Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!think.com!snorkelwacker.mit.edu!ira.uka.de!smurf!urlichs From: urlichs@smurf.sub.org (Matthias Urlichs) Newsgroups: comp.unix.aux Subject: Re: problems with cu Message-ID: Date: 12 Jun 91 03:19:20 GMT References: <1599@ucl-cs.uucp> Organization: University of Karlsruhe, FRG Lines: 36 In comp.unix.aux, article <1599@ucl-cs.uucp>, J.Purchase@cs.ucl.ac.uk (Jan Purchase) writes: < < Firstly, I have been advised that it is good practice to prevent the < uucp spool directory from being world writable. So I made it mode 775: < drwxrwxr-x 3 uucp uucp 512 Jun 10 18:25 /usr/spool/uucp < (A/UX 2.0.1 standard is mode 777). Now however, when disconnecting < from a cu session (as a non privileged user), I get the message: < Can't unlink lock-file cu wisely revverts to the privileges of the real user after creating that lock file. This is not a problem. < The lock file, /usr/spool/uucp/LCK..*, is owned by root with mode 400. < It was created by cu (which runs setuid root), so why can't it be < unlinked by cu? Oddly, the problem does not occur if I run cu as root < (or uucp). Equally oddly, the lock file does *not* stop cu from < opening other sessions on the same device! It does, however stop < kermit, which is very inconvenient. < The lock file contains the process ID (as a longint -- that's why it's four bytes big). If the process in question doesn't exist, the lock file is removed. This method is not 100% failsafe because process IDs get reused after a while. It would be much better if A/UX used a more modern version of UUCP, preferably one which uses /usr/spool/lock or something like that -- the directory name should be of the same length so that older programs can be binary-patched if necessary. That way, the lock directory can be made mode 0777 without compromising anything. Another problem with the stock A/UX Kermit is that it can't talk at 19200 baud. -- Matthias Urlichs -- urlichs@smurf.sub.org -- urlichs@smurf.ira.uka.de /(o\ Humboldtstrasse 7 - 7500 Karlsruhe 1 - FRG -- +49-721-621127(0700-2330) \o)/