| // Copyright (c) 2011 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/types.h> |
| #include <sys/socket.h> |
| #include <sys/stat.h> |
| #include <sys/un.h> |
| |
| #include <string> |
| #include <map> |
| |
| #include "base/command_line.h" |
| #include "base/eintr_wrapper.h" |
| #include "base/file_path.h" |
| #include "base/file_util.h" |
| #include "base/global_descriptors_posix.h" |
| #include "base/logging.h" |
| #include "base/memory/scoped_ptr.h" |
| #include "base/memory/singleton.h" |
| #include "base/process_util.h" |
| #include "base/stl_util-inl.h" |
| #include "base/string_util.h" |
| #include "base/synchronization/lock.h" |
| #include "ipc/ipc_descriptors.h" |
| #include "ipc/ipc_switches.h" |
| #include "ipc/file_descriptor_set_posix.h" |
| #include "ipc/ipc_logging.h" |
| #include "ipc/ipc_message_utils.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 RemoveAndClose(const std::string& channel_id) { |
| base::AutoLock locked(lock_); |
| |
| ChannelToFDMap::iterator i = map_.find(channel_id); |
| if (i != map_.end()) { |
| if (HANDLE_EINTR(close(i->second)) < 0) |
| PLOG(ERROR) << "close " << channel_id; |
| map_.erase(i); |
| } |
| } |
| |
| // 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>; |
| }; |
| |
| //------------------------------------------------------------------------------ |
| // Verify that kMaxPipeNameLength is a decent size. |
| COMPILE_ASSERT(sizeof(((sockaddr_un*)0)->sun_path) >= kMaxPipeNameLength, |
| BAD_SUN_PATH_LENGTH); |
| |
| // Creates a unix domain socket bound to the specified name that is listening |
| // for connections. |
| bool CreateServerUnixDomainSocket(const std::string& pipe_name, |
| int* server_listen_fd) { |
| DCHECK(server_listen_fd); |
| DCHECK_GT(pipe_name.length(), 0u); |
| DCHECK_LT(pipe_name.length(), kMaxPipeNameLength); |
| |
| if (pipe_name.length() == 0 || pipe_name.length() >= kMaxPipeNameLength) { |
| return false; |
| } |
| |
| // Create socket. |
| int fd = socket(AF_UNIX, SOCK_STREAM, 0); |
| if (fd < 0) { |
| return false; |
| } |
| |
| // Make socket non-blocking |
| if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) { |
| PLOG(ERROR) << "fcntl(O_NONBLOCK) " << pipe_name; |
| if (HANDLE_EINTR(close(fd)) < 0) |
| PLOG(ERROR) << "close " << pipe_name; |
| return false; |
| } |
| |
| // Delete any old FS instances. |
| unlink(pipe_name.c_str()); |
| |
| // Make sure the path we need exists. |
| FilePath path(pipe_name); |
| FilePath dir_path = path.DirName(); |
| if (!file_util::CreateDirectory(dir_path)) { |
| return false; |
| } |
| |
| // Create unix_addr structure. |
| struct sockaddr_un unix_addr; |
| memset(&unix_addr, 0, sizeof(unix_addr)); |
| unix_addr.sun_family = AF_UNIX; |
| int path_len = snprintf(unix_addr.sun_path, IPC::kMaxPipeNameLength, |
| "%s", pipe_name.c_str()); |
| DCHECK_EQ(static_cast<int>(pipe_name.length()), path_len); |
| size_t unix_addr_len = offsetof(struct sockaddr_un, |
| sun_path) + path_len + 1; |
| |
| // Bind the socket. |
| if (bind(fd, reinterpret_cast<const sockaddr*>(&unix_addr), |
| unix_addr_len) != 0) { |
| PLOG(ERROR) << "bind " << pipe_name; |
| if (HANDLE_EINTR(close(fd)) < 0) |
| PLOG(ERROR) << "close " << pipe_name; |
| return false; |
| } |
| |
| // Start listening on the socket. |
| const int listen_queue_length = 1; |
| if (listen(fd, listen_queue_length) != 0) { |
| PLOG(ERROR) << "listen " << pipe_name; |
| if (HANDLE_EINTR(close(fd)) < 0) |
| PLOG(ERROR) << "close " << pipe_name; |
