Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 1 | /* vi: set sw=4 ts=4: */ |
| 2 | /* |
| 3 | * update_passwd |
| 4 | * |
| 5 | * update_passwd is a common function for passwd and chpasswd applets; |
| 6 | * it is responsible for updating password file (i.e. /etc/passwd or |
| 7 | * /etc/shadow) for a given user and password. |
| 8 | * |
| 9 | * Moved from loginutils/passwd.c by Alexander Shishkin <virtuoso@slind.org> |
Denis Vlasenko | db12d1d | 2008-12-07 00:52:58 +0000 | [diff] [blame] | 10 | * |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 11 | * Modified to be able to add or delete users, groups and users to/from groups |
| 12 | * by Tito Ragusa <farmatito@tiscali.it> |
| 13 | * |
Denis Vlasenko | db12d1d | 2008-12-07 00:52:58 +0000 | [diff] [blame] | 14 | * Licensed under GPLv2, see file LICENSE in this tarball for details. |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 15 | */ |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 16 | #include "libbb.h" |
| 17 | |
Denis Vlasenko | 2edbc2a | 2007-10-20 02:00:49 +0000 | [diff] [blame] | 18 | #if ENABLE_SELINUX |
| 19 | static void check_selinux_update_passwd(const char *username) |
| 20 | { |
| 21 | security_context_t context; |
| 22 | char *seuser; |
| 23 | |
| 24 | if (getuid() != (uid_t)0 || is_selinux_enabled() == 0) |
| 25 | return; /* No need to check */ |
| 26 | |
| 27 | if (getprevcon_raw(&context) < 0) |
| 28 | bb_perror_msg_and_die("getprevcon failed"); |
| 29 | seuser = strtok(context, ":"); |
| 30 | if (!seuser) |
| 31 | bb_error_msg_and_die("invalid context '%s'", context); |
| 32 | if (strcmp(seuser, username) != 0) { |
| 33 | if (checkPasswdAccess(PASSWD__PASSWD) != 0) |
| 34 | bb_error_msg_and_die("SELinux: access denied"); |
| 35 | } |
| 36 | if (ENABLE_FEATURE_CLEAN_UP) |
| 37 | freecon(context); |
| 38 | } |
| 39 | #else |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 40 | # define check_selinux_update_passwd(username) ((void)0) |
Denis Vlasenko | 2edbc2a | 2007-10-20 02:00:49 +0000 | [diff] [blame] | 41 | #endif |
| 42 | |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 43 | /* |
| 44 | 1) add a user: update_passwd(FILE, USER, REMAINING_PWLINE, NULL) |
| 45 | only if CONFIG_ADDUSER=y and applet_name[0] == 'a' like in adduser |
| 46 | |
| 47 | 2) add a group: update_passwd(FILE, GROUP, REMAINING_GRLINE, NULL) |
| 48 | only if CONFIG_ADDGROUP=y and applet_name[0] == 'a' like in addgroup |
| 49 | |
| 50 | 3) add a user to a group: update_passwd(FILE, GROUP, NULL, MEMBER) |
| 51 | only if CONFIG_FEATURE_ADDUSER_TO_GROUP=y, applet_name[0] == 'a' |
| 52 | like in addgroup and member != NULL |
| 53 | |
| 54 | 4) delete a user: update_passwd(FILE, USER, NULL, NULL) |
| 55 | |
| 56 | 5) delete a group: update_passwd(FILE, GROUP, NULL, NULL) |
| 57 | |
| 58 | 6) delete a user from a group: update_passwd(FILE, GROUP, NULL, MEMBER) |
| 59 | only if CONFIG_FEATURE_DEL_USER_FROM_GROUP=y and member != NULL |
| 60 | |
| 61 | 7) change user's passord: update_passwd(FILE, USER, NEW_PASSWD, NULL) |
| 62 | only if CONFIG_PASSWD=y and applet_name[0] == 'p' like in passwd |
| 63 | or if CONFIG_CHPASSWD=y and applet_name[0] == 'c' like in chpasswd |
| 64 | |
| 65 | This function does not validate the arguments fed to it |
| 66 | so the calling program should take care of that. |
| 67 | |
| 68 | Returns number of lines changed, or -1 on error. |
| 69 | */ |
| 70 | int FAST_FUNC update_passwd(const char *filename, |
| 71 | const char *name, |
| 72 | const char *new_passwd, |
