MONGO_EXPORT bson_bool_t mongo_cmd_authenticate( mongo *conn, const char *db, const char *user, const char *pass ) {
    bson from_db;
    bson cmd;
    const char *nonce;
    int result;

    mongo_md5_state_t st;
    mongo_md5_byte_t digest[16];
    char hex_digest[33];

    if( mongo_simple_int_command( conn, db, "getnonce", 1, &from_db ) == MONGO_OK ) {
        bson_iterator it;
        bson_find( &it, &from_db, "nonce" );
        nonce = bson_iterator_string( &it );
    }
    else {
        return MONGO_ERROR;
    }

    mongo_pass_digest( user, pass, hex_digest );

    mongo_md5_init( &st );
    mongo_md5_append( &st, ( const mongo_md5_byte_t * )nonce, strlen( nonce ) );
    mongo_md5_append( &st, ( const mongo_md5_byte_t * )user, strlen( user ) );
    mongo_md5_append( &st, ( const mongo_md5_byte_t * )hex_digest, 32 );
    mongo_md5_finish( &st, digest );
    digest2hex( digest, hex_digest );

    bson_init( &cmd );
    bson_append_int( &cmd, "authenticate", 1 );
    bson_append_string( &cmd, "user", user );
    bson_append_string( &cmd, "nonce", nonce );
    bson_append_string( &cmd, "key", hex_digest );
    bson_finish( &cmd );

    bson_destroy( &from_db );

    result = mongo_run_command( conn, db, &cmd, NULL );

    bson_destroy( &cmd );

    return result;
}
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.