG) { |
| if (!CreateServerUnixDomainSocket(base::FilePath(pipe_name_), |
| &local_pipe)) { |
| return false; |
| } |
| must_unlink_ = true; |
| } else if (mode_ & MODE_CLIENT_FLAG) { |
| if (!CreateClientUnixDomainSocket(base::FilePath(pipe_name_), |
| &local_pipe)) { |
| return false; |
| } |
| } else { |
| LOG(ERROR) << "Bad mode: " << mode_; |
| return false; |
| } |
| } else { |
| local_pipe = PipeMap::GetInstance()->Lookup(pipe_name_); |
| if (mode_ & MODE_CLIENT_FLAG) { |
| if (local_pipe != -1) { |
| // Case 3 from comment above. |
| // We only allow one connection. |
| local_pipe = HANDLE_EINTR(dup(local_pipe)); |
| PipeMap::GetInstance()->Remove(pipe_name_); |
| } else { |
| // Case 4a from comment above. |
| // Guard against inappropriate reuse of the initial IPC channel. If |
| // an IPC channel closes and someone attempts to reuse it by name, the |
| // initial channel must not be recycled here. http://crbug.com/26754. |
| static bool used_initial_channel = false; |
| if (used_initial_channel) { |
| LOG(FATAL) << "Denying attempt to reuse initial IPC channel for " |
| << pipe_name_; |
| return false; |
| } |
| used_initial_channel = true; |
| |
| local_pipe = |
| base::GlobalDescriptors::GetInstance()->Get(kPrimaryIPCChannel); |
| } |
| } else if (mode_ & MODE_SERVER_FLAG) { |
| // Case 4b from comment above. |
| if (local_pipe != -1) { |
| LOG(ERROR) << "Server already exists for " << pipe_name_; |
| return false; |
| } |
| base::AutoLock lock(client_pipe_lock_); |
| if (!SocketPair(&local_pipe, &client_pipe_)) |
| return false; |
| PipeMap::GetInstance()->Insert(pipe_name_, client_pipe_); |
| } else { |
| LOG(ERROR) << "Bad mode: " << mode_; |
| return false; |
| } |
| } |
| |
| #if defined(IPC_USES_READWRITE) |
| // Create a dedicated socketpair() for exchanging file descriptors. |
| // See comments for IPC_USES_READWRITE for details. |
| if (mode_ & MODE_CLIENT_FLAG) { |
| if (!SocketPair(&fd_pipe_, &remote_fd_pipe_)) { |
| return false; |
| } |
| } |
| #endif // IPC_USES_READWRITE |
| |
| if ((mode_ & MODE_SERVER_FLAG) && (mode_ & MODE_NAMED_FLAG)) { |
| server_listen_pipe_ = local_pipe; |
| local_pipe = -1; |
| } |
| |
| pipe_ = local_pipe; |
| return true; |
| } |
| |
| bool Channel::ChannelImpl::Connect() { |
| if (server_listen_pipe_ == -1 && pipe_ == -1) { |
| DLOG(INFO) << "Channel creation failed: " << pipe_name_; |
| return false; |
| } |
| |
| bool did_connect = true; |
| if (server_listen_pipe_ != -1) { |
| // Watch the pipe for connections, and turn any connections into |
| // active sockets. |
| base::MessageLoopForIO::current()->WatchFileDescriptor( |
| server_listen_pipe_, |
| true, |
| base::MessageLoopForIO::WATCH_READ, |
| &server_listen_connection_watcher_, |
| this); |
| } else { |
| did_connect = AcceptConnection(); |
| } |
| return did_connect; |
| } |
| |
| void Channel::ChannelImpl::CloseFileDescriptors(Message* msg) { |
| #if defined(OS_MACOSX) |
| // There is a bug on OSX which makes it dangerous to close |
| // a file descriptor while it is in transit. So instead we |
| // store the file descriptor in a set and send a message to |
| // the recipient, which is queued AFTER the message that |
| // sent the FD. The recipient will reply to the message, |
