Bernhard Reutner-Fischer | d9cf7ac | 2006-04-12 18:39:58 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 2 | /* |
| 3 | * CRONTAB |
| 4 | * |
| 5 | * usually setuid root, -c option only works if getuid() == geteuid() |
| 6 | * |
| 7 | * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com) |
Mike Frysinger | f284c76 | 2006-04-16 20:38:26 +0000 | [diff] [blame] | 8 | * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002 |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 9 | * |
Mike Frysinger | f284c76 | 2006-04-16 20:38:26 +0000 | [diff] [blame] | 10 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 11 | */ |
| 12 | |
Denis Vlasenko | b6adbf1 | 2007-05-26 19:00:18 +0000 | [diff] [blame] | 13 | #include "libbb.h" |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 14 | |
Denis Vlasenko | ded5dfe | 2009-02-03 23:59:41 +0000 | [diff] [blame^] | 15 | #define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs" |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 16 | #ifndef CRONUPDATE |
| 17 | #define CRONUPDATE "cron.update" |
| 18 | #endif |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 19 | |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 20 | static void change_user(const struct passwd *pas) |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 21 | { |
Denis Vlasenko | b8d1a4c | 2008-09-20 16:28:59 +0000 | [diff] [blame] | 22 | xsetenv("USER", pas->pw_name); |
| 23 | xsetenv("HOME", pas->pw_dir); |
| 24 | xsetenv("SHELL", DEFAULT_SHELL); |
Denis Vlasenko | 94d5d82 | 2006-09-27 19:48:56 +0000 | [diff] [blame] | 25 | |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 26 | /* initgroups, setgid, setuid */ |
Denis Vlasenko | 94d5d82 | 2006-09-27 19:48:56 +0000 | [diff] [blame] | 27 | change_identity(pas); |
| 28 | |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 29 | if (chdir(pas->pw_dir) < 0) { |
| 30 | bb_perror_msg("chdir(%s) by %s failed", |
| 31 | pas->pw_dir, pas->pw_name); |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 32 | xchdir("/tmp"); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 33 | } |
| 34 | } |
| 35 | |
| 36 | static void edit_file(const struct passwd *pas, const char *file) |
| 37 | { |
| 38 | const char *ptr; |
Denis Vlasenko | 82604e9 | 2008-07-01 15:59:42 +0000 | [diff] [blame] | 39 | int pid = vfork(); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 40 | |
Denis Vlasenko | 82604e9 | 2008-07-01 15:59:42 +0000 | [diff] [blame] | 41 | if (pid < 0) /* failure */ |
| 42 | bb_perror_msg_and_die("vfork"); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 43 | if (pid) { /* parent */ |
| 44 | wait4pid(pid); |
| 45 | return; |
| 46 | } |
| 47 | |
| 48 | /* CHILD - change user and run editor */ |
| 49 | change_user(pas); |
| 50 | ptr = getenv("VISUAL"); |
| 51 | if (!ptr) { |
| 52 | ptr = getenv("EDITOR"); |
| 53 | if (!ptr) |
Denis Vlasenko | b44c790 | 2008-03-17 09:29:43 +0000 | [diff] [blame] | 54 | ptr = "vi"; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 55 | } |
| 56 | |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 57 | BB_EXECLP(ptr, ptr, file, NULL); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 58 | bb_perror_msg_and_die("exec %s", ptr); |
| 59 | } |
| 60 | |
| 61 | static int open_as_user(const struct passwd *pas, const char *file) |
| 62 | { |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 63 | pid_t pid; |
| 64 | char c; |
| 65 | |
Denis Vlasenko | 82604e9 | 2008-07-01 15:59:42 +0000 | [diff] [blame] | 66 | pid = vfork(); |
| 67 | if (pid < 0) /* ERROR */ |
| 68 | bb_perror_msg_and_die("vfork"); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 69 | if (pid) { /* PARENT */ |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 70 | if (wait4pid(pid) == 0) { |
| 71 | /* exitcode 0: child says it can read */ |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 72 | return open(file, O_RDONLY); |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 73 | } |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 74 | return -1; |
