Mail: fixed EXTERNAL to be accepted only if enabled. As originally implemented in 6774:bcb107bb89cd, it wasn't possible to disable the EXTERNAL authentication method: it was always accepted (but not advertised unless enabled). It is, however, believed that it is better to reject attempts to use the disabled method, hence in 6869:b2915d99ee8d an attempt was made to address this. This attempt was insufficient though: it was still possible to use the method as long as initial SASL response was used. With this patch both challenge-response and initial response forms are disabled. Additionally, initial response handling for the PLAIN authentication is removed from ngx_mail_auth_parse(), for consistency and to don't provoke such bugs.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_CRC_H_INCLUDED_
#define _NGX_CRC_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


/* 32-bit crc16 */

static ngx_inline uint32_t
ngx_crc(u_char *data, size_t len)
{
    uint32_t  sum;

    for (sum = 0; len; len--) {

        /*
         * gcc 2.95.2 x86 and icc 7.1.006 compile
         * that operator into the single "rol" opcode,
         * msvc 6.0sp2 compiles it into four opcodes.
         */
        sum = sum >> 1 | sum << 31;

        sum += *data++;
    }

    return sum;
}


#endif /* _NGX_CRC_H_INCLUDED_ */