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Moses Moore
Asked: 2023-03-20 21:41:34 +0800 CST

筛选规则以匹配原始标头值

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这在 procmail 中有效，但似乎 procmail在 2001 年 9 月被放弃了。当在“收件人：”标头中使用 utf-8 来使用表情符号或非拉丁字符写我的名字时，我有一个规则可以感知。当我在 Dovecot 的 Sieve 实现“Pigeonhole”中尝试同样的操作时，我很沮丧，因为它似乎丢弃了一些数据。

参考。RFC5228 参考中的筛选规则
。Dovecot Pigeonhole 实施

我尝试了什么：

require ["fileinto"];
if header :contains ["to", "from"] "=?utf-8?B?" {   fileinto "Junk"; }
elsif address :contains :all ["to", "from"] "=?utf-8?B?" {   fileinto "Junk"; }

使用此示例数据：

From: "=?utf-8?B?TWluaSBXdQ==?=" <[email protected]>
To: "=?utf-8?B?Q1VTVA==?=" <[email protected]>
Subject: =?utf-8?B?UmU6TWljcm9jaGlwIFRleGFzIE9mZmVy?=
Date: Mon, 20 Mar 2023 16:12:50 +0900

Hello potential customer! Please stop whatever you're
doing and pay attention to me!

我得到什么：

sieve-test -Tlevel=matching -t - /tmp/badmail.sieve /tmp/badmail.txt

      ## Started executing script 'badmail'
   2: header test
   2:   starting `:contains' match with `i;ascii-casemap' comparator:
   2:   extracting `to' headers from message
   2:   matching value `"CUST" <[email protected]>'
   2:     with key `=?utf-8?B?' => 0
   2:   extracting `from' headers from message
   2:   matching value `"Mini Wu" <[email protected]>'
   2:     with key `=?utf-8?B?' => 0
   2:   finishing match with result: not matched
   2: jump if result is false
   2:   jumping to line 3
   3: address test
   3:   starting `:contains' match with `i;ascii-casemap' comparator:
   3:   extracting `to' headers from message
   3:   parsing address header value `"=?utf-8?B?Q1VTVA==?=" <[email protected]>'
   3:   address value `[email protected]'
   3:   extracting `all' part from address <[email protected]>
   3:   matching value `[email protected]'
   3:     with key `=?utf-8?B?' => 0
   3:   extracting `from' headers from message
   3:   parsing address header value `"=?utf-8?B?TWluaSBXdQ==?=" <[email protected]>'
   3:   address value `[email protected]'
   3:   extracting `all' part from address <[email protected]>
   3:   matching value `[email protected]'
   3:     with key `=?utf-8?B?' => 0
   3:   finishing match with result: not matched
   3: jump if result is false
   3:   jumping to line 3
      ## Finished executing script 'badmail'

Implicit keep:  store message in folder: INBOX

它在跟踪输出中记录了“=?utf-8?B?...”，所以我知道它知道。但是 'header' 测试和 'address' 测试都在执行之前丢弃了该数据。我还尝试了:comparator "i;octet"而不是默认的“i;ascii-casemap”，结果相同。

我如何测试原始标头而不是这些解释值？

dovecot

1 个回答

  1. Best Answer

    所以..您实际上并不是要区分“表情符号或非拉丁字符”，而是要区分‡字符如何在线上传输的细节？

    我想不出让 Sieve 返回原始字节的方法。您可以通过在邮件服务器中进行匹配来解决问题，例如使用 Postfix (RFC2047-ignorant) header_checks 功能来添加自定义标头，例如

    # header_checks = pcre:/etc/postfix/maps/remember_header_encoding
#  pcre is case insensitive by default
/^To:.*=\?utf-8\?B\?/   PREPEND X-Preserve-For-Sieve: RFC2047 marker in header To:

    然后检查 sieve 中是否存在此类标记头。

    即使是今天，我怀疑整个事情在可预见的未来是否会成为可靠的分类标准。一个中继 SMTP 服务器，直到并包括传递给 sieve 的服务器，可能会在以前没有作为消息转换的一部分的地方添加编码。一些邮件客户端会在不需要的地方添加编码，而其他邮件客户端即使应该这样做也不会这样做。检测无意间的差异可能不会静态地影响相同类型的消息。

    ‡ 普通邮件很少有多余编码以外的选择 - Dovecot 还不能保证 8 位干净的传输，例如 SMTPUTF8

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