2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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Fix rmmod/read/write races in /proc entries
Fix following races:
===========================================
1. Write via ->write_proc sleeps in copy_from_user(). Module disappears
meanwhile. Or, more generically, system call done on /proc file, method
supplied by module is called, module dissapeares meanwhile.
pde = create_proc_entry()
if (!pde)
return -ENOMEM;
pde->write_proc = ...
open
write
copy_from_user
pde = create_proc_entry();
if (!pde) {
remove_proc_entry();
return -ENOMEM;
/* module unloaded */
}
*boom*
==========================================
2. bogo-revoke aka proc_kill_inodes()
remove_proc_entry vfs_read
proc_kill_inodes [check ->f_op validness]
[check ->f_op->read validness]
[verify_area, security permissions checks]
->f_op = NULL;
if (file->f_op->read)
/* ->f_op dereference, boom */
NOTE, NOTE, NOTE: file_operations are proxied for regular files only. Let's
see how this scheme behaves, then extend if needed for directories.
Directories creators in /proc only set ->owner for them, so proxying for
directories may be unneeded.
NOTE, NOTE, NOTE: methods being proxied are ->llseek, ->read, ->write,
->poll, ->unlocked_ioctl, ->ioctl, ->compat_ioctl, ->open, ->release.
If your in-tree module uses something else, yell on me. Full audit pending.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:39:00 -07:00
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2005-04-16 15:20:36 -07:00
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2006-01-08 01:04:16 -08:00
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2006-03-26 01:36:55 -08:00
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2007-02-14 00:34:12 -08:00
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2005-04-16 15:20:36 -07:00
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2006-12-08 02:36:36 -08:00
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2005-04-16 15:20:36 -07:00
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2005-12-30 08:39:10 -08:00
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2005-04-16 15:20:36 -07:00
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2007-10-16 01:25:52 -07:00
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2005-04-16 15:20:36 -07:00
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2006-12-08 02:36:36 -08:00
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2005-04-16 15:20:36 -07:00
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2005-12-30 08:39:10 -08:00
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2005-04-16 15:20:36 -07:00
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2008-02-08 04:18:27 -08:00
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2005-04-16 15:20:36 -07:00
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2005-09-06 15:17:18 -07:00
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2007-02-12 00:55:40 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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[PATCH] Fix up symlink function pointers
This fixes up the symlink functions for the calling convention change:
* afs, autofs4, befs, devfs, freevxfs, jffs2, jfs, ncpfs, procfs,
smbfs, sysvfs, ufs, xfs - prototype change for ->follow_link()
* befs, smbfs, xfs - same for ->put_link()
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-20 00:17:39 +01:00
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2005-04-16 15:20:36 -07:00
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[PATCH] Fix up symlink function pointers
This fixes up the symlink functions for the calling convention change:
* afs, autofs4, befs, devfs, freevxfs, jffs2, jfs, ncpfs, procfs,
smbfs, sysvfs, ufs, xfs - prototype change for ->follow_link()
* befs, smbfs, xfs - same for ->put_link()
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-20 00:17:39 +01:00
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2005-04-16 15:20:36 -07:00
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2007-02-12 00:55:40 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2007-12-02 00:33:17 +11:00
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2005-04-16 15:20:36 -07:00
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2007-12-02 00:33:17 +11:00
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2007-05-08 00:25:45 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2008-02-08 04:18:27 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2008-02-08 04:18:27 -08:00
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2005-04-16 15:20:36 -07:00
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2007-05-08 00:25:45 -07:00
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2005-04-16 15:20:36 -07:00
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2006-12-08 02:36:36 -08:00
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2005-04-16 15:20:36 -07:00
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2006-12-08 02:36:36 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2007-05-08 00:25:47 -07:00
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2006-03-26 01:36:55 -08:00
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2007-05-08 00:25:47 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2007-05-08 00:25:47 -07:00
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2005-04-16 15:20:36 -07:00
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2007-05-08 00:25:47 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2007-05-08 00:25:47 -07:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2007-02-12 00:55:34 -08:00
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2005-04-16 15:20:36 -07:00
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2007-02-12 00:55:40 -08:00
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2005-04-16 15:20:36 -07:00
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2005-09-06 15:17:18 -07:00
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2005-04-16 15:20:36 -07:00
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2008-02-08 04:18:29 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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2007-07-15 23:40:09 -07:00
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2008-02-08 04:18:29 -08:00
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2007-07-15 23:40:09 -07:00
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2005-04-16 15:20:36 -07:00
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proc: fix ->open'less usage due to ->proc_fops flip
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:[<c1188c1b>] 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:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] 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 <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 04:18:37 -08:00
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2005-04-16 15:20:36 -07:00
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proc: fix proc_dir_entry refcounting
Creating PDEs with refcount 0 and "deleted" flag has problems (see below).
