linux.git/fs/proc/base.c, branch v2.6.24

restrict reading from /proc//maps to those who share ->mm or can ptrace pid

2008-01-02T21:13:27+00:00

Contents of /proc/*/maps is sensitive and may become sensitive after
open() (e.g.  if target originally shares our ->mm and later does exec
on suid-root binary).

Check at read() (actually, ->start() of iterator) time that mm_struct
we'd grabbed and locked is
 - still the ->mm of target
 - equal to reader's ->mm or the target is ptracable by reader.

Signed-off-by: Al Viro 
Acked-by: Rik van Riel 
Signed-off-by: Linus Torvalds

proc: remove races from proc_id_readdir()

2007-11-29T17:24:52+00:00

Oleg noticed that the call of task_pid_nr_ns() in proc_pid_readdir
is racy with respect to tasks exiting.

After a bit of examination it also appears that the call itself
is completely unnecessary.

So to fix the problem this patch modifies next_tgid() to return
both a tgid and the task struct in question.

A structure is introduced to return these values because it is
slightly cleaner and easier to optimize, and the resulting code
is a little shorter.

Signed-off-by: "Eric W. Biederman" 
Cc: Oleg Nesterov 
Cc: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: simplify and correct proc_flush_task

2007-11-15T02:45:42+00:00

Currently we special case when we have only the initial pid namespace.
Unfortunately in doing so the copied case for the other namespaces was
broken so we don't properly flush the thread directories :(

So this patch removes the unnecessary special case (removing a usage of
proc_mnt) and corrects the flushing of the thread directories.

Signed-off-by: Eric W. Biederman 
Cc: Al Viro 
Cc: Pavel Emelyanov 
Cc: Sukadev Bhattiprolu 
Cc: Kirill Korotaev 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

procfs: fix kernel-doc param warnings

2007-10-23T02:40:02+00:00

Fix mnt_flush_task() misplaced kernel-doc.
Fix typos in some of the doc text.

Warning(linux-2.6.23-git17//fs/proc/base.c:2280): No description found for parameter 'mnt'
Warning(linux-2.6.23-git17//fs/proc/base.c:2280): No description found for parameter 'pid'
Warning(linux-2.6.23-git17//fs/proc/base.c:2280): No description found for parameter 'tgid'

Signed-off-by: Randy Dunlap 
Signed-off-by: Linus Torvalds

Remove unused variables from fs/proc/base.c

2007-10-19T18:53:43+00:00

When removing the explicit task_struct->pid usage I found that
proc_readfd_common() and proc_pident_readdir() get this field, but do not
use it at all.  So this cleanup is a cheap help with the task_struct->pid
isolation.

Signed-off-by: Pavel Emelyanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: export a processes resource limits via /proc/pid

2007-10-19T18:53:42+00:00

Currently, there exists no method for a process to query the resource
limits of another process.  They can be inferred via some mechanisms but
they cannot be explicitly determined.  Given that this information can be
usefull to know during the debugging of an application, I've written this
patch which exports all of a processes limits via /proc//limits.

Signed-off-by: Neil Horman 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Isolate some explicit usage of task->tgid

2007-10-19T18:53:40+00:00

With pid namespaces this field is now dangerous to use explicitly, so hide
it behind the helpers.

Also the pid and pgrp fields o task_struct and signal_struct are to be
deprecated.  Unfortunately this patch cannot be sent right now as this
leads to tons of warnings, so start isolating them, and deprecate later.

Actually the p->tgid == pid has to be changed to has_group_leader_pid(),
but Oleg pointed out that in case of posix cpu timers this is the same, and
thread_group_leader() is more preferable.

Signed-off-by: Pavel Emelyanov 
Acked-by: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: changes to show virtual ids to user

2007-10-19T18:53:40+00:00

This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: Pavel Emelyanov 
Signed-off-by: Alexey Dobriyan 
Cc: Sukadev Bhattiprolu 
Cc: Oleg Nesterov 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: initialize the namespace's proc_mnt

2007-10-19T18:53:40+00:00

The namespace's proc_mnt must be kern_mount-ed to make this pointer always
valid, independently of whether the user space mounted the proc or not.  This
solves raced in proc_flush_task, etc.  with the proc_mnt switching from NULL
to not-NULL.

The initialization is done after the init's pid is created and hashed to make
proc_get_sb() finr it and get for root inode.

Sice the namespace holds the vfsmnt, vfsmnt holds the superblock and the
superblock holds the namespace we must explicitly break this circle to destroy
all the stuff.  This is done after the init of the namespace dies.  Running a
few steps forward - when init exits it will kill all its children, so no
proc_mnt will be needed after its death.

Signed-off-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: make proc_flush_task() actually from entries from multiple namespaces

2007-10-19T18:53:39+00:00

This means that proc_flush_task_mnt() is to be called for many proc mounts and
with different ids, depending on the namespace this pid is to be flushed from.

Signed-off-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds