2005-04-17 06:20:36 +08:00
|
|
|
/*
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|
|
|
* linux/fs/proc/inode.c
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|
|
|
*
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|
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
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|
|
|
*/
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|
|
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|
|
|
#include <linux/time.h>
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|
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#include <linux/proc_fs.h>
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|
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#include <linux/kernel.h>
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|
|
|
#include <linux/mm.h>
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|
|
#include <linux/string.h>
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|
|
#include <linux/stat.h>
|
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>
2007-07-16 14:39:00 +08:00
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|
|
#include <linux/completion.h>
|
2007-09-12 06:23:55 +08:00
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|
|
#include <linux/poll.h>
|
2005-04-17 06:20:36 +08:00
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|
|
#include <linux/file.h>
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|
|
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#include <linux/limits.h>
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#include <linux/init.h>
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|
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#include <linux/module.h>
|
2008-07-15 20:54:06 +08:00
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|
#include <linux/sysctl.h>
|
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
|
|
|
#include <linux/slab.h>
|
2005-04-17 06:20:36 +08:00
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|
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#include <asm/system.h>
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|
#include <asm/uaccess.h>
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|
|
2006-01-08 17:04:16 +08:00
|
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|
#include "internal.h"
|
2005-04-17 06:20:36 +08:00
|
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|
2010-06-05 10:17:56 +08:00
|
|
|
static void proc_evict_inode(struct inode *inode)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
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|
|
|
struct proc_dir_entry *de;
|
2011-03-08 14:25:28 +08:00
|
|
|
struct ctl_table_header *head;
|
2010-03-08 08:41:34 +08:00
|
|
|
const struct proc_ns_operations *ns_ops;
|
2005-04-17 06:20:36 +08:00
|
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|
2005-09-10 04:01:31 +08:00
|
|
|
truncate_inode_pages(&inode->i_data, 0);
|
2010-06-05 10:17:56 +08:00
|
|
|
end_writeback(inode);
|
2005-09-10 04:01:31 +08:00
|
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|
2006-06-26 15:25:55 +08:00
|
|
|
/* Stop tracking associated processes */
|
2006-06-26 15:25:56 +08:00
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|
|
put_pid(PROC_I(inode)->pid);
|
2005-04-17 06:20:36 +08:00
|
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|
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/* Let go of any associated proc directory entry */
|
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|
|
de = PROC_I(inode)->pde;
|
2009-03-26 03:48:06 +08:00
|
|
|
if (de)
|
2009-12-16 08:45:39 +08:00
|
|
|
pde_put(de);
|
2011-03-08 14:25:28 +08:00
|
|
|
head = PROC_I(inode)->sysctl;
|
|
|
|
if (head) {
|
|
|
|
rcu_assign_pointer(PROC_I(inode)->sysctl, NULL);
|
|
|
|
sysctl_head_put(head);
|
|
|
|
}
|
2010-03-08 08:41:34 +08:00
|
|
|