| return false; |
| } |
| |
| *server_listen_fd = fd; |
| return true; |
| } |
| |
| // Accept a connection on a socket we are listening to. |
| bool ServerAcceptConnection(int server_listen_fd, int* server_socket) { |
| DCHECK(server_socket); |
| |
| int accept_fd = HANDLE_EINTR(accept(server_listen_fd, NULL, 0)); |
| if (accept_fd < 0) |
| return false; |
| if (fcntl(accept_fd, F_SETFL, O_NONBLOCK) == -1) { |
| PLOG(ERROR) << "fcntl(O_NONBLOCK) " << accept_fd; |
| if (HANDLE_EINTR(close(accept_fd)) < 0) |
| PLOG(ERROR) << "close " << accept_fd; |
| return false; |
| } |
| |
| *server_socket = accept_fd; |
| return true; |
| } |
| |
| bool CreateClientUnixDomainSocket(const std::string& pipe_name, |
| int* client_socket) { |
| DCHECK(client_socket); |
| DCHECK_GT(pipe_name.length(), 0u); |
| DCHECK_LT(pipe_name.length(), kMaxPipeNameLength); |
| |
| if (pipe_name.length() == 0 || pipe_name.length() >= kMaxPipeNameLength) { |
| return false; |
| } |
| |
| // Create socket. |
| int fd = socket(AF_UNIX, SOCK_STREAM, 0); |
| if (fd < 0) { |
| PLOG(ERROR) << "socket " << pipe_name; |
| return false; |
| } |
| |
| // Make socket non-blocking |
| if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) { |
| PLOG(ERROR) << "fcntl(O_NONBLOCK) " << pipe_name; |
| if (HANDLE_EINTR(close(fd)) < 0) |
| PLOG(ERROR) << "close " << pipe_name; |
| return false; |
| } |
| |
| // Create server side of socket. |
| struct sockaddr_un server_unix_addr; |
| memset(&server_unix_addr, 0, sizeof(server_unix_addr)); |
| server_unix_addr.sun_family = AF_UNIX; |
| int path_len = snprintf(server_unix_addr.sun_path, IPC::kMaxPipeNameLength, |
| "%s", pipe_name.c_str()); |
| DCHECK_EQ(static_cast<int>(pipe_name.length()), path_len); |
| size_t server_unix_addr_len = offsetof(struct sockaddr_un, |
| sun_path) + path_len + 1; |
| |
| if (HANDLE_EINTR(connect(fd, reinterpret_cast<sockaddr*>(&server_unix_addr), |
| server_unix_addr_len)) != 0) { |
| PLOG(ERROR) << "connect " << pipe_name; |
| if (HANDLE_EINTR(close(fd)) < 0) |
| PLOG(ERROR) << "close " << pipe_name; |
| return false; |
| } |
| |
| *client_socket = fd; |
| return true; |
| } |
| |
| 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 |
| //------------------------------------------------------------------------------ |
| |
| Channel::ChannelImpl::ChannelImpl(const IPC::ChannelHandle& channel_handle, |
| Mode mode, Listener* listener) |
| : mode_(mode), |
| 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), |
| listener_(listener), |
| must_unlink_(false) { |
| memset(input_buf_, 0, sizeof(input_buf_)); |
| 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"; |
| // The pipe may have been closed already. |
| 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(pipe_name_, &local_pipe)) { |
| return false; |
| } |
| must_unlink_ = true; |
| } else if (mode_ & MODE_CLIENT_FLAG) { |
| if (!CreateClientUnixDomainSocket(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()->RemoveAndClose(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; |
| } |
| 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. |
| MessageLoopForIO::current()->WatchFileDescriptor( |
| server_listen_pipe_, |
| true, |
| MessageLoopForIO::WATCH_READ, |
| &server_listen_connection_watcher_, |
| this); |
| } else { |
| did_connect = AcceptConnection(); |
| } |
| return did_connect; |
| } |
| |
| bool Channel::ChannelImpl::ProcessIncomingMessages() { |
| ssize_t bytes_read = 0; |
| |