| // letting us know that it is now safe to close the file |
| // descriptor. For more information, see: |
| // http://crbug.com/298276 |
| std::vector<int> to_close; |
| msg->file_descriptor_set()->ReleaseFDsToClose(&to_close); |
| for (size_t i = 0; i < to_close.size(); i++) { |
| fds_to_close_.insert(to_close[i]); |
| QueueCloseFDMessage(to_close[i], 2); |
| } |
| #else |
| msg->file_descriptor_set()->CommitAll(); |
| #endif |
| } |
| |
| bool Channel::ChannelImpl::ProcessOutgoingMessages() { |
| DCHECK(!waiting_connect_); // Why are we trying to send messages if there's |
| // no connection? |
| if (output_queue_.empty()) |
| return true; |
| |
| if (pipe_ == -1) |
| return false; |
| |
| // Write out all the messages we can till the write blocks or there are no |
| // more outgoing messages. |
| while (!output_queue_.empty()) { |
| Message* msg = output_queue_.front(); |
| |
| size_t amt_to_write = msg->size() - message_send_bytes_written_; |
| DCHECK_NE(0U, amt_to_write); |
| const char* out_bytes = reinterpret_cast<const char*>(msg->data()) + |
| message_send_bytes_written_; |
| |
| struct msghdr msgh = {0}; |
| struct iovec iov = {const_cast<char*>(out_bytes), amt_to_write}; |
| msgh.msg_iov = &iov; |
| msgh.msg_iovlen = 1; |
| char buf[CMSG_SPACE( |
| sizeof(int) * FileDescriptorSet::kMaxDescriptorsPerMessage)]; |
| |
| ssize_t bytes_written = 1; |
| int fd_written = -1; |
| |
| if (message_send_bytes_written_ == 0 && |
| !msg->file_descriptor_set()->empty()) { |
| // This is the first chunk of a message which has descriptors to send |
| struct cmsghdr *cmsg; |
| const unsigned num_fds = msg->file_descriptor_set()->size(); |
| |
| DCHECK(num_fds <= FileDescriptorSet::kMaxDescriptorsPerMessage); |
| if (msg->file_descriptor_set()->ContainsDirectoryDescriptor()) { |
| LOG(FATAL) << "Panic: attempting to transport directory descriptor over" |
| " IPC. Aborting to maintain sandbox isolation."; |
| // If you have hit this then something tried to send a file descriptor |
| // to a directory over an IPC channel. Since IPC channels span |
| // sandboxes this is very bad: the receiving process can use openat |
| // with ".." elements in the path in order to reach the real |
| // filesystem. |
| } |
| |
| msgh.msg_control = buf; |
| msgh.msg_controllen = CMSG_SPACE(sizeof(int) * num_fds); |
| cmsg = CMSG_FIRSTHDR(&msgh); |
| cmsg->cmsg_level = SOL_SOCKET; |
| cmsg->cmsg_type = SCM_RIGHTS; |
| cmsg->cmsg_len = CMSG_LEN(sizeof(int) * num_fds); |
| msg->file_descriptor_set()->GetDescriptors( |
| reinterpret_cast<int*>(CMSG_DATA(cmsg))); |
| msgh.msg_controllen = cmsg->cmsg_len; |
| |
| // DCHECK_LE above already checks that |
| // num_fds < kMaxDescriptorsPerMessage so no danger of overflow. |
| msg->header()->num_fds = static_cast<uint16>(num_fds); |
| |
| #if defined(IPC_USES_READWRITE) |
| if (!IsHelloMessage(*msg)) { |
| // Only the Hello message sends the file descriptor with the message. |
| // Subsequently, we can send file descriptors on the dedicated |
| // fd_pipe_ which makes Seccomp sandbox operation more efficient. |
| struct iovec fd_pipe_iov = { const_cast<char *>(""), 1 }; |
| msgh.msg_iov = &fd_pipe_iov; |
| fd_written = fd_pipe_; |
| bytes_written = HANDLE_EINTR(sendmsg(fd_pipe_, &msgh, MSG_DONTWAIT)); |
| msgh.msg_iov = &iov; |
