X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fnspawn%2Fnspawn.c;h=2441758c2a15e2a1523b482a6207301b64d0ad0d;hp=abcee3fb98162fae7c7553a0e1e79f1e2d2bf9ee;hb=08af0da26935e827b58809ff1946e2f7d496e666;hpb=7e2270246b0906675c8f34bc278b1608b969e65c diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index abcee3fb9..2441758c2 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -40,14 +40,19 @@ #include #include #include -#include #include #include +#include +#include #ifdef HAVE_SELINUX #include #endif +#ifdef HAVE_SECCOMP +#include +#endif + #include "sd-daemon.h" #include "sd-bus.h" #include "sd-id128.h" @@ -75,6 +80,10 @@ #include "rtnl-util.h" #include "udev-util.h" +#ifdef HAVE_SECCOMP +#include "seccomp-util.h" +#endif + typedef enum LinkJournal { LINK_NO, LINK_AUTO, @@ -128,6 +137,9 @@ static bool arg_share_system = false; static bool arg_register = true; static bool arg_keep_unit = false; static char **arg_network_interfaces = NULL; +static bool arg_network_veth = false; +static char *arg_network_bridge = NULL; +static unsigned long arg_personality = 0xffffffffLU; static int help(void) { @@ -135,36 +147,43 @@ static int help(void) { "Spawn a minimal namespace container for debugging, testing and building.\n\n" " -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" " -b --boot Boot up full system (i.e. invoke init)\n" " -u --user=USER Run the command under specified user or uid\n" - " --uuid=UUID Set a specific machine UUID for the container\n" " -M --machine=NAME Set the machine name for the container\n" + " --uuid=UUID Set a specific machine UUID for the container\n" " -S --slice=SLICE Place the container in the specified slice\n" + " --private-network Disable network in container\n" + " --network-interface=INTERFACE\n" + " Assign an existing network interface to the\n" + " container\n" + " --network-veth Add a virtual ethernet connection between host\n" + " and container\n" + " --network-bridge=INTERFACE\n" + " Add a virtual ethernet connection between host\n" + " and container and add it to an existing bridge on\n" + " the host\n" " -Z --selinux-context=SECLABEL\n" " Set the SELinux security context to be used by\n" " processes in the container\n" " -L --selinux-apifs-context=SECLABEL\n" " Set the SELinux security context to be used by\n" " API/tmpfs file systems in the container\n" - " --private-network Disable network in container\n" - " --network-interface=INTERFACE\n" - " Assign an existing network interface to the container\n" - " --share-system Share system namespaces with host\n" - " --read-only Mount the root directory read-only\n" " --capability=CAP In addition to the default, retain specified\n" " capability\n" " --drop-capability=CAP Drop the specified capability from the default set\n" " --link-journal=MODE Link up guest journal, one of no, auto, guest, host\n" " -j Equivalent to --link-journal=host\n" + " --read-only Mount the root directory read-only\n" " --bind=PATH[:PATH] Bind mount a file or directory from the host into\n" " the container\n" " --bind-ro=PATH[:PATH] Similar, but creates a read-only bind mount\n" " --setenv=NAME=VALUE Pass an environment variable to PID 1\n" + " --share-system Share system namespaces with host\n" " --register=BOOLEAN Register container as machine\n" " --keep-unit Do not register a scope for the machine, reuse\n" - " the service unit nspawn is running in\n" - " -q --quiet Do not show status information\n", + " the service unit nspawn is running in\n", program_invocation_short_name); return 0; @@ -186,7 +205,10 @@ static int parse_argv(int argc, char *argv[]) { ARG_SHARE_SYSTEM, ARG_REGISTER, ARG_KEEP_UNIT, - ARG_NETWORK_INTERFACE + ARG_NETWORK_INTERFACE, + ARG_NETWORK_VETH, + ARG_NETWORK_BRIDGE, + ARG_PERSONALITY, }; static const struct option options[] = { @@ -213,6 +235,9 @@ static int parse_argv(int argc, char *argv[]) { { "register", required_argument, NULL, ARG_REGISTER }, { "keep-unit", no_argument, NULL, ARG_KEEP_UNIT }, { "network-interface", required_argument, NULL, ARG_NETWORK_INTERFACE }, + { "network-veth", no_argument, NULL, ARG_NETWORK_VETH }, + { "network-bridge", required_argument, NULL, ARG_NETWORK_BRIDGE }, + { "personality", required_argument, NULL, ARG_PERSONALITY }, {} }; @@ -252,6 +277,18 @@ static int parse_argv(int argc, char *argv[]) { break; + case ARG_NETWORK_BRIDGE: + arg_network_bridge = strdup(optarg); + if (!arg_network_bridge) + return log_oom(); + + /* fall through */ + + case ARG_NETWORK_VETH: + arg_network_veth = true; + arg_private_network = true; + break; + case ARG_NETWORK_INTERFACE: if (strv_push(&arg_network_interfaces, optarg) < 0) return log_oom(); @@ -441,6 +478,16 @@ static int parse_argv(int argc, char *argv[]) { arg_keep_unit = true; break; + case ARG_PERSONALITY: + + arg_personality = personality_from_string(optarg); + if (arg_personality == 0xffffffffLU) { + log_error("Unknown or unsupported personality '%s'.", optarg); + return -EINVAL; + } + + break; + case '?': return -EINVAL; @@ -696,7 +743,7 @@ static int setup_resolv_conf(const char *dest) { static int setup_boot_id(const char *dest) { _cleanup_free_ char *from = NULL, *to = NULL; - sd_id128_t rnd; + sd_id128_t rnd = {}; char as_uuid[37]; int r; @@ -1255,9 +1302,163 @@ static int reset_audit_loginuid(void) { return 0; } -static int move_network_interfaces(pid_t pid) { +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; + int r; + + if (!arg_private_network) + return 0; + + if (!arg_network_veth) + return 0; + + /* Use two different interface name prefixes depending whether + * we are in bridge mode or not. */ + if (arg_network_bridge) + memcpy(iface_name, "vb-", 3); + else + memcpy(iface_name, "ve-", 3); + + strncpy(iface_name+3, arg_machine, IFNAMSIZ - 3); + + r = sd_rtnl_open(&rtnl, 0); + if (r < 0) { + log_error("Failed to connect to netlink: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINK, 0); + if (r < 0) { + log_error("Failed to allocate netlink message: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_append_string(m, IFLA_IFNAME, iface_name); + if (r < 0) { + log_error("Failed to add netlink interface name: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_open_container(m, IFLA_LINKINFO); + if (r < 0) { + log_error("Failed to open netlink container: %s", strerror(-r)); + 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); + if (r < 0) { + log_error("Failed to open netlink container: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_open_container(m, VETH_INFO_PEER); + if (r < 0) { + log_error("Failed to open netlink container: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_append_string(m, IFLA_IFNAME, "host0"); + if (r < 0) { + log_error("Failed to add netlink interface name: %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)); + return r; + } + + r = sd_rtnl_message_close_container(m); + if (r < 0) { + log_error("Failed to close netlink container: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_close_container(m); + if (r < 0) { + log_error("Failed to close netlink container: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_close_container(m); + if (r < 0) { + log_error("Failed to close netlink container: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_call(rtnl, m, 0, NULL); + if (r < 0) { + log_error("Failed to add new veth interfaces: %s", strerror(-r)); + return r; + } + + return 0; +} + +static int setup_bridge(const char veth_name[]) { + _cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL; _cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL; + int r, bridge; + + if (!arg_private_network) + return 0; + + if (!arg_network_veth) + return 0; + + if (!arg_network_bridge) + return 0; + + bridge = (int) if_nametoindex(arg_network_bridge); + if (bridge <= 0) { + log_error("Failed to resolve interface %s: %m", arg_network_bridge); + return -errno; + } + + r = sd_rtnl_open(&rtnl, 0); + if (r < 0) { + log_error("Failed to connect to netlink: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_message_new_link(rtnl, &m, RTM_SETLINK, 0); + if (r < 0) { + log_error("Failed to allocate netlink message: %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)); + return r; + } + + r = sd_rtnl_message_append_u32(m, IFLA_MASTER, bridge); + if (r < 0) { + log_error("Failed to add netlink master field: %s", strerror(-r)); + return r; + } + + r = sd_rtnl_call(rtnl, m, 0, NULL); + if (r < 0) { + log_error("Failed to add