| struct msghdr msg = {0}; |
| struct iovec iov = {input_buf_, Channel::kReadBufferSize}; |
| |
| msg.msg_iovlen = 1; |
| msg.msg_control = input_cmsg_buf_; |
| |
| for (;;) { |
| msg.msg_iov = &iov; |
| |
| if (bytes_read == 0) { |
| if (pipe_ == -1) |
| return false; |
| |
| // Read from pipe. |
| // 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_, input_buf_, |
| Channel::kReadBufferSize)); |
| 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 true; |
| #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 false; |
| #endif // OS_MACOSX |
| } else if (errno == ECONNRESET || errno == EPIPE) { |
| return false; |
| } else { |
| PLOG(ERROR) << "pipe error (" << pipe_ << ")"; |
| return false; |
| } |
| } else if (bytes_read == 0) { |
| // The pipe has closed... |
| return false; |
| } |
| } |
| DCHECK(bytes_read); |
| |
| if (client_pipe_ != -1) { |
| PipeMap::GetInstance()->RemoveAndClose(pipe_name_); |
| client_pipe_ = -1; |
| } |
| |
| // a pointer to an array of |num_wire_fds| file descriptors from the read |
| const int* wire_fds = NULL; |
| unsigned num_wire_fds = 0; |
| |
| // walk the list of control messages and, if we find an array of file |
| // descriptors, save a pointer to the array |
| |
| // This next if statement is to work around an OSX issue where |
| // CMSG_FIRSTHDR will return non-NULL in the case that controllen == 0. |
| // Here's a test case: |
| // |
| // int main() { |
| // struct msghdr msg; |
| // msg.msg_control = &msg; |
| // msg.msg_controllen = 0; |
| // if (CMSG_FIRSTHDR(&msg)) |
| // printf("Bug found!\n"); |
| // } |
| if (msg.msg_controllen > 0) { |
| // On OSX, CMSG_FIRSTHDR doesn't handle the case where controllen is 0 |
| // and will return a pointer into nowhere. |
| for (struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg); cmsg; |
| cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| if (cmsg->cmsg_level == SOL_SOCKET && |
| cmsg->cmsg_type == SCM_RIGHTS) { |
| const unsigned payload_len = cmsg->cmsg_len - CMSG_LEN(0); |
| DCHECK_EQ(0U, payload_len % sizeof(int)); |
| wire_fds = reinterpret_cast<int*>(CMSG_DATA(cmsg)); |
| num_wire_fds = payload_len / 4; |
| |
| if (msg.msg_flags & MSG_CTRUNC) { |
| LOG(ERROR) << "SCM_RIGHTS message was truncated" |
| << " cmsg_len:" << cmsg->cmsg_len |
| << " fd:" << pipe_; |
| for (unsigned i = 0; i < num_wire_fds; ++i) |
| if (HANDLE_EINTR(close(wire_fds[i])) < 0) |
| PLOG(ERROR) << "close " << i; |
| return false; |
| } |
| break; |
| } |
| } |
| } |
| |
| // Process messages from input buffer. |
| const char *p; |
| const char *end; |
| if (input_overflow_buf_.empty()) { |
| p = input_buf_; |
| end = p + bytes_read; |
| } else { |
| if (input_overflow_buf_.size() > |
| static_cast<size_t>(kMaximumMessageSize - bytes_read)) { |
| input_overflow_buf_.clear(); |
| LOG(ERROR) << "IPC message is too big"; |
| return false; |
| } |
| input_overflow_buf_.append(input_buf_, bytes_read); |
| p = input_overflow_buf_.data(); |
| end = p + input_overflow_buf_.size(); |
| } |
| |
| // A pointer to an array of |num_fds| file descriptors which includes any |
| // fds that have spilled over from a previous read. |
| const int* fds = NULL; |
| unsigned num_fds = 0; |
| unsigned fds_i = 0; // the index of the first unused descriptor |
| |
| if (input_overflow_fds_.empty()) { |
| fds = wire_fds; |
| num_fds = num_wire_fds; |
| } else { |
| if (num_wire_fds > 0) { |
| const size_t prev_size = input_overflow_fds_.size(); |