| 73 | const char *member) |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 74 | { |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 75 | #if !(ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP) |
| 76 | #define member NULL |
| 77 | #endif |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 78 | struct stat sb; |
| 79 | struct flock lock; |
| 80 | FILE *old_fp; |
| 81 | FILE *new_fp; |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 82 | char *fnamesfx; |
| 83 | char *sfx_char; |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 84 | unsigned user_len; |
| 85 | int old_fd; |
| 86 | int new_fd; |
| 87 | int i; |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 88 | int changed_lines; |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 89 | int ret = -1; /* failure */ |
Denys Vlasenko | 189f74d | 2009-07-13 01:15:30 +0200 | [diff] [blame] | 90 | /* used as a bool: "are we modifying /etc/shadow?" */ |
| 91 | #if ENABLE_FEATURE_SHADOWPASSWDS |
| 92 | const char *shadow = strstr(filename, "shadow"); |
| 93 | #else |
| 94 | # define shadow NULL |
| 95 | #endif |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 96 | |
Paul Fox | 599bbfb | 2007-11-08 20:00:36 +0000 | [diff] [blame] | 97 | filename = xmalloc_follow_symlinks(filename); |
Paul Fox | 53bd401 | 2007-11-08 01:12:38 +0000 | [diff] [blame] | 98 | if (filename == NULL) |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 99 | return ret; |
Paul Fox | 53bd401 | 2007-11-08 01:12:38 +0000 | [diff] [blame] | 100 | |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 101 | check_selinux_update_passwd(name); |
Denis Vlasenko | 2edbc2a | 2007-10-20 02:00:49 +0000 | [diff] [blame] | 102 | |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 103 | /* New passwd file, "/etc/passwd+" for now */ |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 104 | fnamesfx = xasprintf("%s+", filename); |
| 105 | sfx_char = &fnamesfx[strlen(fnamesfx)-1]; |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 106 | name = xasprintf("%s:", name); |
| 107 | user_len = strlen(name); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 108 | |
Denys Vlasenko | 189f74d | 2009-07-13 01:15:30 +0200 | [diff] [blame] | 109 | if (shadow) |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 110 | old_fp = fopen(filename, "r+"); |
| 111 | else |
| 112 | old_fp = fopen_or_warn(filename, "r+"); |
Denys Vlasenko | c6fb2a6 | 2009-11-02 19:18:49 +0100 | [diff] [blame^] | 113 | if (!old_fp) { |
| 114 | if (shadow) |
| 115 | ret = 0; /* missing shadow is not an error */ |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 116 | goto free_mem; |
Denys Vlasenko | c6fb2a6 | 2009-11-02 19:18:49 +0100 | [diff] [blame^] | 117 | } |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 118 | old_fd = fileno(old_fp); |
| 119 | |
Denis Vlasenko | 2edbc2a | 2007-10-20 02:00:49 +0000 | [diff] [blame] | 120 | selinux_preserve_fcontext(old_fd); |
| 121 | |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 122 | /* Try to create "/etc/passwd+". Wait if it exists. */ |
| 123 | i = 30; |
| 124 | do { |
| 125 | // FIXME: on last iteration try w/o O_EXCL but with O_TRUNC? |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 126 | new_fd = open(fnamesfx, O_WRONLY|O_CREAT|O_EXCL, 0600); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 127 | if (new_fd >= 0) goto created; |
| 128 | if (errno != EEXIST) break; |
| 129 | usleep(100000); /* 0.1 sec */ |
| 130 | } while (--i); |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 131 | bb_perror_msg("can't create '%s'", fnamesfx); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 132 | goto close_old_fp; |
| 133 | |
| 134 | created: |
| 135 | if (!fstat(old_fd, &sb)) { |
| 136 | fchmod(new_fd, sb.st_mode & 0777); /* ignore errors */ |
| 137 | fchown(new_fd, sb.st_uid, sb.st_gid); |
| 138 | } |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 139 | errno = 0; |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 140 | new_fp = fdopen(new_fd, "w"); |
| 141 | if (!new_fp) { |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 142 | bb_perror_nomsg(); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 143 | close(new_fd); |
| 144 | goto unlink_new; |
| 145 | } |
| 146 | |
| 147 | /* Backup file is "/etc/passwd-" */ |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 148 | *sfx_char = '-'; |
| 149 | /* Delete old backup */ |
| 150 | i = (unlink(fnamesfx) && errno != ENOENT); |
| 151 | /* Create backup as a hardlink to current */ |
| 152 | if (i || link(filename, fnamesfx)) |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 153 | bb_perror_msg("warning: can't create backup copy '%s'", |
| 154 | fnamesfx); |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 155 | *sfx_char = '+'; |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 156 | |
| 157 | /* Lock the password file before updating */ |
| 158 | lock.l_type = F_WRLCK; |
| 159 | lock.l_whence = SEEK_SET; |
| 160 | lock.l_start = 0; |
| 161 | lock.l_len = 0; |
| 162 | if (fcntl(old_fd, F_SETLK, &lock) < 0) |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 163 | bb_perror_msg("warning: can't lock '%s'", filename); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 164 | lock.l_type = F_UNLCK; |
| 165 | |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 166 | /* Read current password file, write updated /etc/passwd+ */ |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 167 | changed_lines = 0; |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 168 | while (1) { |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 169 | char *cp, *line; |
| 170 | |
| 171 | line = xmalloc_fgetline(old_fp); |
| 172 | if (!line) /* EOF/error */ |
| 173 | break; |
| 174 | if (strncmp(name, line, user_len) != 0) { |
| 175 | fprintf(new_fp, "%s\n", line); |
| 176 | goto next; |
| 177 | } |
| 178 | |
| 179 | /* We have a match with "name:"... */ |
| 180 | cp = line + user_len; /* move past name: */ |
| 181 | |
| 182 | #if ENABLE_FEATURE_ADDUSER_TO_GROUP || ENABLE_FEATURE_DEL_USER_FROM_GROUP |
| 183 | if (member) { |
| 184 | /* It's actually /etc/group+, not /etc/passwd+ */ |
| 185 | if (ENABLE_FEATURE_ADDUSER_TO_GROUP |
| 186 | && applet_name[0] == 'a' |
| 187 | ) { |
| 188 | /* Add user to group */ |
| 189 | fprintf(new_fp, "%s%s%s\n", line, |
| 190 | last_char_is(line, ':') ? "" : ",", |
| 191 | member); |
| 192 | changed_lines++; |
| 193 | } else if (ENABLE_FEATURE_DEL_USER_FROM_GROUP |
| 194 | /* && applet_name[0] == 'd' */ |
| 195 | ) { |
| 196 | /* Delete user from group */ |
| 197 | char *tmp; |
| 198 | const char *fmt = "%s"; |
| 199 | |
| 200 | /* find the start of the member list: last ':' */ |
| 201 | cp = strrchr(line, ':'); |
| 202 | /* cut it */ |
| 203 | *cp++ = '\0'; |
| 204 | /* write the cut line name:passwd:gid: |
| 205 | * or name:!:: */ |
| 206 | fprintf(new_fp, "%s:", line); |
| 207 | /* parse the tokens of the member list */ |
| 208 | tmp = cp; |
| 209 | while ((cp = strsep(&tmp, ",")) != NULL) { |
| 210 | if (strcmp(member, cp) != 0) { |
| 211 | fprintf(new_fp, fmt, cp); |
| 212 | fmt = ",%s"; |
| 213 | } else { |
| 214 | /* found member, skip it */ |
| 215 | changed_lines++; |
| 216 | } |
| 217 | } |