| msgh.msg_controllen = 0; |
| if (bytes_written > 0) { |
| CloseFileDescriptors(msg); |
| } |
| } |
| #endif // IPC_USES_READWRITE |
| } |
| |
| if (bytes_written == 1) { |
| fd_written = pipe_; |
| #if defined(IPC_USES_READWRITE) |
| if ((mode_ & MODE_CLIENT_FLAG) && IsHelloMessage(*msg)) { |
| DCHECK_EQ(msg->file_descriptor_set()->size(), 1U); |
| } |
| if (!msgh.msg_controllen) { |
| bytes_written = HANDLE_EINTR(write(pipe_, out_bytes, amt_to_write)); |
| } else |
| #endif // IPC_USES_READWRITE |
| { |
| bytes_written = HANDLE_EINTR(sendmsg(pipe_, &msgh, MSG_DONTWAIT)); |
| } |
| } |
| if (bytes_written > 0) |
| CloseFileDescriptors(msg); |
| |
| if (bytes_written < 0 && !SocketWriteErrorIsRecoverable()) { |
| #if defined(OS_MACOSX) |
| // On OSX writing to a pipe with no listener returns EPERM. |
| if (errno == EPERM) { |
| Close(); |
| return false; |
| } |
| #endif // OS_MACOSX |
| if (errno == EPIPE) { |
| Close(); |
| return false; |
| } |
| PLOG(ERROR) << "pipe error on " |
| << fd_written |
| << " Currently writing message of size: " |
| << msg->size(); |
| return false; |
| } |
| |
| if (static_cast<size_t>(bytes_written) != amt_to_write) { |
| if (bytes_written > 0) { |
| // If write() fails with EAGAIN then bytes_written will be -1. |
| message_send_bytes_written_ += bytes_written; |
| } |
| |
| // Tell libevent to call us back once things are unblocked. |
| is_blocked_on_write_ = true; |
| base::MessageLoopForIO::current()->WatchFileDescriptor( |
| pipe_, |
| false, // One shot |
| base::MessageLoopForIO::WATCH_WRITE, |
| &write_watcher_, |
| this); |
| return true; |
| } else { |
| message_send_bytes_written_ = 0; |
| |
| // Message sent OK! |
| DVLOG(2) << "sent message @" << msg << " on channel @" << this |
| << " with type " << msg->type() << " on fd " << pipe_; |
| delete output_queue_.front(); |
| output_queue_.pop(); |
| } |
| } |
| return true; |
| } |
| |
| bool Channel::ChannelImpl::Send(Message* message) { |
| DVLOG(2) << "sending message @" << message << " on channel @" << this |
| << " with type " << message->type() |
| << " (" << output_queue_.size() << " in queue)"; |
| |
| #ifdef IPC_MESSAGE_LOG_ENABLED |
| Logging::GetInstance()->OnSendMessage(message, ""); |
| #endif // IPC_MESSAGE_LOG_ENABLED |
| |
| message->TraceMessageBegin(); |
| output_queue_.push(message); |
| if (!is_blocked_on_write_ && !waiting_connect_) { |
| return ProcessOutgoingMessages(); |
| } |
| |
| return true; |
| } |
| |
| int Channel::ChannelImpl::GetClientFileDescriptor() { |
| base::AutoLock lock(client_pipe_lock_); |
| return client_pipe_; |
| } |
| |
| int Channel::ChannelImpl::TakeClientFileDescriptor() { |
| base::AutoLock lock(client_pipe_lock_); |
| int fd = client_pipe_; |
| if (client_pipe_ != -1) { |
| PipeMap::GetInstance()->Remove(pipe_name_); |
| client_pipe_ = -1; |
| } |
| return fd; |
| } |
| |
| void Channel::ChannelImpl::CloseClientFileDescriptor() { |
| base::AutoLock lock(client_pipe_lock_); |
| if (client_pipe_ != -1) { |
| PipeMap::GetInstance()->Remove(pipe_name_); |
| if (HANDLE_EINTR(close(client_pipe_)) < 0) |
| PLOG(ERROR) << "close " << pipe_name_; |
| client_pipe_ = -1; |
| } |
| } |
| |
| bool Channel::ChannelImpl::AcceptsConnections() const { |
| return server_listen_pipe_ != -1; |