| input_overflow_fds_.resize(prev_size + num_wire_fds); |
| memcpy(&input_overflow_fds_[prev_size], wire_fds, |
| num_wire_fds * sizeof(int)); |
| } |
| fds = &input_overflow_fds_[0]; |
| num_fds = input_overflow_fds_.size(); |
| } |
| |
| while (p < end) { |
| const char* message_tail = Message::FindNext(p, end); |
| if (message_tail) { |
| int len = static_cast<int>(message_tail - p); |
| Message m(p, len); |
| const uint16 header_fds = m.header()->num_fds; |
| if (header_fds) { |
| // the message has file descriptors |
| const char* error = NULL; |
| if (header_fds > num_fds - fds_i) { |
| // the message has been completely received, but we didn't get |
| // enough file descriptors. |
| #if defined(IPC_USES_READWRITE) |
| char dummy; |
| struct iovec fd_pipe_iov = { &dummy, 1 }; |
| msg.msg_iov = &fd_pipe_iov; |
| msg.msg_controllen = sizeof(input_cmsg_buf_); |
| ssize_t n = HANDLE_EINTR(recvmsg(fd_pipe_, &msg, MSG_DONTWAIT)); |
| if (n == 1 && msg.msg_controllen > 0) { |
| for (struct cmsghdr* cmsg = CMSG_FIRSTHDR(&msg); cmsg; |
| cmsg = CMSG_NXTHDR(&msg, cmsg)) { |
| if (cmsg->cmsg_level == SOL_SOCKET && |
| cmsg->cmsg_type == SCM_RIGHTS) { |
| const unsigned payload_len = cmsg->cmsg_len - CMSG_LEN(0); |
| DCHECK_EQ(0U, payload_len % sizeof(int)); |
| wire_fds = reinterpret_cast<int*>(CMSG_DATA(cmsg)); |
| num_wire_fds = payload_len / 4; |
| |
| if (msg.msg_flags & MSG_CTRUNC) { |
| LOG(ERROR) << "SCM_RIGHTS message was truncated" |
| << " cmsg_len:" << cmsg->cmsg_len |
| << " fd:" << pipe_; |
| for (unsigned i = 0; i < num_wire_fds; ++i) |
| if (HANDLE_EINTR(close(wire_fds[i])) < 0) |
| PLOG(ERROR) << "close " << i; |
| return false; |
| } |
| break; |
| } |
| } |
| if (input_overflow_fds_.empty()) { |
| fds = wire_fds; |
| num_fds = num_wire_fds; |
| } else { |
| if (num_wire_fds > 0) { |
| const size_t prev_size = input_overflow_fds_.size(); |
| input_overflow_fds_.resize(prev_size + num_wire_fds); |
| memcpy(&input_overflow_fds_[prev_size], wire_fds, |
| num_wire_fds * sizeof(int)); |
| } |
| fds = &input_overflow_fds_[0]; |
| num_fds = input_overflow_fds_.size(); |
| } |
| } |
| if (header_fds > num_fds - fds_i) |
| #endif // IPC_USES_READWRITE |
| error = "Message needs unreceived descriptors"; |
| } |
| |
| if (header_fds > |
| FileDescriptorSet::MAX_DESCRIPTORS_PER_MESSAGE) { |
| // There are too many descriptors in this message |
| error = "Message requires an excessive number of descriptors"; |
| } |
| |
| if (error) { |
| LOG(WARNING) << error |
| << " channel:" << this |
| << " message-type:" << m.type() |
| << " header()->num_fds:" << header_fds |
| << " num_fds:" << num_fds |
| << " fds_i:" << fds_i; |
| #if defined(CHROMIUM_SELINUX) |
| LOG(WARNING) << "In the case of SELinux this can be caused when " |
| "using a --user-data-dir to which the default " |
| "policy doesn't give the renderer access to. "; |
| #endif // CHROMIUM_SELINUX |
| // close the existing file descriptors so that we don't leak them |
| for (unsigned i = fds_i; i < num_fds; ++i) |
| if (HANDLE_EINTR(close(fds[i])) < 0) |
| PLOG(ERROR) << "close " << i; |
| input_overflow_fds_.clear(); |
| // abort the connection |
| return false; |
| } |
| |
| m.file_descriptor_set()->SetDescriptors( |
| &fds[fds_i], header_fds); |
| fds_i += header_fds; |
| } |
| DVLOG(2) << "received message on channel @" << this |
| << " with type " << m.type() << " on fd " << pipe_; |
| if (IsHelloMessage(&m)) { |
| // The Hello message contains only the process id. |
