#include <sys/syscall.h>
#include <limits.h>
#include <linux/fs.h>
+#include <sys/file.h>
#include "strv.h"
#include "util.h"
#include "namespace.h"
#include "missing.h"
#include "execute.h"
+#include "loopback-setup.h"
typedef enum MountMode {
/* This is ordered by priority! */
const char *path;
MountMode mode;
bool done;
+ bool ignore;
} BindMount;
static int append_mounts(BindMount **p, char **strv, MountMode mode) {
char **i;
+ assert(p);
+
STRV_FOREACH(i, strv) {
+ (*p)->ignore = false;
+
+ if ((mode == INACCESSIBLE || mode == READONLY) && (*i)[0] == '-') {
+ (*p)->ignore = true;
+ (*i)++;
+ }
+
if (!path_is_absolute(*i))
return -EINVAL;
r = mount(what, m->path, NULL, MS_BIND|MS_REC, NULL);
if (r >= 0)
log_debug("Successfully mounted %s to %s", what, m->path);
+ else if (m->ignore && errno == ENOENT)
+ r = 0;
return r;
}
return 0;
r = mount(NULL, m->path, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY|MS_REC, NULL);
- if (r < 0)
+ if (r < 0 && !(m->ignore && errno == ENOENT))
return -errno;
return 0;
}
-int setup_tmpdirs(char **tmp_dir,
- char **var_tmp_dir) {
- int r = 0;
- char tmp_dir_template[] = "/tmp/systemd-private-XXXXXX",
- var_tmp_dir_template[] = "/var/tmp/systemd-private-XXXXXX";
+int setup_namespace(
+ char** read_write_dirs,
+ char** read_only_dirs,
+ char** inaccessible_dirs,
+ char* tmp_dir,
+ char* var_tmp_dir,
+ unsigned mount_flags) {
- assert(tmp_dir);
- assert(var_tmp_dir);
+ BindMount *m, *mounts = NULL;
+ unsigned n;
+ int r = 0;
- r = create_tmp_dir(tmp_dir_template, tmp_dir);
- if (r < 0)
- return r;
+ if (mount_flags == 0)
+ mount_flags = MS_SHARED;
- r = create_tmp_dir(var_tmp_dir_template, var_tmp_dir);
- if (r == 0)
- return 0;
+ if (unshare(CLONE_NEWNS) < 0)
+ return -errno;
- /* failure */
- rmdir(*tmp_dir);
- rmdir(tmp_dir_template);
- free(*tmp_dir);
- *tmp_dir = NULL;
+ n = !!tmp_dir + !!var_tmp_dir +
+ strv_length(read_write_dirs) +
+ strv_length(read_only_dirs) +
+ strv_length(inaccessible_dirs);
- return r;
-}
+ if (n > 0) {
+ m = mounts = (BindMount *) alloca(n * sizeof(BindMount));
+ r = append_mounts(&m, read_write_dirs, READWRITE);
+ if (r < 0)
+ return r;
-int setup_namespace(char** read_write_dirs,
- char** read_only_dirs,
- char** inaccessible_dirs,
- char* tmp_dir,
- char* var_tmp_dir,
- bool private_tmp,
- unsigned mount_flags) {
-
- unsigned n = strv_length(read_write_dirs) +
- strv_length(read_only_dirs) +
- strv_length(inaccessible_dirs) +
- (private_tmp ? 2 : 0);
- BindMount *m, *mounts;
- int r = 0;
+ r = append_mounts(&m, read_only_dirs, READONLY);
+ if (r < 0)
+ return r;
- if (!mount_flags)
- mount_flags = MS_SHARED;
+ r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE);
+ if (r < 0)
+ return r;
- if (unshare(CLONE_NEWNS) < 0) {
- r = -errno;
- goto fail;
- }
+ if (tmp_dir) {
+ m->path = "/tmp";
+ m->mode = PRIVATE_TMP;
+ m++;
+ }
- m = mounts = (BindMount *) alloca(n * sizeof(BindMount));
- if ((r = append_mounts(&m, read_write_dirs, READWRITE)) < 0 ||
- (r = append_mounts(&m, read_only_dirs, READONLY)) < 0 ||
- (r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE)) < 0)
- goto fail;
+ if (var_tmp_dir) {
+ m->path = "/var/tmp";
+ m->mode = PRIVATE_VAR_TMP;
+ m++;
+ }
- if (private_tmp) {
- m->path = "/tmp";
- m->mode = PRIVATE_TMP;
- m++;
+ assert(mounts + n == m);
- m->path = "/var/tmp";
- m->mode = PRIVATE_VAR_TMP;
- m++;
+ qsort(mounts, n, sizeof(BindMount), mount_path_compare);
+ drop_duplicates(mounts, &n);
}
- assert(mounts + n == m);
-
- qsort(mounts, n, sizeof(BindMount), mount_path_compare);
- drop_duplicates(mounts, &n);
-
/* Remount / as SLAVE so that nothing now mounted in the namespace
shows up in the parent */
- if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) {
