On 2025-10-31 21:31:32 +0000, David wrote: > On Fri, 31 Oct 2025 at 17:43, Vincent Lefevre <[email protected]> wrote: > > And one can make xterm on trixie (not that old) crash: > > > xterm -k8 -e 'printf "\x9a\x85\x08"; sleep 2' > > Thanks for the runnable demo! [...] > When I copied and pasted the above into vim to write this message, I can > see that the 'echo *' did output the bytes <9a><85>. I guess there might > have also been a bell <08> that I did not hear (for whatever reason, that's > not important).
It is the bell character, but it ends an escape sequence, i.e. it has a special meaning. > But the xterm did not crash, it continued to function. Not sure whether you did it right, but to make the crash occurs depends on the context. > So that made your demo less convincing to me, I was hoping it would crash. > > Do you have a better example? Perhaps something like an escape sequence to clear the screen first (just before the \x9a\x85\x08). I have not tried. > Why did you choose the bytes \x9a\x85\x08 ? The bug initially occurred when I ran a command generating binary data for which I forgot to redirect the output to a file. The file was initially huge (several MB, IIRC). Then I tried to get a minimal example. To make things easier, I did my tests with something like xterm -e 'cat file' (the -k8 is not needed for me since this is from my default config via X resources -- I had added it in 2005 for more security, at the time ISO-8859-1 was still in use, to prevent the characters 128-159 from being regarded as control characters). I think that the "sleep 2" was not needed initially because there were additional characters from the file that were introducing the needed delay. In a text editor, I reduced the file with some form of dichotomy, and eventually obtained a file reduced to the above 3 characters. -- Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / Pascaline project (LIP, ENS-Lyon)