| void *iter = NULL; |
| int pid; |
| if (!m.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(m.file_descriptor_set()->size(), 1U); |
| base::FileDescriptor descriptor; |
| if (!m.ReadFileDescriptor(&iter, &descriptor)) { |
| NOTREACHED(); |
| } |
| fd_pipe_ = descriptor.fd; |
| CHECK(descriptor.auto_close); |
| } |
| #endif // IPC_USES_READWRITE |
| listener_->OnChannelConnected(pid); |
| } else { |
| listener_->OnMessageReceived(m); |
| } |
| p = message_tail; |
| } else { |
| // Last message is partial. |
| break; |
| } |
| input_overflow_fds_ = std::vector<int>(&fds[fds_i], &fds[num_fds]); |
| fds_i = 0; |
| fds = vector_as_array(&input_overflow_fds_); |
| num_fds = input_overflow_fds_.size(); |
| } |
| input_overflow_buf_.assign(p, end - p); |
| input_overflow_fds_ = std::vector<int>(&fds[fds_i], &fds[num_fds]); |
| |
| // When the input data buffer is empty, the overflow fds should be too. If |
| // this is not the case, we probably have a rogue renderer which is trying |
| // to fill our descriptor table. |
| if (input_overflow_buf_.empty() && !input_overflow_fds_.empty()) { |
| // We close these descriptors in Close() |
| return false; |
| } |
| |
| bytes_read = 0; // Get more data. |
| } |
| } |
| |
| 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::MAX_DESCRIPTORS_PER_MESSAGE]))]; |
| |
| 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_LE(num_fds, FileDescriptorSet::MAX_DESCRIPTORS_PER_MESSAGE); |
| 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 < MAX_DESCRIPTORS_PER_MESSAGE 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) { |
| msg->file_descriptor_set()->CommitAll(); |
| } |
| } |
| #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) |
| msg->file_descriptor_set()->CommitAll(); |
| |
| 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; |
| MessageLoopForIO::current()->WatchFileDescriptor( |
| pipe_, |
| false, // One shot |
| 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 |
| |
| output_queue_.push(message); |
| if (!is_blocked_on_write_ && !waiting_connect_) { |
| return ProcessOutgoingMessages(); |
| } |
| |
| return true; |
| } |
| |
| int Channel::ChannelImpl::GetClientFileDescriptor() const { |
| return client_pipe_; |
| } |
| |
| bool Channel::ChannelImpl::AcceptsConnections() const { |
| return server_listen_pipe_ != -1; |
| } |
| |
| bool Channel::ChannelImpl::HasAcceptedConnection() const { |
| return AcceptsConnections() && pipe_ != -1; |
| } |
| |
| bool Channel::ChannelImpl::GetClientEuid(uid_t* client_euid) const { |
| DCHECK(HasAcceptedConnection()); |
| #if defined(OS_MACOSX) |
| uid_t peer_euid; |
| gid_t peer_gid; |
| if (getpeereid(pipe_, &peer_euid, &peer_gid) != 0) { |
| PLOG(ERROR) << "getpeereid " << pipe_; |
| return false; |
| } |
| *client_euid = peer_euid; |
| return true; |
| #elif defined(OS_SOLARIS) |
| return false; |
| #else |
| struct ucred cred; |
| socklen_t cred_len = sizeof(cred); |
| if (getsockopt(pipe_, SOL_SOCKET, SO_PEERCRED, &cred, &cred_len) != 0) { |
| PLOG(ERROR) << "getsockopt " << pipe_; |
| return false; |
| } |
| if (cred_len < sizeof(cred)) { |
| NOTREACHED() << "Truncated ucred from SO_PEERCRED?"; |
| return false; |
| } |
| *client_euid = cred.uid; |
| return true; |
| #endif |
| } |
| |
| 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. |
| for (std::vector<int>::iterator |
| i = input_overflow_fds_.begin(); i != input_overflow_fds_.end(); ++i) { |
| if (HANDLE_EINTR(close(*i)) < 0) |
| PLOG(ERROR) << "close"; |
