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author | Thomas Schwinge <thomas@codesourcery.com> | 2012-05-24 23:08:09 +0200 |
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committer | Thomas Schwinge <thomas@codesourcery.com> | 2012-05-24 23:08:09 +0200 |
commit | 2910b7c5b1d55bc304344b584a25ea571a9075fb (patch) | |
tree | bfbfbc98d4c0e205d2726fa44170a16e8421855e /hurd/translator/procfs | |
parent | 35b719f54c96778f571984065579625bc9f15bf5 (diff) |
Prepare toolchain/logs/master branch.
Diffstat (limited to 'hurd/translator/procfs')
-rw-r--r-- | hurd/translator/procfs/jkoenig.mdwn | 23 | ||||
-rw-r--r-- | hurd/translator/procfs/jkoenig/discussion.mdwn | 220 |
2 files changed, 0 insertions, 243 deletions
diff --git a/hurd/translator/procfs/jkoenig.mdwn b/hurd/translator/procfs/jkoenig.mdwn deleted file mode 100644 index 9543b658..00000000 --- a/hurd/translator/procfs/jkoenig.mdwn +++ /dev/null @@ -1,23 +0,0 @@ -[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]] - -[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable -id="license" text="Permission is granted to copy, distribute and/or modify this -document under the terms of the GNU Free Documentation License, Version 1.2 or -any later version published by the Free Software Foundation; with no Invariant -Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license -is included in the section entitled [[GNU Free Documentation -License|/fdl]]."]]"""]] - -In August 2010, Jérémie Koenig [published another, new -version](http://lists.gnu.org/archive/html/bug-hurd/2010-08/msg00165.html). -This can be found in <http://git.savannah.gnu.org/cgit/hurd/procfs.git/>, -branch *jkoenig/master*. - -Testing it is as simple as this: - - $ git clone git://git.savannah.gnu.org/hurd/procfs.git - $ cd procfs/ - $ git checkout jkoenig/master - $ make - $ settrans -ca proc procfs --compatible - $ ls -l proc/ diff --git a/hurd/translator/procfs/jkoenig/discussion.mdwn b/hurd/translator/procfs/jkoenig/discussion.mdwn deleted file mode 100644 index 339fab50..00000000 --- a/hurd/translator/procfs/jkoenig/discussion.mdwn +++ /dev/null @@ -1,220 +0,0 @@ -[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]] - -[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable -id="license" text="Permission is granted to copy, distribute and/or modify this -document under the terms of the GNU Free Documentation License, Version 1.2 or -any later version published by the Free Software Foundation; with no Invariant -Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license -is included in the section entitled [[GNU Free Documentation -License|/fdl]]."]]"""]] - -[[!tag open_issue_hurd]] - -[[!toc]] - - -# Miscellaneous - -IRC, #hurd, around September 2010 - - <youpi> jkoenig: from a quick read, your procfs implementation seems quite - simple, probably much more what I was expecting from Madhusudan (who - probably now hates you :) ) - <youpi> jkoenig: is it not possible to provide a /proc/self which points at - the client's pid? - <pinotree> (also, shouldn't /proc/version say something else than "Linux"?) - <youpi> to make linux tools work, no :/ - <youpi> kfreebsd does that too - <pinotree> really? - <youpi> yes - <youpi> (kfreebsd, not freebsd) - <pinotree> does kbsd's one print just "Linux version x.y.z" too, or - something more eg in a second line? - <pinotree> (as curiosity) - <youpi> % cat /proc/version - <youpi> Linux version 2.6.16 (des@freebsd.org) (gcc version 4.3.5) #4 Sun - Dec 18 04:30:00 CET 1977 - <pinotree> k - <giselher> I had some problems with killall5 to read the pid from /proc, Is - this now more reliable? - <youpi> I haven't tested with jkoenig's implementation - [...] - <pinotree> looks like he did 'self' too, see rootdir_entries[] in rootdir.c - <youpi> but it doesn't point at self - <antrik> youpi: there is no way to provide /proc/self, because the server - doesn't know the identity of the client - <youpi> :/ - <antrik> youpi: using the existing mechanisms, we would need another magic - lookup type - <antrik> an