Subject: Linux-Development Digest #163
From: Digestifier <Linux-Development-Request@senator-bedfellow.MIT.EDU>
To: Linux-Development@senator-bedfellow.MIT.EDU
Reply-To: Linux-Development@senator-bedfellow.MIT.EDU
Date:     Wed, 13 Oct 93 17:29:18 EDT

Linux-Development Digest #163, Volume #1         Wed, 13 Oct 93 17:29:18 EDT

Contents:
  set*id (Thomas Koenig)
  Re: The %&#$@ speaks again -or- An apology (Byron A Jeff)
  Scanner-Driver (Andreas Matthias)
  Re: adjtime() for Linux: tunable real time clock (time of day) (Philip Gladstone)
  Re: The %&#$@ speaks again -or- An apology
  Re: The %&#$@ speaks again -or- An apology (Aaron Barnhart)
  Re: Linux Slowly Dying Off? + Lets make a game for Linux (Grant Edwards)
  Re: Loopback mounts ? (Theodore Ts'o)
  Re: Questions Flamewar (Open letter to Ian Jackson) (Carl Schott)
  Solution to question/attitude problem... (Yves LACHANCE)
  Re: Questions are permitted on c.o.l.d (Jim Graham)
  Re: possible bug in virtual console switching (Olaf Schlueter)
  Re: The %&#$@ speaks again -or- An apology (marauder)

----------------------------------------------------------------------------

From: ig25@fg30.rz.uni-karlsruhe.de (Thomas Koenig)
Subject: set*id
Date: 13 Oct 1993 17:15:41 GMT

Both the BSD and the POSIX ways of dealing with setuid programs
and set*uid() calls are flawed; Linux implements both of them ;-)

It is good form for a suid root program to temporarily give up
its privileges, so errors in the program cannot threaten system
security.

BSD - style setreuid has the flaw that effective userid's are inherited
across exec() - calls; in other words, if the executable is somehow
tricked into exec()ing an untrusted program, bad things can happen.
The classic example of this was the fingerd bug which overran a
buffer and got a shell for its pains...

About POSIX - style setuid, to quote the kernel sources:

 * Note that SAVED_ID's is deficient in that a setuid root program
 * like sendmail, for example, cannot set its uid to be a normal
 * user and then switch back, because if you're root, setuid() sets
 * the saved uid too.  If you don't like this, blame the bright people
 * in the POSIX commmittee and/or USG.  Note that the BSD-style setreuid()
 * will allow a root program to temporarily drop privileges and be able to
 * regain them by swapping the real and effective uid.

Soo... what is there to do?

It would appear that HP has found a good solution for this; maybe it
would be a good idea for Linux, as well.  Here's what the HP-UX 8
manpages have to say:

      int setresuid(uid_t ruid, uid_t euid, uid_t suid);

      setresuid sets the real, effective and/or saved user ID of the calling
      process.

      If the current real, effective or saved user ID is equal to the
      super-user's user ID, setresuid sets the real, effective and saved
      user IDs to ruid, euid, and suid, respectively.  Otherwise, setresuid
      only sets the real, effective, and saved user IDs if ruid, euid, and
      suid each match at least one of the current real, effective, or saved
      user IDs.

      If ruid, euid, or suid is -1, setresuid leaves the current real,
      effective or saved user ID unchanged.

[equivalent for setgid etc...]

And the exec(2) manpage tells us:

      The saved-user-ID and saved-group-ID of the process are always set to
      the effective-user-ID and effective-group-ID, respectively, of the
      process at the end of the exec, whether or not set-user(group)-ID is
      in effect.

To my mind, this is a far better solution.  Suggestion:  use the HP way
for Linux and implement setuid() and setreuid() in terms of it for
people who need bug compatibility.

Comments, anybody?
-- 
Thomas Kvnig, ig25@rz.uni-karlsruhe.de, ig25@dkauni2.bitnet
The joy of engineering is to find a straight line on a double
logarithmic diagram.

------------------------------

Crossposted-To: comp.os.linux.misc
From: byron@cc.gatech.edu (Byron A Jeff)
Subject: Re: The %&#$@ speaks again -or- An apology
Date: Wed, 13 Oct 1993 17:17:40 GMT

BTW I'm following up to c.o.l.misc because this discussion doesn't belong
in c.o.l.d.

In article <CEuB7p.7pF@ra.nrl.navy.mil>,
Eric Youngdale <eric@tantalus.nrl.navy.mil> wrote:
>In article <dnebing-121093210959@m252-67.bgsu.edu> dnebing@andy.bgsu.edu (Dave Nebinger) writes:
>>  Who is to decide when a poster should be flamed or not?  I don't
>>want to start an argument (or get flamed myself), but there are
>>cases where one would say "enough is enough" and flame someone for
>>posting something which was ligitimate to them but dumb to anyone
>>else.
>
>       In my opinion, a poster should never be flamed for asking a stupid
>question, or asking someting in the wrong newsgroup.  Even if they start to
>flame themselves (i.e. they flame other people :-), a polite message asking
>them to take it elsewhere would probably be more effective.  If you have a hard
>time keeping a cool head when composing a response to these sorts of messages,
>then I suggest that you either not respond, or write a polite canned post of
>some kind that you send via email in these situations.  It will not only save
>you time, but your whole day will be more enjoyable, and the rest of us would
>be spared the ensuing flamewar.

Good idea. In fact I've started conducting a survey of why people post 
questions to anywhere but help. I do it by Email. It's in a neutral tone
and doesn't flame. I figure if we can find out why people post to where
they post we may be able to circumvent some of the misdirected questions.

>
>       Frankly, I am a little surprised that people are concerned about the
>bandwidth of c.o.l.d.  There are far fewer messages coming through here than
>there were on c.o.l before the split, and I find it quite easy to skip over the
>postings which I have no interest in.  Note that I do not have time to read any
>of the other c.o.l.* groups any more because of the enormous volume  (I do
>recognize that some people pay money for their newsfeed).

Well the issue is the fact that there is another forum specifically for
these other types of questions. I figure some newbies will always wander
into a group: That's no problem. It's our obligation to help them and to
point them to the correct spot. The problem is that every questions
generates 10 "me too"'s and a non development discussion. The solution
is not to post the answer but to send Email to the person saying they're
in the wrong place and directing them to the right place. Also for the
few that read before they post maybe a weekly posting of the "Welcome"
message might be appropriate.

Incidentally this is true of the admin group also.

>
>       Finally, some people have talked about the size of the FAQ and the
>difficulty in parsing it and so forth.  I guess I am somewhat sympathetic -
>given it's size, it would take quite a bit of paper to print out, and then the
>whole thing would have to be studied to locate the relevant section. I have the
>following suggestion to make:

Well the FAQ has really shrunk due to the HOWTO's (which seem to be regularly
posted to the announce newsgroup). So I don't think size is that much an 
issue.

>
>       Someone could develop a program which can be run interactively that
>will ask questions and take you through a series of menus.  This will in effect
>contain the information in the FAQ, and the FAQ could in fact be used as the
>database for this, but the idea is that there would be a sort of "expert
>system" that would guide you through the thing to the appropriate answers.
>Ideally there would be a way to cross-index different topics that on the
>surface may not seem related (and might be far from each other in the
>information tree), but in fact are relevant to each other.

How about gopher/xmosaic? The hypertext type format would suit this type
of indexing nicely. And the application is already available?

>
>       An info reader could in fact be a prototype for what I am suggesting -
>the information in the FAQ would just need to be rearranged to be used in this
>way, of course, but it is pretty close in principle to what would be needed.
>
>       This program could be set up to run in a captive anonymous telnet on
>some machines, or it could be set up to run on BBS systems.  It could be
>supplied with cdrom distributions, and depending upon the size of the database,
>it could be supplied with some floppy distributions.  It could even be
>downloaded and run on local systems (and even ported to DOS).  If done
>properly, this could become the first line of defense for the new-user types of
>questions.  The users would know that they can get instant, authoritative
>answers 24 hours a day from the expert system instead of waiting for the
>posting (and any subsequent responses) to filter through the various newsfeeds.
>

Excellent idea. Unfortunately I have no time to work on it.

Later,

BAJ
---
Another random extraction from the mental bit stream of...
Byron A. Jeff - PhD student operating in parallel!
Georgia Tech, Atlanta GA 30332   Internet: byron@cc.gatech.edu

------------------------------

Date: Tue, 12 Oct 93 22:40:30 +0100
From: Andreas_Matthias@p43.rollo.central.de (Andreas Matthias)
Subject: Scanner-Driver

Hi,

since nobody seems to be working on a non-SCSI-scanner driver I hereby 
announce that I began writing one. It will be a driver for Logitech ScanMan 
32 scanners, other types might follow if I succeed on the first one.

If anybody has ANY hints, infos, help, or code, please email.
If some people are already writing such a driver, please send a note, so we 
don't duplicate the effort.

