diff options
Diffstat (limited to 'auth.c')
| -rw-r--r-- | auth.c | 154 |
1 files changed, 1 insertions, 153 deletions
@@ -1,4 +1,4 @@ -/* $OpenBSD: auth.c,v 1.150 2020/12/20 23:36:51 djm Exp $ */ +/* $OpenBSD: auth.c,v 1.151 2020/12/22 00:12:22 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -841,158 +841,6 @@ auth_get_canonical_hostname(struct ssh *ssh, int use_dns) } } -/* - * Runs command in a subprocess with a minimal environment. - * Returns pid on success, 0 on failure. - * The child stdout and stderr maybe captured, left attached or sent to - * /dev/null depending on the contents of flags. - * "tag" is prepended to log messages. - * NB. "command" is only used for logging; the actual command executed is - * av[0]. - */ -pid_t -subprocess(const char *tag, struct passwd *pw, const char *command, - int ac, char **av, FILE **child, u_int flags) -{ - FILE *f = NULL; - struct stat st; - int fd, devnull, p[2], i; - pid_t pid; - char *cp, errmsg[512]; - u_int envsize; - char **child_env; - - if (child != NULL) - *child = NULL; - - debug3_f("%s command \"%s\" running as %s (flags 0x%x)", - tag, command, pw->pw_name, flags); - - /* Check consistency */ - if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && - (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) { - error_f("inconsistent flags"); - return 0; - } - if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) { - error_f("inconsistent flags/output"); - return 0; - } - - /* - * If executing an explicit binary, then verify the it exists - * and appears safe-ish to execute - */ - if (!path_absolute(av[0])) { - error("%s path is not absolute", tag); - return 0; - } - temporarily_use_uid(pw); - if (stat(av[0], &st) == -1) { - error("Could not stat %s \"%s\": %s", tag, - av[0], strerror(errno)); - restore_uid(); - return 0; - } - if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) { - error("Unsafe %s \"%s\": %s", tag, av[0], errmsg); - restore_uid(); - return 0; - } - /* Prepare to keep the child's stdout if requested */ - if (pipe(p) == -1) { - error("%s: pipe: %s", tag, strerror(errno)); - restore_uid(); - return 0; - } - restore_uid(); - - switch ((pid = fork())) { - case -1: /* error */ - error("%s: fork: %s", tag, strerror(errno)); - close(p[0]); - close(p[1]); - return 0; - case 0: /* child */ - /* Prepare a minimal environment for the child. */ - envsize = 5; - child_env = xcalloc(sizeof(*child_env), envsize); - child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH); - child_set_env(&child_env, &envsize, "USER", pw->pw_name); - child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name); - child_set_env(&child_env, &envsize, "HOME", pw->pw_dir); - if ((cp = getenv("LANG")) != NULL) - child_set_env(&child_env, &envsize, "LANG", cp); - - for (i = 0; i < NSIG; i++) - ssh_signal(i, SIG_DFL); - - if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { - error("%s: open %s: %s", tag, _PATH_DEVNULL, - strerror(errno)); - _exit(1); - } - if (dup2(devnull, STDIN_FILENO) == -1) { - error("%s: dup2: %s", tag, strerror(errno)); - _exit(1); - } - - /* Set up stdout as requested; leave stderr in place for now. */ - fd = -1; - if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) - fd = p[1]; - else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0) - fd = devnull; - if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) { - error("%s: dup2: %s", tag, strerror(errno)); - _exit(1); - } - closefrom(STDERR_FILENO + 1); - - /* Don't use permanently_set_uid() here to avoid fatal() */ - if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) { - error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid, - strerror(errno)); - _exit(1); - } - if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) { - error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid, - strerror(errno)); - _exit(1); - } - /* stdin is pointed to /dev/null at this point */ - if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 && - dup2(STDIN_FILENO, STDERR_FILENO) == -1) { - error("%s: dup2: %s", tag, strerror(errno)); - _exit(1); - } - - execve(av[0], av, child_env); - error("%s exec \"%s\": %s", tag, command, strerror(errno)); - _exit(127); - default: /* parent */ - break; - } - - close(p[1]); - if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) - close(p[0]); - else if ((f = fdopen(p[0], "r")) == NULL) { - error("%s: fdopen: %s", tag, strerror(errno)); - close(p[0]); - /* Don't leave zombie child */ - kill(pid, SIGTERM); - while (waitpid(pid, NULL, 0) == -1 && errno == EINTR) - ; - return 0; - } - /* Success */ - debug3_f("%s pid %ld", tag, (long)pid); - if (child != NULL) - *child = f; - return pid; -} - /* These functions link key/cert options to the auth framework */ /* Log sshauthopt options locally and (optionally) for remote transmission */ |