/*
 * HttpAuth
 *
 * Copyright (C) 2004 Stefan Walter
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* On some linux this is required to get crypt to show itself */
#define _XOPEN_SOURCE

#include "usuals.h"
#include "httpauthd.h"
#include "defaults.h"
#include "hash.h"
#include "bd.h"
#include "md5.h"
#include "stringx.h"

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>

#define SIMPLE_MAXLINE 256

/* -------------------------------------------------------------------------------
 * Structures
 */

typedef struct simple_context
{
    /* Base Handler ------------------------------------------------------ */
    bd_context_t bd;

    /* Read Only --------------------------------------------------------- */
    const char* filename;           /* The file name with the user names */
}
simple_context_t;

/* Forward declarations for callbacks */
static int validate_digest(ha_request_t* rq, const char* user, digest_context_t* dg, char ***groups);
static int validate_basic(ha_request_t* rq, const char* user, const char* password, char ***groups);

/* The defaults for the context */
static const simple_context_t simple_defaults =
{
    BD_CALLBACKS(validate_digest, validate_basic, NULL),
    NULL               /* filename */
};

/* -------------------------------------------------------------------------------
 * Internal Functions
 */

static int validate_digest(ha_request_t* rq, const char* user,
                           digest_context_t* dg, char ***groups)
{
    simple_context_t* ctx = (simple_context_t*)rq->context->ctx_data;
    FILE* f;
    char* t;
    char* t2;
    size_t len;
    char line[SIMPLE_MAXLINE];
    int ret = HA_FALSE;
    int foundinvalid = 0;
    int foundgood = 0;

    ASSERT(ctx && rq && user && user[0]);
    ha_messagex(rq, LOG_DEBUG, "searching password file for user's ha1: %s", user);

    f = fopen(ctx->filename, "r");
    if(!f)
    {
        ha_message(rq, LOG_ERR, "can't open file for digest auth: %s", ctx->filename);
        return HA_FAILED;
    }

    /*
     * Note: There should be no returns or jumps between
     * this point and the closing of the file below.
     */

    /* Now look through the whole file */
    while(!feof(f))
    {
        fgets(line, SIMPLE_MAXLINE, f);

        if(ferror(f))
        {
            ha_message(rq, LOG_ERR, "error reading basic password file");
            ret = HA_FAILED;
            break;
        }

        t = strchr(line, ':');
        if(!t)
            continue;

        /* Split the line */
        *t = 0;
        t++;

        /* Check the user */
        if(strcmp(line, user) != 0)
            continue;

        t2 = strchr(t, ':');
        if(!t2)
        {
            /* An invalid line without a realm */
            foundinvalid = 1;
            continue;
        }

        /* Split the line */
        *t2 = 0;
        t2++;

        /* Check the realm */
        if(strcmp(t, rq->context->realm) != 0)
            continue;

        /* Now try and decode the ha1  */
        len = MD5_LEN;
        t = ha_bufdechex(rq->buf, t2, &len);

        if(!t || len != MD5_LEN)
        {
            /* An invalid ha1 */
            foundinvalid = 1;
            continue;
        }

        ha_messagex(rq, LOG_DEBUG, "found ha1 for user: %s", user);
        memcpy(dg->server_ha1, t, MD5_LEN);
        foundgood = 1;

        /* Try to do the validation */
        ret = digest_complete_check(dg, rq->context, rq->buf);

        /* If invalid then continue search */
        if(ret == HA_FALSE)
            continue;

        /* Success or an error ends here */
        break;
    }


    if(foundinvalid && !foundgood)
        ha_messagex(rq, LOG_WARNING, "user '%s' found in file, but password not in digest format", user);

    fclose(f);

    if(CHECK_RBUF(rq))
        return HA_CRITERROR;

    return ret;
}

static int validate_basic(ha_request_t* rq, const char* user,
                          const char* password, char ***groups)
{
    simple_context_t* ctx = (simple_context_t*)rq->context->ctx_data;
    FILE* f;
    char line[SIMPLE_MAXLINE];
    unsigned char ha1[MD5_LEN];
    char* t;
    char* t2;
    size_t len;
    int ret = HA_FALSE;

