X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fnspawn%2Fnspawn.c;h=84724d59c9177cae9a16acafb70c4c24f8340525;hp=1fe641b7ca1a1ca28461725f5c5f9636edec147d;hb=d8e538ecd9e62f841242f07e3df5c835c1ba6313;hpb=9875fd7875d433eea5c6e3319916e1be18722086 diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index 1fe641b7c..84724d59c 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -44,6 +44,7 @@ #include #include #include +#include #ifdef HAVE_SELINUX #include @@ -53,6 +54,10 @@ #include #endif +#ifdef HAVE_BLKID +#include +#endif + #include "sd-daemon.h" #include "sd-bus.h" #include "sd-id128.h" @@ -79,6 +84,9 @@ #include "def.h" #include "rtnl-util.h" #include "udev-util.h" +#include "blkid-util.h" +#include "gpt.h" +#include "siphash24.h" #ifdef HAVE_SECCOMP #include "seccomp-util.h" @@ -141,6 +149,7 @@ static char **arg_network_macvlan = NULL; static bool arg_network_veth = false; static const char *arg_network_bridge = NULL; static unsigned long arg_personality = 0xffffffffLU; +static const char *arg_image = NULL; static int help(void) { @@ -149,7 +158,8 @@ static int help(void) { " -h --help Show this help\n" " --version Print version string\n" " -q --quiet Do not show status information\n" - " -D --directory=NAME Root directory for the container\n" + " -D --directory=PATH Root directory for the container\n" + " -i --image=PATH File system device or image for the container\n" " -b --boot Boot up full system (i.e. invoke init)\n" " -u --user=USER Run the command under specified user or uid\n" " -M --machine=NAME Set the machine name for the container\n" @@ -244,6 +254,7 @@ static int parse_argv(int argc, char *argv[]) { { "network-veth", no_argument, NULL, ARG_NETWORK_VETH }, { "network-bridge", required_argument, NULL, ARG_NETWORK_BRIDGE }, { "personality", required_argument, NULL, ARG_PERSONALITY }, + { "image", required_argument, NULL, 'i' }, {} }; @@ -253,7 +264,7 @@ static int parse_argv(int argc, char *argv[]) { assert(argc >= 0); assert(argv); - while ((c = getopt_long(argc, argv, "+hD:u:bL:M:jS:Z:q", options, NULL)) >= 0) { + while ((c = getopt_long(argc, argv, "+hD:u:bL:M:jS:Z:qi:", options, NULL)) >= 0) { switch (c) { @@ -275,6 +286,10 @@ static int parse_argv(int argc, char *argv[]) { break; + case 'i': + arg_image = optarg; + break; + case 'u': free(arg_user); arg_user = strdup(optarg); @@ -517,6 +532,11 @@ static int parse_argv(int argc, char *argv[]) { return -EINVAL; } + if (arg_directory && arg_image) { + log_error("--directory= and --image= may not be combined."); + return -EINVAL; + } + arg_retain = (arg_retain | plus | (arg_private_network ? 1ULL << CAP_NET_ADMIN : 0)) & ~minus; return 1; @@ -618,7 +638,7 @@ static int mount_binds(const char *dest, char **l, unsigned long flags) { int r; if (stat(*x, &source_st) < 0) { - log_error("failed to stat %s: %m", *x); + log_error("Failed to stat %s: %m", *x); return -errno; } @@ -860,23 +880,19 @@ static int setup_ptmx(const char *dest) { } static int setup_dev_console(const char *dest, const char *console) { + _cleanup_umask_ mode_t u; + const char *to; struct stat st; - _cleanup_free_ char *to = NULL; int r; - _cleanup_umask_ mode_t u; assert(dest); assert(console); u = umask(0000); - if (stat(console, &st) < 0) { - log_error("Failed to stat %s: %m", console); + if (stat("/dev/null", &st) < 0) { + log_error("Failed to stat /dev/null: %m"); return -errno; - - } else if (!S_ISCHR(st.st_mode)) { - log_error("/dev/console is not a char device"); - return -EIO; } r = chmod_and_chown(console, 0600, 0, 0); @@ -885,16 +901,15 @@ static int setup_dev_console(const char *dest, const char *console) { return r; } - if (asprintf(&to, "%s/dev/console", dest) < 0) - return log_oom(); - /* We need to bind mount the right tty to /dev/console since * ptys can only exist on pts file systems. To have something - * to bind mount things on we create a device node first, that - * has the right major/minor (note that the major minor - * doesn't actually matter here, since we mount it over - * anyway). */ + * to bind mount things on we create a device node first, and + * use /dev/null for that since we the cgroups device policy + * allows us to create that freely, while we cannot create + * /dev/console. (Note that the major minor doesn't actually + * matter here, since we mount it over anyway). */ + to = strappenda(dest, "/dev/console"); if (mknod(to, (st.st_mode & ~07777) | 0600, st.st_rdev) < 0) { log_error("mknod() for /dev/console