dav/pwd.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2018 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 <netinet/in.h>

#include "pwd.h"

#include <ucx/buffer.h>
#include <ucx/utils.h>


PwdStore* pwdstore_open(const char *file) {
    FILE *in = fopen(file, "r");
    if(!in) {
        return NULL;
    }
    
    UcxBuffer *buf = ucx_buffer_new(NULL, 2048, UCX_BUFFER_AUTOEXTEND);
    ucx_stream_copy(in, buf, (read_func)fread, (write_func)ucx_buffer_write);
    fclose(in);
    
    if(buf->size < PWDS_HEADER_SIZE || buf->space[0] != PWDS_MAGIC_CHAR) {
        ucx_buffer_free(buf);
        return NULL;
    }
    
    PwdStore *p = malloc(sizeof(PwdStore));
    p->pwds = ucx_map_new(16);
    p->content = buf;
    p->key = NULL;
    p->isdecrypted = 0;
    
    return p;
}

PwdStore* pwdstore_new(void) {
    PwdStore *p = calloc(1, sizeof(PwdStore));
    p->pwds = ucx_map_new(16);
    p->content = ucx_buffer_new(NULL, PWDS_HEADER_SIZE, UCX_BUFFER_AUTOEXTEND);
    PWDS_MAGIC(p) = PWDS_MAGIC_CHAR;
    PWDS_VERSION(p) = 1;
    PWDS_ENC(p) = DAV_KEY_AES256;
    PWDS_PWFUNC(p) = DAV_PWFUNC_PBKDF2_SHA256;
    dav_rand_bytes(p->content->space+4, 16);
    return p;
}

static int read_pwdentry(PwdStore *p, UcxBuffer *in) {
    int type = ucx_buffer_getc(in);
    if(type == EOF || type != 0) {
        // only type 0 supported yet
        return 0;
    }
    
    uint32_t ulen = 0;
    uint32_t plen = 0;
    
    if(ucx_buffer_read(&ulen, 1, sizeof(uint32_t), in) != sizeof(uint32_t)) {
        return 0;
    }
    ulen = ntohl(ulen);
    if(ulen == 0 || ulen > PWDSTORE_MAX_LEN) {
        return 0;
    }
    
    char *user = malloc(ulen+1);
    user[ulen] = 0;
    if(ucx_buffer_read(user, 1, ulen, in) != ulen) {
        free(user);
        return 0;
    }
    
    if(ucx_buffer_read(&plen, 1, sizeof(uint32_t), in) != sizeof(uint32_t)) {
        return 0;
    }
    plen = ntohl(plen);
    if(plen == 0 || plen > PWDSTORE_MAX_LEN) {
        return 0;
    }
    char *password = malloc(plen+1);
    password[plen] = 0;
    if(ucx_buffer_read(password, 1, plen, in) != plen) {
        free(user);
        free(password);
        return 0;
    }
    
    pwdstore_put(p, user, password);
    free(user);
    free(password);
    return 1;
    
}

int pwdstore_decrypt(PwdStore *p) {
    if(!p->key) {
        return 1;
    }
    
    // decrypt contet
    size_t encsz = p->content->size - PWDS_HEADER_SIZE;
    UcxBuffer *enc = ucx_buffer_new(p->content->space + PWDS_HEADER_SIZE, encsz, 0);
    enc->size = encsz;
    enc->size = p->content->size - PWDS_HEADER_SIZE;
    UcxBuffer *content = aes_decrypt_buffer(enc, p->key);
    ucx_buffer_free(enc);
    if(!content) {
        return 1;
    }
    
    while(read_pwdentry(p, content)) {}
    
    ucx_buffer_free(content);
    
    return 0;
}

int pwdstore_setpassword(PwdStore *p, const char *password) {
    DavKey *key = dav_pw2key(
            password,
            p->content->space + 4,
            16,
            PWDS_PWFUNC(p),
            PWDS_ENC(p));
    if(!key) {
        return 1;
    }
    
    p->key = key;
    return 0;
}

void pwdstore_encsettings(PwdStore *p, uint8_t enc, uint8_t pwfunc) {
    PWDS_ENC(p) = enc;
    PWDS_PWFUNC(p) = pwfunc;
}

static void free_entry(PwdEntry *e) {
    free(e->user);
    free(e->password);
    free(e);
}

void pwdstore_free(PwdStore* p) {
    ucx_map_free_content(p->pwds, (ucx_destructor)free_entry);
    ucx_map_free(p->pwds);
    
    if(p->content) {
        ucx_buffer_free(p->content);
    }
    
    free(p);
}

PwdEntry* pwdstore_get(PwdStore *p, const char *username) {
    return ucx_map_cstr_get(p->pwds, username);
}

void pwdstore_put(PwdStore *p, const char *username, const char *password) {
    PwdEntry *entry = malloc(sizeof(PwdEntry));
    entry->user = strdup(username);
    entry->password = strdup(password);
    ucx_map_cstr_put(p->pwds, entry->user, entry);
}

int pwdstore_store(PwdStore *p, const char *file) {
    if(!p->key) {
        return 1;
    }
    
    UcxBuffer *content = ucx_buffer_new(NULL, 2048, UCX_BUFFER_AUTOEXTEND);
    
    UcxMapIterator i = ucx_map_iterator(p->pwds);
    PwdEntry *value;
    UCX_MAP_FOREACH(key, value, i) {
        ucx_buffer_putc(content, 0); // type
        uint32_t ulen = strlen(value->user);
        uint32_t plen = strlen(value->password);
        uint32_t netulen = htonl(ulen);
        uint32_t netplen = htonl(plen);
        ucx_buffer_write(&netulen, 1, sizeof(uint32_t), content);
        ucx_buffer_write(value->user, 1, ulen, content);
        ucx_buffer_write(&netplen, 1, sizeof(uint32_t), content);
        ucx_buffer_write(value->password, 1, plen, content);
    }
    
    content->pos = 0;
    UcxBuffer *enc = aes_encrypt_buffer(content, p->key);

    p->content->pos = PWDS_HEADER_SIZE;
    p->content->size = PWDS_HEADER_SIZE;
    ucx_buffer_write(enc->space, 1, enc->size, p->content);
    
    ucx_buffer_free(enc);
    
    FILE *out = fopen(file, "w");
    if(!out) {
        return 1;
    }
    fwrite(p->content->space, 1, p->content->size, out);
    fclose(out);
    
    return 0;
}