Switch to usual scheme:
* PDE is created with refcount 1
* every de_get does +1
* every de_put() and remove_proc_entry() do -1
* once refcount reaches 0, PDE is freed.
This elegantly fixes at least two following races (both observed) without
introducing new locks, without abusing old locks, without spreading
lock_kernel():
1) PDE leak
remove_proc_entry de_put
----------------- ------
[refcnt = 1]
if (atomic_read(&de->count) == 0)
if (atomic_dec_and_test(&de->count))
if (de->deleted)
/* also not taken! */
free_proc_entry(de);
else
de->deleted = 1;
[refcount=0, deleted=1]
2) use after free
remove_proc_entry de_put
----------------- ------
[refcnt = 1]
if (atomic_dec_and_test(&de->count))
if (atomic_read(&de->count) == 0)
free_proc_entry(de);
/* boom! */
if (de->deleted)
free_proc_entry(de);
BUG: unable to handle kernel paging request at virtual address 6b6b6b6b
printing eip: c10acdda *pdpt = 00000000338f8001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 23161, comm: cat Not tainted (2.6.24-rc2-8c0863403f109a43d7000b4646da4818220d501f #4)
EIP: 0060:[<c10acdda>] EFLAGS: 00210097 CPU: 1
EIP is at strnlen+0x6/0x18
EAX: 6b6b6b6b EBX: 6b6b6b6b ECX: 6b6b6b6b EDX: fffffffe
ESI: c128fa3b EDI: f380bf34 EBP: ffffffff ESP: f380be44
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 23161, ti=f380b000 task=f38f2570 task.ti=f380b000)
Stack: c10ac4f0 00000278 c12ce000 f43cd2a8 00000163 00000000 7da86067 00000400
c128fa20 00896b18 f38325a8 c128fe20 ffffffff 00000000 c11f291e 00000400
f75be300 c128fa20 f769c9a0 c10ac779 f380bf34 f7bfee70 c1018e6b f380bf34
Call Trace:
[<c10ac4f0>] vsnprintf+0x2ad/0x49b
[<c10ac779>] vscnprintf+0x14/0x1f
[<c1018e6b>] vprintk+0xc5/0x2f9
[<c10379f1>] handle_fasteoi_irq+0x0/0xab
[<c1004f44>] do_IRQ+0x9f/0xb7
[<c117db3b>] preempt_schedule_irq+0x3f/0x5b
[<c100264e>] need_resched+0x1f/0x21
[<c10190ba>] printk+0x1b/0x1f
[<c107c8ad>] de_put+0x3d/0x50
[<c107c8f8>] proc_delete_inode+0x38/0x41
[<c107c8c0>] proc_delete_inode+0x0/0x41
[<c1066298>] generic_delete_inode+0x5e/0xc6
[<c1065aa9>] iput+0x60/0x62
[<c1063c8e>] d_kill+0x2d/0x46
[<c1063fa9>] dput+0xdc/0xe4
[<c10571a1>] __fput+0xb0/0xcd
[<c1054e49>] filp_close+0x48/0x4f
[<c1055ee9>] sys_close+0x67/0xa5
[<c10026b6>] sysenter_past_esp+0x5f/0x85
=======================
Code: c9 74 0c f2 ae 74 05 bf 01 00 00 00 4f 89 fa 5f 89 d0 c3 85 c9 57 89 c7 89 d0 74 05 f2 ae 75 01 4f 89 f8 5f c3 89 c1 89 c8 eb 06 <80> 38 00 74 07 40 4a 83 fa ff 75 f4 29 c8 c3 90 90 90 57 83 c9
EIP: [<c10acdda>] strnlen+0x6/0x18 SS:ESP 0068:f380be44
Also, remove broken usage of ->deleted from reiserfs: if sget() succeeds,
module is already pinned and remove_proc_entry() can't happen => nobody
can mark PDE deleted.
Dummy proc root in netns code is not marked with refcount 1. AFAICS, we
never get it, it's just for proper /proc/net removal. I double checked
CLONE_NETNS continues to work.
