source: storage_xml.c @ aaaed5e

  /********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2006 Wilmer van der Gaast and others                *
  \********************************************************************/

/* Storage backend that uses an XMLish format for all data. */

/*
  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 59 Temple Place,
  Suite 330, Boston, MA  02111-1307  USA
*/

#define BITLBEE_CORE
#include "bitlbee.h"
#include "base64.h"
#include "rc4.h"
#include "md5.h"

typedef enum
{
        XML_PASS_CHECK_ONLY = -1,
        XML_PASS_UNKNOWN = 0,
        XML_PASS_WRONG,
        XML_PASS_OK
} xml_pass_st;

/* To make it easier later when extending the format: */
#define XML_FORMAT_VERSION 1

struct xml_parsedata
{
        irc_t *irc;
        char *current_setting;
        account_t *current_account;
        char *given_nick;
        char *given_pass;
        xml_pass_st pass_st;
};

static char *xml_attr( const gchar **attr_names, const gchar **attr_values, const gchar *key )
{
        int i;
        
        for( i = 0; attr_names[i]; i ++ )
                if( g_strcasecmp( attr_names[i], key ) == 0 )
                        return (char*) attr_values[i];
        
        return NULL;
}

static void xml_destroy_xd( gpointer data )
{
        struct xml_parsedata *xd = data;
        
        g_free( xd->given_nick );
        g_free( xd->given_pass );
        g_free( xd );
}

static void xml_start_element( GMarkupParseContext *ctx, const gchar *element_name, const gchar **attr_names, const gchar **attr_values, gpointer data, GError **error )
{
        struct xml_parsedata *xd = data;
        irc_t *irc = xd->irc;
        
        if( g_strcasecmp( element_name, "user" ) == 0 )
        {
                char *nick = xml_attr( attr_names, attr_values, "nick" );
                char *pass = xml_attr( attr_names, attr_values, "password" );
                md5_byte_t *pass_dec = NULL;
                
                if( !nick || !pass )
                {
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Missing attributes for %s element", element_name );
                }
                else if( base64_decode( pass, &pass_dec ) != 21 )
                {
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Error while decoding password attribute" );
                }
                else
                {
                        md5_byte_t pass_md5[16];
                        md5_state_t md5_state;
                        int i;
                        
                        md5_init( &md5_state );
                        md5_append( &md5_state, (md5_byte_t*) xd->given_pass, strlen( xd->given_pass ) );
                        md5_append( &md5_state, (md5_byte_t*) pass_dec + 16, 5 ); /* Hmmm, salt! */
                        md5_finish( &md5_state, pass_md5 );
                        
                        for( i = 0; i < 16; i ++ )
                        {
                                if( pass_dec[i] != pass_md5[i] )
                                {
                                        xd->pass_st = XML_PASS_WRONG;
                                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                                     "Password mismatch" );
                                        break;
                                }
                        }
                        
                        /* If we reached the end of the loop, it was a match! */
                        if( i == 16 )
                        {
                                if( xd->pass_st != XML_PASS_CHECK_ONLY )
                                        xd->pass_st = XML_PASS_OK;
                        }
                }
                
                g_free( pass_dec );
        }
        else if( xd->pass_st < XML_PASS_OK )
        {
                /* Let's not parse anything else if we only have to check
                   the password. */
        }
        else if( g_strcasecmp( element_name, "account" ) == 0 )
        {
                char *protocol, *handle, *server, *password = NULL, *autoconnect;
                char *pass_b64 = NULL, *pass_rc4 = NULL;
                int pass_len;
                struct prpl *prpl = NULL;
                
                handle = xml_attr( attr_names, attr_values, "handle" );
                pass_b64 = xml_attr( attr_names, attr_values, "password" );
                server = xml_attr( attr_names, attr_values, "server" );
                autoconnect = xml_attr( attr_names, attr_values, "autoconnect" );
                
                protocol = xml_attr( attr_names, attr_values, "protocol" );
                if( protocol )
                        prpl = find_protocol( protocol );
                
