From remailer-operators-owner-usura=replay.com@anon.lcs.mit.edu  Sat Feb 22 00:37:29 1997
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Date: Fri, 21 Feb 1997 19:00:05 -0500 (EST)
From: "Mark M." <markm@voicenet.com>
To: remailer-operators@anon.lcs.mit.edu, Jeff Burchell <toxic@hotwired.com>
Subject: Re: Blocking From: headers.
In-Reply-To: <3.0.32.19970220191912.009c5a60@get.hotwired.com>
Message-ID: <Pine.LNX.3.95.970221185036.1408A-100000@purple.voicenet.com>
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Status: OR

On Thu, 20 Feb 1997, Jeff Burchell wrote:

> I'd like to tell huge.cajones not to allow the pasting of From: headers (or
> possibly convert them to X-Might-Be-From:).  Unfortunately, I'm not a C
> coder.  So, if there's someone out there who is,  can you tell me what I
> need to put in the following chunk of code to do this?

The following will completely prevent the pasting of "From:" lines:

  /* Paste in ## headers if present */
  if(input[0]=='#'&&input[1]=='#') {
   /* Kill Reply-To lines with blocked addresses to prevent
      mailbombs via alt.test */
    while(fgets(input,255,infile)>0&&input[0]>31) {
      if ((input[0]=='R'||input[0]=='r')&&input[1]=='e'&&input[2]=='p') {
        block_addr(input,BLOCKTO);if (input[0]!=0)
fprintf(outfile,"%s",input);
      /* Block ## pasted Newsgroups: */
      }else
if((input[0]|32=='n')&&input[1]=='e'&&input[2]=='w'&&input[3]=='s')
      {
        block_addr(input,BLOCKTO);if (input[0]!=0)
fprintf(outfile,"%s",input);
      }else
      if(input[0]=='F'&&input[1]=='r'&&input[2]=='o'&&input[3]=='m') {
        /* nothing */
      }else fprintf(outfile,"%s",input);
    }
    fprintf(outfile,"\n");
  }else{
    fprintf(outfile,"\n%s",input);
    if(replykey[0]>0&&input[0]=='*'&&input[1]=='*') {
      reencrypt();
    }
  }

Here's the cooresponding patch:

*** remailer.c.orig	Fri Feb 21 18:52:19 1997
--- remailer.c	Fri Feb 21 18:54:55 1997
***************
*** 802,812 ****
        mailbombs via alt.test */
      while(fgets(input,255,infile)>0&&input[0]>31) {
        if ((input[0]=='R'||input[0]=='r')&&input[1]=='e'&&input[2]=='p') {
!         block_addr(input,BLOCKTO);if (input[0]!=0) fprintf(outfile,"%s",input);
        /* Block ## pasted Newsgroups: */
!       }else if((input[0]|32=='n')&&input[1]=='e'&&input[2]=='w'&&input[3]=='s')
        {
!         block_addr(input,BLOCKTO);if (input[0]!=0) fprintf(outfile,"%s",input);
        }else fprintf(outfile,"%s",input);
      }
      fprintf(outfile,"\n");
--- 802,818 ----
        mailbombs via alt.test */
      while(fgets(input,255,infile)>0&&input[0]>31) {
        if ((input[0]=='R'||input[0]=='r')&&input[1]=='e'&&input[2]=='p') {
!         block_addr(input,BLOCKTO);if (input[0]!=0)
! fprintf(outfile,"%s",input);
        /* Block ## pasted Newsgroups: */
!       }else
! if((input[0]|32=='n')&&input[1]=='e'&&input[2]=='w'&&input[3]=='s')
        {
!         block_addr(input,BLOCKTO);if (input[0]!=0)
! fprintf(outfile,"%s",input);
!       }else
!       if(input[0]=='F'&&input[1]=='r'&&input[2]=='o'&&input[3]=='m') {
!         /* nothing */
        }else fprintf(outfile,"%s",input);
      }
      fprintf(outfile,"\n");


Mark