Patch survives many hours of modprobe/rmmod/cat loops without new bugs
which can be attributed to refcounting.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-04 23:45:28 -08:00
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Fix rmmod/read/write races in /proc entries
Fix following races:
===========================================
1. Write via ->write_proc sleeps in copy_from_user(). Module disappears
meanwhile. Or, more generically, system call done on /proc file, method
supplied by module is called, module dissapeares meanwhile.
pde = create_proc_entry()
if (!pde)
return -ENOMEM;
pde->write_proc = ...
open
write
copy_from_user
pde = create_proc_entry();
if (!pde) {
remove_proc_entry();
return -ENOMEM;
/* module unloaded */
}
*boom*
==========================================
2. bogo-revoke aka proc_kill_inodes()
remove_proc_entry vfs_read
proc_kill_inodes [check ->f_op validness]
[check ->f_op->read validness]
[verify_area, security permissions checks]
->f_op = NULL;
if (file->f_op->read)
/* ->f_op dereference, boom */
NOTE, NOTE, NOTE: file_operations are proxied for regular files only. Let's
see how this scheme behaves, then extend if needed for directories.
Directories creators in /proc only set ->owner for them, so proxying for
directories may be unneeded.
NOTE, NOTE, NOTE: methods being proxied are ->llseek, ->read, ->write,
->poll, ->unlocked_ioctl, ->ioctl, ->compat_ioctl, ->open, ->release.
If your in-tree module uses something else, yell on me. Full audit pending.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:39:00 -07:00
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2005-04-16 15:20:36 -07:00
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proc: fix ->open'less usage due to ->proc_fops flip
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:[<c1188c1b>] 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:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] 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 <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 04:18:37 -08:00
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2005-04-16 15:20:36 -07:00
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proc: fix ->open'less usage due to ->proc_fops flip
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:[<c1188c1b>] 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:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] 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 <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 04:18:37 -08:00
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2005-04-16 15:20:36 -07:00
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proc: fix ->open'less usage due to ->proc_fops flip
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:[<c1188c1b>] 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:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] 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 <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 04:18:37 -08:00
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2005-04-16 15:20:36 -07:00
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proc: fix ->open'less usage due to ->proc_fops flip
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:[<c1188c1b>] 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:
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c106f7ce>] seq_read+0x24/0x28a
[<c106f7aa>] seq_read+0x0/0x28a
[<c10818b8>] proc_reg_read+0x60/0x73
[<c1081858>] proc_reg_read+0x0/0x73
[<c105a34f>] vfs_read+0x6c/0x8b
[<c105a6f3>] sys_read+0x3c/0x63
[<c10025f2>] sysenter_past_esp+0x5f/0xa5
[<c10697a7>] 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 <f0> fe 4e 04 79 0a f3 90 80 7e 04 00 7e f8 eb f0 39 76 34 74 33
EIP: [<c1188c1b>] mutex_lock_nested+0x75/0x25d SS:ESP 0068:e8ea1ef8
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08 04:18:37 -08:00
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2005-04-16 15:20:36 -07:00
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2008-02-08 04:18:28 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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Fix rmmod/read/write races in /proc entries
Fix following races:
===========================================
1. Write via ->write_proc sleeps in copy_from_user(). Module disappears
meanwhile. Or, more generically, system call done on /proc file, method
supplied by module is called, module dissapeares meanwhile.
pde = create_proc_entry()
if (!pde)
return -ENOMEM;
pde->write_proc = ...
open
write
copy_from_user
pde = create_proc_entry();
if (!pde) {
remove_proc_entry();
return -ENOMEM;
/* module unloaded */
}
*boom*
==========================================
2. bogo-revoke aka proc_kill_inodes()
remove_proc_entry vfs_read
proc_kill_inodes [check ->f_op validness]
[check ->f_op->read validness]
[verify_area, security permissions checks]
->f_op = NULL;
if (file->f_op->read)
/* ->f_op dereference, boom */
NOTE, NOTE, NOTE: file_operations are proxied for regular files only. Let's
see how this scheme behaves, then extend if needed for directories.
Directories creators in /proc only set ->owner for them, so proxying for
directories may be unneeded.
NOTE, NOTE, NOTE: methods being proxied are ->llseek, ->read, ->write,
->poll, ->unlocked_ioctl, ->ioctl, ->compat_ioctl, ->open, ->release.
If your in-tree module uses something else, yell on me. Full audit pending.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-15 23:39:00 -07:00
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2005-04-16 15:20:36 -07:00
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proc: fix proc_dir_entry refcounting
Creating PDEs with refcount 0 and "deleted" flag has problems (see below).