failed: %m"); return -errno; @@ -971,7 +986,7 @@ static int setup_kmsg(const char *dest, int kmsg_socket) { /* Store away the fd in the socket, so that it stays open as * long as we run the child */ k = sendmsg(kmsg_socket, &mh, MSG_DONTWAIT|MSG_NOSIGNAL); - close_nointr_nofail(fd); + safe_close(fd); if (k < 0) { log_error("Failed to send FIFO fd: %m"); @@ -1244,7 +1259,7 @@ static int register_machine(pid_t pid) { return r; } - r = sd_bus_message_append(m, "(sv)", "DeviceAllow", "a(ss)", 8, + r = sd_bus_message_append(m, "(sv)", "DeviceAllow", "a(ss)", 10, /* Allow the container to * access and create the API * device nodes, so that @@ -1263,7 +1278,18 @@ static int register_machine(pid_t pid) { * container to ever create * these device nodes. */ "/dev/pts/ptmx", "rw", - "char-pts", "rw"); + "char-pts", "rw", + /* Allow the container + * access to all kdbus + * devices. Again, the + * container cannot create + * these nodes, only use + * them. We use a pretty + * open match here, so that + * the kernel API can still + * change. */ + "char-kdbus", "rw", + "char-kdbus/*", "rw"); if (r < 0) { log_error("Failed to add device whitelist: %s", strerror(-r)); return r; @@ -1349,7 +1375,7 @@ static int reset_audit_loginuid(void) { return 0; r = read_one_line_file("/proc/self/loginuid", &p); - if (r == -EEXIST) + if (r == -ENOENT) return 0; if (r < 0) { log_error("Failed to read /proc/self/loginuid: %s", strerror(-r)); @@ -1374,9 +1400,46 @@ static int reset_audit_loginuid(void) { return 0; } +#define HASH_KEY SD_ID128_MAKE(c3,c4,f9,19,b5,57,b2,1c,e6,cf,14,27,03,9c,ee,a2) + +static int get_mac(struct ether_addr *mac) { + int r; + + uint8_t result[8]; + size_t l, sz; + uint8_t *v; + + l = strlen(arg_machine); + sz = sizeof(sd_id128_t) + l; + v = alloca(sz); + + /* fetch some persistent data unique to the host */ + r = sd_id128_get_machine((sd_id128_t*) v); + if (r < 0) + return r; + + /* combine with some data unique (on this host) to this + * container instance */ + memcpy(v + sizeof(sd_id128_t), arg_machine, l); + + /* Let's hash the host machine ID plus the container name. We + * use a fixed, but originally randomly created hash key here. */ + siphash24(result, v, sz, HASH_KEY.bytes); + + assert_cc(ETH_ALEN <= sizeof(result)); + memcpy(mac->ether_addr_octet, result, ETH_ALEN); + + /* see eth_random_addr in the kernel */ + mac->ether_addr_octet[0] &= 0xfe; /* clear multicast bit */ + mac->ether_addr_octet[0] |= 0x02; /* set local assignment bit (IEEE802) */ + + return 0; +} + static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) { _cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL; _cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL; + struct ether_addr mac; int r; if (!arg_private_network) @@ -1391,9 +1454,14 @@ static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) { memcpy(iface_name, "vb-", 3); else memcpy(iface_name, "ve-", 3); - strncpy(iface_name+3, arg_machine, IFNAMSIZ - 3); + r = get_mac(&mac); + if (r < 0) { + log_error("Failed to generate predictable MAC address for host0"); + return r; + } + r = sd_rtnl_open(&rtnl, 0); if (r < 0) { log_error("Failed to connect to netlink: %s", strerror(-r)); @@ -1418,13 +1486,7 @@ static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) { return r; } - r = sd_rtnl_message_append_string(m, IFLA_INFO_KIND, "veth"); - if (r < 0) { - log_error("Failed to append netlink kind: %s", strerror(-r)); - return r; - } - - r = sd_rtnl_message_open_container(m, IFLA_INFO_DATA); + r = sd_rtnl_message_open_container_union(m, IFLA_INFO_DATA, "veth"); if (r < 0) { log_error("Failed to open netlink container: %s", strerror(-r)); return r; @@ -1442,6 +1504,12 @@ static int setup_veth(pid_t pid, char iface_name[IFNAMSIZ]) { return r; } + r = sd_rtnl_message_append_ether_addr(m, IFLA_ADDRESS, &mac); + if (r < 0) { + log_error("Failed to add netlink MAC address: %s", strerror(-r)); + return r; + } + r = sd_rtnl_message_append_u32(m, IFLA_NET_NS_PID, pid); if (r < 0) { log_error("Failed to add netlink namespace field: %s", strerror(-r)); @@ -1507,6 +1575,12 @@ static int setup_bridge(const char veth_name[]) { return r; } + r = sd_rtnl_message_link_set_flags(m, IFF_UP, IFF_UP); + if (r < 0) { + log_error("Failed to set IFF_UP flag: %s", strerror(-r)); + return r; + } + r = sd_rtnl_message_append_string(m, IFLA_IFNAME, veth_name); if (r < 0) { log_error("Failed to add netlink interface name field: %s", strerror(-r)); @@ -1677,13 +1751,7 @@ static int setup_macvlan(pid_t pid) { return r; } - r = sd_rtnl_message_append_string(m, IFLA_INFO_KIND, "macvlan"); - if (r < 0) { - log_error("Failed to append netlink kind: %s", strerror(-r)); - return r; - } - - r = sd_rtnl_message_open_container(m, IFLA_INFO_DATA); + r = sd_rtnl_message_open_container_union(m, IFLA_INFO_DATA, "macvlan"); if (r < 0) { log_error("Failed to open netlink container: %s", strerror(-r)); return r; @@ -1774,18 +1842,742 @@ finish: } +static int setup_image(char **device_path, int *loop_nr) { + struct loop_info64 info = { + .lo_flags = LO_FLAGS_AUTOCLEAR|LO_FLAGS_PARTSCAN + }; + _cleanup_close_ int fd = -1, control = -1, loop = -1; + _cleanup_free_ char* loopdev = NULL; + struct stat st; + int r, nr; + + assert(device_path); + assert(loop_nr); + + fd = open(arg_image, O_CLOEXEC|(arg_read_only ? O_RDONLY : O_RDWR)|O_NONBLOCK|O_NOCTTY); + if (fd < 0) { + log_error("Failed to open %s: %m", arg_image); + return -errno; + } + + if (fstat(fd, &st) < 0) { + log_error("Failed to stat %s: %m", arg_image); + return -errno; + } + + if (S_ISBLK(st.st_mode)) { + char *p; + + p = strdup(arg_image); + if (!p) + return log_oom(); + + *device_path = p; + + *loop_nr = -1; + + r = fd; + fd = -1; + + return r; + } + + if (!S_ISREG(st.st_mode)) { + log_error("%s is not a regular file or block device: %m", arg_image); + return -EINVAL; + } + + control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); + if (control < 0) { + log_error("Failed to open /dev/loop-control: %m"); + return -errno; + } + + nr = ioctl(control, LOOP_CTL_GET_FREE); + if (nr < 0) { + log_error("Failed to allocate loop device: %m"); + return -errno; + } + + if (asprintf(&loopdev, "/dev/loop%i", nr) < 0) + return log_oom(); + + loop = open(loopdev, O_CLOEXEC|(arg_read_only ? O_RDONLY : O_RDWR)|O_NONBLOCK|O_NOCTTY); + if (loop < 0) { + log_error("Failed to open loop device %s: %m", loopdev); + return -errno; + } + + if (ioctl(loop, LOOP_SET_FD, fd) < 0) { + log_error("Failed to set loopback file descriptor on %s: %m", loopdev); + return -errno; + } + + if (arg_read_only) + info.lo_flags |= LO_FLAGS_READ_ONLY; + + if (ioctl(loop, LOOP_SET_STATUS64, &info) < 0) { + log_error("Failed to set loopback settings on %s: %m", loopdev); + return -errno; + } + + *device_path = loopdev; + loopdev = NULL; + + *loop_nr = nr; + + r = loop; + loop = -1; + + return r; +} + +static int dissect_image( + int fd, + char **root_device, bool *root_device_rw, + char **home_device, bool *home_device_rw, + char **srv_device, bool *srv_device_rw, + bool *secondary) { + +#ifdef HAVE_BLKID + int home_nr = -1, root_nr = -1, secondary_root_nr = -1, srv_nr = -1; + _cleanup_free_ char *home = NULL, *root = NULL, *secondary_root = NULL, *srv = NULL; + _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL; + _cleanup_udev_device_unref_ struct udev_device *d = NULL; + _cleanup_blkid_free_probe_ blkid_probe b = NULL; + _cleanup_udev_unref_ struct udev *udev = NULL; + struct udev_list_entry *first, *item; + bool home_rw = true, root_rw = true, secondary_root_rw = true, srv_rw = true; + const char *pttype = NULL; + blkid_partlist pl; + struct stat st; + int r; + + assert(fd >= 0); + assert(root_device); + assert(home_device); + assert(srv_device); + assert(secondary); + + b = blkid_new_probe(); + if (!b) + return log_oom(); + + errno = 0; + r = blkid_probe_set_device(b, fd, 0, 0); + if (r != 0) { + if (errno == 0) + return log_oom(); + + log_error("Failed to set device on blkid probe: %m"); + return -errno; + } + + blkid_probe_enable_partitions(b, 1); + blkid_probe_set_partitions_flags(b, BLKID_PARTS_ENTRY_DETAILS); + + errno = 0; + r = blkid_do_safeprobe(b); + if (r == -2 || r == 1) { + log_error("Failed to identify any partition table on %s.\n" + "Note that the disk image needs to follow http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/ to be supported by systemd-nspawn.", arg_image); + return -EINVAL; + } else if (r != 0) { + if (errno == 0) + errno = EIO; + log_error("Failed to probe: %m"); + return -errno; + } + + blkid_probe_lookup_value(b, "PTTYPE", &pttype, NULL); + if (!streq_ptr(pttype, "gpt")) { + log_error("Image %s does not carry a GUID Partition Table.