9fans - fans of the OS Plan 9 from Bell Labs
 help / color / mirror / Atom feed
From: Mike Haertel <mike@ducky.net>
To: 9fans@cse.psu.edu
Subject: [9fans] authentication protocol question
Date: Thu,  1 Nov 2001 10:57:09 -0800	[thread overview]
Message-ID: <200111011857.fA1Iv9701688@ducky.net> (raw)

I am puzzled by the following code in /sys/src/fs/port/auth.c.

	/*
	 *  the id must be in a valid range.  the range is specified by a
	 *  lower bount (idoffset) and a bit vector (idvec) where a
	 *  bit set to 1 means unusable
	 */
	lock(&cp->idlock);
	x = a.id - cp->idoffset;
	bit = 1<<x;
	if(x < 0 || x > 31 || (bit&cp->idvec)){
		unlock(&cp->idlock);
print("id out of range: idoff %ld idvec %lux id %ld\n", cp->idoffset, cp->idvec, a.id);
		return 0;
	}
	cp->idvec |= bit;

 From the auth(6) man page, I had the impression that the id
field was supposed to be a simple sequence number.  Is there a
race in some client in which the order of the sequence numbers
can get rearranged?  What is the race?


             reply	other threads:[~2001-11-01 18:57 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-11-01 18:57 Mike Haertel [this message]
2001-11-01 19:01 presotto

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=200111011857.fA1Iv9701688@ducky.net \
    --to=mike@ducky.net \
    --cc=9fans@cse.psu.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).