Ciao,
Andreas


------------------------------

From: philip@charon.citicorp.com (Philip Gladstone)
Subject: Re: adjtime() for Linux: tunable real time clock (time of day)
Date: 13 Oct 1993 13:44:23 -0400
Reply-To: Philip.Gladstone@mail.citicorp.com

Torsten Duwe (duwe@immd4.informatik.uni-erlangen.de) wrote:

: Don't waste any more of your precious time on that task ! Philip Gladstone
: made a working port of xntp3 to Linux 0.99.11, which for some reason didn't
: make it into the standard distributions and unluckily became outdated due to
: changes in xntp's syscall interface, which ironically were inspired by
: Philip's port. 

The reason that all this didn't make it into the standard distribution 
was that I didn't know how to acheive this! Thanks to Torsten for his
help with this!

Philip
-- 
Philip Gladstone - Consultant
Citicorp Global Information Network
I don't speak for Citicorp. I presume that somebody else does!

------------------------------

Crossposted-To: news.groups
From: jwest@jwest.ecen.okstate.edu ()
Subject: Re: The %&#$@ speaks again -or- An apology
Date: Wed, 13 Oct 1993 18:25:59 GMT

>: >
>: >I've been flamed when I ask people to post the article to the correct
>: >group(s).  I've been flamed when I say what I know about the subject and
>: >then refer them to the FAQ (the HOWTOs).  The usual response is
>: >"I'm sicking tired of people telling me to read the FAQ."
>: >
>: >If people ask you to read the FAQ, don't take it as an insult.  Maybe the
>: >amount of people asking you to read the FAQ has something to do with the
>: >fact that you haven't read it thouroughly.
>

Several months ago when I first learned about Linux, I was flamed for
*reading* the FAQ (one of the FAQ's). First, I asked an FAQ on c.o.l (no
.* yet) because I didn't know what an FAQ was yet. I ignored the resulting
flames and followed the FAQ after that. A few days later I followed the
FAQ on something else, it didn't work, so I posted on c.o.l explaining the
situation. I got flamed because (something on the lines of) "Linux is a
dynamic OS so any idiot should know you can't trust the FAQ and you should
have looked around *all* the archive sights until you found such-and-such
document that explains the problem". Only the patient intervention of
Matt Welsh (ie direct email) kept me from telling the whole Linux community
to f*** off. (The documentation situation is much better now of course.)
No matter what a person does, it seems someone is going to take major
offense.

Lighten, up people. Life is too stressful as it is without amplifying
every little breach of net-conduct to catastrophic levels. In the scheme 
of things, posting to a wrong group is pretty trivial, and certainly not
worth raising your blood-pressure.

Flames will be gladly accepted, but most likely ignored, and I will have
a nice day despite it. (Follow-ups sent to c.o.l.m)

Jim

==========
Jim West
Associate Professor
Electrical and Computer Engineering
Oklahoma State University
jwest@master.ceat.okstate.edu

------------------------------

From: barnhart@Notwerk.mcs.com (Aaron Barnhart)
Crossposted-To: news.groups
Subject: Re: The %&#$@ speaks again -or- An apology
Date: 13 Oct 1993 14:31:40 -0500

rich@mulvey.com (Rich At Mulveycom) wrote:
:[in response to someone else who writes:]
:
:: So until such a facility comes into being, cut the newbies some slack, eh?
:
:No, we won't.  Being a newbie isn't a crime - there are lots of things
:that *I'm* a newbie at.  But I make a substantial effort to find the
:answers to my questions without bothering people.  And when I *do*
:encounter something that I'm lost about, then I post a *useful and
:complete* description of my problem, what I've tried, and what I think
:may be wrong.  The morons who post things like "My smail doesn't work.
:What do I do?" have no place in any of these groups, or in society as
:a whole, for that matter, until they learn how to not waste other
:people's time.  Flaming the hell out of them is a useful memory-enhancing
:technique that makes them think twice before asking stupid
:questions again.
:
:-- 
:Rich Mulvey                 Amateur Radio: N2VDS              Rochester, NY
:rich@mulvey.com         "Ignorance should be painful."

I would say at the rate you're going, Rich, ignorance will only
be painful for those who don't learn to work the kill file.  

Since the Net continues to grow at approximately 30% a month,
you can fairly expect to be "flaming the hell" out of a lot of
people .. and it will still be a losing game, because for every
one you thrill at sizzling to a crisp, there will be 200 others
who will continue to torment you with their stupidity and
ignorance ... until as I say they learn to hold the Control key
while pressing K.