- r = -errno;
- goto fail;
- }
+ if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0)
+ return -errno;
for (m = mounts; m < mounts + n; ++m) {
r = apply_mount(m, tmp_dir, var_tmp_dir);
if (r < 0)
- goto undo_mounts;
+ goto fail;
}
for (m = mounts; m < mounts + n; ++m) {
r = make_read_only(m);
if (r < 0)
- goto undo_mounts;
+ goto fail;
}
/* Remount / as the desired mode */
if (mount(NULL, "/", NULL, mount_flags | MS_REC, NULL) < 0) {
r = -errno;
- goto undo_mounts;
+ goto fail;
}
return 0;
-undo_mounts:
- for (m = mounts; m < mounts + n; ++m) {
+fail:
+ for (m = mounts; m < mounts + n; ++m)
if (m->done)
umount2(m->path, MNT_DETACH);
+
+ return r;
+}
+
+static int setup_one_tmp_dir(const char *id, const char *prefix, char **path) {
+ _cleanup_free_ char *x = NULL;
+ char bid[SD_ID128_STRING_MAX];
+ sd_id128_t boot_id;
+ int r;
+
+ assert(id);
+ assert(prefix);
+ assert(path);
+
+ /* We include the boot id in the directory so that after a
+ * reboot we can easily identify obsolete directories. */
+
+ r = sd_id128_get_boot(&boot_id);
+ if (r < 0)
+ return r;
+
+ x = strjoin(prefix, "/systemd-private-", sd_id128_to_string(boot_id, bid), "-", id, "-XXXXXX", NULL);
+ if (!x)
+ return -ENOMEM;
+
+ RUN_WITH_UMASK(0077)
+ if (!mkdtemp(x))
+ return -errno;
+
+ RUN_WITH_UMASK(0000) {
+ char *y;
+
+ y = strappenda(x, "/tmp");
+
+ if (mkdir(y, 0777 | S_ISVTX) < 0)
+ return -errno;
+ }
+
+ *path = x;
+ x = NULL;
+
+ return 0;
+}
+
+int setup_tmp_dirs(const char *id, char **tmp_dir, char **var_tmp_dir) {
+ char *a, *b;
+ int r;
+
+ assert(id);
+ assert(tmp_dir);
+ assert(var_tmp_dir);
+
+ r = setup_one_tmp_dir(id, "/tmp", &a);
+ if (r < 0)
+ return r;
+
+ r = setup_one_tmp_dir(id, "/var/tmp", &b);
+ if (r < 0) {
+ char *t;
+
+ t = strappenda(a, "/tmp");
+ rmdir(t);
+ rmdir(a);
+
+ free(a);
+ return r;
+ }
+
+ *tmp_dir = a;
+ *var_tmp_dir = b;
+
+ return 0;
+}
+
+int setup_netns(int netns_storage_socket[2]) {
+ _cleanup_close_ int netns = -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;
+ int r;
+
+ assert(netns_storage_socket);
+ assert(netns_storage_socket[0] >= 0);
+ assert(netns_storage_socket[1] >= 0);
+
+ /* We use the passed socketpair as a storage buffer for our
+ * namespace reference fd. Whatever process runs this first
+ * shall create a new namespace, all others should just join
+ * it. To serialize that we use a file lock on the socket
+ * pair.
+ *
+ * It's a bit crazy, but hey, works great! */
+
+ if (lockf(netns_storage_socket[0], F_LOCK, 0) < 0)
+ return -errno;
+
+ if (recvmsg(netns_storage_socket[0], &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) < 0) {
+ if (errno != EAGAIN) {
+ r = -errno;
+ goto fail;
+ }
+
+ /* Nothing stored yet, so let's create a new namespace */
+
+ if (unshare(CLONE_NEWNET) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ loopback_setup();
+
+ netns = open("/proc/self/ns/net", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (netns < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = 1;
+ } else {
+ /* Yay, found something, so let's join the namespace */
+
+ for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+ if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
+ assert(cmsg->cmsg_len == CMSG_LEN(sizeof(int)));
+ netns = *(int*) CMSG_DATA(cmsg);
+ }
+ }
+
+ if (setns(netns, CLONE_NEWNET) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = 0;
+ }
+
+ 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), &netns, sizeof(int));
+ mh.msg_controllen = cmsg->cmsg_len;
+
+ if (sendmsg(netns_storage_socket[1], &mh, MSG_DONTWAIT|MSG_NOSIGNAL) < 0) {
+ r = -errno;
+ goto fail;
}
fail:
+ lockf(netns_storage_socket[0], F_ULOCK, 0);
+
return r;
}
~ianmdlvl / elogind.git / blobdiff