\n" + "Note that the disk image needs to follow http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/ to be supported by systemd-nspawn.", arg_image); + return -EINVAL; + } + + errno = 0; + pl = blkid_probe_get_partitions(b); + if (!pl) { + if (errno == 0) + return log_oom(); + + log_error("Failed to list partitions of %s", arg_image); + return -errno; + } + + udev = udev_new(); + if (!udev) + return log_oom(); + + if (fstat(fd, &st) < 0) { + log_error("Failed to stat block device: %m"); + return -errno; + } + + d = udev_device_new_from_devnum(udev, 'b', st.st_rdev); + if (!d) + return log_oom(); + + e = udev_enumerate_new(udev); + if (!e) + return log_oom(); + + r = udev_enumerate_add_match_parent(e, d); + if (r < 0) + return log_oom(); + + r = udev_enumerate_scan_devices(e); + if (r < 0) { + log_error("Failed to scan for partition devices of %s: %s", arg_image, strerror(-r)); + return r; + } + + first = udev_enumerate_get_list_entry(e); + udev_list_entry_foreach(item, first) { + _cleanup_udev_device_unref_ struct udev_device *q; + const char *stype, *node; + unsigned long long flags; + sd_id128_t type_id; + blkid_partition pp; + dev_t qn; + int nr; + + errno = 0; + q = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item)); + if (!q) { + if (!errno) + errno = ENOMEM; + + log_error("Failed to get partition device of %s: %m", arg_image); + return -errno; + } + + qn = udev_device_get_devnum(q); + if (major(qn) == 0) + continue; + + if (st.st_rdev == qn) + continue; + + node = udev_device_get_devnode(q); + if (!node) + continue; + + pp = blkid_partlist_devno_to_partition(pl, qn); + if (!pp) + continue; + + flags = blkid_partition_get_flags(pp); + if (flags & GPT_FLAG_NO_AUTO) + continue; + + nr = blkid_partition_get_partno(pp); + if (nr < 0) + continue; + + stype = blkid_partition_get_type_string(pp); + if (!stype) + continue; + + if (sd_id128_from_string(stype, &type_id) < 0) + continue; + + if (sd_id128_equal(type_id, GPT_HOME)) { + + if (home && nr >= home_nr) + continue; + + home_nr = nr; + home_rw = !(flags & GPT_FLAG_READ_ONLY); + + free(home); + home = strdup(node); + if (!home) + return log_oom(); + } else if (sd_id128_equal(type_id, GPT_SRV)) { + + if (srv && nr >= srv_nr) + continue; + + srv_nr = nr; + srv_rw = !(flags & GPT_FLAG_READ_ONLY); + + free(srv); + srv = strdup(node); + if (!srv) + return log_oom(); + } +#ifdef GPT_ROOT_NATIVE + else if (sd_id128_equal(type_id, GPT_ROOT_NATIVE)) { + + if (root && nr >= root_nr) + continue; + + root_nr = nr; + root_rw = !(flags & GPT_FLAG_READ_ONLY); + + free(root); + root = strdup(node); + if (!root) + return log_oom(); + } +#endif +#ifdef GPT_ROOT_SECONDARY + else if (sd_id128_equal(type_id, GPT_ROOT_SECONDARY)) { + + if (secondary_root && nr >= secondary_root_nr) + continue; + + secondary_root_nr = nr; + secondary_root_rw = !(flags & GPT_FLAG_READ_ONLY); + + + free(secondary_root); + secondary_root = strdup(node); + if (!secondary_root) + return log_oom(); + } +#endif + } + + if (!root && !secondary_root) { + log_error("Failed to identify root partition in disk image %s.\n" + "Note that the disk image needs to follow http://www.freedesktop.org/wiki/Specifications/DiscoverablePartitionsSpec/ to be supported by systemd-nspawn.", arg_image); + return -EINVAL; + } + + if (root) { + *root_device = root; + root = NULL; + + *root_device_rw = root_rw; + *secondary = false; + } else if (secondary_root) { + *root_device = secondary_root; + secondary_root = NULL; + + *root_device_rw = secondary_root_rw; + *secondary = true; + } + + if (home) { + *home_device = home; + home = NULL; + + *home_device_rw = home_rw; + } + + if (srv) { + *srv_device = srv; + srv = NULL; + + *srv_device_rw = srv_rw; + } + + return 0; +#else + log_error("--image= is not supported, compiled without blkid support."); + return -ENOTSUP; +#endif +} + +static int mount_device(const char *what, const char *where, const char *directory, bool rw) { +#ifdef HAVE_BLKID + _cleanup_blkid_free_probe_ blkid_probe b = NULL; + const char *fstype, *p; + int r; + + assert(what); + assert(where); + + if (arg_read_only) + rw = false; + + if (directory) + p = strappenda(where, directory); + else + p = where; + + errno = 0; + b = blkid_new_probe_from_filename(what); + if (!b) { + if (errno == 0) + return log_oom(); + log_error("Failed to allocate prober for %s: %m", what); + return -errno; + } + + blkid_probe_enable_superblocks(b, 1); + blkid_probe_set_superblocks_flags(b, BLKID_SUBLKS_TYPE); + + errno = 0; + r = blkid_do_safeprobe(b); + if (r == -1 || r == 1) { + log_error("Cannot determine file system type of %s", what); + return -EINVAL; + } else if (r != 0) { + if (errno == 0) + errno = EIO; + log_error("Failed to probe %s: %m", what); + return -errno; + } + + errno = 0; + if (blkid_probe_lookup_value(b, "TYPE", &fstype, NULL) < 0) { + if (errno == 0) + errno = EINVAL; + log_error("Failed to determine file system type of %s", what); + return -errno; + } + + if (streq(fstype, "crypto_LUKS")) { + log_error("nspawn currently does not support LUKS disk images."); + return -ENOTSUP; + } + + if (mount(what, p, fstype, MS_NODEV|(rw ? 