diff options
Diffstat (limited to 'src/libsystemd/bus-container.c')
| -rw-r--r-- | src/libsystemd/bus-container.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/src/libsystemd/bus-container.c b/src/libsystemd/bus-container.c new file mode 100644 index 0000000000..d330363b6f --- /dev/null +++ b/src/libsystemd/bus-container.c @@ -0,0 +1,241 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + 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 <unistd.h> +#include <fcntl.h> + +#include "util.h" +#include "fileio.h" +#include "bus-internal.h" +#include "bus-socket.h" +#include "bus-container.h" + +int bus_container_connect_socket(sd_bus *b) { + _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1; + pid_t leader, child; + siginfo_t si; + int r; + + assert(b); + assert(b->input_fd < 0); + assert(b->output_fd < 0); + + r = container_get_leader(b->machine, &leader); + if (r < 0) + return r; + + r = namespace_open(leader, &pidnsfd, &mntnsfd, &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); + + child = fork(); + if (child < 0) + return -errno; + + if (child == 0) { + pid_t grandchild; + + r = namespace_enter(pidnsfd, mntnsfd, rootfd); + if (r < 0) + _exit(255); + + /* 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(255); + + if (grandchild == 0) { + + r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size); + if (r < 0) { + if (errno == EINPROGRESS) + _exit(1); + + _exit(255); + } + + _exit(EXIT_SUCCESS); + } + + r = wait_for_terminate(grandchild, &si); + if (r < 0) + _exit(255); + + if (si.si_code != CLD_EXITED) + _exit(255); + + _exit(si.si_status); + } + + r = wait_for_terminate(child, &si); + if (r < 0) + return r; + + if (si.si_code != CLD_EXITED) + return -EIO; + + if (si.si_status == 1) + return 1; + + if (si.si_status != EXIT_SUCCESS) + return -EIO; + + return bus_socket_start_auth(b); +} + +int bus_container_connect_kernel(sd_bus *b) { + _cleanup_close_pipe_ int pair[2] = { -1, -1 }; + _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1; + union { + struct cmsghdr cmsghdr; + uint8_t buf[CMSG_SPACE(sizeof(int))]; + } control = {}; + struct msghdr mh = { + .msg_control = &control, + .msg_controllen = sizeof(control), + }; + struct cmsghdr *cmsg; + pid_t leader, child; + siginfo_t si; + int r; + _cleanup_close_ int fd = -1; + + assert(b); + assert(b->input_fd < 0); + assert(b->output_fd < 0); + + r = container_get_leader(b->machine, &leader); + if (r < 0) + return r; + + r = namespace_open(leader, &pidnsfd, &mntnsfd, &rootfd); + if (r < 0) + return r; + + if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0) + return -errno; + + child = fork(); + if (child < 0) + return -errno; + + if (child == 0) { + pid_t grandchild; + + close_nointr_nofail(pair[0]); + pair[0] = -1; + + r = namespace_enter(pidnsfd, mntnsfd, 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) + _exit(EXIT_FAILURE); + + cmsg = CMSG_FIRSTHDR(&mh); + cmsg->cmsg_level = SOL_SOCKET; + cmsg->cmsg_type = SCM_RIGHTS; + cmsg->cmsg_len = CMSG_LEN(sizeof(int)); + memcpy(CMSG_DATA(cmsg), &fd, sizeof(int)); + + mh.msg_controllen = cmsg->cmsg_len; + + if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 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); + } + + close_nointr_nofail(pair[1]); + pair[1] = -1; + + r = wait_for_terminate(child, &si); + if (r < 0) + return r; + + if (si.si_code != CLD_EXITED) + return -EIO; + + if (si.si_status != EXIT_SUCCESS) + return -EIO; + + if (recvmsg(pair[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) < 0) + return -errno; + + for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) + if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { + int *fds; + unsigned n_fds; + + 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]; + } + + b->input_fd = b->output_fd = fd; + fd = -1; + + return bus_kernel_take_fd(b); +} |