                if( !handle || !pass_b64 || !protocol )
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Missing attributes for %s element", element_name );
                else if( !prpl )
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Unknown protocol: %s", protocol );
                else if( ( pass_len = base64_decode( pass_b64, (unsigned char**) &pass_rc4 ) ) &&
                                rc4_decode( (unsigned char*) pass_rc4, pass_len,
                                            (unsigned char**) &password, xd->given_pass ) )
                {
                        xd->current_account = account_add( irc, prpl, handle, password );
                        if( server )
                                set_setstr( &xd->current_account->set, "server", server );
                        if( autoconnect )
                                set_setstr( &xd->current_account->set, "auto_connect", autoconnect );
                }
                else
                {
                        /* Actually the _decode functions don't even return error codes,
                           but maybe they will later... */
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Error while decrypting account password" );
                }
                
                g_free( pass_rc4 );
                g_free( password );
        }
        else if( g_strcasecmp( element_name, "setting" ) == 0 )
        {
                char *setting;
                
                if( xd->current_setting )
                {
                        g_free( xd->current_setting );
                        xd->current_setting = NULL;
                }
                
                if( ( setting = xml_attr( attr_names, attr_values, "name" ) ) )
                        xd->current_setting = g_strdup( setting );
                else
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Missing attributes for %s element", element_name );
        }
        else if( g_strcasecmp( element_name, "buddy" ) == 0 )
        {
                char *handle, *nick;
                
                handle = xml_attr( attr_names, attr_values, "handle" );
                nick = xml_attr( attr_names, attr_values, "nick" );
                
                if( xd->current_account && handle && nick )
                {
                        nick_set( xd->current_account, handle, nick );
                }
                else
                {
                        g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_INVALID_CONTENT,
                                     "Missing attributes for %s element", element_name );
                }
        }
        else
        {
                g_set_error( error, G_MARKUP_ERROR, G_MARKUP_ERROR_UNKNOWN_ELEMENT,
                             "Unkown element: %s", element_name );
        }
}

static void xml_end_element( GMarkupParseContext *ctx, const gchar *element_name, gpointer data, GError **error )
{
        struct xml_parsedata *xd = data;
        
        if( g_strcasecmp( element_name, "setting" ) == 0 && xd->current_setting )
        {
                g_free( xd->current_setting );
                xd->current_setting = NULL;
        }
        else if( g_strcasecmp( element_name, "account" ) == 0 )
        {
                xd->current_account = NULL;
        }
}

static void xml_text( GMarkupParseContext *ctx, const gchar *text_orig, gsize text_len, gpointer data, GError **error )
{
        char text[text_len+1];
        struct xml_parsedata *xd = data;
        irc_t *irc = xd->irc;
        
        strncpy( text, text_orig, text_len );
        text[text_len] = 0;
        
        if( xd->pass_st < XML_PASS_OK )
        {
                /* Let's not parse anything else if we only have to check
                   the password, or if we didn't get the chance to check it
                   yet. */
        }
        else if( g_strcasecmp( g_markup_parse_context_get_element( ctx ), "setting" ) == 0 && xd->current_setting )
        {
                set_setstr( xd->current_account ? &xd->current_account->set : &irc->set,
                            xd->current_setting, (char*) text );
                g_free( xd->current_setting );
                xd->current_setting = NULL;
        }
}

GMarkupParser xml_parser =
{
        xml_start_element,
        xml_end_element,
        xml_text,
        NULL,
        NULL
};

static void xml_init( void )
{
        if( access( global.conf->configdir, F_OK ) != 0 )
                log_message( LOGLVL_WARNING, "The configuration directory %s does not exist. Configuration won't be saved.", CONFIG );
        else if( access( global.conf->configdir, R_OK ) != 0 || access( global.conf->configdir, W_OK ) != 0 )
                log_message( LOGLVL_WARNING, "Permission problem: Can't read/write from/to %s.", global.conf->configdir );
}

static storage_status_t xml_load_real( const char *my_nick, const char *password, irc_t *irc, xml_pass_st action )
{
        GMarkupParseContext *ctx;
        struct xml_parsedata *xd;
        char *fn, buf[512];
        GError *gerr = NULL;
        int fd, st;
        
        if( irc && irc->status & USTATUS_IDENTIFIED )
                return( 1 );
        