0 : MS_RDONLY), NULL) < 0) { + log_error("Failed to mount %s: %m", what); + return -errno; + } + + return 0; +#else + log_error("--image= is not supported, compiled without blkid support."); + return -ENOTSUP; +#endif +} + +static int mount_devices( + const char *where, + const char *root_device, bool root_device_rw, + const char *home_device, bool home_device_rw, + const char *srv_device, bool srv_device_rw) { + int r; + + assert(where); + + if (root_device) { + r = mount_device(root_device, arg_directory, NULL, root_device_rw); + if (r < 0) { + log_error("Failed to mount root directory: %s", strerror(-r)); + return r; + } + } + + if (home_device) { + r = mount_device(home_device, arg_directory, "/home", home_device_rw); + if (r < 0) { + log_error("Failed to mount home directory: %s", strerror(-r)); + return r; + } + } + + if (srv_device) { + r = mount_device(srv_device, arg_directory, "/srv", srv_device_rw); + if (r < 0) { + log_error("Failed to mount server data directory: %s", strerror(-r)); + return r; + } + } + + return 0; +} + +static void loop_remove(int nr, int *image_fd) { + _cleanup_close_ int control = -1; + + if (nr < 0) + return; + + if (image_fd && *image_fd >= 0) { + ioctl(*image_fd, LOOP_CLR_FD); + *image_fd = safe_close(*image_fd); + } + + control = open("/dev/loop-control", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK); + if (control < 0) + return; + + ioctl(control, LOOP_CTL_REMOVE, nr); +} + +static int spawn_getent(const char *database, const char *key, pid_t *rpid) { + int pipe_fds[2]; + pid_t pid; + + assert(database); + assert(key); + assert(rpid); + + if (pipe2(pipe_fds, O_CLOEXEC) < 0) { + log_error("Failed to allocate pipe: %m"); + return -errno; + } + + pid = fork(); + if (pid < 0) { + log_error("Failed to fork getent child: %m"); + return -errno; + } else if (pid == 0) { + int nullfd; + char *empty_env = NULL; + + if (dup3(pipe_fds[1], STDOUT_FILENO, 0) < 0) + _exit(EXIT_FAILURE); + + if (pipe_fds[0] > 2) + safe_close(pipe_fds[0]); + if (pipe_fds[1] > 2) + safe_close(pipe_fds[1]); + + nullfd = open("/dev/null", O_RDWR); + if (nullfd < 0) + _exit(EXIT_FAILURE); + + if (dup3(nullfd, STDIN_FILENO, 0) < 0) + _exit(EXIT_FAILURE); + + if (dup3(nullfd, STDERR_FILENO, 0) < 0) + _exit(EXIT_FAILURE); + + if (nullfd > 2) + safe_close(nullfd); + + reset_all_signal_handlers(); + close_all_fds(NULL, 0); + + execle("/usr/bin/getent", "getent", database, key, NULL, &empty_env); + execle("/bin/getent", "getent", database, key, NULL, &empty_env); + _exit(EXIT_FAILURE); + } + + pipe_fds[1] = safe_close(pipe_fds[1]); + + *rpid = pid; + + return pipe_fds[0]; +} + +static int change_uid_gid(char **_home) { + char line[LINE_MAX], *w, *x, *state, *u, *g, *h; + _cleanup_free_ uid_t *uids = NULL; + _cleanup_free_ char *home = NULL; + _cleanup_fclose_ FILE *f = NULL; + _cleanup_close_ int fd = -1; + unsigned n_uids = 0; + size_t sz, l; + uid_t uid; + gid_t gid; + pid_t pid; + int r; + + assert(_home); + + if (!arg_user || streq(arg_user, "root") || streq(arg_user, "0")) { + /* Reset everything fully to 0, just in case */ + + if (setgroups(0, NULL) < 0) { + log_error("setgroups() failed: %m"); + return -errno; + } + + if (setresgid(0, 0, 0) < 0) { + log_error("setregid() failed: %m"); + return -errno; + } + + if (setresuid(0, 0, 0) < 0) { + log_error("setreuid() failed: %m"); + return -errno; + } + + *_home = NULL; + return 0; + } + + /* First, get user credentials */ + fd = spawn_getent("passwd", arg_user, &pid); + if (fd < 0) + return fd; + + f = fdopen(fd, "r"); + if (!f) + return log_oom(); + fd = -1; + + if (!fgets(line, sizeof(line), f)) { + + if (!ferror(f)) { + log_error("Failed to resolve user %s.", arg_user); + return -ESRCH; + } + + log_error("Failed to read from getent: %m"); + return -errno; + } + + truncate_nl(line); + + wait_for_terminate_and_warn("getent passwd", pid); + + x = strchr(line, ':'); + if (!x) { + log_error("/etc/passwd entry has invalid user field."); + return -EIO; + } + + u = strchr(x+1, ':'); + if (!u) { + log_error("/etc/passwd