| } |
| |
| bool Channel::ChannelImpl::HasAcceptedConnection() const { |
| return AcceptsConnections() && pipe_ != -1; |
| } |
| |
| bool Channel::ChannelImpl::GetPeerEuid(uid_t* peer_euid) const { |
| DCHECK(!(mode_ & MODE_SERVER) || HasAcceptedConnection()); |
| return IPC::GetPeerEuid(pipe_, peer_euid); |
| } |
| |
| void Channel::ChannelImpl::ResetToAcceptingConnectionState() { |
| // Unregister libevent for the unix domain socket and close it. |
| read_watcher_.StopWatchingFileDescriptor(); |
| write_watcher_.StopWatchingFileDescriptor(); |
| if (pipe_ != -1) { |
| if (HANDLE_EINTR(close(pipe_)) < 0) |
| PLOG(ERROR) << "close pipe_ " << pipe_name_; |
| pipe_ = -1; |
| } |
| #if defined(IPC_USES_READWRITE) |
| if (fd_pipe_ != -1) { |
| if (HANDLE_EINTR(close(fd_pipe_)) < 0) |
| PLOG(ERROR) << "close fd_pipe_ " << pipe_name_; |
| fd_pipe_ = -1; |
| } |
| if (remote_fd_pipe_ != -1) { |
| if (HANDLE_EINTR(close(remote_fd_pipe_)) < 0) |
| PLOG(ERROR) << "close remote_fd_pipe_ " << pipe_name_; |
| remote_fd_pipe_ = -1; |
| } |
| #endif // IPC_USES_READWRITE |
| |
| while (!output_queue_.empty()) { |
| Message* m = output_queue_.front(); |
| output_queue_.pop(); |
| delete m; |
| } |
| |
| // Close any outstanding, received file descriptors. |
| ClearInputFDs(); |
| |
| #if defined(OS_MACOSX) |
| // Clear any outstanding, sent file descriptors. |
| for (std::set<int>::iterator i = fds_to_close_.begin(); |
| i != fds_to_close_.end(); |
| ++i) { |
| if (HANDLE_EINTR(close(*i)) < 0) |
| PLOG(ERROR) << "close"; |
| } |
| fds_to_close_.clear(); |
| #endif |
| } |
| |
| // static |
| bool Channel::ChannelImpl::IsNamedServerInitialized( |
| const std::string& channel_id) { |
| return base::PathExists(base::FilePath(channel_id)); |
| } |
| |
| #if defined(OS_LINUX) |
| // static |
| void Channel::ChannelImpl::SetGlobalPid(int pid) { |
| global_pid_ = pid; |
| } |
| #endif // OS_LINUX |
| |
| // Called by libevent when we can read from the pipe without blocking. |
| void Channel::ChannelImpl::OnFileCanReadWithoutBlocking(int fd) { |
| if (fd == server_listen_pipe_) { |
| int new_pipe = 0; |
| if (!ServerAcceptConnection(server_listen_pipe_, &new_pipe) || |
| new_pipe < 0) { |
| Close(); |
| listener()->OnChannelListenError(); |
| } |
| |
| if (pipe_ != -1) { |
| // We already have a connection. We only handle one at a time. |
| // close our new descriptor. |
| if (HANDLE_EINTR(shutdown(new_pipe, SHUT_RDWR)) < 0) |
| DPLOG(ERROR) << "shutdown " << pipe_name_; |
| if (HANDLE_EINTR(close(new_pipe)) < 0) |
| DPLOG(ERROR) << "close " << pipe_name_; |
| listener()->OnChannelDenied(); |
| return; |
| } |
| pipe_ = new_pipe; |
| |
| if ((mode_ & MODE_OPEN_ACCESS_FLAG) == 0) { |
| // Verify that the IPC channel peer is running as the same user. |
| uid_t client_euid; |
| if (!GetPeerEuid(&client_euid)) { |
| DLOG(ERROR) << "Unable to query client euid"; |
| ResetToAcceptingConnectionState(); |
| return; |
| } |
| if (client_euid != geteuid()) { |
| DLOG(WARNING) << "Client euid is not authorised"; |
| ResetToAcceptingConnectionState(); |
| return; |
| } |
| } |
| |
| if (!AcceptConnection()) { |
| NOTREACHED() << "AcceptConnection should not fail on server"; |
| } |
| waiting_connect_ = false; |
| } else if (fd == pipe_) { |
