Subject: manpages-dev: recvmsg(2) doesn't mention that MSG_CTRUNC can be set due to
permissions errors
Date: Wed, 27 Jan 2010 11:26:42 +0200
Package: manpages-dev
Version: 3.23-1
Severity: normal
"man 2 recvmsg" says:
MSG_CTRUNC
indicates that some control data were discarded due to lack of space in the buffer for ancillary data.
That doesn't mention that MSG_CTRUNC can be set due to a permission error also.
SELinux can deny file descriptor passing, in which case the receiving
application gets a message with MSG_CTRUNC set and controllen zero!
See here for one example where this happens https://wwws.clamav.net/bugzilla/show_bug.cgi?id=1700#c3
-- System Information:
Debian Release: squeeze/sid
APT prefers unstable
APT policy: (990, 'unstable'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Kernel: Linux 2.6.32.4 (SMP w/4 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages manpages-dev depends on:
ii manpages 3.23-1 Manual pages about using a GNU/Lin
manpages-dev recommends no packages.
Versions of packages manpages-dev suggests:
ii konqueror [man-browser] 4:4.3.4-1 KDE 4's advanced file manager, web
ii man-db [man-browser] 2.5.6-5 on-line manual pager
-- no debconf information
Subject: Re: Bug#567094: manpages-dev: recvmsg(2) doesn't mention that
MSG_CTRUNC can be set due to permissions errors
Date: Wed, 3 Feb 2010 06:00:46 +0100
2010/1/27 Török Edwin <[email protected]>:
> Package: manpages-dev
> Version: 3.23-1
> Severity: normal
>
> "man 2 recvmsg" says:
> MSG_CTRUNC
> indicates that some control data were discarded due to lack of space in the buffer for ancillary data.
>
> That doesn't mention that MSG_CTRUNC can be set due to a permission error also.
> SELinux can deny file descriptor passing, in which case the receiving
> application gets a message with MSG_CTRUNC set and controllen zero!
>
> See here for one example where this happens https://wwws.clamav.net/bugzilla/show_bug.cgi?id=1700#c3
(Upstream maintainer here...)
I created an account on this bugzilla, but still it tells me:
"You are not authorized to access bug #1700. "
So, I can't read this bug to get more info.
Cheers,
Michael
> -- System Information:
> Debian Release: squeeze/sid
> APT prefers unstable
> APT policy: (990, 'unstable'), (500, 'stable'), (1, 'experimental')
> Architecture: amd64 (x86_64)
>
> Kernel: Linux 2.6.32.4 (SMP w/4 CPU cores; PREEMPT)
> Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/bash
>
> Versions of packages manpages-dev depends on:
> ii manpages 3.23-1 Manual pages about using a GNU/Lin
>
> manpages-dev recommends no packages.
>
> Versions of packages manpages-dev suggests:
> ii konqueror [man-browser] 4:4.3.4-1 KDE 4's advanced file manager, web
> ii man-db [man-browser] 2.5.6-5 on-line manual pager
>
> -- no debconf information
>
>
>
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface" http://blog.man7.org/
Acknowledgement sent
to Török Edwin <[email protected]>:
Extra info received and forwarded to list. Copy sent to Martin Schulze <[email protected]>.
(Wed, 03 Feb 2010 10:36:05 GMT) (full text, mbox, link).
Subject: Re: Bug#567094: manpages-dev: recvmsg(2) doesn't mention that MSG_CTRUNC
can be set due to permissions errors
Date: Wed, 03 Feb 2010 12:34:34 +0200
On 02/03/2010 07:00 AM, Michael Kerrisk wrote:
> 2010/1/27 Török Edwin <[email protected]>:
>
>> Package: manpages-dev
>> Version: 3.23-1
>> Severity: normal
>>
>> "man 2 recvmsg" says:
>> MSG_CTRUNC
>> indicates that some control data were discarded due to lack of space in the buffer for ancillary data.
>>
>> That doesn't mention that MSG_CTRUNC can be set due to a permission error also.
>> SELinux can deny file descriptor passing, in which case the receiving
>> application gets a message with MSG_CTRUNC set and controllen zero!
>>
>> See here for one example where this happens https://wwws.clamav.net/bugzilla/show_bug.cgi?id=1700#c3
>>
>
> (Upstream maintainer here...)
>
> I created an account on this bugzilla, but still it tells me:
>
> "You are not authorized to access bug #1700. "
>
> So, I can't read this bug to get more info.
>
>
Sorry about that, I fixed it, the bug should be publicly accessible now.
The relevant part to MSG_CTRUNC starts at comment #3.
There is also a similar issue described here:
http://osdir.com/ml/fedora-selinux/2009-09/msg00071.html
Best regards,
--Edwin
Changed Bug title to 'recvmsg(2): please mention that MSG_CTRUNC can be set due to permissions errors' from 'manpages-dev: recvmsg(2) doesn't mention that MSG_CTRUNC can be set due to permissions errors'
Request was from Stéphane Aulery <[email protected]>
to [email protected].
(Sun, 08 Mar 2015 19:45:14 GMT) (full text, mbox, link).