| 218 | fprintf(new_fp, "\n"); |
| 219 | } |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 220 | } else |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 221 | #endif |
| 222 | if ((ENABLE_PASSWD && applet_name[0] == 'p') |
| 223 | || (ENABLE_CHPASSWD && applet_name[0] == 'c') |
| 224 | ) { |
| 225 | /* Change passwd */ |
| 226 | cp = strchrnul(cp, ':'); /* move past old passwd */ |
Denys Vlasenko | 189f74d | 2009-07-13 01:15:30 +0200 | [diff] [blame] | 227 | |
| 228 | if (shadow && *cp == ':') { |
| 229 | /* /etc/shadow's field 3 (passwd change date) needs updating */ |
| 230 | /* move past old change date */ |
| 231 | cp = strchrnul(cp + 1, ':'); |
| 232 | /* "name:" + "new_passwd" + ":" + "change date" + ":rest of line" */ |
| 233 | fprintf(new_fp, "%s%s:%u%s\n", name, new_passwd, |
| 234 | (unsigned)(time(NULL)) / (24*60*60), cp); |
| 235 | } else { |
| 236 | /* "name:" + "new_passwd" + ":rest of line" */ |
| 237 | fprintf(new_fp, "%s%s%s\n", name, new_passwd, cp); |
| 238 | } |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 239 | changed_lines++; |
| 240 | } /* else delete user or group: skip the line */ |
| 241 | next: |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 242 | free(line); |
| 243 | } |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 244 | |
| 245 | if (changed_lines == 0) { |
Denis Vlasenko | 7f95937 | 2009-04-14 08:06:59 +0000 | [diff] [blame] | 246 | #if ENABLE_FEATURE_DEL_USER_FROM_GROUP |
| 247 | if (member) |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 248 | bb_error_msg("can't find %s in %s", member, filename); |
Denis Vlasenko | 7f95937 | 2009-04-14 08:06:59 +0000 | [diff] [blame] | 249 | #endif |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 250 | if ((ENABLE_ADDUSER || ENABLE_ADDGROUP) |
| 251 | && applet_name[0] == 'a' && !member |
| 252 | ) { |
| 253 | /* add user or group */ |
| 254 | fprintf(new_fp, "%s%s\n", name, new_passwd); |
| 255 | changed_lines++; |
| 256 | } |
| 257 | } |
| 258 | |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 259 | fcntl(old_fd, F_SETLK, &lock); |
| 260 | |
| 261 | /* We do want all of them to execute, thus | instead of || */ |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 262 | errno = 0; |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 263 | if ((ferror(old_fp) | fflush(new_fp) | fsync(new_fd) | fclose(new_fp)) |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 264 | || rename(fnamesfx, filename) |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 265 | ) { |
| 266 | /* At least one of those failed */ |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 267 | bb_perror_nomsg(); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 268 | goto unlink_new; |
| 269 | } |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 270 | /* Success: ret >= 0 */ |
| 271 | ret = changed_lines; |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 272 | |
| 273 | unlink_new: |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 274 | if (ret < 0) |
| 275 | unlink(fnamesfx); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 276 | |
| 277 | close_old_fp: |
| 278 | fclose(old_fp); |
| 279 | |
| 280 | free_mem: |
Denis Vlasenko | 557fb71 | 2007-07-21 13:25:28 +0000 | [diff] [blame] | 281 | free(fnamesfx); |
Paul Fox | 53bd401 | 2007-11-08 01:12:38 +0000 | [diff] [blame] | 282 | free((char *)filename); |
Denis Vlasenko | 829bbd3 | 2009-04-14 00:51:05 +0000 | [diff] [blame] | 283 | free((char *)name); |
Denis Vlasenko | 1ec5eae | 2007-07-20 21:29:49 +0000 | [diff] [blame] | 284 | return ret; |
| 285 | } |