X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fnspawn.c;h=a1ed425f05818ab970d262447e467ad71ac63351;hp=aaa5d1f9d0c0d43aafeb0fa47887ec6b2d0732e9;hb=b9b2b042c5564dfff730eeab43db9ac4bbe4c650;hpb=715ac17a84f7d721dec613d86d83e671704fafcc diff --git a/src/nspawn.c b/src/nspawn.c index aaa5d1f9d..a1ed425f0 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; @@ -111,15 +124,17 @@ static int mount_all(const char *dest) { } MountPoint; static const MountPoint mount_table[] = { - { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, - { "/proc/sys", "/proc/sys", "bind", NULL, MS_BIND, true }, /* Bind mount first */ - { "/proc/sys", "/proc/sys", "bind", NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, true }, /* Then, make it r/o */ - { "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 }, + { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true }, + { "/proc/sys", "/proc/sys", "bind", NULL, MS_BIND, true }, /* Bind mount first */ + { "/proc/sys", "/proc/sys", "bind", NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, true }, /* Then, make it r/o */ + { "/sys", "/sys", "bind", NULL, MS_BIND, true }, /* Bind mount first */ + { "/sys", "/sys", "bind", NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, true }, /* Then, make it r/o */ + { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID, true }, + { "/dev/pts", "/dev/pts", "bind", NULL, MS_BIND, 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 }, + { "/sys/fs/selinux", "/sys/fs/selinux", "bind", NULL, MS_BIND, false }, /* Bind mount first */ + { "/sys/fs/selinux", "/sys/fs/selinux", "bind", NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, false }, /* Then, make it r/o */ #endif }; @@ -332,7 +347,7 @@ 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++) @@ -347,7 +362,7 @@ 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; @@ -374,6 +389,7 @@ 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; @@ -464,11 +480,13 @@ 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; } @@ -481,7 +499,7 @@ static int process_pty(int master, sigset_t *mask) { if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) >= 0) ioctl(master, TIOCSWINSZ, &ws); } else { - r = -EINTR; + r = 0; goto finish; } } @@ -501,6 +519,7 @@ static int process_pty(int master, sigset_t *mask) { stdin_readable = false; else { log_error("read(): %m"); + r = -errno; goto finish; } } else @@ -515,6 +534,7 @@ static int process_pty(int master, sigset_t *mask) { master_writable = false; else { log_error("write(): %m"); + r = -errno; goto finish; } @@ -533,6 +553,7 @@ static int process_pty(int master, sigset_t *mask) { master_readable = false; else { log_error("read(): %m"); + r = -errno; goto finish; } } else @@ -547,6 +568,7 @@ static int process_pty(int master, sigset_t *mask) { stdout_writable = false; else { log_error("write(): %m"); + r = -errno; goto finish; } @@ -686,14 +708,19 @@ 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); @@ -714,6 +741,10 @@ int main(int argc, char *argv[]) { if (prctl(PR_SET_PDEATHSIG, SIGKILL) < 0) goto child_fail; + /* Mark / as private, in case somebody marked it shared */ + if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) < 0) + goto child_fail; + if (mount_all(arg_directory) < 0) goto child_fail; @@ -750,13 +781,53 @@ 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); }