entry has invalid password field."); + return -EIO; + } + + u++; + g = strchr(u, ':'); + if (!g) { + log_error("/etc/passwd entry has invalid UID field."); + return -EIO; + } + + *g = 0; + g++; + x = strchr(g, ':'); + if (!x) { + log_error("/etc/passwd entry has invalid GID field."); + return -EIO; + } + + *x = 0; + h = strchr(x+1, ':'); + if (!h) { + log_error("/etc/passwd entry has invalid GECOS field."); + return -EIO; + } + + h++; + x = strchr(h, ':'); + if (!x) { + log_error("/etc/passwd entry has invalid home directory field."); + return -EIO; + } + + *x = 0; + + r = parse_uid(u, &uid); + if (r < 0) { + log_error("Failed to parse UID of user."); + return -EIO; + } + + r = parse_gid(g, &gid); + if (r < 0) { + log_error("Failed to parse GID of user."); + return -EIO; + } + + home = strdup(h); + if (!home) + return log_oom(); + + /* Second, get group memberships */ + fd = spawn_getent("initgroups", arg_user, &pid); + if (fd < 0) + return fd; + + fclose(f); + f = fdopen(fd, "r"); + if (!f) + return log_oom(); + fd = -1; + + if (!fgets(line, sizeof(line), f)) { + if (!ferror(f)) { + log_error("Failed to resolve user %s.", arg_user); + return -ESRCH; + } + + log_error("Failed to read from getent: %m"); + return -errno; + } + + truncate_nl(line); + + wait_for_terminate_and_warn("getent initgroups", pid); + + /* Skip over the username and subsequent separator whitespace */ + x = line; + x += strcspn(x, WHITESPACE); + x += strspn(x, WHITESPACE); + + FOREACH_WORD(w, l, x, state) { + char c[l+1]; + + memcpy(c, w, l); + c[l] = 0; + + if (!GREEDY_REALLOC(uids, sz, n_uids+1)) + return log_oom(); + + r = parse_uid(c, &uids[n_uids++]); + if (r < 0) { + log_error("Failed to parse group data from getent."); + return -EIO; + } + } + + r = mkdir_parents(home, 0775); + if (r < 0) { + log_error("Failed to make home root directory: %s", strerror(-r)); + return r; + } + + r = mkdir_safe(home, 0755, uid, gid); + if (r < 0 && r != -EEXIST) { + log_error("Failed to make home directory: %s", strerror(-r)); + return r; + } + + fchown(STDIN_FILENO, uid, gid); + fchown(STDOUT_FILENO, uid, gid); + fchown(STDERR_FILENO, uid, gid); + + if (setgroups(n_uids, uids) < 0) { + log_error("Failed to set auxiliary groups: %m"); + return -errno; + } + + if (setresgid(gid, gid, gid) < 0) { + log_error("setregid() failed: %m"); + return -errno; + } + + if (setresuid(uid, uid, uid) < 0) { + log_error("setreuid() failed: %m"); + return -errno; + } + + if (_home) { + *_home = home; + home = NULL; + } + + return 0; +} + int main(int argc, char *argv[]) { - _cleanup_close_ int master = -1, kdbus_fd = -1, sync_fd = -1; - _cleanup_close_pipe_ int kmsg_socket_pair[2] = { -1, -1 }; - _cleanup_free_ char *kdbus_domain = NULL; + _cleanup_free_ char *kdbus_domain = NULL, *device_path = NULL, *root_device = NULL, *home_device = NULL, *srv_device = NULL; + bool root_device_rw = true, home_device_rw = true, srv_device_rw = true; + _cleanup_close_ int master = -1, kdbus_fd = -1, image_fd = -1; + _cleanup_close_pair_ int kmsg_socket_pair[2] = { -1, -1 }; _cleanup_fdset_free_ FDSet *fds = NULL; + int r = EXIT_FAILURE, k, n_fd_passed, loop_nr = -1; const char *console = NULL; - int r = EXIT_FAILURE, k; - int n_fd_passed; + char veth_name[IFNAMSIZ]; + bool secondary = false; pid_t pid = 0; sigset_t mask; - char veth_name[IFNAMSIZ]; log_parse_environment(); log_open(); @@ -1798,24 +2590,25 @@ int main(int argc, char *argv[]) { goto finish; } - if (arg_directory) { - char *p; + if (!arg_image) { + if (arg_directory) { + char *p; - p = path_make_absolute_cwd(arg_directory); - free(arg_directory); - arg_directory = p; - } else - arg_directory = get_current_dir_name(); + p = path_make_absolute_cwd(arg_directory); + free(arg_directory); + arg_directory = p; + } else + arg_directory = get_current_dir_name(); - if (!arg_directory) { - log_error("Failed to determine path, please use -D."); - goto finish; + if (!arg_directory) { + log_error("Failed to determine path, please use -D."); + goto finish; + } + path_kill_slashes(arg_directory); } - path_kill_slashes(arg_directory); - if (!arg_machine) { - arg_machine = strdup(basename(arg_directory)); + arg_machine = strdup(basename(arg_image ? arg_image : arg_directory)); if (!arg_machine) { log_oom(); goto finish; @@ -1838,39 +2631,65 @@ int main(int argc, char *argv[]) { goto finish; } - if (path_equal(arg_directory, "/")) { - log_error("Spawning container on root directory not supported."); - goto