280 lines
8.5 KiB
C
280 lines
8.5 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2013 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <fcntl.h>
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#include <unistd.h>
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#include "bus-container.h"
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#include "bus-internal.h"
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#include "bus-socket.h"
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#include "fd-util.h"
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#include "process-util.h"
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#include "util.h"
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int bus_container_connect_socket(sd_bus *b) {
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_cleanup_close_pair_ int pair[2] = { -1, -1 };
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_cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
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pid_t child;
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siginfo_t si;
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int r, error_buf = 0;
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ssize_t n;
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assert(b);
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assert(b->input_fd < 0);
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assert(b->output_fd < 0);
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assert(b->nspid > 0 || b->machine);
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if (b->nspid <= 0) {
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r = container_get_leader(b->machine, &b->nspid);
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if (r < 0)
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return r;
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}
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r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
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if (r < 0)
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return r;
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b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
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if (b->input_fd < 0)
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return -errno;
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b->output_fd = b->input_fd;
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bus_socket_setup(b);
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if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0)
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return -errno;
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child = fork();
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if (child < 0)
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return -errno;
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if (child == 0) {
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pid_t grandchild;
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pair[0] = safe_close(pair[0]);
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r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
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if (r < 0)
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_exit(EXIT_FAILURE);
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/* We just changed PID namespace, however it will only
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* take effect on the children we now fork. Hence,
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* let's fork another time, and connect from this
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* grandchild, so that SO_PEERCRED of our connection
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* comes from a process from within the container, and
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* not outside of it */
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grandchild = fork();
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if (grandchild < 0)
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_exit(EXIT_FAILURE);
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if (grandchild == 0) {
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r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
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if (r < 0) {
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/* Try to send error up */
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error_buf = errno;
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(void) write(pair[1], &error_buf, sizeof(error_buf));
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_exit(EXIT_FAILURE);
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}
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_exit(EXIT_SUCCESS);
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}
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r = wait_for_terminate(grandchild, &si);
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if (r < 0)
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_exit(EXIT_FAILURE);
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if (si.si_code != CLD_EXITED)
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_exit(EXIT_FAILURE);
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_exit(si.si_status);
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}
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pair[1] = safe_close(pair[1]);
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r = wait_for_terminate(child, &si);
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if (r < 0)
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return r;
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n = read(pair[0], &error_buf, sizeof(error_buf));
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if (n < 0)
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return -errno;
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if (n > 0) {
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if (n != sizeof(error_buf))
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return -EIO;
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if (error_buf < 0)
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return -EIO;
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if (error_buf == EINPROGRESS)
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return 1;
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if (error_buf > 0)
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return -error_buf;
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}
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if (si.si_code != CLD_EXITED)
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return -EIO;
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if (si.si_status != EXIT_SUCCESS)
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return -EIO;
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return bus_socket_start_auth(b);
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}
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int bus_container_connect_kernel(sd_bus *b) {
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_cleanup_close_pair_ int pair[2] = { -1, -1 };
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_cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
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union {
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struct cmsghdr cmsghdr;
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uint8_t buf[CMSG_SPACE(sizeof(int))];
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} control = {};
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int error_buf = 0;
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struct iovec iov = {
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.iov_base = &error_buf,
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.iov_len = sizeof(error_buf),
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};
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struct msghdr mh = {
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.msg_control = &control,
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.msg_controllen = sizeof(control),
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.msg_iov = &iov,
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.msg_iovlen = 1,
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};
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struct cmsghdr *cmsg;
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pid_t child;
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siginfo_t si;
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int r, fd = -1;
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ssize_t n;
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assert(b);
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assert(b->input_fd < 0);
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assert(b->output_fd < 0);
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assert(b->nspid > 0 || b->machine);
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if (b->nspid <= 0) {
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r = container_get_leader(b->machine, &b->nspid);
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if (r < 0)
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return r;
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}
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r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
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if (r < 0)
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return r;
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if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0)
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return -errno;
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child = fork();
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if (child < 0)
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return -errno;
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if (child == 0) {
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pid_t grandchild;
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pair[0] = safe_close(pair[0]);
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r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
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if (r < 0)
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_exit(EXIT_FAILURE);
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/* We just changed PID namespace, however it will only
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* take effect on the children we now fork. Hence,
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* let's fork another time, and connect from this
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* grandchild, so that kdbus only sees the credentials
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* of this process which comes from within the
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* container, and not outside of it */
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grandchild = fork();
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if (grandchild < 0)
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_exit(EXIT_FAILURE);
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if (grandchild == 0) {
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fd = open(b->kernel, O_RDWR|O_NOCTTY|O_CLOEXEC);
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if (fd < 0) {
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/* Try to send error up */
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error_buf = errno;
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(void) write(pair[1], &error_buf, sizeof(error_buf));
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_exit(EXIT_FAILURE);
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}
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r = send_one_fd(pair[1], fd, 0);
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if (r < 0)
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_exit(EXIT_FAILURE);
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_exit(EXIT_SUCCESS);
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}
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r = wait_for_terminate(grandchild, &si);
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if (r < 0)
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_exit(EXIT_FAILURE);
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if (si.si_code != CLD_EXITED)
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_exit(EXIT_FAILURE);
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_exit(si.si_status);
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}
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pair[1] = safe_close(pair[1]);
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r = wait_for_terminate(child, &si);
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if (r < 0)
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return r;
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n = recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
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if (n < 0)
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return -errno;
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CMSG_FOREACH(cmsg, &mh) {
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if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
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int *fds;
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unsigned n_fds;
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assert(fd < 0);
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fds = (int*) CMSG_DATA(cmsg);
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n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
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if (n_fds != 1) {
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close_many(fds, n_fds);
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return -EIO;
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}
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fd = fds[0];
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}
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}
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/* If there's an fd passed, we are good. */
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if (fd >= 0) {
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b->input_fd = b->output_fd = fd;
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return bus_kernel_take_fd(b);
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}
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/* If there's an error passed, use it */
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if (n == sizeof(error_buf) && error_buf > 0)
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return -error_buf;
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/* Otherwise, we have no clue */
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return -EIO;
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}
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