linux.git/fs/proc/proc_net.c, branch v2.6.26

netns: assign PDE->data before gluing entry into /proc tree

2008-05-02T11:12:41+00:00

In this unfortunate case, proc_mkdir_mode wrapper can't be used anymore and
this is no way to reuse proc_create_data due to nlinks assignment. So,
copy the code from proc_mkdir and assign PDE->data at the appropriate
moment.

Signed-off-by: Denis V. Lunev 
Signed-off-by: David S. Miller

[NETNS]: Remove ifdef CONFIG_NET braces in fs/proc/proc_net.c.

2008-04-02T07:10:04+00:00

They are redundant as this file is linked in iff CONFIG_NET is turned
on.

Signed-off-by: Denis V. Lunev 
Signed-off-by: David S. Miller

[NETNS]: Compile NET /proc support only if CONFIG_NET is set.

2008-03-27T21:25:53+00:00

This fix broken compilation for 'allnoconfig'. This was introduced by
Introduced by commit 1218854afa6f659be90b748cf1bc7badee954a35 ("[NET]
NETNS: Omit seq_net_private->net without CONFIG_NET_NS.")

Signed-off-by: Denis V. Lunev 
Acked-by: YOSHIFUJI Hideaki 
Signed-off-by: David S. Miller

[NET] NETNS: Omit seq_net_private->net without CONFIG_NET_NS.

2008-03-25T19:39:56+00:00

Without CONFIG_NET_NS, no namespace other than &init_net exists,
no need to store net in seq_net_private.

Signed-off-by: YOSHIFUJI Hideaki

[NET]: Make /proc/net a symlink on /proc/self/net (v3)

2008-03-07T19:08:40+00:00

Current /proc/net is done with so called "shadows", but current
implementation is broken and has little chances to get fixed.

The problem is that dentries subtree of /proc/net directory has
fancy revalidation rules to make processes living in different
net namespaces see different entries in /proc/net subtree, but
currently, tasks see in the /proc/net subdir the contents of any
other namespace, depending on who opened the file first.

The proposed fix is to turn /proc/net into a symlink, which points
to /proc/self/net, which in turn shows what previously was in
/proc/net - the network-related info, from the net namespace the
appropriate task lives in.

# ls -l /proc/net
lrwxrwxrwx  1 root root 8 Mar  5 15:17 /proc/net -> self/net

In other words - this behaves like /proc/mounts, but unlike
"mounts", "net" is not a file, but a directory.

Changes from v2:
* Fixed discrepancy of /proc/net nlink count and selinux labeling
  screwup pointed out by Stephen.

  To get the correct nlink count the ->getattr callback for /proc/net
  is overridden to read one from the net->proc_net entry.

  To make selinux still work the net->proc_net entry is initialized
  properly, i.e. with the "net" name and the proc_net parent.

Selinux fixes are
Acked-by:  Stephen Smalley 

Changes from v1:
* Fixed a task_struct leak in get_proc_task_net, pointed out by Paul.

Signed-off-by: Pavel Emelyanov 
Acked-by: "Eric W. Biederman" 
Signed-off-by: David S. Miller

proc: fix ->open'less usage due to ->proc_fops flip

2008-02-08T17:22:24+00:00

Typical PDE creation code looks like:

	pde = create_proc_entry("foo", 0, NULL);
	if (pde)
		pde->proc_fops = &foo_proc_fops;

Notice that PDE is first created, only then ->proc_fops is set up to
final value. This is a problem because right after creation
a) PDE is fully visible in /proc , and
b) ->proc_fops are proc_file_operations which do not have ->open callback. So, it's
   possible to ->read without ->open (see one class of oopses below).

The fix is new API called proc_create() which makes sure ->proc_fops are
set up before gluing PDE to main tree. Typical new code looks like:

	pde = proc_create("foo", 0, NULL, &foo_proc_fops);
	if (!pde)
		return -ENOMEM;

Fix most networking users for a start.

In the long run, create_proc_entry() for regular files will go.