| if (waiting_connect_ && (mode_ & MODE_SERVER_FLAG)) { |
| waiting_connect_ = false; |
| } |
| if (!ProcessIncomingMessages()) { |
| // ClosePipeOnError may delete this object, so we mustn't call |
| // ProcessOutgoingMessages. |
| ClosePipeOnError(); |
| return; |
| } |
| } else { |
| NOTREACHED() << "Unknown pipe " << fd; |
| } |
| |
| // If we're a server and handshaking, then we want to make sure that we |
| // only send our handshake message after we've processed the client's. |
| // This gives us a chance to kill the client if the incoming handshake |
| // is invalid. This also flushes any closefd messagse. |
| if (!is_blocked_on_write_) { |
| if (!ProcessOutgoingMessages()) { |
| ClosePipeOnError(); |
| } |
| } |
| } |
| |
| // Called by libevent when we can write to the pipe without blocking. |
| void Channel::ChannelImpl::OnFileCanWriteWithoutBlocking(int fd) { |
| DCHECK_EQ(pipe_, fd); |
| is_blocked_on_write_ = false; |
| if (!ProcessOutgoingMessages()) { |
| ClosePipeOnError(); |
| } |
| } |
| |
| bool Channel::ChannelImpl::AcceptConnection() { |
| base::MessageLoopForIO::current()->WatchFileDescriptor( |
| pipe_, true, base::MessageLoopForIO::WATCH_READ, &read_watcher_, this); |
| QueueHelloMessage(); |
| |
| if (mode_ & MODE_CLIENT_FLAG) { |
| // If we are a client we want to send a hello message out immediately. |
| // In server mode we will send a hello message when we receive one from a |
| // client. |
| waiting_connect_ = false; |
| return ProcessOutgoingMessages(); |
| } else if (mode_ & MODE_SERVER_FLAG) { |
| waiting_connect_ = true; |
| return true; |
| } else { |
| NOTREACHED(); |
| return false; |
| } |
| } |
| |
| void Channel::ChannelImpl::ClosePipeOnError() { |
| if (HasAcceptedConnection()) { |
| ResetToAcceptingConnectionState(); |
| listener()->OnChannelError(); |
| } else { |
| Close(); |
| if (AcceptsConnections()) { |
| listener()->OnChannelListenError(); |
| } else { |
| listener()->OnChannelError(); |
| } |
| } |
| } |
| |
| int Channel::ChannelImpl::GetHelloMessageProcId() { |
| int pid = base::GetCurrentProcId(); |
| #if defined(OS_LINUX) |
| // Our process may be in a sandbox with a separate PID namespace. |
| if (global_pid_) { |
| pid = global_pid_; |
| } |
| #endif |
| return pid; |
| } |
| |
| void Channel::ChannelImpl::QueueHelloMessage() { |
| // Create the Hello message |
| scoped_ptr<Message> msg(new Message(MSG_ROUTING_NONE, |
| HELLO_MESSAGE_TYPE, |
| IPC::Message::PRIORITY_NORMAL)); |
| if (!msg->WriteInt(GetHelloMessageProcId())) { |
| NOTREACHED() << "Unable to pickle hello message proc id"; |
| } |
| #if defined(IPC_USES_READWRITE) |
| scoped_ptr<Message> hello; |
| if (remote_fd_pipe_ != -1) { |
| if (!msg->WriteFileDescriptor(base::FileDescriptor(remote_fd_pipe_, |
| false))) { |
| NOTREACHED() << "Unable to pickle hello message file descriptors"; |
| } |
| DCHECK_EQ(msg->file_descriptor_set()->size(), 1U); |
| } |
| #endif // IPC_USES_READWRITE |
| output_queue_.push(msg.release()); |
| } |
| |
| Channel::ChannelImpl::ReadState Channel::ChannelImpl::ReadData( |
| char* buffer, |
| int buffer_len, |
| int* bytes_read) { |
| if (pipe_ == -1) |
| return READ_FAILED; |
| |
| struct msghdr msg = {0}; |
| |
| struct iovec iov = {buffer, static_cast<size_t>(buffer_len)}; |
