Gidday,
The Linux man-pages maintainer proudly announces:
man-pages-3.82 - man pages for Linux
Tarball download:
http://www.kernel.org/doc/man-pages/download.html
Git repository:
https://git.kernel.org/cgit/docs/man-pages/man-pages.git/
Online changelog:
http://man7.org/linux/man-pages/changelog.html#release_3.82
A short summary of the release is blogged at:
http://linux-man-pages.blogspot.com/2015/03/man-pages-382-is-released.html
A selection of changes in this release that may be interesting
for readers of this list is shown below.
Cheers,
Michael
==================== Changes in man-pages-3.82 ====================
Released: 2015-03-29, Paris
Contributors
------------
The following people contributed patches/fixes or (noted in brackets
in the changelog below) reports, notes, and ideas that have been
incorporated in changes in this release:
Alban Crequy <alban.cre...@gmail.com>
Andy Lutomirski <l...@amacapital.net>
Bert Wesarg <bert.wes...@googlemail.com>
Bill Pemberton <wf...@worldbroken.com>
Chris Delozier <c.s.deloz...@gmail.com>
David Madore <david.mad...@ens.fr>
Dmitry Deshevoy <mity...@gmail.com>
Eric W. Biederman <ebied...@xmission.com>
Heinrich Schuchardt <xypron.g...@gmx.de>
Jakub Wilk <uba...@users.sf.net>
Jann Horn <j...@thejh.net>
Jason Vas Dias <jason.vas.d...@gmail.com>
Josh Triplett <j...@joshtriplett.org>
J William Piggott <elseift...@gmx.com>
Kees Cook <keesc...@chromium.org>
Konstantin Shemyak <konstan...@shemyak.com>
Ma Shimiao <mashimiao.f...@cn.fujitsu.com>
Matt Turner <matts...@gmail.com>
Michael Kerrisk <mtk.manpa...@gmail.com>
Michael Witten <mfwit...@gmail.com>
Mikael Pettersson <mikpeli...@gmail.com>
Namhyung Kim <namhy...@gmail.com>
Nicolas FRANCOIS <nicolas.franc...@centraliens.net>
Paul E Condon <pecon...@mesanetworks.net>
Peter Adkins <peter.adk...@kernelpicnic.net>
Scot Doyle <lkm...@scotdoyle.com>
Shawn Landden <sh...@churchofgit.com>
Stéphane Aulery <saul...@free.fr>
Stephen Smalley <s...@tycho.nsa.gov>
Taisuke Yamada <t...@rakugaki.org>
Torvald Riegel <trie...@redhat.com>
Vincent Lefevre <vinc...@vinc17.net>
<yg...@ygrex.ru>
Yuri Kozlov <yu...@komyakino.ru>
Apologies if I missed anyone!
New and rewritten pages
-----------------------
nptl.7
Michael Kerrisk
New page with details of the NPTL POSIX threads implementation
Newly documented interfaces in existing pages
---------------------------------------------
user_namespaces.7
Eric W. Biederman [Michael Kerrisk]
Document /proc/[pid]/setgroups
Changes to individual pages
---------------------------
clone.2
Josh Triplett
Document that clone() silently ignores CLONE_PID and CLONE_STOPPED
Normally, system calls return EINVAL for flags they don't support.
Explicitly document that clone does *not* produce an error for
these two obsolete flags.
getgroups.2
Michael Kerrisk [Shawn Landden]
Add discussion of NPTL credential-changing mechanism
At the kernel level, credentials (UIDs and GIDs) are a per-thread
attribute. NPTL uses a signal-based mechanism to ensure that
when one thread changes its credentials, all other threads change
credentials to the same values. By this means, the NPTL
implementation conforms to the POSIX requirement that the threads
in a process share credentials.