veth interface to bridge: %s", strerror(-r)); + return r; + } + + return 0; +} + +static int move_network_interfaces(pid_t pid) { _cleanup_udev_unref_ struct udev *udev = NULL; + _cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL; char **i; int r; @@ -1267,7 +1468,7 @@ static int move_network_interfaces(pid_t pid) { if (strv_isempty(arg_network_interfaces)) return 0; - r = sd_rtnl_open(0, &rtnl); + r = sd_rtnl_open(&rtnl, 0); if (r < 0) { log_error("Failed to connect to netlink: %s", strerror(-r)); return r; @@ -1303,7 +1504,7 @@ static int move_network_interfaces(pid_t pid) { return -EBUSY; } - r = sd_rtnl_message_new_link(RTM_NEWLINK, ifi, &m); + r = sd_rtnl_message_new_link(rtnl, &m, RTM_NEWLINK, ifi); if (r < 0) { log_error("Failed to allocate netlink message: %s", strerror(-r)); return r; @@ -1325,16 +1526,75 @@ static int move_network_interfaces(pid_t pid) { return 0; } +static int audit_still_doesnt_work_in_containers(void) { + +#ifdef HAVE_SECCOMP + scmp_filter_ctx seccomp; + int r; + + /* + Audit is broken in containers, much of the userspace audit + hookup will fail if running inside a container. We don't + care and just turn off creation of audit sockets. + + This will make socket(AF_NETLINK, *, NETLINK_AUDIT) fail + with EAFNOSUPPORT which audit userspace uses as indication + that audit is disabled in the kernel. + */ + + seccomp = seccomp_init(SCMP_ACT_ALLOW); + if (!seccomp) + return log_oom(); + + r = seccomp_add_secondary_archs(seccomp); + if (r < 0 && r != -EEXIST) { + log_error("Failed to add secondary archs to seccomp filter: %s", strerror(-r)); + goto finish; + } + + r = seccomp_rule_add( + seccomp, + SCMP_ACT_ERRNO(EAFNOSUPPORT), + SCMP_SYS(socket), + 2, + SCMP_A0(SCMP_CMP_EQ, AF_NETLINK), + SCMP_A2(SCMP_CMP_EQ, NETLINK_AUDIT)); + if (r < 0) { + log_error("Failed to add audit seccomp rule: %s", strerror(-r)); + goto finish; + } + + r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0); + if (r < 0) { + log_error("Failed to unset NO_NEW_PRIVS: %s", strerror(-r)); + goto finish; + } + + r = seccomp_load(seccomp); + if (r < 0) + log_error("Failed to install seccomp audit filter: %s", strerror(-r)); + +finish: + seccomp_release(seccomp); + return r; +#else + return 0; +#endif + +} + int main(int argc, char *argv[]) { - pid_t pid = 0; - int r = EXIT_FAILURE, k; + _cleanup_close_ int master = -1, kdbus_fd = -1, sync_fd = -1; - int n_fd_passed; - const char *console = NULL; - sigset_t mask; _cleanup_close_pipe_ int kmsg_socket_pair[2] = { -1, -1 }; - _cleanup_fdset_free_ FDSet *fds = NULL; _cleanup_free_ char *kdbus_domain = NULL; + _cleanup_fdset_free_ FDSet *fds = NULL; + const char *console = NULL; + int r = EXIT_FAILURE, k; + int n_fd_passed; + pid_t pid = 0; + sigset_t mask; + char veth_name[IFNAMSIZ]; log_parse_environment(); log_open(); @@ -1392,9 +1652,21 @@ int main(int argc, char *argv[]) { goto finish; } - if (arg_boot && 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; + 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; + + } } log_close(); @@ -1429,7 +1701,6 @@ int main(int argc, char *argv[]) { goto finish; } - if (access("/dev/kdbus/control", F_OK) >= 0) { if (arg_share_system) { @@ -1584,6 +1855,9 @@ int main(int argc, char *argv[]) { dev_setup(arg_directory); + if (audit_still_doesnt_work_in_containers() < 0) + goto child_fail; + if (setup_dev_console(arg_directory, console) < 0) goto child_fail; @@ -1730,6 +2004,13 @@ int main(int argc, char *argv[]) { setup_hostname(); + if (arg_personality != 0xffffffffLU) { + if (personality(arg_personality) < 0) { + log_error("personality() failed: %m"); + goto child_fail; + } + } + eventfd_read(sync_fd, &x); close_nointr_nofail(sync_fd); sync_fd = -1; @@ -1775,6 +2056,7 @@ int main(int argc, char *argv[]) { else { chdir(home ? home : "/root"); execle("/bin/bash", "-bash", NULL, env_use); + execle("/bin/sh", "-sh", NULL, env_use); } log_error("execv() failed: %m"); @@ -1794,6 +2076,14 @@ int main(int argc, char *argv[]) { if (r < 0) goto finish; + r = setup_veth(pid, veth_name); + if (r < 0) + goto finish; + + r = setup_bridge(veth_name); + if (r < 0) + goto finish; + eventfd_write(sync_fd, 1); close_nointr_nofail(sync_fd); sync_fd = -1;