| msg.msg_iov = &iov; |
| msg.msg_iovlen = 1; |
| |
| msg.msg_control = input_cmsg_buf_; |
| |
| // recvmsg() returns 0 if the connection has closed or EAGAIN if no data |
| // is waiting on the pipe. |
| #if defined(IPC_USES_READWRITE) |
| if (fd_pipe_ >= 0) { |
| *bytes_read = HANDLE_EINTR(read(pipe_, buffer, buffer_len)); |
| msg.msg_controllen = 0; |
| } else |
| #endif // IPC_USES_READWRITE |
| { |
| msg.msg_controllen = sizeof(input_cmsg_buf_); |
| *bytes_read = HANDLE_EINTR(recvmsg(pipe_, &msg, MSG_DONTWAIT)); |
| } |
| if (*bytes_read < 0) { |
| if (errno == EAGAIN) { |
| return READ_PENDING; |
| #if defined(OS_MACOSX) |
| } else if (errno == EPERM) { |
| // On OSX, reading from a pipe with no listener returns EPERM |
| // treat this as a special case to prevent spurious error messages |
| // to the console. |
| return READ_FAILED; |
| #endif // OS_MACOSX |
| } else if (errno == ECONNRESET || errno == EPIPE) { |
| return READ_FAILED; |
| } else { |
| PLOG(ERROR) << "pipe error (" << pipe_ << ")"; |
| return READ_FAILED; |
| } |
| } else if (*bytes_read == 0) { |
| // The pipe has closed... |
| return READ_FAILED; |
| } |
| DCHECK(*bytes_read); |
| |
| CloseClientFileDescriptor(); |
| |
| // Read any file descriptors from the message. |
| if (!ExtractFileDescriptorsFromMsghdr(&msg)) |
| return READ_FAILED; |
| return READ_SUCCEEDED; |
| } |
| |
| #if defined(IPC_USES_READWRITE) |
| bool Channel::ChannelImpl::ReadFileDescriptorsFromFDPipe() { |
| char dummy; |
| struct iovec fd_pipe_iov = { &dummy, 1 }; |
| |
| struct msghdr msg = { 0 }; |
| msg.msg_iov = &fd_pipe_iov; |
| msg.msg_iovlen = 1; |
| msg.msg_control = input_cmsg_buf_; |
| msg.msg_controllen = sizeof(input_cmsg_buf_); |
| ssize_t bytes_received = HANDLE_EINTR(recvmsg(fd_pipe_, &msg, MSG_DONTWAIT)); |
| |
| if (bytes_received != 1) |
| return true; // No message waiting. |
| |
| if (!ExtractFileDescriptorsFromMsghdr(&msg)) |
| return false; |
| return true; |
| } |
| #endif |
| |
| // On Posix, we need to fix up the file descriptors before the input message |
| // is dispatched. |
| // |
| // This will read from the input_fds_ (READWRITE mode only) and read more |
| // handles from the FD pipe if necessary. |
| bool Channel::ChannelImpl::WillDispatchInputMessage(Message* msg) { |
| uint16 header_fds = msg->header()->num_fds; |
| if (!header_fds) |
| return true; // Nothing to do. |
| |
| // The message has file descriptors. |
| const char* error = NULL; |
| if (header_fds > input_fds_.size()) { |
| // The message has been completely received, but we didn't get |
| // enough file descriptors. |
| #if defined(IPC_USES_READWRITE) |
| if (!ReadFileDescriptorsFromFDPipe()) |
| return false; |
| if (header_fds > input_fds_.size()) |
| #endif // IPC_USES_READWRITE |
| error = "Message needs unreceived descriptors"; |
| } |
| |
| if (header_fds > FileDescriptorSet::kMaxDescriptorsPerMessage) |
| error = "Message requires an excessive number of descriptors"; |
| |
| if (error) { |
| LOG(WARNING) << error |
| << " channel:" << this |
| << " message-type:" << msg->type() |
| << " header()->num_fds:" << header_fds; |
| // Abort the connection. |
| ClearInputFDs(); |
| return false; |
| } |
| |
| // The shenaniganery below with &foo.front() requires input_fds_ to have |