getpid.2
Michael Kerrisk
Note that getppid() returns 0 if parent is in different PID namespace
getsockopt.2
Konstantin Shemyak
Note RETURN VALUE details when netfilter is involved
msgop.2
Bill Pemberton
Add an example program
open.2
Michael Kerrisk [Jason Vas Dias]
Mention blocking semantics for FIFO opens
See https://bugzilla.kernel.org/show_bug.cgi?id=95191
seccomp.2
Jann Horn [Kees Cook, Mikael Pettersson, Andy Lutomirski]
Add note about alarm(2) not being sufficient to limit runtime
Jann Horn
Explain blacklisting problems, expand example
setgid.2
Michael Kerrisk [Shawn Landden]
Add discussion of NPTL credential-changing mechanism
At the kernel level, credentials (UIDs and GIDs) are a per-thread
attribute. NPTL uses a signal-based mechanism to ensure that
when one thread changes its credentials, all other threads change
credentials to the same values. By this means, the NPTL
implementation conforms to the POSIX requirement that the threads
in a process share credentials.
setresuid.2
Michael Kerrisk [Shawn Landden]
Add discussion of NPTL credential-changing mechanism
At the kernel level, credentials (UIDs and GIDs) are a per-thread
attribute. NPTL uses a signal-based mechanism to ensure that
when one thread changes its credentials, all other threads change
credentials to the same values. By this means, the NPTL
implementation conforms to the POSIX requirement that the threads
in a process share credentials.
setreuid.2
Michael Kerrisk [Shawn Landden]
Add discussion of NPTL credential-changing mechanism
At the kernel level, credentials (UIDs and GIDs) are a per-thread
attribute. NPTL uses a signal-based mechanism to ensure that
when one thread changes its credentials, all other threads change
credentials to the same values. By this means, the NPTL
implementation conforms to the POSIX requirement that the threads
in a process share credentials.
setuid.2
Michael Kerrisk [Shawn Landden]
Add discussion of NPTL credential-changing mechanism
At the kernel level, credentials (UIDs and GIDs) are a per-thread
attribute. NPTL uses a signal-based mechanism to ensure that
when one thread changes its credentials, all other threads change
credentials to the same values. By this means, the NPTL
implementation conforms to the POSIX requirement that the threads
in a process share credentials.
sigaction.2
Michael Kerrisk
Add discussion of rt_sigaction(2)
Michael Kerrisk
Note treatment of signals used internally by NPTL
The glibc wrapper gives an EINVAL error on attempts to change the
disposition of either of the two real-time signals used by NPTL.
sigpending.2
Michael Kerrisk
Add discussion of rt_sigpending(2)
sigprocmask.2
Michael Kerrisk
Add discussion of rt_sigprocmask(2)
Michael Kerrisk
Note treatment of signals used internally by NPTL
The glibc wrapper silently ignores attempts to block the two
real-time signals used by NPTL.
sigreturn.2
Michael Kerrisk
Add discussion of rt_sigreturn(2)
sigsuspend.2
Michael Kerrisk
Add discussion of rt_sigsuspend(2)
sigwaitinfo.2
Michael Kerrisk
Note treatment of signals used internally by NPTL
The glibc wrappers silently ignore attempts to wait for
signals used by NPTL.
Michael Kerrisk
Add discussion of rt_sigtimedwait(2)
syscall.2
Jann Horn
Add x32 ABI
umount.2
Eric W. Biederman
Document the effect of shared subtrees on umount(2)
Eric W. Biederman
Correct the description of MNT_DETACH
dlopen.3
Michael Kerrisk
Amend error in description of dlclose() behavior
The current text says that unloading depends on whether
the reference count falls to zero *and no other libraries
are using symbols in this library*. That latter text has
been there since man-pages-1.29, but it seems rather dubious.
How could the implementation know whether other libraries
are still using symbols in this library? Furthermore, no
other implementation's man page mentions this point.
Seems best to drop this point.
Michael Kerrisk
Add some details for RTLD_DEFAULT
Michael Kerrisk
Add some details on RTLD_NEXT and preloading
Michael Kerrisk
RTLD_NEXT works for symbols generally, not just functions
The common use case is for functions, but RTLD_NEXT
also applies to variable symbols.
