3
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* Mandos plugin runner - Run Mandos plugins
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* Copyright © 2008-2013 Teddy Hogeborn
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* Copyright © 2008-2013 Björn Påhlsson
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* Copyright © 2008,2009 Teddy Hogeborn
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* Copyright © 2008,2009 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <mandos@recompile.se>.
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* Contact the authors at <mandos@fukt.bsnet.se>.
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
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asprintf(), O_CLOEXEC */
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#include <stddef.h> /* size_t, NULL */
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#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
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#include <stdbool.h> /* bool, true, false */
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#include <stdio.h> /* fileno(), fprintf(),
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stderr, STDOUT_FILENO, fclose() */
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#include <sys/types.h> /* DIR, fdopendir(), fstat(), struct
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#include <stdio.h> /* perror, fileno(), fprintf(),
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stderr, STDOUT_FILENO */
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#include <sys/types.h> /* DIR, fdopendir(), stat(), struct
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stat, waitpid(), WIFEXITED(),
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WEXITSTATUS(), wait(), pid_t,
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uid_t, gid_t, getuid(), getgid(),
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#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
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WEXITSTATUS(), WTERMSIG(),
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#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
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#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
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#include <iso646.h> /* and, or, not */
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#include <dirent.h> /* DIR, struct dirent, fdopendir(),
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readdir(), closedir(), dirfd() */
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#include <unistd.h> /* fcntl(), F_GETFD, F_SETFD,
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FD_CLOEXEC, write(), STDOUT_FILENO,
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struct stat, fstat(), close(),
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setgid(), setuid(), S_ISREG(),
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faccessat() pipe(), fork(),
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_exit(), dup2(), fexecve(), read()
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#include <unistd.h> /* struct stat, stat(), S_ISREG(),
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fcntl(), setuid(), setgid(),
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F_GETFD, F_SETFD, FD_CLOEXEC,
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access(), pipe(), fork(), close()
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dup2(), STDOUT_FILENO, _exit(),
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execv(), write(), read(),
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#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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FD_CLOEXEC, openat() */
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#include <string.h> /* strsep, strlen(), strsignal(),
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strcmp(), strncmp() */
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#include <string.h> /* strsep, strlen(), asprintf(),
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#include <errno.h> /* errno */
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#include <argp.h> /* struct argp_option, struct
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argp_state, struct argp,
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#include <inttypes.h> /* intmax_t, PRIdMAX, strtoimax() */
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#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_IOERR,
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EX_CONFIG, EX_UNAVAILABLE, EX_OK */
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#include <errno.h> /* errno */
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#include <error.h> /* error() */
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#define BUFFER_SIZE 256
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/* Gets an existing plugin based on name,
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or if none is found, creates a new one */
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__attribute__((warn_unused_result))
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static plugin *getplugin(char *name){
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/* Check for existing plugin with that name */
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for(plugin *p = plugin_list; p != NULL; p = p->next){
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/* Helper function for add_argument and add_environment */
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__attribute__((nonnull, warn_unused_result))
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static bool add_to_char_array(const char *new, char ***array,
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/* Resize the pointed-to array to hold one more pointer */
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char **new_array = NULL;
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new_array = realloc(*array, sizeof(char *)
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* (size_t) ((*len) + 2));
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} while(new_array == NULL and errno == EINTR);