| // contiguous underlying storage (such as a simple array or a std::vector). |
| // This is why the header warns not to make input_fds_ a deque<>. |
| msg->file_descriptor_set()->SetDescriptors(&input_fds_.front(), |
| header_fds); |
| input_fds_.erase(input_fds_.begin(), input_fds_.begin() + header_fds); |
| return true; |
| } |
| |
| bool Channel::ChannelImpl::DidEmptyInputBuffers() { |
| // When the input data buffer is empty, the fds should be too. If this is |
| // not the case, we probably have a rogue renderer which is trying to fill |
| // our descriptor table. |
| return input_fds_.empty(); |
| } |
| |
| bool Channel::ChannelImpl::ExtractFileDescriptorsFromMsghdr(msghdr* msg) { |
| // Check that there are any control messages. On OSX, CMSG_FIRSTHDR will |
| // return an invalid non-NULL pointer in the case that controllen == 0. |
| if (msg->msg_controllen == 0) |
| return true; |
| |
| for (cmsghdr* cmsg = CMSG_FIRSTHDR(msg); |
| cmsg; |
| cmsg = CMSG_NXTHDR(msg, cmsg)) { |
| if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { |
| unsigned payload_len = cmsg->cmsg_len - CMSG_LEN(0); |
| DCHECK_EQ(0U, payload_len % sizeof(int)); |
| const int* file_descriptors = reinterpret_cast<int*>(CMSG_DATA(cmsg)); |
| unsigned num_file_descriptors = payload_len / 4; |
| input_fds_.insert(input_fds_.end(), |
| file_descriptors, |
| file_descriptors + num_file_descriptors); |
| |
| // Check this after adding the FDs so we don't leak them. |
| if (msg->msg_flags & MSG_CTRUNC) { |
| ClearInputFDs(); |
| return false; |
| } |
| |
| return true; |
| } |
| } |
| |
| // No file descriptors found, but that's OK. |
| return true; |
| } |
| |
| void Channel::ChannelImpl::ClearInputFDs() { |
| for (size_t i = 0; i < input_fds_.size(); ++i) { |
| if (HANDLE_EINTR(close(input_fds_[i])) < 0) |
| PLOG(ERROR) << "close "; |
| } |
| input_fds_.clear(); |
| } |
| |
| void Channel::ChannelImpl::QueueCloseFDMessage(int fd, int hops) { |
| switch (hops) { |
| case 1: |
| case 2: { |
| // Create the message |
| scoped_ptr<Message> msg(new Message(MSG_ROUTING_NONE, |
| CLOSE_FD_MESSAGE_TYPE, |
| IPC::Message::PRIORITY_NORMAL)); |
| if (!msg->WriteInt(hops - 1) || !msg->WriteInt(fd)) { |
| NOTREACHED() << "Unable to pickle close fd."; |
| } |
| // Send(msg.release()); |
| output_queue_.push(msg.release()); |
| break; |
| } |
| |
| default: |
| NOTREACHED(); |
| break; |
| } |
| } |
| |
| void Channel::ChannelImpl::HandleInternalMessage(const Message& msg) { |
| // The Hello message contains only the process id. |
| PickleIterator iter(msg); |
| |
| switch (msg.type()) { |
| default: |
| NOTREACHED(); |
| break; |
| |
| case Channel::HELLO_MESSAGE_TYPE: |
| int pid; |
| if (!msg.ReadInt(&iter, &pid)) |
| NOTREACHED(); |
| |
| #if defined(IPC_USES_READWRITE) |
| if (mode_ & MODE_SERVER_FLAG) { |
| // With IPC_USES_READWRITE, the Hello message from the client to the |
| // server also contains the fd_pipe_, which will be used for all |
| // subsequent file descriptor passing. |
| DCHECK_EQ(msg.file_descriptor_set()->size(), 1U); |
| base::FileDescriptor descriptor; |
| if (!msg.ReadFileDescriptor(&iter, &descriptor)) { |
| NOTREACHED(); |
| } |
| fd_pipe_ = descriptor.fd; |
| CHECK(descriptor.auto_close); |
| } |
| #endif // IPC_USES_READWRITE |