        xd = g_new0( struct xml_parsedata, 1 );
        xd->irc = irc;
        xd->given_nick = g_strdup( my_nick );
        xd->given_pass = g_strdup( password );
        xd->pass_st = action;
        nick_lc( xd->given_nick );
        
        fn = g_strdup_printf( "%s%s%s", global.conf->configdir, xd->given_nick, ".xml" );
        if( ( fd = open( fn, O_RDONLY ) ) < 0 )
        {
                xml_destroy_xd( xd );
                g_free( fn );
                return STORAGE_NO_SUCH_USER;
        }
        g_free( fn );
        
        ctx = g_markup_parse_context_new( &xml_parser, 0, xd, xml_destroy_xd );
        
        while( ( st = read( fd, buf, sizeof( buf ) ) ) > 0 )
        {
                if( !g_markup_parse_context_parse( ctx, buf, st, &gerr ) || gerr )
                {
                        xml_pass_st pass_st = xd->pass_st;
                        
                        g_markup_parse_context_free( ctx );
                        close( fd );
                        
                        if( pass_st == XML_PASS_WRONG )
                        {
                                g_clear_error( &gerr );
                                return STORAGE_INVALID_PASSWORD;
                        }
                        else
                        {
                                if( gerr && irc )
                                        irc_usermsg( irc, "Error from XML-parser: %s", gerr->message );
                                
                                g_clear_error( &gerr );
                                return STORAGE_OTHER_ERROR;
                        }
                }
        }
        /* Just to be sure... */
        g_clear_error( &gerr );
        
        g_markup_parse_context_free( ctx );
        close( fd );
        
        if( action == XML_PASS_CHECK_ONLY )
                return STORAGE_OK;
        
        irc->status |= USTATUS_IDENTIFIED;
        
        return STORAGE_OK;
}

static storage_status_t xml_load( const char *my_nick, const char *password, irc_t *irc )
{
        return xml_load_real( my_nick, password, irc, XML_PASS_UNKNOWN );
}

static storage_status_t xml_check_pass( const char *my_nick, const char *password )
{
        /* This is a little bit risky because we have to pass NULL for the
           irc_t argument. This *should* be fine, if I didn't miss anything... */
        return xml_load_real( my_nick, password, NULL, XML_PASS_CHECK_ONLY );
}

static int xml_printf( int fd, int indent, char *fmt, ... )
{
        va_list params;
        char *out;
        char tabs[9] = "\t\t\t\t\t\t\t\t";
        int len;
        
        /* Maybe not very clean, but who needs more than 8 levels of indentation anyway? */
        if( write( fd, tabs, indent <= 8 ? indent : 8 ) != indent )
                return 0;
        
        va_start( params, fmt );
        out = g_markup_vprintf_escaped( fmt, params );
        va_end( params );
        
        len = strlen( out );
        len -= write( fd, out, len );
        g_free( out );
        
        return len == 0;
}

static gboolean xml_save_nick( gpointer key, gpointer value, gpointer data );

static storage_status_t xml_save( irc_t *irc, int overwrite )
{
        char path[512], *path2, *pass_buf = NULL;
        set_t *set;
        account_t *acc;
        int fd;
        md5_byte_t pass_md5[21];
        md5_state_t md5_state;
        
        if( irc->password == NULL )
        {
                irc_usermsg( irc, "Please register yourself if you want to save your settings." );
                return STORAGE_OTHER_ERROR;
        }
        
        path2 = g_strdup( irc->nick );
        nick_lc( path2 );
        g_snprintf( path, sizeof( path ) - 2, "%s%s%s", global.conf->configdir, path2, ".xml" );
        g_free( path2 );
        
        if( !overwrite && access( path, F_OK ) != -1 )
                return STORAGE_ALREADY_EXISTS;
        
        strcat( path, "~" );
        if( ( fd = open( path, O_WRONLY | O_CREAT, 0600 ) ) < 0 )
        {
                irc_usermsg( irc, "Error while opening configuration file." );
                return STORAGE_OTHER_ERROR;
        }
        
