Re: [exim] demime -> acl_smtp_mime

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Autore: Lena
Data:  
To: exim-users
Oggetto: Re: [exim] demime -> acl_smtp_mime
> From: Marco Gaiarin <gaio@???>

> but a condition like:
>
>   deny
>     message = Serious MIME defect detected ($demime_reason)
>     demime = *
>     condition = ${if >{$demime_errorlevel}{2}{1}{0}}

>
> how can be converted in 'acl_smtp_mime' lingo?


No way I think. I'm curious: how often did you see messages triggering
this rejection?

More elaborate checks:

P7ZIP = /usr/local/bin/7z
# port archivers/p7zip in case of FreeBSD
GREP = /usr/bin/grep
SHELL = /bin/sh
BINFORBIDDEN = Windows-executable attachments forbidden
WINBIN = exe|com|js|pif|scr|bat|jse|cpl|vbe|vbs|ace
# more cautious: exe|com|js|pif|scr|bat|flv|reg|btm|chm|cmd|cpl|dat|dll|hta|jse|jsp|lnk|msi|prf|sys|vb|vbe|vbs|ace
# WinRAR can uncompress .ace, so trojans are sometimes compressed .ace
# Perhaps "jar" should be added.
COMPREXT = zip|rar|7z|arj|bz2|gz|uue|xz|z|tar
check_rfc2047_length = false
acl_smtp_mime = acl_check_mime

begin acl
acl_check_mime:
  deny message = BINFORBIDDEN
       log_message = forbidden attachment: filename=$mime_filename, \
                     content-type=$mime_content_type, recipients=$recipients
       condition = ${if or{\
        {match{$mime_content_type}\
              {(?i)executable|application/x-ace-compressed}}\
        {match{$mime_filename}{\N(?i)\.(WINBIN)(\.(COMPREXT))*$\N}}\
                          }}


  deny message = Compressed BINFORBIDDEN
       condition = ${if or{\
                           {match{$mime_content_type}{(?i)application/\
                                     (octet-stream|x(-zip)?-compressed|zip)}}\
                           {match{$mime_filename}{\N(?i)\.(COMPREXT)$\N}}\
                          }}
       condition = ${if <{$message_size}{1500K}}
       decode = default
       log_message = forbidden binary in attachment: filename=$mime_filename, \
                     recipients=$recipients
       condition = ${if match{${run{P7ZIP l -y $mime_decoded_filename}}}\
                             {\N(?i)\n[12].+\.(COMPREXT|WINBIN)\n\N}}


  deny message = Windows-executable inside an Office file attachment
       condition = ${if or{\
         {match{$mime_content_type}{(?i)openxmlformats-officedocument}}\
         {match{$mime_filename}{\N(?i)\.(doc|xls|ppt)(x|m)$\N}}\
                          }}
       decode = default
       log_message = forbidden binary in Office file attachment: \
                     filename=$mime_filename, recipients=$recipients
       set acl_m_ud = ${sg{$mime_decoded_filename}{[^/]+\$}{}}
       condition = ${run{SHELL -c \
         "cd $acl_m_ud; \
          P7ZIP x -y $mime_decoded_filename; \
          GREP -r -a -s -E \
           'rundll32|This program cannot be run in DOS mode|\
            This program must be run under|Embedded Object|\
            WScript\\.Sh|Shell\\.Application|Location: file:' \
           $acl_m_ud"}{1}{0}}


accept