finish; + log_close(); + n_fd_passed = sd_listen_fds(false); + if (n_fd_passed > 0) { + k = fdset_new_listen_fds(&fds, false); + if (k < 0) { + log_error("Failed to collect file descriptors: %s", strerror(-k)); + goto finish; + } } + fdset_close_others(fds); + log_open(); - if (arg_boot) { - if (path_is_os_tree(arg_directory) <= 0) { - log_error("Directory %s doesn't look like an OS root directory (/etc/os-release is missing). Refusing.", arg_directory); + if (arg_directory) { + if (path_equal(arg_directory, "/")) { + log_error("Spawning container on root directory not supported."); goto finish; } + + if (arg_boot) { + if (path_is_os_tree(arg_directory) <= 0) { + log_error("Directory %s doesn't look like an OS root directory (/etc/os-release is missing). Refusing.", arg_directory); + goto finish; + } + } else { + const char *p; + + p = strappenda(arg_directory, + argc > optind && path_is_absolute(argv[optind]) ? argv[optind] : "/usr/bin/"); + if (access(p, F_OK) < 0) { + log_error("Directory %s lacks the binary to execute or doesn't look like a binary tree. Refusing.", arg_directory); + goto finish; + + } + } } else { - const char *p; + char template[] = "/tmp/nspawn-root-XXXXXX"; - p = strappenda(arg_directory, - argc > optind && path_is_absolute(argv[optind]) ? argv[optind] : "/usr/bin/"); - if (access(p, F_OK) < 0) { - log_error("Directory %s lacks the binary to execute or doesn't look like a binary tree. Refusing.", arg_directory); + if (!mkdtemp(template)) { + log_error("Failed to create temporary directory: %m"); + r = -errno; goto finish; + } + arg_directory = strdup(template); + if (!arg_directory) { + r = log_oom(); + goto finish; } - } - log_close(); - n_fd_passed = sd_listen_fds(false); - if (n_fd_passed > 0) { - k = fdset_new_listen_fds(&fds, false); - if (k < 0) { - log_error("Failed to collect file descriptors: %s", strerror(-k)); + image_fd = setup_image(&device_path, &loop_nr); + if (image_fd < 0) { + r = image_fd; goto finish; } + + r = dissect_image(image_fd, &root_device, &root_device_rw, &home_device, &home_device_rw, &srv_device, &srv_device_rw, &secondary); + if (r < 0) + goto finish; } - fdset_close_others(fds); - log_open(); master = posix_openpt(O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY); if (master < 0) { @@ -1885,7 +2704,7 @@ int main(int argc, char *argv[]) { } if (!arg_quiet) - log_info("Spawning container %s on %s. Press ^] three times within 1s to abort execution.", arg_machine, arg_directory); + log_info("Spawning container %s on %s. Press ^] three times within 1s to abort execution.", arg_machine, arg_image ? arg_image : arg_directory); if (unlockpt(master) < 0) { log_error("Failed to unlock tty: %m"); @@ -1924,10 +2743,18 @@ int main(int argc, char *argv[]) { assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0); for (;;) { + int parent_ready_fd = -1, child_ready_fd = -1; siginfo_t status; + eventfd_t x; - sync_fd = eventfd(0, EFD_CLOEXEC); - if (sync_fd < 0) { + parent_ready_fd = eventfd(0, EFD_CLOEXEC); + if (parent_ready_fd < 0) { + log_error("Failed to create event fd: %m"); + goto finish; + } + + child_ready_fd = eventfd(0, EFD_CLOEXEC); + if (child_ready_fd < 0) { log_error("Failed to create event fd: %m"); goto finish; } @@ -1947,9 +2774,7 @@ int main(int argc, char *argv[]) { if (pid == 0) { /* child */ - const char *home = NULL; - uid_t uid = (uid_t) -1; - gid_t gid = (gid_t) -1; + _cleanup_free_ char *home = NULL; unsigned n_env = 2; const char *envp[] = { "PATH=" DEFAULT_PATH_SPLIT_USR, @@ -1964,21 +2789,18 @@ int main(int argc, char *argv[]) { NULL }; char **env_use; - eventfd_t x; envp[n_env] = strv_find_prefix(environ, "TERM="); if (envp[n_env]) n_env ++; - close_nointr_nofail(master); - master = -1; + master = safe_close(master); close_nointr(STDIN_FILENO); close_nointr(STDOUT_FILENO); close_nointr(STDERR_FILENO); - close_nointr_nofail(kmsg_socket_pair[0]); - kmsg_socket_pair[0] = -1; + kmsg_socket_pair[0] = safe_close(kmsg_socket_pair[0]); reset_all_signal_handlers(); @@ -1988,7 +2810,7 @@ int main(int argc, char *argv[]) { k = open_terminal(console, O_RDWR); if (k != STDIN_FILENO) { if (k >= 0) { - close_nointr_nofail(k); + safe_close(k); k = -EINVAL; } @@ -2023,6 +2845,12 @@ int main(int argc, char *argv[]) { goto child_fail; } + if (mount_devices(arg_directory, + root_device, root_device_rw, + home_device, home_device_rw, + srv_device, srv_device_rw) < 0) + goto child_fail; + /* Turn directory