Bug#1110769: xterm: segfault in ScrnWriteText on 3-byte binary data

[Vincent Lefevre <vincent@vinc17.net>]

On 2025-08-11 01:09:26 +0200, Vincent Lefevre wrote:
> I've just noticed that it is very easy to make xterm crash with
> some binary data:
> 
>   /usr/bin/xterm -e 'printf "\x9a\x85\x08"; sleep 2'

Something important: this depends on the xterm settings.
One needs the following in the XTerm resources:

*allowC1Printable:  true
*VT100.reverseWrap: true

/usr/share/doc/xterm/ctlseqs.txt.gz says

ESC E
     Next Line (NEL  is 0x85).

ESC Z
     Return Terminal ID (DECID is 0x9a).  Obsolete form of CSI c  (DA).

So, to restrict to ASCII:

  /usr/bin/xterm -e 'printf "\eZ\n\x08"; sleep 2'

which still makes xterm segfault. And with this one, one just needs

*VT100.reverseWrap: true

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Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
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