| } |
| input_overflow_fds_.clear(); |
| } |
| |
| // Called by libevent when we can read from the pipe without blocking. |
| void Channel::ChannelImpl::OnFileCanReadWithoutBlocking(int fd) { |
| bool send_server_hello_msg = false; |
| if (fd == server_listen_pipe_) { |
| int new_pipe = 0; |
| if (!ServerAcceptConnection(server_listen_pipe_, &new_pipe)) { |
| 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) |
| PLOG(ERROR) << "shutdown " << pipe_name_; |
| if (HANDLE_EINTR(close(new_pipe)) < 0) |
| PLOG(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 (!GetClientEuid(&client_euid)) { |
| LOG(ERROR) << "Unable to query client euid"; |
| ResetToAcceptingConnectionState(); |
| return; |
| } |
| if (client_euid != geteuid()) { |
| LOG(WARNING) << "Client euid is not authorised"; |
| ResetToAcceptingConnectionState(); |
| return; |
| } |
| } |
| |
| if (!AcceptConnection()) { |
| NOTREACHED() << "AcceptConnection should not fail on server"; |
| } |
| send_server_hello_msg = true; |
| waiting_connect_ = false; |
| } else if (fd == pipe_) { |
| if (waiting_connect_ && (mode_ & MODE_SERVER_FLAG)) { |
| send_server_hello_msg = true; |
| waiting_connect_ = false; |
| } |
| if (!ProcessIncomingMessages()) { |
| // ClosePipeOnError may delete this object, so we mustn't call |
| // ProcessOutgoingMessages. |
| send_server_hello_msg = false; |
| ClosePipeOnError(); |
| } |
| } 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. |
| if (send_server_hello_msg) { |
| ProcessOutgoingMessages(); |
| } |
| } |
| |
| // 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() { |
| MessageLoopForIO::current()->WatchFileDescriptor(pipe_, |
| true, |
| 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(); |
| } |
| } |
| } |
| |
| 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(base::GetCurrentProcId())) { |
| 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()); |
| } |
| |
| bool Channel::ChannelImpl::IsHelloMessage(const Message* m) const { |
| return m->routing_id() == MSG_ROUTING_NONE && m->type() == HELLO_MESSAGE_TYPE; |
| } |
| |
| 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) |
| PLOG(ERROR) << "close " << server_listen_pipe_; |
| server_listen_pipe_ = -1; |
| // Unregister libevent for the listening socket and close it. |
| server_listen_connection_watcher_.StopWatchingFileDescriptor(); |
| } |
| |
| if (client_pipe_ != -1) { |
| PipeMap::GetInstance()->RemoveAndClose(pipe_name_); |
| client_pipe_ = -1; |
| } |
| } |
| |
| //------------------------------------------------------------------------------ |
| // 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() { |
| channel_impl_->Close(); |
| } |
| |
| void Channel::set_listener(Listener* listener) { |
| channel_impl_->set_listener(listener); |
| } |
| |
| bool Channel::Send(Message* message) { |
| return channel_impl_->Send(message); |
| } |
| |
| int Channel::GetClientFileDescriptor() const { |
| return channel_impl_->GetClientFileDescriptor(); |
| } |
| |
| bool Channel::AcceptsConnections() const { |
| return channel_impl_->AcceptsConnections(); |
| } |
| |
| bool Channel::HasAcceptedConnection() const { |
| return channel_impl_->HasAcceptedConnection(); |
| } |
| |
| bool Channel::GetClientEuid(uid_t* client_euid) const { |
| return channel_impl_->GetClientEuid(client_euid); |
| } |
| |
| void Channel::ResetToAcceptingConnectionState() { |
| channel_impl_->ResetToAcceptingConnectionState(); |
| } |
| |
| } // namespace IPC |