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000024
printing eip: c1188c1b *pdpt = 000000002929e001 *pde = 0000000000000000
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
last sysfs file: /sys/block/sda/sda1/dev
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom

Pid: 24679, comm: cat Not tainted (2.6.24-rc3-mm1 #2)
EIP: 0060:[] EFLAGS: 00210002 CPU: 0
EIP is at mutex_lock_nested+0x75/0x25d
EAX: 000006fe EBX: fffffffb ECX: 00001000 EDX: e9340570
ESI: 00000020 EDI: 00200246 EBP: e9340570 ESP: e8ea1ef8
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 24679, ti=E8EA1000 task=E9340570 task.ti=E8EA1000)
Stack: 00000000 c106f7ce e8ee05b4 00000000 00000001 458003d0 f6fb6f20 fffffffb
       00000000 c106f7aa 00001000 c106f7ce 08ae9000 f6db53f0 00000020 00200246
       00000000 00000002 00000000 00200246 00200246 e8ee05a0 fffffffb e8ee0550
Call Trace:
 [] seq_read+0x24/0x28a
 [] seq_read+0x0/0x28a
 [] seq_read+0x24/0x28a
 [] seq_read+0x0/0x28a
 [] proc_reg_read+0x60/0x73
 [] proc_reg_read+0x0/0x73
 [] vfs_read+0x6c/0x8b
 [] sys_read+0x3c/0x63
 [] sysenter_past_esp+0x5f/0xa5
 [] destroy_inode+0x24/0x33
 =======================
INFO: lockdep is turned off.
Code: 75 21 68 e1 1a 19 c1 68 87 00 00 00 68 b8 e8 1f c1 68 25 73 1f c1 e8 84 06 e9 ff e8 52 b8 e7 ff 83 c4 10 9c 5f fa e8 28 89 ea ff  fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan 
Cc: "Eric W. Biederman" 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[ATM]: Oops reading net/atm/arp

2008-01-28T23:01:36+00:00

cat /proc/net/atm/arp causes the NULL pointer dereference in the
get_proc_net+0xc/0x3a. This happens as proc_get_net believes that the
parent proc dir entry contains struct net.

Fix this assumption for "net/atm" case.

The problem is introduced by the commit c0097b07abf5f92ab135d024dd41bd2aada1512f
from Eric W. Biederman/Daniel Lezcano.

Signed-off-by: Denis V. Lunev 
Signed-off-by: David S. Miller

[NET]: Consolidate net namespace related proc files creation.

2008-01-28T22:54:28+00:00

Signed-off-by: Denis V. Lunev 
Signed-off-by: Pavel Emelyanov 
Signed-off-by: David S. Miller

[NETNS]: Fix /proc/net breakage

2007-12-01T13:33:17+00:00

Well I clearly goofed when I added the initial network namespace support
for /proc/net.  Currently things work but there are odd details visible to
user space, even when we have a single network namespace.

Since we do not cache proc_dir_entry dentries at the moment we can just
modify ->lookup to return a different directory inode depending on the
network namespace of the process looking at /proc/net, replacing the
current technique of using a magic and fragile follow_link method.

To accomplish that this patch:
- introduces a shadow_proc method to allow different dentries to
  be returned from proc_lookup.
- Removes the old /proc/net follow_link magic
- Fixes a weakness in our not caching of proc generic dentries.

As shadow_proc uses a task struct to decided which dentry to return we can
go back later and fix the proc generic caching without modifying any code
that uses the shadow_proc method.

Signed-off-by: Eric W. Biederman 
Cc: "Rafael J. Wysocki" 
Cc: Pavel Machek 
Cc: Pavel Emelyanov 
Cc: "David S. Miller" 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Herbert Xu

[NET]: Move unneeded data to initdata section.

2007-11-13T11:23:50+00:00

This patch reverts Eric's commit 2b008b0a8e96b726c603c5e1a5a7a509b5f61e35

It diets .text & .data section of the kernel if CONFIG_NET_NS is not set.
This is safe after list operations cleanup.

Signed-of-by: Denis V. Lunev 
Signed-off-by: David S. Miller