Switch to usual scheme:
* PDE is created with refcount 1
* every de_get does +1
* every de_put() and remove_proc_entry() do -1
* once refcount reaches 0, PDE is freed.
This elegantly fixes at least two following races (both observed) without
introducing new locks, without abusing old locks, without spreading
lock_kernel():
1) PDE leak
remove_proc_entry de_put
----------------- ------
[refcnt = 1]
if (atomic_read(&de->count) == 0)
if (atomic_dec_and_test(&de->count))
if (de->deleted)
/* also not taken! */
free_proc_entry(de);
else
de->deleted = 1;
[refcount=0, deleted=1]
2) use after free
remove_proc_entry de_put
----------------- ------
[refcnt = 1]
if (atomic_dec_and_test(&de->count))
if (atomic_read(&de->count) == 0)
free_proc_entry(de);
/* boom! */
if (de->deleted)
free_proc_entry(de);
BUG: unable to handle kernel paging request at virtual address 6b6b6b6b
printing eip: c10acdda *pdpt = 00000000338f8001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 23161, comm: cat Not tainted (2.6.24-rc2-8c0863403f109a43d7000b4646da4818220d501f #4)
EIP: 0060:[<c10acdda>] EFLAGS: 00210097 CPU: 1
EIP is at strnlen+0x6/0x18
EAX: 6b6b6b6b EBX: 6b6b6b6b ECX: 6b6b6b6b EDX: fffffffe
ESI: c128fa3b EDI: f380bf34 EBP: ffffffff ESP: f380be44
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 23161, ti=f380b000 task=f38f2570 task.ti=f380b000)
Stack: c10ac4f0 00000278 c12ce000 f43cd2a8 00000163 00000000 7da86067 00000400
c128fa20 00896b18 f38325a8 c128fe20 ffffffff 00000000 c11f291e 00000400
f75be300 c128fa20 f769c9a0 c10ac779 f380bf34 f7bfee70 c1018e6b f380bf34
Call Trace:
[<c10ac4f0>] vsnprintf+0x2ad/0x49b
[<c10ac779>] vscnprintf+0x14/0x1f
[<c1018e6b>] vprintk+0xc5/0x2f9
[<c10379f1>] handle_fasteoi_irq+0x0/0xab
[<c1004f44>] do_IRQ+0x9f/0xb7
[<c117db3b>] preempt_schedule_irq+0x3f/0x5b
[<c100264e>] need_resched+0x1f/0x21
[<c10190ba>] printk+0x1b/0x1f
[<c107c8ad>] de_put+0x3d/0x50
[<c107c8f8>] proc_delete_inode+0x38/0x41
[<c107c8c0>] proc_delete_inode+0x0/0x41
[<c1066298>] generic_delete_inode+0x5e/0xc6
[<c1065aa9>] iput+0x60/0x62
[<c1063c8e>] d_kill+0x2d/0x46
[<c1063fa9>] dput+0xdc/0xe4
[<c10571a1>] __fput+0xb0/0xcd
[<c1054e49>] filp_close+0x48/0x4f
[<c1055ee9>] sys_close+0x67/0xa5
[<c10026b6>] sysenter_past_esp+0x5f/0x85
=======================
Code: c9 74 0c f2 ae 74 05 bf 01 00 00 00 4f 89 fa 5f 89 d0 c3 85 c9 57 89 c7 89 d0 74 05 f2 ae 75 01 4f 89 f8 5f c3 89 c1 89 c8 eb 06 <80> 38 00 74 07 40 4a 83 fa ff 75 f4 29 c8 c3 90 90 90 57 83 c9
EIP: [<c10acdda>] strnlen+0x6/0x18 SS:ESP 0068:f380be44
Also, remove broken usage of ->deleted from reiserfs: if sget() succeeds,
module is already pinned and remove_proc_entry() can't happen => nobody
can mark PDE deleted.
Dummy proc root in netns code is not marked with refcount 1. AFAICS, we
never get it, it's just for proper /proc/net removal. I double checked
CLONE_NETNS continues to work.
Patch survives many hours of modprobe/rmmod/cat loops without new bugs
which can be attributed to refcounting.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-04 23:45:28 -08:00
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2005-04-16 15:20:36 -07:00
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2006-03-26 01:36:55 -08:00
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2005-04-16 15:20:36 -07:00
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