X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fnspawn.c;h=50d7c2e2895717a6ae8a81d19efa8410a31f2a7e;hb=b8590c197deceab623d37dbb95e30eec9cf47d14;hp=f8a190097ae1d0f1433a88833988f2a5b4837d71;hpb=a258bf2648fa5e3005b96203c60b9751807bacf0;p=elogind.git diff --git a/src/nspawn.c b/src/nspawn.c index f8a190097..50d7c2e28 100644 --- a/src/nspawn.c +++ b/src/nspawn.c @@ -36,6 +36,7 @@ #include #include #include +#include #include "log.h" #include "util.h" @@ -45,13 +46,15 @@ #include "strv.h" static char *arg_directory = NULL; +static char *arg_user = NULL; static int help(void) { printf("%s [OPTIONS...] [PATH] [ARGUMENTS...]\n\n" "Spawn a minimal namespace container for debugging, testing and building.\n\n" " -h --help Show this help\n" - " -D --directory=NAME Root directory for the container\n", + " -D --directory=NAME Root directory for the container\n" + " -u --user=USER Run the command under specified user or uid\n", program_invocation_short_name); return 0; @@ -62,6 +65,7 @@ static int parse_argv(int argc, char *argv[]) { static const struct option options[] = { { "help", no_argument, NULL, 'h' }, { "directory", required_argument, NULL, 'D' }, + { "user", optional_argument, NULL, 'u' }, { NULL, 0, NULL, 0 } }; @@ -70,7 +74,7 @@ static int parse_argv(int argc, char *argv[]) { assert(argc >= 0); assert(argv); - while ((c = getopt_long(argc, argv, "+hD:", options, NULL)) >= 0) { + while ((c = getopt_long(argc, argv, "+hD:u:", options, NULL)) >= 0) { switch (c) { @@ -87,6 +91,15 @@ static int parse_argv(int argc, char *argv[]) { break; + case 'u': + free(arg_user); + if (!(arg_user = strdup(optarg))) { + log_error("Failed to duplicate user name."); + return -ENOMEM; + } + + break; + case '?': return -EINVAL; @@ -117,7 +130,7 @@ static int mount_all(const char *dest) { { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, true }, { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID, true }, { "/dev/pts", "/dev/pts", "bind", NULL, MS_BIND, true }, - { "tmpfs", "/dev/.run", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, + { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV, true }, #ifdef HAVE_SELINUX { "selinux", "/selinux", "selinuxfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, false }, #endif @@ -125,9 +138,9 @@ static int mount_all(const char *dest) { unsigned k; int r = 0; + char *where; for (k = 0; k < ELEMENTSOF(mount_table); k++) { - char *where; int t; if (asprintf(&where, "%s/%s", dest, mount_table[k].where) < 0) { @@ -167,6 +180,13 @@ static int mount_all(const char *dest) { free(where); } + /* Fix the timezone, if possible */ + if (asprintf(&where, "%s/%s", dest, "/etc/localtime") >= 0) { + mount("/etc/localtime", where, "bind", MS_BIND, NULL); + mount("/etc/localtime", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL); + free(where); + } + return r; } @@ -325,7 +345,7 @@ static int drop_capabilities(void) { unsigned long l; - for (l = 0; l <= MAX(63LU, (unsigned long) CAP_LAST_CAP); l ++) { + for (l = 0; l <= MAX(63LU, (unsigned long) CAP_LAST_CAP); l++) { unsigned i; for (i = 0; i < ELEMENTSOF(retain); i++) @@ -340,7 +360,7 @@ static int drop_capabilities(void) { /* If this capability is not known, EINVAL * will be returned, let's ignore this. */ if (errno == EINVAL) - continue; + break; log_error("PR_CAPBSET_DROP failed: %m"); return -errno; @@ -367,11 +387,11 @@ static int is_os_tree(const char *path) { #define BUFFER_SIZE 1024 static int process_pty(int master, sigset_t *mask) { + char in_buffer[BUFFER_SIZE], out_buffer[BUFFER_SIZE]; size_t in_buffer_full = 0, out_buffer_full = 0; struct epoll_event stdin_ev, stdout_ev, master_ev, signal_ev; bool stdin_readable = false, stdout_writable = false, master_readable = false, master_writable = false; - bool stdin_rhup = false, stdout_whup = false, master_rhup = false, master_whup = false; int ep = -1, signal_fd = -1, r; fd_nonblock(STDIN_FILENO, 1); @@ -415,7 +435,7 @@ static int process_pty(int master, sigset_t *mask) { goto finish; } - do { + for (;;) { struct epoll_event ev[16]; ssize_t k; int i, nfds; @@ -435,30 +455,20 @@ static int process_pty(int master, sigset_t *mask) { for (i = 0; i < nfds; i++) { if (ev[i].data.fd == STDIN_FILENO) { - if (!stdin_rhup && (ev[i].events & (EPOLLHUP|EPOLLIN))) + if (ev[i].events & (EPOLLIN|EPOLLHUP)) stdin_readable = true; } else if (ev[i].data.fd == STDOUT_FILENO) { - if (ev[i].events & EPOLLHUP) { - stdout_writable = false; - stdout_whup = true; - } - - if (!stdout_whup && (ev[i].events & EPOLLOUT)) + if (ev[i].events & (EPOLLOUT|EPOLLHUP)) stdout_writable = true; } else if (ev[i].data.fd == master) { - /* We don't connect EPOLLHUP to - * master_whup here, since EPOLLHUP - * can happen when noone has opened - * the other side */ - - if (!master_rhup && (ev[i].events & (EPOLLHUP|EPOLLIN))) + if (ev[i].events & (EPOLLIN|EPOLLHUP)) master_readable = true; - if (!master_whup && (ev[i].events & EPOLLOUT)) + if (ev[i].events & (EPOLLOUT|EPOLLHUP)) master_writable = true; } else if (ev[i].data.fd == signal_fd) { @@ -468,11 +478,13 @@ static int process_pty(int master, sigset_t *mask) { if ((n = read(signal_fd, &sfsi, sizeof(sfsi))) != sizeof(sfsi)) { if (n >= 0) { + log_error("Failed to read from signalfd: invalid block size"); r = -EIO; goto finish; } if (errno != EINTR && errno != EAGAIN) { + log_error("Failed to read from signalfd: %m"); r = -errno; goto finish; } @@ -482,11 +494,10 @@ static int process_pty(int master, sigset_t *mask) { struct winsize ws; /* The window size changed, let's forward that. */ - if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) >= 0) ioctl(master, TIOCSWINSZ, &ws); } else { - r = -EINTR; + r = 0; goto finish; } } @@ -502,35 +513,26 @@ static int process_pty(int master, sigset_t *mask) { if ((k = read(STDIN_FILENO, in_buffer + in_buffer_full, BUFFER_SIZE - in_buffer_full)) < 0) { - if (errno == EAGAIN) + if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) stdin_readable = false; - else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) - k = 0; else { log_error("read(): %m"); + r = -errno; goto finish; } } else in_buffer_full += (size_t) k; - - if (k == 0) { - stdin_rhup = true; - stdin_readable = false; - shutdown(STDIN_FILENO, SHUT_RD); - } } if (master_writable && in_buffer_full > 0) { if ((k = write(master, in_buffer, in_buffer_full)) < 0) { - if (errno == EAGAIN) - master_writable = false; - else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) { - master_whup = true; + if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) master_writable = false; - } else { + else { log_error("write(): %m"); + r = -errno; goto finish; } @@ -545,34 +547,26 @@ static int process_pty(int master, sigset_t *mask) { if ((k = read(master, out_buffer + out_buffer_full, BUFFER_SIZE - out_buffer_full)) < 0) { - if (errno == EAGAIN) + if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) master_readable = false; - else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) - k = 0; else { log_error("read(): %m"); + r = -errno; goto finish; } } else out_buffer_full += (size_t) k; - - if (k == 0) { - master_rhup = true; - master_readable = false; - } } if (stdout_writable && out_buffer_full > 0) { if ((k = write(STDOUT_FILENO, out_buffer, out_buffer_full)) < 0) { - if (errno == EAGAIN) - stdout_writable = false; - else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) { - stdout_whup = true; + if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO) stdout_writable = false; - } else { + else { log_error("write(): %m"); + r = -errno; goto finish; } @@ -583,19 +577,7 @@ static int process_pty(int master, sigset_t *mask) { } } } - - if (stdin_rhup && in_buffer_full <= 0 && !master_whup) { - master_whup = true; - master_writable = false; - } - - if (master_rhup && out_buffer_full <= 0 && !stdout_whup) { - stdout_whup = true; - stdout_writable = false; - shutdown(STDOUT_FILENO, SHUT_WR); - } - - } while (!stdout_whup || !master_whup); + } finish: if (ep >= 0) @@ -724,14 +706,19 @@ int main(int argc, char *argv[]) { /* child */ const char *hn; + const char *home = NULL; + uid_t uid = (uid_t) -1; + gid_t gid = (gid_t) -1; const char *envp[] = { - "HOME=/root", "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", - NULL, + NULL, /* TERM */ + NULL, /* HOME */ + NULL, /* USER */ + NULL, /* LOGNAME */ NULL }; - envp[2] = strv_find_prefix(environ, "TERM="); + envp[1] = strv_find_prefix(environ, "TERM="); close_nointr_nofail(master); @@ -788,13 +775,53 @@ int main(int argc, char *argv[]) { if (drop_capabilities() < 0) goto child_fail; + if (arg_user) { + + if (get_user_creds((const char**)&arg_user, &uid, &gid, &home) < 0) { + log_error("get_user_creds() failed: %m"); + goto child_fail; + } + + if (mkdir_parents(home, 0775) < 0) { + log_error("mkdir_parents() failed: %m"); + goto child_fail; + } + + if (safe_mkdir(home, 0775, uid, gid) < 0) { + log_error("safe_mkdir() 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; + } + } + + if ((asprintf((char**)(envp + 2), "HOME=%s", home? home: "/root") < 0) || + (asprintf((char**)(envp + 3), "USER=%s", arg_user? arg_user : "root") < 0) || + (asprintf((char**)(envp + 4), "LOGNAME=%s", arg_user? arg_user : "root") < 0)) { + log_error("Out of memory"); + goto child_fail; + } + if ((hn = file_name_from_path(arg_directory))) sethostname(hn, strlen(hn)); if (argc > optind) execvpe(argv[optind], argv + optind, (char**) envp); else { - chdir("/root"); + chdir(home ? home : "/root"); execle("/bin/bash", "-bash", NULL, (char**) envp); }