I have a counterplan (as the future amateur-radio nuts used to
say when they did high-school debate).  IGNORE THE IGNORAMUSES.
Someone nice will give them the pointers to the FAQs and soon
they'll be posting well-educated "guess-tions" to these groups
and you won't answer them, either, I predict.  After all, what
fun is that?

--
Aaron Barnhart                                          Evanston, Ill.
aaron@barnhart.com      "Everyone should have their own node."

------------------------------

From: grante@aquarius.rosemount.com (Grant Edwards)
Subject: Re: Linux Slowly Dying Off? + Lets make a game for Linux
Date: Wed, 13 Oct 1993 19:17:22 GMT

Dale J. Chatham (dchatham@afit.af.mil) wrote:

[regarding MS Windows]

: It may old, it may be clunky, it may be techically inferior.  However, in
: the real, non-academic world, folks actually do very useful stuff with
: the piece of refuse!

He's right folks.  In the real world, lots (and I mean LOTS) of work
gets done using MS Windows.

: Gotta give the devil his due.  Gates was there first with the only solution
: to the problem that most could afford!

Remeber, the market doesn't go to the best solution, it goes to the
first one that's just barely good enough.

--
Grant Edwards                                 |Yow!  My vaseline is
Rosemount Inc.                                |RUNNING...
                                              |
grante@rosemount.com                          |

------------------------------

From: tytso@athena.mit.edu (Theodore Ts'o)
Subject: Re: Loopback mounts ?
Date: 13 Oct 1993 16:10:56 -0400
Reply-To: tytso@athena.mit.edu (Theodore Ts'o)

   From: byron@cc.gatech.edu (Byron A Jeff)
   Date: Wed, 13 Oct 1993 13:23:55 GMT

   In article <1993Oct13.085812.775@cs.utwente.nl>,
   Steef S.G. de Bruijn <debruijn@cs.utwente.nl> wrote:
   >hm@ix.de wrote:
   >: Subject says all -- is anybody working on the implementation
   >: of loopback mounts?
   >
   >What are you talking about?  Loopback is standard in the network
   >stuff (I thought). At least, I can telnet and FTP to myself.
   >Am I missing the point now, or is your question answered?

   You're missing the point. At one point in time there was a patch that
   allowed you to mount a regular file as a filesystem. But I'm sure it
   needs to be updated.

TSX-11:/pub/linux/BETA/loop

It's set up so that you make a file or another device appear as a block
device, which you can then mount.  It can be set up to mount the file or
device with an optional offset, if desired, and you can also make the
data pass through an encryption/decryption layer as well.  

The code was originally writen by myself, but I've since turned it over
to Warner Almesberger to maintian.  Since it's structured as a block
device driver, it shouldn't require much updating for newer versions of
the kernel. 

                                                - Ted


------------------------------

From: carl@news.cac.psu.edu (Carl Schott)
Crossposted-To: comp.os.linux.misc
Subject: Re: Questions Flamewar (Open letter to Ian Jackson)
Date: 13 Oct 1993 20:30:58 GMT
Reply-To: cgs103@psu.edu


Well, I tried to stay out of this but this last attack was just too
much...

Ian, can't you see that your "solution" to the signal-to-noise problem
is worse than the original problem?  Your weekly posts are a service to the
group, but public name-calling only incites these flame wars!  If you can't 
be more polite than this in your posts, please don't post.

I don't condone what Mr. Peoples and Mr. Lukka did, but your last post
is equally offensive.  Mr. Peoples apologized, and you responded with
yet another round of insults and name-calling!  If you're half the man
he is you'll issue a public apology IMMEDIATELY and refrain from this activity
in the future.

Let's try to keep all of this in perspective--looking at traffic on my
news host, c.o.l.d has the second lowest number of postings in the Linux
hierarchy (second to .announce).  So it seems to me that for the most
part people ARE refraining from posting to this group.  There will
always be some signal-to-noise problem--let's all accept that and learn to live
and let live.  I have very much enjoyed reading the developers' posts in this
group--it's a great way to learn about Linux architecture and internals.
I'd hate to see that discussion end over something as silly as this.

Yes, I cross-posted! (so sue me!)  This has already gone on far too long,
and moving the discussion to another group won't help.  The best way to
end it is for you to apologize for your part of it, Ian.

