alpine 3.6
access weakness #491


Weakness Breakdown


An access weakness occurs when software does not properly implement permissions that could have unintended consequences if exploited by malicious actors. An example of this weakness is when a default username and password are set by the developer but do not get changed by the system administrator.

Warning code(s):

Ensure that umask is given most restrictive possible setting.

File Name:



The highlighted line of code below is the trigger point of this particular Alpine 3.6 access weakness.

     int r;
    mode_t u;

    pw = NULL;
    gr = NULL;

    /* Get user/group ID */

    if (!no_drop_root) {

        if (!(pw = getpwnam(AVAHI_AUTOIPD_USER))) {
            daemon_log(LOG_ERR, "Failed to find user '"AVAHI_AUTOIPD_USER"'.");
            return -1;

        if (!(gr = getgrnam(AVAHI_AUTOIPD_GROUP))) {
            daemon_log(LOG_ERR, "Failed to find group '"AVAHI_AUTOIPD_GROUP"'.");
            return -1;

        daemon_log(LOG_INFO, "Found user '"AVAHI_AUTOIPD_USER"' (UID %lu) and group '"AVAHI_AUTOIPD_GROUP"' (GID %lu).", (unsigned long) pw->pw_uid, (unsigned long) gr->gr_gid);

    /* Create directory */
    u = umask(0000);
    r = mkdir(AVAHI_IPDATA_DIR, 0755);

    if (r < 0 && errno != EEXIST) {
        daemon_log(LOG_ERR, "mkdir(\""AVAHI_IPDATA_DIR"\"): %s", strerror(errno));
        return -1;

    /* Convey working directory */

    if (!no_drop_root) {
        struct stat st;

        chown(AVAHI_IPDATA_DIR, pw->pw_uid, gr->gr_gid);

        if (stat(AVAHI_IPDATA_DIR, &st) < 0) {
            daemon_log(LOG_ERR, "stat(): %s\n", strerror(errno));
            return -1;

        if (!S_ISDIR(st.st_mode) || st.st_uid != pw->pw_uid || st.st_gid != gr->gr_gid) {
            daemon_log(LOG_ERR, "Failed to create runtime directory "AVAHI_IPDATA_DIR".");
            return -1;

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