Michael Kerrisk
dlclose() recursively closes dependent libraries
Note that dlclose() recursively closes dependent libraries
that were loaded by dlopen()
console_codes.4
Scot Doyle
Add Console Private CSI sequence 15
An undocumented escape sequence in drivers/tty/vt/vt.c brings the
previously accessed virtual terminal to the foreground.
mtk: Patch misattributed to Taisuke Yamada in Git commit
because of a muck up on my part.
proc.5
Taisuke Yamada
Document /proc/PID/status VmPin field
See https://bugs.launchpad.net/bugs/1071746
Michael Kerrisk
Document (the obsolete) /proc/PID/seccomp
Taisuke Yamada
Fix SELinux /proc/pid/attr/current example
Since the /proc/pid/attr API was added to the kernel, there
have been a couple of changes to the SELinux handling of
/proc/pid/attr/current. Fix the SELinux /proc/pid/attr/current
example text to reflect these changes and note which kernel
versions first included the changes.
feature_test_macros.7
Michael Kerrisk
Update discussion of _FORTIFY_SOURCE
Since the initial implementation a lot more checks were added.
Describe all the checks would be too verbose (and would soon
fall out of date as more checks are added). So instead, describe
the kinds of checks that are done more generally.
Also a few other minor edits to the text.
packet.7
Michael Kerrisk
Remove mention of needing UID 0 to create packet socket
The existing text makes no sense. The check is based
purely on a capability check. (Kernel function
net/packet/af_packet.c::packet_create()
signal.7
Michael Kerrisk
Note when Linux added realtime signals
Michael Kerrisk
Correct the range of realtime signals
Michael Kerrisk
Summarize 2.2 system call changes that resulted from larger signal sets
tcp.7
Peter Adkins
Document removal of TCP_SYNQ_HSIZE
Looking over the man page for 'tcp' I came across a reference to
tuning the 'TCP_SYNQ_HSIZE' parameter when increasing
'tcp_max_syn_backlog' above 1024. However, this static sizing was
removed back in Linux 2.6.20 in favor of dynamic scaling - as
part of commit 72a3effaf633bcae9034b7e176bdbd78d64a71db.
user_namespaces.7
Eric W. Biederman
Update the documentation to reflect the fixes for negative groups
Files with access permissions such as rwx---rwx give fewer
permissions to their group then they do to everyone else. Which
means dropping groups with setgroups(0, NULL) actually grants a
process privileges.
The unprivileged setting of gid_map turned out not to be safe
after this change. Privileged setting of gid_map can be
interpreted as meaning yes it is ok to drop groups. [ Eric
additionally noted: Setting of gid_map with privilege has been
clarified to mean that dropping groups is ok. This allows
existing programs that set gid_map with privilege to work
without changes. That is, newgidmap(1) continues to work
unchanged.]
To prevent this problem and future problems, user namespaces were
changed in such a way as to guarantee a user can not obtain
credentials without privilege that they could not obtain without
the help of user namespaces.
This meant testing the effective user ID and not the filesystem
user ID, as setresuid(2) and setregid(2) allow setting any process
UID or GID (except the supplementary groups) to the effective ID.
Furthermore, to preserve in some form the useful applications
that have been setting gid_map without privilege, the file
/proc/[pid]/setgroups was added to allow disabling setgroups(2).
With setgroups(2) permanently disabled in a user namespace, it
again becomes safe to allow writes to gid_map without privilege.
Michael Kerrisk
Rework some text describing permission rules for updating map files
No (intentional) change to the facts, but this restructuring
should make the meaning easier to grasp.
Michael Kerrisk
Update kernel version associated with 5-line limit for map files
As at Linux 3.18, the limit is still five lines, so mention the
more recent kernel version in the text.
Michael Kerrisk [Alban Crequy]
Handle /proc/PID/setgroups in the example program
Michael Kerrisk
Rework text describing restrictions on updating /proc/PID/setgroups
No (intentional) changes to factual description, but the
restructured text is hopefully easier to grasp.
Michael Kerrisk
Explain why the /proc/PID/setgroups file was added
ldconfig.8
Michael Kerrisk
Note use of /lib64 and /usr/lib64 on some 64-bit architectures
ld.so.8
Michael Kerrisk
Note the use of /lib64 and /usr/lib64 on some 64-bit architectures
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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