| /*** |
| This file is part of systemd. |
| |
| Copyright 2013 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <fcntl.h> |
| #include <unistd.h> |
| |
| #include "bus-container.h" |
| #include "bus-internal.h" |
| #include "bus-socket.h" |
| #include "fd-util.h" |
| #include "process-util.h" |
| #include "util.h" |
| |
| int bus_container_connect_socket(sd_bus *b) { |
| _cleanup_close_pair_ int pair[2] = { -1, -1 }; |
| _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1; |
| pid_t child; |
| siginfo_t si; |
| int r, error_buf = 0; |
| ssize_t n; |
| |
| assert(b); |
| assert(b->input_fd < 0); |
| assert(b->output_fd < 0); |
| assert(b->nspid > 0 || b->machine); |
| |
| if (b->nspid <= 0) { |
| r = container_get_leader(b->machine, &b->nspid); |
| if (r < 0) |
| return r; |
| } |
| |
| r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd); |
| if (r < 0) |
| return r; |
| |
| b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); |
| if (b->input_fd < 0) |
| return -errno; |
| |
| b->output_fd = b->input_fd; |
| |
| bus_socket_setup(b); |
| |
| if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0) |
| return -errno; |
| |
| child = fork(); |
| if (child < 0) |
| return -errno; |
| |
| if (child == 0) { |
| pid_t grandchild; |
| |
| pair[0] = safe_close(pair[0]); |
| |
| r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd); |
| if (r < 0) |
| _exit(EXIT_FAILURE); |
| |
| /* We just changed PID namespace, however it will only |
| * take effect on the children we now fork. Hence, |
| * let's fork another time, and connect from this |
| * grandchild, so that SO_PEERCRED of our connection |
| * comes from a process from within the container, and |
| * not outside of it */ |
| |
| grandchild = fork(); |
| if (grandchild < 0) |
| _exit(EXIT_FAILURE); |
| |
| if (grandchild == 0) { |
| |
| r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size); |
| if (r < 0) { |
| /* Try to send error up */ |
| error_buf = errno; |
| (void) write(pair[1], &error_buf, sizeof(error_buf)); |
| _exit(EXIT_FAILURE); |
| } |
| |
| _exit(EXIT_SUCCESS); |
| } |
| |
| r = wait_for_terminate(grandchild, &si); |
| if (r < 0) |
| _exit(EXIT_FAILURE); |
| |
| if (si.si_code != CLD_EXITED) |
| _exit(EXIT_FAILURE); |
| |
| _exit(si.si_status); |
| } |
| |
| pair[1] = safe_close(pair[1]); |
| |
| r = wait_for_terminate(child, &si); |
| if (r < 0) |
| return r; |
| |
| n = read(pair[0], &error_buf, sizeof(error_buf)); |
| if (n < 0) |
| return -errno; |
| |
| if (n > 0) { |
| if (n != sizeof(error_buf)) |
| return -EIO; |
| |
| if (error_buf < 0) |
| return -EIO; |
| |
| if (error_buf == EINPROGRESS) |
| return 1; |
| |
| if (error_buf > 0) |
| return -error_buf; |
| } |
| |
| if (si.si_code != CLD_EXITED) |
| return -EIO; |
| |
| if (si.si_status != EXIT_SUCCESS) |
| return -EIO; |
| |
| return bus_socket_start_auth(b); |
| } |
| |
| int bus_container_connect_kernel(sd_bus *b) { |
| _cleanup_close_pair_ int pair[2] = { -1, -1 }; |
| _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1; |
| union { |
| struct cmsghdr cmsghdr; |
| uint8_t buf[CMSG_SPACE(sizeof(int))]; |
| } control = {}; |
| int error_buf = 0; |
| struct iovec iov = { |
| .iov_base = &error_buf, |
| .iov_len = sizeof(error_buf), |
| }; |
| struct msghdr mh = { |
| .msg_control = &control, |
| .msg_controllen = sizeof(control), |
| .msg_iov = &iov, |
| .msg_iovlen = 1, |
| }; |
| struct cmsghdr *cmsg; |
| pid_t child; |
| siginfo_t si; |
| int r, fd = -1; |
| ssize_t n; |
| |
| assert(b); |
| assert(b->input_fd < 0); |
| assert(b->output_fd < 0); |
| assert(b->nspid > 0 || b->machine); |
| |
| if (b->nspid <= 0) { |
| r = container_get_leader(b->machine, &b->nspid); |
| if (r < 0) |
| return r; |
| } |
| |
| r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd); |
| if (r < 0) |
| return r; |
| |
| if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0) |
| return -errno; |
| |
| child = fork(); |
| if (child < 0) |
| return -errno; |
| |
| if (child == 0) { |
| pid_t grandchild; |
| |
| pair[0] = safe_close(pair[0]); |
| |
| r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd); |
| if (r < 0) |
| _exit(EXIT_FAILURE); |
| |
| /* We just changed PID namespace, however it will only |
| * take effect on the children we now fork. Hence, |
| * let's fork another time, and connect from this |
| * grandchild, so that kdbus only sees the credentials |
| * of this process which comes from within the |
| * container, and not outside of it */ |
| |
| grandchild = fork(); |
| if (grandchild < 0) |
| _exit(EXIT_FAILURE); |
| |
| if (grandchild == 0) { |
| fd = open(b->kernel, O_RDWR|O_NOCTTY|O_CLOEXEC); |
| if (fd < 0) { |
| /* Try to send error up */ |
| error_buf = errno; |
| (void) write(pair[1], &error_buf, sizeof(error_buf)); |
| _exit(EXIT_FAILURE); |
| } |
| |
| r = send_one_fd(pair[1], fd, 0); |
| if (r < 0) |
| _exit(EXIT_FAILURE); |
| |
| _exit(EXIT_SUCCESS); |
| } |
| |
| r = wait_for_terminate(grandchild, &si); |
| if (r < 0) |
| _exit(EXIT_FAILURE); |
| |
| if (si.si_code != CLD_EXITED) |
| _exit(EXIT_FAILURE); |
| |
| _exit(si.si_status); |
| } |
| |
| pair[1] = safe_close(pair[1]); |
| |
| r = wait_for_terminate(child, &si); |
| if (r < 0) |
| return r; |
| |
| n = recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC); |
| if (n < 0) |
| return -errno; |
| |
| CMSG_FOREACH(cmsg, &mh) { |
| if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { |
| int *fds; |
| unsigned n_fds; |
| |
| assert(fd < 0); |
| |
| fds = (int*) CMSG_DATA(cmsg); |
| n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); |
| |
| if (n_fds != 1) { |
| close_many(fds, n_fds); |
| return -EIO; |
| } |
| |
| fd = fds[0]; |
| } |
| } |
| |
| /* If there's an fd passed, we are good. */ |
| if (fd >= 0) { |
| b->input_fd = b->output_fd = fd; |
| return bus_kernel_take_fd(b); |
| } |
| |
| /* If there's an error passed, use it */ |
| if (n == sizeof(error_buf) && error_buf > 0) |
| return -error_buf; |
| |
| /* Otherwise, we have no clue */ |
| return -EIO; |
| } |