        /* Generate a salted md5sum of the password. Use 5 bytes for the salt
           (to prevent dictionary lookups of passwords) to end up with a 21-
           byte password hash, more convenient for base64 encoding. */
        random_bytes( pass_md5 + 16, 5 );
        md5_init( &md5_state );
        md5_append( &md5_state, (md5_byte_t*) irc->password, strlen( irc->password ) );
        md5_append( &md5_state, pass_md5 + 16, 5 ); /* Add the salt. */
        md5_finish( &md5_state, pass_md5 );
        /* Save the hash in base64-encoded form. */
        pass_buf = base64_encode( (char*) pass_md5, 21 );
        
        if( !xml_printf( fd, 0, "<user nick=\"%s\" password=\"%s\" version=\"%d\">\n", irc->nick, pass_buf, XML_FORMAT_VERSION ) )
                goto write_error;
        
        g_free( pass_buf );
        
        for( set = irc->set; set; set = set->next )
                if( set->value && set->def )
                        if( !xml_printf( fd, 1, "<setting name=\"%s\">%s</setting>\n", set->key, set->value ) )
                                goto write_error;
        
        for( acc = irc->accounts; acc; acc = acc->next )
        {
                char *pass_rc4, *pass_b64;
                int pass_len;
                
                pass_len = rc4_encode( (unsigned char*) acc->pass, strlen( acc->pass ), (unsigned char**) &pass_rc4, irc->password );
                pass_b64 = base64_encode( pass_rc4, pass_len );
                g_free( pass_rc4 );
                
                if( !xml_printf( fd, 1, "<account protocol=\"%s\" handle=\"%s\" password=\"%s\" autoconnect=\"%d\"", acc->prpl->name, acc->user, pass_b64, acc->auto_connect ) )
                {
                        g_free( pass_b64 );
                        goto write_error;
                }
                g_free( pass_b64 );
                
                if( acc->server && acc->server[0] && !xml_printf( fd, 0, " server=\"%s\"", acc->server ) )
                        goto write_error;
                if( !xml_printf( fd, 0, ">\n" ) )
                        goto write_error;
                
                for( set = acc->set; set; set = set->next )
                        if( set->value && set->def && !( set->flags & ACC_SET_NOSAVE ) )
                                if( !xml_printf( fd, 2, "<setting name=\"%s\">%s</setting>\n", set->key, set->value ) )
                                        goto write_error;
                
                /* This probably looks pretty strange. g_hash_table_foreach
                   is quite a PITA already (but it can't get much better in
                   C without using #define, I'm afraid), and since it
                   doesn't seem to be possible to abort the foreach on write
                   errors, so instead let's use the _find function and
                   return TRUE on write errors. Which means, if we found
                   something, there was an error. :-) */
                if( g_hash_table_find( acc->nicks, xml_save_nick, (gpointer) fd ) )
                        goto write_error;
                
                if( !xml_printf( fd, 1, "</account>\n" ) )
                        goto write_error;
        }
        
        if( !xml_printf( fd, 0, "</user>\n" ) )
                goto write_error;
        
        close( fd );
        
        path2 = g_strndup( path, strlen( path ) - 1 );
        if( rename( path, path2 ) != 0 )
        {
                irc_usermsg( irc, "Error while renaming temporary configuration file." );
                
                g_free( path2 );
                unlink( path );
                
                return STORAGE_OTHER_ERROR;
        }
        
        g_free( path2 );
        
        return STORAGE_OK;

write_error:
        g_free( pass_buf );
        
        irc_usermsg( irc, "Write error. Disk full?" );
        close( fd );
        
        return STORAGE_OTHER_ERROR;
}

static gboolean xml_save_nick( gpointer key, gpointer value, gpointer data )
{
        return !xml_printf( (int) data, 2, "<buddy handle=\"%s\" nick=\"%s\" />\n", key, value );
}

static storage_status_t xml_remove( const char *nick, const char *password )
{
        char s[512];
        storage_status_t status;

        status = xml_check_pass( nick, password );
        if( status != STORAGE_OK )
                return status;

        g_snprintf( s, 511, "%s%s%s", global.conf->configdir, nick, ".xml" );
        if( unlink( s ) == -1 )
                return STORAGE_OTHER_ERROR;
        
        return STORAGE_OK;
}

storage_t storage_xml = {
        .name = "xml",
        .init = xml_init,
        .check_pass = xml_check_pass,
        .remove = xml_remove,
        .load = xml_load,
        .save = xml_save
};