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*array = realloc(*array, sizeof(char *)
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* (size_t) ((*len) + 2));
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} while(*array == NULL and errno == EINTR);
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/* Malloc check */
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if(new_array == NULL){
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/* Make a copy of the new string */
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/* namelen = length of name of environment variable */
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size_t namelen = (size_t)(strchrnul(def, '=') - def);
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/* Search for this environment variable */
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for(char **envdef = p->environ; *envdef != NULL; envdef++){
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if(strncmp(*envdef, def, namelen + 1) == 0){
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for(char **e = p->environ; *e != NULL; e++){
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if(strncmp(*e, def, namelen + 1) == 0){
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/* It already exists */
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new_envdef = realloc(*envdef, strlen(def) + 1);
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} while(new_envdef == NULL and errno == EINTR);
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if(new_envdef == NULL){
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new = realloc(*e, strlen(def) + 1);
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} while(new == NULL and errno == EINTR);
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*envdef = new_envdef;
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strcpy(*envdef, def);
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.sa_flags = SA_NOCLDSTOP };
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char **custom_argv = NULL;
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int custom_argc = 0;
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/* Establish a signal handler */
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sigemptyset(&sigchld_action.sa_mask);
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ret = sigaddset(&sigchld_action.sa_mask, SIGCHLD);
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error(0, errno, "sigaddset");
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exitstatus = EX_OSERR;
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ret = sigaction(SIGCHLD, &sigchld_action, &old_sigchld_action);
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error(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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plugin *p = getplugin(arg);
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p->disabled = false;
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case 128: /* --plugin-dir */
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plugindir = strdup(arg);
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if(plugindir != NULL){
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case 129: /* --config-file */
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/* This is already done by parse_opt_config_file() */
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case 130: /* --userid */
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tmp_id = strtoimax(arg, &tmp, 10);
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tmpmax = strtoimax(arg, &tmp, 10);
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if(errno != 0 or tmp == arg or *tmp != '\0'
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or tmp_id != (uid_t)tmp_id){
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or tmpmax != (uid_t)tmpmax){
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argp_error(state, "Bad user ID number: \"%s\", using %"
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PRIdMAX, arg, (intmax_t)uid);
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case 131: /* --groupid */
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tmp_id = strtoimax(arg, &tmp, 10);
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tmpmax = strtoimax(arg, &tmp, 10);
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if(errno != 0 or tmp == arg or *tmp != '\0'
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or tmp_id != (gid_t)tmp_id){
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or tmpmax != (gid_t)tmpmax){
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argp_error(state, "Bad group ID number: \"%s\", using %"
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PRIdMAX, arg, (intmax_t)gid);
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case 132: /* --debug */
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new_arg = strdup(p);
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if(new_arg == NULL){
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error(0, errno, "strdup");
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exitstatus = EX_OSERR;
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custom_argc += 1;
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char **new_argv = realloc(custom_argv, sizeof(char *)
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if(new_argv == NULL){
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error(0, errno, "realloc");
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exitstatus = EX_OSERR;
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custom_argv = new_argv;
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custom_argv = realloc(custom_argv, sizeof(char *)
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* ((unsigned int) custom_argc + 1));
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if(custom_argv == NULL){
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exitstatus = EX_OSERR;
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custom_argv[custom_argc-1] = new_arg;
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custom_argv[custom_argc] = NULL;
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/* Work around Debian bug #633582:
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<http://bugs.debian.org/633582> */