    ASSERT(ctx && rq);
    ASSERT(user && user[0] && password);
    ha_messagex(rq, LOG_DEBUG, "validating user against password file: %s", user);

    f = fopen(ctx->filename, "r");
    if(!f)
    {
        ha_message(rq, LOG_ERR, "can't open file for basic auth: %s", ctx->filename);
        return HA_FAILED;
    }

    digest_makeha1(ha1, user, rq->context->realm, password);

    /*
     * Note: There should be no returns or jumps between
     * this point and the closing of the file below.
     */

    /* Now look through the whole file */
    while(!feof(f))
    {
        fgets(line, SIMPLE_MAXLINE, f);

        if(ferror(f))
        {
            ha_message(rq, LOG_ERR, "error reading basic password file");
            ret = HA_FAILED;
            break;
        }

        /* Take white space off end of line */
        trim_end(line);

        t = strchr(line, ':');
        if(!t)
            continue;

        /* Split the line */
        *t = 0;
        t++;

        /* Check the user */
        if(strcmp(line, user) != 0)
            continue;

        /* Not sure if crypt is thread safe so we lock */
        ha_lock(NULL);

            /* Check the password */
            t2 = (char*)crypt(password, t);

        ha_unlock(NULL);

        if(strcmp(t2, t) == 0)
        {
            ha_messagex(rq, LOG_DEBUG, "found valid crypt password for user: %s", user);
            ret = HA_OK;
            break;
        }

        /* Otherwise it might be a digest type ha1. */
        t2 = strchr(t, ':');
        if(!t2)
            continue;

        /* Split the line */
        *t2 = 0;
        t2++;

        /* Check the realm */
        if(strcmp(t, rq->context->realm) != 0)
            continue;

        /* Now try antd decode the ha1  */
        len = MD5_LEN;

        t = ha_bufdechex(rq->buf, t2, &len);
        if(!t || len != MD5_LEN)
            continue;

        if(memcmp(ha1, t, MD5_LEN) == 0)
        {
            ha_messagex(rq, LOG_DEBUG, "found valid ha1 for user: %s", user);
            ret = HA_OK;
            break;
        }

        if(CHECK_RBUF(rq))
            break;
    }

    fclose(f);

    if(CHECK_RBUF(rq))
        return HA_CRITERROR;

    return ret;
}

/* -------------------------------------------------------------------------------
 * Handler Functions
 */

int simple_config(ha_context_t* context, const char* name, const char* value)
{
    simple_context_t* ctx = (simple_context_t*)(context->ctx_data);

    ASSERT(name && name[0] && value && value[0]);

    if(strcmp(name, "passwordfile") == 0)
    {
        ctx->filename = value;
        return HA_OK;
    }

    return HA_FALSE;
}

int simple_init(ha_context_t* context)
{
    int r;

    if((r = bd_init(context)) != HA_OK)
        return r;

    if(context)
    {
        simple_context_t* ctx = (simple_context_t*)(context->ctx_data);
        int fd;

        ASSERT(ctx);

        /* Check to make sure the file exists */
        if(!ctx->filename)
        {
            ha_messagex(NULL, LOG_ERR, "configuration incomplete. "
                                       "Must have a PasswordFile configured.");
            return HA_FAILED;
        }

        fd = open(ctx->filename, O_RDONLY);
        if(fd == -1)
        {
            ha_message(NULL, LOG_ERR, "can't open file for authentication: %s", ctx->filename);
            return HA_FAILED;
        }

        close(fd);

        ha_messagex(NULL, LOG_INFO, "initialized simple handler");
    }

    return HA_OK;
}


/* -------------------------------------------------------------------------------
 * Handler Definition
 */

ha_handler_t simple_handler =
{
    "SIMPLE",                /* The type */
    simple_init,             /* Initialization function */
    bd_destroy,              /* Uninitialization routine */
    simple_config,           /* Config routine */
    bd_process,              /* Processing routine */
    &simple_defaults,        /* A default context */
    sizeof(simple_context_t) /* Size of the context */
};