Date: Thu, 6 Apr 1995 10:50:10 -0600 (MDT) From: mbarkah@teton.Mines.Colorado.EDU (Ade Barkah) To: joerg_wunsch@uriah.heep.sax.de Cc: freebsd-hackers@FreeBSD.org, ports@FreeBSD.org Subject: Re: lsof 3.25 now available for fbsd 2.0 Message-ID: <9504061650.AA42466@teton.Mines.Colorado.EDU>
next in thread | raw e-mail | index | archive | help
J Wunsch wrote: >> ... The version uploaded was compiled with -DHASSECURITY which >> restricts non-priviledged users from listing other people's open >> files. ... > > Does this make sense? I'm perfectly able to look at any open file > with fstat(1). So why restrict lsof to less than fstat can do? Well, lsof is capable in displaying much more than fstat by default, to the point that other user's privacy might be invaded, so I decided to restrict the output. `lsof' uses the kernel name cache to get the file name associated with an open descriptor (if any). fstat, on the other hand, limits itself to the mountpoint of the file unless you specifically give the file name as an argument. For example, here are two lines from fstat about me and my vi editor: | mbarkah vi 10325 3 /usr2 3920 -rw-rw-r-- 0 r | mbarkah vi 10325 5 /tmp 4 -rw------- 0 rw However, here are the corresponding output from `lsof': | vi 10325 mbarkah 3rW VREG 4, 13 0 3920 /usr2 -- | m/mbarkah/verypersonalfile | | vi 10325 mbarkah 4u VREG 4, 0 0 7834 / -- | var/tmp/vi.recover/vi.010325 Notice that lsof actually shows which file I'm editing, whereas fstat has no such information. Another example.... here's what fstat shows about my working directory: | mbarkah csh 10126 wd /usr 92285 drwxrwxr-x 512 r `lsof' goes further than displaying only the /usr mountpoint: | csh 10126 mbarkah cwd VDIR 4, 12 512 92285 /usr -- | src/sys and it shows my working directory to be /usr/src/sys. Without the HASSECURITY option, any user on the system can too easily spy on another user, watching exactly what processes he is running and which files he is working on, his current directory, network connections, etc., and I'm not sure this is what most people want. However, I'd be happy to replace the current version with a lenient version if the net so desires. Since lsof is setgid, people should compile their own anyhow, rather than trusting (the possibly evil) me. =) Regards, -Ade Barkah
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9504061650.AA42466>