Author: branden Date: 2004-10-15 11:36:01 -0500 (Fri, 15 Oct 2004) New Revision: 1954
Modified: trunk/debian/CHANGESETS trunk/debian/changelog trunk/debian/local/FAQ.xhtml Log: Add FAQ entry: Sometimes I get garbage characters like 1;2c in my xterm windows; what's happening? Modified: trunk/debian/CHANGESETS =================================================================== --- trunk/debian/CHANGESETS 2004-10-13 17:39:17 UTC (rev 1953) +++ trunk/debian/CHANGESETS 2004-10-15 16:36:01 UTC (rev 1954) @@ -142,4 +142,8 @@ XFree86? 1948, 1949 +Add FAQ entry: Sometimes I get garbage characters like 1;2c in my xterm +windows; what's happening? + 1954 + vim:set ai et sts=4 sw=4 tw=80: Modified: trunk/debian/changelog =================================================================== --- trunk/debian/changelog 2004-10-13 17:39:17 UTC (rev 1953) +++ trunk/debian/changelog 2004-10-15 16:36:01 UTC (rev 1954) @@ -51,6 +51,9 @@ * Add FAQ entry: What are Debian's plans with respect to X.Org and XFree86? + * Add FAQ entry: Sometimes I get garbage characters like 1;2c in my xterm + windows; what's happening? + Changes by Denis Barbier and Fabio M. Di Nitto: * Edit xc/programs/xkbcomp/symbols/pc/Imakefile so that the new pc/us_intl @@ -121,7 +124,7 @@ + Set UseBios default to "no" for PROSAVAGE_DDR and PROSAVAGE_DDRK, as described at <URL: http://www.probo.com/timr/savage40.html >. - -- Branden Robinson <[EMAIL PROTECTED]> Tue, 12 Oct 2004 13:32:51 -0500 + -- Branden Robinson <[EMAIL PROTECTED]> Fri, 15 Oct 2004 11:34:49 -0500 xfree86 (4.3.0.dfsg.1-8) unstable; urgency=high Modified: trunk/debian/local/FAQ.xhtml =================================================================== --- trunk/debian/local/FAQ.xhtml 2004-10-13 17:39:17 UTC (rev 1953) +++ trunk/debian/local/FAQ.xhtml 2004-10-15 16:36:01 UTC (rev 1954) @@ -158,6 +158,9 @@ why is it messed up now?</a></li> <li><a href="#composeinput">Why does composing characters work in some applications but not others?</a></li> +<li><a href="#xtermresizenoise">Sometimes I get garbage characters like + <code class="other">1;2c</code> in my <code class="command">xterm</code> + windows; what's happening?</a></li> </ul> <h2><a href="#acknowledgements">Acknowledgements</a></h2> @@ -3035,6 +3038,50 @@ class="filespec">.profile</code>, <code class="filespec">.bashrc</code>, or whatever your shell uses as an initialization file.</p> +<h3><a id="xtermresizenoise">Sometimes I get garbage characters like + <code class="other">1;2c</code> in my <code class="command">xterm</code> + windows; what's happening?</a></h3> + +<p><em>Thanks to Thomas Dickey for contributing much of this entry.</em></p> + +<p>Occasionally people are concerned that this is a security problem — +they fear that some rogue application may be trying to inject keystrokes at +their shell prompt, for example. While <code class="command">xterm</code> and +other terminal emulators have had bugs like that in the past (see <a +href="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0063">MITRE's CVE +candidate CAN-2003-0063</a>), this is not such a situation.</p> + +<p>What you're seeing is part of the VT100 escape sequence that uses the cursor +position of the lower-right corner to determine the screen size. You're only +seeing part of it because the "wrong" application had eaten part of the +response. (I get that sort of thing if I log into certain machines from the +FreeBSD console — it doesn't respond as a VT100 would).</p> + +<p>Normally I'd see this only due to a misconfiguration and/or combination with +a timeout. It's annoying but relatively harmless. It's not like the answerback +or title strings — the response is determined by the terminal geometry and +can't contain arbitrary text.</p> + +<p>If <code class="command">resize</code> cannot get useful information by a +system call, it positions the cursor far right/down, and then asks the terminal +where it really got to. Real VT100 terminals won't wrap when positioning the +cursor to (999,999), but will just move it in that direction until it +stops<sup>*</sup>.</p> + +<p>The response looks like:</p> + +<p><code class="other">ESC [ <em>row</em> ; <em>column</em> R</code></p> + +<p>where <em>row</em> and <em>column</em> are positive decimal integers. If one +is in the habit of filling up their <code class="filespec">bin</code> directory +with malicious scripts named <code class="filespec">79R</code>, <code +class="filespec">80R</code>, etc., that could be a problem — but I think +it's a fairly low probability.</p> + +<p><sup>*</sup> Some day I'll see a bug report from someone who's got a +1200x1200 <code class="command">xterm</code>, and (with a script of course), +they'll determine that resize doesn't give the correct result.</p> + <h2><a id="acknowledgements">Acknowledgements</a></h2> <p>The author would like to thank Andreas Metzler, Guillem Jover, Ingo Saitz,