src/server/daemon/keyfile_auth.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2013 Olaf Wintermann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/sha.h>

#include "../util/atomic.h"
#include "../util/util.h"

#include "keyfile_auth.h"

Keyfile* keyfile_new() {
    Keyfile *keyfile = malloc(sizeof(Keyfile));
    keyfile->authdb.get_user = keyfile_get_user;
    keyfile->authdb.use_cache = 0;
    keyfile->users = ucx_map_new(16);
    keyfile->ref = 1;
    return keyfile;
}

void keyfile_ref(Keyfile *keyfile) {
    ws_atomic_inc32(&keyfile->ref);
}

void keyfile_unref(Keyfile *keyfile) {
    uint32_t ref = ws_atomic_dec32(&keyfile->ref);
    if(ref == 0) { 
        UcxMapIterator i = ucx_map_iterator(keyfile->users);
        KeyfileUser *user;
        UCX_MAP_FOREACH(key, user, i) {
            free(user->user.name);
            free(user->hash);
            for(int n=0;n<user->numgroups;n++) {
                free(user->groups[n].ptr);
            }
            free(user->groups);
        }
        ucx_map_free(keyfile->users);
        
        free(keyfile->authdb.name);
        free(keyfile);
    }
}

void keyfile_add_user(
        Keyfile *keyfile,
        sstr_t name,
        enum KeyfileHashType hash_type,
        sstr_t hash,
        sstr_t *groups,
        size_t ngroups)
{
    if(hash.length < 12) {
        // hash too short
        // TODO: log
        return;
    }
    
    KeyfileUser *user = malloc(sizeof(KeyfileUser));
    user->user.name = sstrdup(name).ptr;
    user->user.uid = -1;
    user->user.gid = -1;
    user->user.verify_password = keyfile_user_verify_password;
    user->user.check_group = keyfile_user_check_group;
    user->user.free = keyfile_user_free;
    
    user->hash_type = hash_type;
    user->hash = malloc(hash.length + 1);
    user->hashlen = util_base64decode(hash.ptr, hash.length, user->hash);
    
    user->groups = calloc(ngroups, sizeof(sstr_t));
    for(int i=0;i<ngroups;i++) {
        user->groups[i] = sstrdup(groups[i]);
    }
    
    // add to keyfile
    ucx_map_sstr_put(keyfile->users, name, user);
}

// authdb functions

User* keyfile_get_user(AuthDB *db, char *user) {
    Keyfile *keyfile = (Keyfile*)db;
    return ucx_map_cstr_get(keyfile->users, user);
}

int keyfile_user_verify_password(User *user, char *password) {
    KeyfileUser *usr = (KeyfileUser*)user;
    switch(usr->hash_type) {
        case KEYFILE_SSHA: return ssha_verify(usr, password);
    }
    return 0;
}

int keyfile_user_check_group(User *user, char *group) {
    KeyfileUser *usr = (KeyfileUser*)user;
    sstr_t grp = sstr(group);
    for(int i=0;i<usr->numgroups;i++) {
        if(!sstrcmp(usr->groups[i], grp)) {
            return 1;
        }
    }
    return 0;
}

void keyfile_user_free(User *user) {
    // don't free, it will be freed by keyfile_unref
}


int ssha_verify(KeyfileUser *user, char *password) {
    /*
     * SSHA: SHA1(pw + salt) + 8 bytes salt
     * user->hash is already base64 decoded
     */
    
    // TODO: variable length salt
    
    char *salt = user->hash + user->hashlen - 8; // last 8 bytes are the salt 
    size_t pwlen = strlen(password);
    
    size_t saltpwlen = pwlen + 8;
    char *saltpw = malloc(saltpwlen);
    memcpy(saltpw, password, pwlen);
    memcpy(saltpw + pwlen, salt, 8);
    
    unsigned char pwhash[20];
    SHA1((const unsigned char*)saltpw, saltpwlen, pwhash);
    
    if(!memcmp(user->hash, pwhash, 20)) {
        return 1;
    } else {
        return 0;
    }
}