| 75 | } |
| 76 | |
| 77 | /* CHILD */ |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 78 | /* initgroups, setgid, setuid */ |
| 79 | change_identity(pas); |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 80 | /* We just try to read one byte. If it works, file is readable |
| 81 | * under this user. We signal that by exiting with 0. */ |
| 82 | _exit(safe_read(xopen(file, O_RDONLY), &c, 1) < 0); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 83 | } |
| 84 | |
| 85 | int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
Denis Vlasenko | a60f84e | 2008-07-05 09:18:54 +0000 | [diff] [blame] | 86 | int crontab_main(int argc UNUSED_PARAM, char **argv) |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 87 | { |
| 88 | const struct passwd *pas; |
| 89 | const char *crontab_dir = CRONTABS; |
| 90 | char *tmp_fname; |
| 91 | char *new_fname; |
| 92 | char *user_name; /* -u USER */ |
| 93 | int fd; |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 94 | int src_fd; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 95 | int opt_ler; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 96 | |
| 97 | /* file [opts] Replace crontab from file |
| 98 | * - [opts] Replace crontab from stdin |
| 99 | * -u user User |
| 100 | * -c dir Crontab directory |
| 101 | * -l List crontab for user |
| 102 | * -e Edit crontab for user |
| 103 | * -r Delete crontab for user |
| 104 | * bbox also supports -d == -r, but most other crontab |
| 105 | * implementations do not. Deprecated. |
| 106 | */ |
| 107 | enum { |
| 108 | OPT_u = (1 << 0), |
| 109 | OPT_c = (1 << 1), |
| 110 | OPT_l = (1 << 2), |
| 111 | OPT_e = (1 << 3), |
| 112 | OPT_r = (1 << 4), |
| 113 | OPT_ler = OPT_l + OPT_e + OPT_r, |
| 114 | }; |
| 115 | |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 116 | opt_complementary = "?1:dr"; /* max one argument; -d implies -r */ |
| 117 | opt_ler = getopt32(argv, "u:c:lerd", &user_name, &crontab_dir); |
| 118 | argv += optind; |
| 119 | |
Denis Vlasenko | c9ca0a3 | 2008-02-18 11:08:33 +0000 | [diff] [blame] | 120 | if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */ |
| 121 | /* run by non-root? */ |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 122 | if (opt_ler & (OPT_u|OPT_c)) |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 123 | bb_error_msg_and_die("only root can use -c or -u"); |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 124 | } |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 125 | |
| 126 | if (opt_ler & OPT_u) { |
Denis Vlasenko | d7a805e | 2008-12-03 19:05:55 +0000 | [diff] [blame] | 127 | pas = xgetpwnam(user_name); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 128 | } else { |
Denis Vlasenko | 0c68a87 | 2008-12-02 22:56:59 +0000 | [diff] [blame] | 129 | pas = xgetpwuid(getuid()); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 130 | } |
| 131 | |
| 132 | #define user_name DONT_USE_ME_BEYOND_THIS_POINT |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 133 | |
| 134 | /* From now on, keep only -l, -e, -r bits */ |
| 135 | opt_ler &= OPT_ler; |
| 136 | if ((opt_ler - 1) & opt_ler) /* more than one bit set? */ |
| 137 | bb_show_usage(); |
| 138 | |
| 139 | /* Read replacement file under user's UID/GID/group vector */ |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 140 | src_fd = STDIN_FILENO; |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 141 | if (!opt_ler) { /* Replace? */ |
| 142 | if (!argv[0]) |
| 143 | bb_show_usage(); |
| 144 | if (NOT_LONE_DASH(argv[0])) { |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 145 | src_fd = open_as_user(pas, argv[0]); |
| 146 | if (src_fd < 0) |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 147 | bb_error_msg_and_die("user %s cannot read %s", |
| 148 | pas->pw_name, argv[0]); |