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int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
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if(plugindir_fd == -1){
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error(0, errno, "open(\"" PDIR "\")");
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ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
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error(0, errno, "fstat");
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if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
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ret = fchown(plugindir_fd, uid, gid);
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error(0, errno, "fchown");
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TEMP_FAILURE_RETRY(close(plugindir_fd));
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/* Lower permissions */
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/* Strip permissions down to nobody */
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error(0, errno, "setgid");
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ret = setuid(uid);
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error(0, errno, "setuid");
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/* Open plugin directory with close_on_exec flag */
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dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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if(plugindir == NULL){
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dir_fd = open(PDIR, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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dir_fd = open(plugindir, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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if(dir_fd == -1){
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error(0, errno, "Could not open plugin dir");
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perror("Could not open plugin dir");
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exitstatus = EX_UNAVAILABLE;
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bool bad_name = false;
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const char * const bad_prefixes[] = { ".", "#", NULL };
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const char const *bad_prefixes[] = { ".", "#", NULL };
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const char * const bad_suffixes[] = { "~", "#", ".dpkg-new",
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const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
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".dpkg-divert", NULL };
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wcast-qual"
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for(const char **pre = (const char **)bad_prefixes;
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*pre != NULL; pre++){
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#pragma GCC diagnostic pop
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for(const char **pre = bad_prefixes; *pre != NULL; pre++){
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size_t pre_len = strlen(*pre);
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if((d_name_len >= pre_len)
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and strncmp((dirst->d_name), *pre, pre_len) == 0){
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wcast-qual"
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for(const char **suf = (const char **)bad_suffixes;
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*suf != NULL; suf++){
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#pragma GCC diagnostic pop
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for(const char **suf = bad_suffixes; *suf != NULL; suf++){
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size_t suf_len = strlen(*suf);
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if((d_name_len >= suf_len)
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and (strcmp((dirst->d_name) + d_name_len-suf_len, *suf)
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and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
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fprintf(stderr, "Ignoring plugin dir entry \"%s\""
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int plugin_fd = openat(dir_fd, dirst->d_name, O_RDONLY |
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#else /* not O_CLOEXEC */
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#endif /* not O_CLOEXEC */
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error(0, errno, "Could not open plugin");
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if(plugindir == NULL){
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ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
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ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",
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/* Set the FD_CLOEXEC flag on the plugin FD */
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ret = set_cloexec_flag(plugin_fd);
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error(0, errno, "set_cloexec_flag");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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#endif /* O_CLOEXEC */
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ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
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ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
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error(0, errno, "stat");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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/* Ignore non-executable files */
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if(not S_ISREG(st.st_mode)
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or (TEMP_FAILURE_RETRY(faccessat(dir_fd, dirst->d_name, X_OK,
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or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
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fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
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" with bad type or mode\n",