| peer_pid_ = pid; |
| listener()->OnChannelConnected(pid); |
| break; |
| |
| #if defined(OS_MACOSX) |
| case Channel::CLOSE_FD_MESSAGE_TYPE: |
| int fd, hops; |
| if (!msg.ReadInt(&iter, &hops)) |
| NOTREACHED(); |
| if (!msg.ReadInt(&iter, &fd)) |
| NOTREACHED(); |
| if (hops == 0) { |
| if (fds_to_close_.erase(fd) > 0) { |
| if (HANDLE_EINTR(close(fd)) < 0) |
| PLOG(ERROR) << "close"; |
| } else { |
| NOTREACHED(); |
| } |
| } else { |
| QueueCloseFDMessage(fd, hops); |
| } |
| break; |
| #endif |
| } |
| } |
| |
| void Channel::ChannelImpl::Close() { |
| // Close can be called multiple time, so we need to make sure we're |
| // idempotent. |
| |
| ResetToAcceptingConnectionState(); |
| |
| if (must_unlink_) { |
| unlink(pipe_name_.c_str()); |
| must_unlink_ = false; |
| } |
| if (server_listen_pipe_ != -1) { |
| if (HANDLE_EINTR(close(server_listen_pipe_)) < 0) |
| DPLOG(ERROR) << "close " << server_listen_pipe_; |
| server_listen_pipe_ = -1; |
| // Unregister libevent for the listening socket and close it. |
| server_listen_connection_watcher_.StopWatchingFileDescriptor(); |
| } |
| |
| CloseClientFileDescriptor(); |
| } |
| |
| //------------------------------------------------------------------------------ |
| // Channel's methods simply call through to ChannelImpl. |
| Channel::Channel(const IPC::ChannelHandle& channel_handle, Mode mode, |
| Listener* listener) |
| : channel_impl_(new ChannelImpl(channel_handle, mode, listener)) { |
| } |
| |
| Channel::~Channel() { |
| delete channel_impl_; |
| } |
| |
| bool Channel::Connect() { |
| return channel_impl_->Connect(); |
| } |
| |
| void Channel::Close() { |
| if (channel_impl_) |
| channel_impl_->Close(); |
| } |
| |
| base::ProcessId Channel::peer_pid() const { |
| return channel_impl_->peer_pid(); |
| } |
| |
| bool Channel::Send(Message* message) { |
| return channel_impl_->Send(message); |
| } |
| |
| int Channel::GetClientFileDescriptor() const { |
| return channel_impl_->GetClientFileDescriptor(); |
| } |
| |
| int Channel::TakeClientFileDescriptor() { |
| return channel_impl_->TakeClientFileDescriptor(); |
| } |
| |
| bool Channel::AcceptsConnections() const { |
| return channel_impl_->AcceptsConnections(); |
| } |
| |
| bool Channel::HasAcceptedConnection() const { |
| return channel_impl_->HasAcceptedConnection(); |
| } |
| |
| bool Channel::GetPeerEuid(uid_t* peer_euid) const { |
| return channel_impl_->GetPeerEuid(peer_euid); |
| } |
| |
| void Channel::ResetToAcceptingConnectionState() { |
| channel_impl_->ResetToAcceptingConnectionState(); |
| } |
| |
| // static |
| bool Channel::IsNamedServerInitialized(const std::string& channel_id) { |
| return ChannelImpl::IsNamedServerInitialized(channel_id); |
| } |
| |
| // static |
| std::string Channel::GenerateVerifiedChannelID(const std::string& prefix) { |
| // A random name is sufficient validation on posix systems, so we don't need |
| // an additional shared secret. |
| |
| std::string id = prefix; |
| if (!id.empty()) |
| id.append("."); |
| |
| return id.append(GenerateUniqueRandomChannelID()); |
| } |
| |
| |
| #if defined(OS_LINUX) |
| // static |
| void Channel::SetGlobalPid(int pid) { |
| ChannelImpl::SetGlobalPid(pid); |
| } |
| #endif // OS_LINUX |
| |
| } // namespace IPC |