Denis Vlasenko | 94d5d82 | 2006-09-27 19:48:56 +0000 | [diff] [blame] | 149 | } |
| 150 | } |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 151 | |
| 152 | /* cd to our crontab directory */ |
| 153 | xchdir(crontab_dir); |
| 154 | |
| 155 | tmp_fname = NULL; |
| 156 | |
| 157 | /* Handle requested operation */ |
| 158 | switch (opt_ler) { |
| 159 | |
| 160 | default: /* case OPT_r: Delete */ |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 161 | unlink(pas->pw_name); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 162 | break; |
| 163 | |
| 164 | case OPT_l: /* List */ |
| 165 | { |
| 166 | char *args[2] = { pas->pw_name, NULL }; |
| 167 | return bb_cat(args); |
| 168 | /* list exits, |
| 169 | * the rest go play with cron update file */ |
| 170 | } |
| 171 | |
| 172 | case OPT_e: /* Edit */ |
Denis Vlasenko | 7fc294c | 2008-02-16 13:47:57 +0000 | [diff] [blame] | 173 | tmp_fname = xasprintf("%s.%u", crontab_dir, (unsigned)getpid()); |
Denis Vlasenko | b44c790 | 2008-03-17 09:29:43 +0000 | [diff] [blame] | 174 | /* No O_EXCL: we don't want to be stuck if earlier crontabs |
| 175 | * were killed, leaving stale temp file behind */ |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 176 | src_fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC, 0600); |
| 177 | fchown(src_fd, pas->pw_uid, pas->pw_gid); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 178 | fd = open(pas->pw_name, O_RDONLY); |
| 179 | if (fd >= 0) { |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 180 | bb_copyfd_eof(fd, src_fd); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 181 | close(fd); |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 182 | xlseek(src_fd, 0, SEEK_SET); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 183 | } |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 184 | close_on_exec_on(src_fd); /* don't want editor to see this fd */ |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 185 | edit_file(pas, tmp_fname); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 186 | /* fall through */ |
| 187 | |
| 188 | case 0: /* Replace (no -l, -e, or -r were given) */ |
| 189 | new_fname = xasprintf("%s.new", pas->pw_name); |
| 190 | fd = open(new_fname, O_WRONLY|O_CREAT|O_TRUNC|O_APPEND, 0600); |
| 191 | if (fd >= 0) { |
Denis Vlasenko | 30cfdf9 | 2008-09-21 15:29:29 +0000 | [diff] [blame] | 192 | bb_copyfd_eof(src_fd, fd); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 193 | close(fd); |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 194 | xrename(new_fname, pas->pw_name); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 195 | } else { |
| 196 | bb_error_msg("cannot create %s/%s", |
| 197 | crontab_dir, new_fname); |
| 198 | } |
| 199 | if (tmp_fname) |
Denis Vlasenko | 03b4c14 | 2008-02-17 14:30:03 +0000 | [diff] [blame] | 200 | unlink(tmp_fname); |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 201 | /*free(tmp_fname);*/ |
| 202 | /*free(new_fname);*/ |
| 203 | |
| 204 | } /* switch */ |
| 205 | |
| 206 | /* Bump notification file. Handle window where crond picks file up |
| 207 | * before we can write our entry out. |
| 208 | */ |
Bernhard Reutner-Fischer | 27dd495 | 2008-02-18 18:35:53 +0000 | [diff] [blame] | 209 | while ((fd = open(CRONUPDATE, O_WRONLY|O_CREAT|O_APPEND, 0600)) >= 0) { |
Denis Vlasenko | 069e347 | 2008-02-16 13:17:13 +0000 | [diff] [blame] | 210 | struct stat st; |
| 211 | |
| 212 | fdprintf(fd, "%s\n", pas->pw_name); |
| 213 | if (fstat(fd, &st) != 0 || st.st_nlink != 0) { |
| 214 | /*close(fd);*/ |
| 215 | break; |
| 216 | } |
| 217 | /* st.st_nlink == 0: |
| 218 | * file was deleted, maybe crond missed our notification */ |
| 219 | close(fd); |
| 220 | /* loop */ |
| 221 | } |
| 222 | if (fd < 0) { |
| 223 | bb_error_msg("cannot append to %s/%s", |
| 224 | crontab_dir, CRONUPDATE); |
| 225 | } |
| 226 | return 0; |
Eric Andersen | f6f7bfb | 2002-10-22 12:24:59 +0000 | [diff] [blame] | 227 | } |