into bind mount */ if (mount(arg_directory, arg_directory, "bind", MS_BIND|MS_REC, NULL) < 0) { log_error("Failed to make bind mount."); @@ -2055,8 +2883,7 @@ int main(int argc, char *argv[]) { if (setup_kmsg(arg_directory, kmsg_socket_pair[1]) < 0) goto child_fail; - close_nointr_nofail(kmsg_socket_pair[1]); - kmsg_socket_pair[1] = -1; + kmsg_socket_pair[1] = safe_close(kmsg_socket_pair[1]); if (setup_boot_id(arg_directory) < 0) goto child_fail; @@ -2079,6 +2906,12 @@ int main(int argc, char *argv[]) { if (setup_kdbus(arg_directory, kdbus_domain) < 0) goto child_fail; + /* Tell the parent that we are ready, and that + * it can cgroupify us to that we lack access + * to certain devices and resources. */ + eventfd_write(child_ready_fd, 1); + child_ready_fd = safe_close(child_ready_fd); + if (chdir(arg_directory) < 0) { log_error("chdir(%s) failed: %m", arg_directory); goto child_fail; @@ -2109,61 +2942,9 @@ int main(int argc, char *argv[]) { goto child_fail; } - if (arg_user) { - - /* Note that this resolves user names - * inside the container, and hence - * accesses the NSS modules from the - * container and not the host. This is - * a bit weird... */ - - if (get_user_creds((const char**)&arg_user, &uid, &gid, &home, NULL) < 0) { - log_error("get_user_creds() failed: %m"); - goto child_fail; - } - - if (mkdir_parents_label(home, 0775) < 0) { - log_error("mkdir_parents_label() failed: %m"); - goto child_fail; - } - - if (mkdir_safe_label(home, 0775, uid, gid) < 0) { - log_error("mkdir_safe_label() failed: %m"); - goto child_fail; - } - - if (initgroups((const char*)arg_user, gid) < 0) { - log_error("initgroups() failed: %m"); - goto child_fail; - } - - if (setresgid(gid, gid, gid) < 0) { - log_error("setregid() failed: %m"); - goto child_fail; - } - - if (setresuid(uid, uid, uid) < 0) { - log_error("setreuid() failed: %m"); - goto child_fail; - } - } else { - /* Reset everything fully to 0, just in case */ - - if (setgroups(0, NULL) < 0) { - log_error("setgroups() failed: %m"); - goto child_fail; - } - - if (setresgid(0, 0, 0) < 0) { - log_error("setregid() failed: %m"); - goto child_fail; - } - - if (setresuid(0, 0, 0) < 0) { - log_error("setreuid() failed: %m"); - goto child_fail; - } - } + r = change_uid_gid(&home); + if (r < 0) + goto child_fail; if ((asprintf((char**)(envp + n_env++), "HOME=%s", home ? home: "/root") < 0) || (asprintf((char**)(envp + n_env++), "USER=%s", arg_user ? arg_user : "root") < 0) || @@ -2200,11 +2981,20 @@ int main(int argc, char *argv[]) { log_error("personality() failed: %m"); goto child_fail; } + } else if (secondary) { + if (personality(PER_LINUX32) < 0) { + log_error("personality() failed: %m"); + goto child_fail; + } } - eventfd_read(sync_fd, &x); - close_nointr_nofail(sync_fd); - sync_fd = -1; +#ifdef HAVE_SELINUX + if (arg_selinux_context) + if (setexeccon((security_context_t) arg_selinux_context) < 0) { + log_error("setexeccon(\"%s\") failed: %m", arg_selinux_context); + goto child_fail; + } +#endif if (!strv_isempty(arg_setenv)) { char **n; @@ -2219,11 +3009,10 @@ int main(int argc, char *argv[]) { } else env_use = (char**) envp; -#ifdef HAVE_SELINUX - if (arg_selinux_context) - if (setexeccon((security_context_t) arg_selinux_context) < 0) - log_error("setexeccon(\"%s\") failed: %m", arg_selinux_context); -#endif + /* Wait until the parent is ready with the setup, too... */ + eventfd_read(parent_ready_fd, &x); + parent_ready_fd = safe_close(parent_ready_fd); + if (arg_boot) { char **a; size_t l; @@ -2259,6 +3048,12 @@ int main(int argc, char *argv[]) { fdset_free(fds); fds = NULL; + /* Wait until the child reported that it is ready with + * all it needs to do with priviliges. After we got + * the notification we can make the process join its + * cgroup which might limit what it can do */ + eventfd_read(child_ready_fd, &x); + r = register_machine(pid); if (r < 0) goto finish; @@ -2279,9 +3074,10 @@ int main(int argc, char *argv[]) { if (r < 0) goto finish; - eventfd_write(sync_fd, 1); - close_nointr_nofail(sync_fd); - sync_fd = -1; + /* Notify the child that the parent is ready with all + * its setup, and thtat the child can now hand over + * control to the code to run inside the container. */ + eventfd_write(parent_ready_fd, 1); k = process_pty(master, &mask, arg_boot ? pid : 0, SIGRTMIN+3); if (k < 0) { @@ -2343,6 +3139,8 @@ int main(int argc, char *argv[]) { } finish: + loop_remove(loop_nr, &image_fd); + if (pid > 0) kill(pid, SIGKILL);