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plugindir != NULL ? plugindir : PDIR, dirst->d_name);
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fprintf(stderr, "Ignoring plugin dir entry \"%s\""
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" with bad type or mode\n", filename);
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TEMP_FAILURE_RETRY(close(plugin_fd));
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plugin *p = getplugin(dirst->d_name);
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error(0, errno, "getplugin");
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TEMP_FAILURE_RETRY(close(plugin_fd));
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for(char **a = g->argv + 1; *a != NULL; a++){
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if(not add_argument(p, *a)){
987
error(0, errno, "add_argument");
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perror("add_argument");
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/* Add global environment variables */
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for(char **e = g->environ; *e != NULL; e++){
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if(not add_environment(p, *e, false)){
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error(0, errno, "add_environment");
921
perror("add_environment");
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/* If this plugin has any environment variables, we need to
999
duplicate the environment from this process, too. */
926
/* If this plugin has any environment variables, we will call
927
using execve and need to duplicate the environment from this
1000
929
if(p->environ[0] != NULL){
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for(char **e = environ; *e != NULL; e++){
1002
931
if(not add_environment(p, *e, false)){
1003
error(0, errno, "add_environment");
932
perror("add_environment");
1009
938
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
1011
error(0, errno, "pipe");
1012
941
exitstatus = EX_OSERR;
1015
944
/* Ask OS to automatic close the pipe on exec */
1016
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ret = set_cloexec_flag(pipefd[0]);
1018
error(0, errno, "set_cloexec_flag");
947
perror("set_cloexec_flag");
1019
948
exitstatus = EX_OSERR;
1022
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ret = set_cloexec_flag(pipefd[1]);
1024
error(0, errno, "set_cloexec_flag");
953
perror("set_cloexec_flag");
1025
954
exitstatus = EX_OSERR;
1048
977
/* this is the child process */
1049
978
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1051
error(0, errno, "sigaction");
1052
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_exit(EX_OSERR);
1054
983
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1056
error(0, errno, "sigprocmask");
985
perror("sigprocmask");
1057
986
_exit(EX_OSERR);
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989
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1062
error(0, errno, "dup2");
1063
992
_exit(EX_OSERR);
1068
997
above and must now close it manually here. */
1071
if(fexecve(plugin_fd, p->argv,
1072
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1073
error(0, errno, "fexecve for %s/%s",
1074
plugindir != NULL ? plugindir : PDIR, dirst->d_name);
1000
if(p->environ[0] == NULL){
1001
if(execv(filename, p->argv) < 0){
1006
if(execve(filename, p->argv, p->environ) < 0){
1077
1011
/* no return */
1079
1013
/* Parent process */
1080
1014
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
1082
TEMP_FAILURE_RETRY(close(plugin_fd));
1083
1017
plugin *new_plugin = getplugin(dirst->d_name);
1084
1018
if(new_plugin == NULL){
1085
error(0, errno, "getplugin");
1019
perror("getplugin");
1086
1020
ret = (int)(TEMP_FAILURE_RETRY
1087
1021
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
1090
error(0, errno, "sigprocmask");
1024
perror("sigprocmask");
1092
1026
exitstatus = EX_OSERR;
1102
1036
&sigchld_action.sa_mask,
1105
error(0, errno, "sigprocmask");
1039
perror("sigprocmask");
1106
1040
exitstatus = EX_OSERR;
1110
#if defined (__GNUC__) and defined (__GLIBC__)
1111
#if not __GLIBC_PREREQ(2, 16)
1112
#pragma GCC diagnostic push
1113
#pragma GCC diagnostic ignored "-Wsign-conversion"
1116
1044
FD_SET(new_plugin->fd, &rfds_all); /* Spurious warning from
1117
-Wconversion in GNU libc
1119
#if defined (__GNUC__) and defined (__GLIBC__)
1120
#if not __GLIBC_PREREQ(2, 16)
1121
#pragma GCC diagnostic pop
1125
1047
if(maxfd < new_plugin->fd){
1126
1048
maxfd = new_plugin->fd;
1182
1104
/* Remove the plugin */
1183
#if defined (__GNUC__) and defined (__GLIBC__)
1184
#if not __GLIBC_PREREQ(2, 16)
1185
#pragma GCC diagnostic push
1186
#pragma GCC diagnostic ignored "-Wsign-conversion"
1189
1105
FD_CLR(proc->fd, &rfds_all); /* Spurious warning from
1190
-Wconversion in GNU libc
1192
#if defined (__GNUC__) and defined (__GLIBC__)
1193
#if not __GLIBC_PREREQ(2, 16)
1194
#pragma GCC diagnostic pop
1198
1108
/* Block signal while modifying process_list */
1199
1109
ret = (int)TEMP_FAILURE_RETRY(sigprocmask
1232
1142
bool bret = print_out_password(proc->buffer,
1233
1143
proc->buffer_length);
1235
error(0, errno, "print_out_password");
1145
perror("print_out_password");
1236
1146
exitstatus = EX_IOERR;
1241
1151
/* This process has not completed. Does it have any output? */
1242
#if defined (__GNUC__) and defined (__GLIBC__)
1243
#if not __GLIBC_PREREQ(2, 16)
1244
#pragma GCC diagnostic push
1245
#pragma GCC diagnostic ignored "-Wsign-conversion"
1248
1152
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){ /* Spurious
1254
#if defined (__GNUC__) and defined (__GLIBC__)
1255
#if not __GLIBC_PREREQ(2, 16)
1256
#pragma GCC diagnostic pop
1259
1155
/* This process had nothing to say at this time */
1260
1156
proc = proc->next;
1263
1159
/* Before reading, make the process' data buffer large enough */
1264
1160
if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
1265
char *new_buffer = realloc(proc->buffer, proc->buffer_size
1266
+ (size_t) BUFFER_SIZE);
1267
if(new_buffer == NULL){
1268
error(0, errno, "malloc");
1161
proc->buffer = realloc(proc->buffer, proc->buffer_size
1162
+ (size_t) BUFFER_SIZE);
1163
if(proc->buffer == NULL){
1269
1165
exitstatus = EX_OSERR;
1272
proc->buffer = new_buffer;
1273
1168
proc->buffer_size += BUFFER_SIZE;
1275
1170
/* Read from the process */