void cmsg_close_all(struct msghdr *mh) {
struct cmsghdr *cmsg;
assert(mh);
CMSG_FOREACH(cmsg, mh)
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
close_many((int*) CMSG_DATA(cmsg), (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int));
}
static void test_close_many(void) {
int fds[3];
char name0[] = "/tmp/test-close-many.XXXXXX";
char name1[] = "/tmp/test-close-many.XXXXXX";
char name2[] = "/tmp/test-close-many.XXXXXX";
fds[0] = mkstemp(name0);
fds[1] = mkstemp(name1);
fds[2] = mkstemp(name2);
close_many(fds, 2);
assert_se(fcntl(fds[0], F_GETFD) == -1);
assert_se(fcntl(fds[1], F_GETFD) == -1);
assert_se(fcntl(fds[2], F_GETFD) >= 0);
close_nointr_nofail(fds[2]);
unlink(name0);
unlink(name1);
unlink(name2);
}
static void test_close_many(void) {
int fds[3];
char name0[] = "/tmp/test-close-many.XXXXXX";
char name1[] = "/tmp/test-close-many.XXXXXX";
char name2[] = "/tmp/test-close-many.XXXXXX";
fds[0] = mkostemp_safe(name0, O_RDWR|O_CLOEXEC);
fds[1] = mkostemp_safe(name1, O_RDWR|O_CLOEXEC);
fds[2] = mkostemp_safe(name2, O_RDWR|O_CLOEXEC);
close_many(fds, 2);
assert_se(fcntl(fds[0], F_GETFD) == -1);
assert_se(fcntl(fds[1], F_GETFD) == -1);
assert_se(fcntl(fds[2], F_GETFD) >= 0);
safe_close(fds[2]);
unlink(name0);
unlink(name1);
unlink(name2);
}
int bus_container_connect_kernel(sd_bus *b) {
_cleanup_close_pair_ 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;
pair[0] = safe_close(pair[0]);
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);
}
pair[1] = safe_close(pair[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);
}