Carl Schott







------------------------------

From: yveslach@binkley.cs.mcgill.ca (Yves LACHANCE)
Subject: Solution to question/attitude problem...
Date: 13 Oct 1993 19:52:59 GMT

A brief note to:

1) mention that I posted a message in the The %&#$@ speaks again -or- An
apology thread moved to c.o.l.misc (where it probably belongs) and it might
have an important impact on the number of questions already answered in
FAQs in the newsgroups, especially where they don't belong.

2) humbly suggest that all the threads related to "this issue" be
(rightfully?) moved to c.o.l.misc.

------------------------------

From: jim@n5ial.mythical.com (Jim Graham)
Subject: Re: Questions are permitted on c.o.l.d
Date: Wed, 13 Oct 1993 02:08:50 GMT

In article <1993Oct11.082019.11571@hip-hop.suvl.ca.us>
remco@hip-hop.suvl.ca.us (Remco Treffkorn) writes:

>I think we are all idiots, because we swallowed the flame bait.

I didn't....I just put him in the same file as the other people who
deliberately try to start a flame-war with stupid, childish posts.  This
file has a rather appropriate name:  'KILL'.  But then, why am I reading
this thread?  Beats me...I guess I'm just bored (waiting for ftpmail to
get around to sending me the epson DVI driver, eps033, so I can get on
with moving TeX off of the dog partition)....  :-)

IMHO, that's the best way to handle those types...just ignore them---they
eventually get bored, and try to harass another newsgroup.  And since I'm
way off-topic with this post, myself, I think I'll leave it at that!  :-)

Later,
   --jim

--
#include <std_disclaimer.h>                                  73 DE N5IAL (/4)
=========================< Running Linux 0.99 PL10 >==========================
INTERNET: jim@n5ial.mythical.com  |  j.graham@ieee.org     ICBM: 30.23N 86.32W
AMATEUR RADIO:  (packet station temporarily offline)       AMTOR SELCAL: NIAL
==============================================================================
E-mail me for information about KAMterm (host mode for Kantronics TNCs).


------------------------------

From: olaf@toppoint.de (Olaf Schlueter)
Subject: Re: possible bug in virtual console switching
Date: 13 Oct 1993 20:28:00 +0100

joel@rac2.wam.umd.edu (Joel M. Hoffman) writes:

>In article <29c2o5$dfi@klaava.Helsinki.FI> kankkune@cs.Helsinki.FI (Risto Kankkunen) writes:
>>There was a bug in the keyboard driver that made it confuse the state of
>>modifier keys when switching between raw and nonraw consoles. I thought
>>that was fixed in pl13, at least a patch for that was sent to Linus. (I
>>can't currently verify that with dosemu or X, I don't have a working
>>version of them installed.)


>Well, I'm running pl12, so that would make sense.  Can anyone confirm
>(or deny) that the bug was fixed in pl13?

The bug is still in pl13. I'm using loadkeys 0.81. 
-- 
Olaf Schl|ter, Sandkuhle 4-6, 24103 Kiel, Germany, Toppoint Mailbox e.V.
"MSDOS didn't get as bad as it is overnight -- it took over ten years
of careful development."                                David Megginson


------------------------------

Crossposted-To: news.groups
From: marauder@netsys.com (marauder)
Subject: Re: The %&#$@ speaks again -or- An apology
Date: Wed, 13 Oct 1993 21:17:45 GMT


: No, we won't.  Being a newbie isn't a crime - there are lots of things
: that *I'm* a newbie at.  But I make a substantial effort to find the
: answers to my questions without bothering people.  And when I *do*
: encounter something that I'm lost about, then I post a *useful and
: complete* description of my problem, what I've tried, and what I think
: may be wrong.  The morons who post things like "My smail doesn't work.
: What do I do?" have no place in any of these groups, or in society as
: a whole, for that matter, until they learn how to not waste other
: people's time.  Flaming the hell out of them is a useful memory-enhancing
: technique that makes them think twice before asking stupid
: questions again.

: - Rich

: -- 
: Rich Mulvey                 Amateur Radio: N2VDS              Rochester, NY
: rich@mulvey.com         "Ignorance should be painful."

Richard, 

That has got to be the lamest attempt at rationalizing a stupid activity as I
think I've seen, and Ive been at this little telecom game a long time. If it
makes you feel important, and superior to "flame the hell" out of a new user,
fine, but please do us the favour of admitting to the tru motivation for your
measly activity. In short Rich, grow up.

Marauder
Legion of Doom! (ret)
(todd)

------------------------------


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