alternative idea I discussed with cfhammer once would be for - the client to voluntarily provide it's identity to the server... but that - would be a rather fundamental change that requires careful consideration - <antrik> also, object migration could be used, so the implementation would - be provided by the server, but the execution would happen in the - client... but that's even more involved :-) - <youpi> but we've seen how much that'd help with a lot of other stuff - <antrik> I'm not sure whether we discussed this on the ML at some point, or - only on IRC - <youpi> it "just" needs to be commited :) - <antrik> in either case, it can't hurt to bring this up again :-) - - -# root group - -IRC, #hurd, around October 2010 - - <pinotree> the only glitch is that files/dirs have the right user as - owner, but always with root group - - -# `/proc/$pid/stat` being 400 and not 444, and some more - -IRC, freenode, #hurd, 2011-03-27 - - <pochu> is there a reason for /proc/$pid/stat to be 400 and not 444 like on - Linux? - <pochu> there is an option to procfs to make it 444 like Linux - <pochu> jkoenig: ^ - <jkoenig> pochu, hi - <jkoenig> /proc/$pid/stat reveals information which is not usually - available on Hurd - <jkoenig> so I made it 400 by default to avoid leaking anything - <pochu> is there a security risk in providing that info? - <jkoenig> probably not so much, but it seemed like it's not really a - descision procfs should make - <jkoenig> I'm not sure which information we're speaking about, though, I - just remember the abstract reason. - <pochu> things like the pid, the memory, the priority, the state... - <pochu> sounds safe to expose - <jkoenig> also it's 0444 by default in "compatible" mode - <jkoenig> (which is necessary for the linux tools to work well) - <pochu> yeah I saw that :) - <pochu> my question is, should we change it to 0444 by default? if there - are no security risks and this improves compatibility, sounds like a good - thing to me - <pochu> we're already 'leaking' part of that info through e.g. ps - <jkoenig> I think /proc should be translated by /hurd/procfs --compatible - by default (I'm not sure whether it's already the case) - <jkoenig> also I'm not sure why hurd-ps is setuid root, rather than the - proc server being less paranoid, but maybe I'm missing something. - <pochu> jkoenig: it's not, at least not on Debian - <pochu> youpi: hi, what do you think about starting procfs with - --compatible by default? - <pochu> youpi: or changing /proc/$pid/stat to 0444 like on Linux - (--compatible does that among a few other things) - <youpi> I guess you need it for something? - <pochu> I'm porting libgtop :) - <youpi> k - <pochu> though I still think we should do this in procfs itself - <youpi> ymmv - <jkoenig> pochu, youpi, --compatible is also needed because mach's high - reported sysconf(_SC_CLK_TCK) makes some integers overflow (IIRC) - <youpi> agreed - <jkoenig> luckily, tools which use procfs usually try to detect the value - /proc uses rather than rely on CLK_TCK - <jkoenig> (so we can choose whatever reasonable value we want) - -IRC, freenode, #hurd, 2011-03-28 - - <antrik> jkoenig: does procfs expose any information that is not available - to everyone through the proc server?... - <antrik> also, why is --compatible not the default; or rather, why is there - even another mode? the whole point of procfs is compatibility... - <jkoenig> antrik, yes, through the <pid>/environ and (as mentionned above) - <pid>/stat files, but I've been careful to make these files readable only - to the process owner - <jkoenig> --compatible is not the default because it relaxes this paranoia - wrt. the stat file, and does not conform to the specification with regard - to clock tick counters - <antrik> what specification? - <jkoenig> the linux proc(5) manpage - <jkoenig> which says clock tick counters are in units of - 1/sysconf(_SC_CLK_TCK) - <antrik> so you are saying that there is some information that the Hurd - proc server doesn't expose to unprivileged processes, but linux /proc - does? - <jkoenig> yes - <antrik> that's odd. I wonder what the reasoning behind that could be - <antrik> but this information is available through Hurd ps? - <antrik> BTW, what exactly is _SC_CLK_TCK supposed to be? - <pinotree> jkoenig: hm, just tried with two random processes on linux - (2.6.32), and enrivon is 400 - <pinotree> (which makes sense, as you could have sensible informations eg - in http_proxy or other envvars) - <jkoenig> antrik, CLK_TCK is similar to HZ (maybe clock resolution instead - of time slices ?) - <jkoenig> sysconf(3) says "The number of clock ticks per second." - <jkoenig> antrik, I don't remember precisely what information this was, but - ps-hurd is setuid root. - <jkoenig> anyway, if you run procfs --compatible as a user and try to read - foo/1/stat, the result is an I/O error, which is the result of the proc - server denying access. - <antrik> but Linux /proc acutally uses HZ as the unit IIRC? or is - _SC_CLK_TCK=HZ on Linux?... - <jkoenig> I expect they're equal. - <jkoenig> in practice procps uses heuristics to guess what value /proc uses - (for compatibility purposes with older kernels) - <jkoenig> I don't think HZ is POSIX, while _SC_CLK_TCK is specifies as the - unit for (at least) the values returned by times() - <jkoenig> s/specifies/specified/ - <jkoenig> antrik, some the information is fetched directly from mach by - libps, and understandably, the proc server does not give the task port to - anyone who asks. - <antrik> well, as long as the information is exposed through ps, there is - no point in hiding it in procfs... - <antrik> and I'm aware of the crazy guessing in libproc... I was actually - mentoring the previous procfs implementation - <antrik> (though I never got around to look at his buggy code...) - <jkoenig> ok - -IRC, freenode, #hurd, 2011-07-22 - - <pinotree> hm, why /proc/$pid/stat is 600 instead of 644 of linux? - <jkoenig> pinotree, it reveals information which, while not that sensitive, - would not be available to users through the normal proc interface. - <jkoenig> (it's available through the ps command which is setuid root) - <jkoenig> we discussed at some point making it 644, IIRC. - <pinotree> hm, then why is it not a problem on eg linux? - <jkoenig> (btw you can change it with the -s option.) - <jkoenig> pinotree, it's not a problem because the information is not that - sensitive, but when rewriting procfs I preferred to play it self and - consider it's not procfs' job to decide what is sensitive or not. - <jkoenig> IIRC it's not sensitive but you need the task port to query it. - <jkoenig> like, thread times or something. - <pinotree> status is 644 though - <jkoenig> but status contains information which anyone can ask to the proc - server anyway, I think. - - -# `/proc/mounts`, `/proc/$pid/mounts` - -IRC, freenode, #hurd, 2011-07-25 - - < pinotree> jkoenig: btw, what do you think about providing empty - /proc/mounts and /proc/$pid/mounts files? - < jkoenig> pinotree, I guess one would have to evaluate the consequences - wrt. existing use cases (in other words, "I have absolutely no clue - whatsoever about whether that would be desirable" :-) - < jkoenig> pinotree, the thing is, an error message like "/proc/mounts: No - such file or directory" is rather explicit, whereas errors which would be - caused by missing data in /proc/mounts would maybe be harder to track - < braunr> this seems reasonable though - < braunr> there already are many servers with e.g. grsecurity or chrooted - environments where mounts is empty - < pinotree> well, currently we also have an empty mtab - < braunr> pinotree: but what do you need that for ? - < braunr> pinotree: the init system ? - < pinotree> and the mnt C api already returns no entries (or it bails out, - i don't remember) - < pinotree> not a strict need - - -# `/proc/[PID]/auxv`, `/proc/[PID]/exe`, `/proc/[PID]/mem` - -Needed by glibc's `pldd` tool (commit -11988f8f9656042c3dfd9002ac85dff33173b9bd). - - -# `/proc/self/exe` - -[[!message-id "alpine.LFD.2.02.1110111111260.2016@akari"]] |