/* Release any associated namespace */
|
|
|
|
ns_ops = PROC_I(inode)->ns_ops;
|
|
|
|
if (ns_ops && ns_ops->put)
|
|
|
|
ns_ops->put(PROC_I(inode)->ns);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2006-12-07 12:33:20 +08:00
|
|
|
static struct kmem_cache * proc_inode_cachep;
|
2005-04-17 06:20:36 +08:00
|
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|
|
|
|
|
static struct inode *proc_alloc_inode(struct super_block *sb)
|
|
|
|
{
|
|
|
|
struct proc_inode *ei;
|
|
|
|
struct inode *inode;
|
|
|
|
|
2006-12-07 12:33:17 +08:00
|
|
|
ei = (struct proc_inode *)kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!ei)
|
|
|
|
return NULL;
|
2006-06-26 15:25:56 +08:00
|
|
|
ei->pid = NULL;
|
2006-06-26 15:25:44 +08:00
|
|
|
ei->fd = 0;
|
2005-04-17 06:20:36 +08:00
|
|
|
ei->op.proc_get_link = NULL;
|
|
|
|
ei->pde = NULL;
|
2008-07-15 20:54:06 +08:00
|
|
|
ei->sysctl = NULL;
|
|
|
|
ei->sysctl_entry = NULL;
|
2010-03-08 08:41:34 +08:00
|
|
|
ei->ns = NULL;
|
|
|
|
ei->ns_ops = NULL;
|
2005-04-17 06:20:36 +08:00
|
|
|
inode = &ei->vfs_inode;
|
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
|
|
return inode;
|
|
|
|
}
|
|
|
|
|
2011-01-07 14:49:49 +08:00
|
|
|
static void proc_i_callback(struct rcu_head *head)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2011-01-07 14:49:49 +08:00
|
|
|
struct inode *inode = container_of(head, struct inode, i_rcu);
|
|
|
|
INIT_LIST_HEAD(&inode->i_dentry);
|
2005-04-17 06:20:36 +08:00
|
|
|
kmem_cache_free(proc_inode_cachep, PROC_I(inode));
|
|
|
|
}
|
|
|
|
|
2011-01-07 14:49:49 +08:00
|
|
|
static void proc_destroy_inode(struct inode *inode)
|
|
|
|
{
|
|
|
|
call_rcu(&inode->i_rcu, proc_i_callback);
|
|
|
|
}
|
|
|
|
|
2008-07-26 10:45:34 +08:00
|
|
|
static void init_once(void *foo)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
struct proc_inode *ei = (struct proc_inode *) foo;
|
|
|
|
|
2007-05-17 13:10:57 +08:00
|
|
|
inode_init_once(&ei->vfs_inode);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2007-07-20 09:11:58 +08:00
|
|
|
|
2008-10-17 07:43:55 +08:00
|
|
|
void __init proc_init_inodecache(void)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
proc_inode_cachep = kmem_cache_create("proc_inode_cache",
|
|
|
|
sizeof(struct proc_inode),
|
2006-03-24 19:16:06 +08:00
|
|
|
0, (SLAB_RECLAIM_ACCOUNT|
|
2007-10-17 14:26:10 +08:00
|
|
|
SLAB_MEM_SPREAD|SLAB_PANIC),
|
2007-07-20 09:11:58 +08:00
|
|
|
init_once);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2007-02-12 16:55:41 +08:00
|
|
|
static const struct super_operations proc_sops = {
|
2005-04-17 06:20:36 +08:00
|
|
|
.alloc_inode = proc_alloc_inode,
|
|
|
|
.destroy_inode = proc_destroy_inode,
|
|
|
|
.drop_inode = generic_delete_inode,
|
2010-06-05 10:17:56 +08:00
|
|
|
.evict_inode = proc_evict_inode,
|
2005-04-17 06:20:36 +08:00
|
|
|
.statfs = simple_statfs,
|
|
|
|
};
|
|
|
|
|
2008-07-25 16:48:29 +08:00
|
|
|
static void __pde_users_dec(struct proc_dir_entry *pde)
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
{
|
|
|
|
pde->pde_users--;
|
|
|
|
if (pde->pde_unload_completion && pde->pde_users == 0)
|
|
|
|
complete(pde->pde_unload_completion);
|
2008-07-25 16:48:29 +08:00
|
|
|
}
|
|
|
|
|
2009-02-20 22:04:33 +08:00
|
|
|
void pde_users_dec(struct proc_dir_entry *pde)
|
2008-07-25 16:48:29 +08:00
|
|
|
{
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
__pde_users_dec(pde);
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
|
|
|
loff_t rv = -EINVAL;
|
|
|
|
loff_t (*llseek)(struct file *, loff_t, int);
|
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
/*
|
|
|
|
* remove_proc_entry() is going to delete PDE (as part of module
|
|
|
|
* cleanup sequence). No new callers into module allowed.
|
|
|
|
*/
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Bump refcount so that remove_proc_entry will wail for ->llseek to
|
|
|
|
* complete.
|
|
|
|
*/
|
|
|
|
pde->pde_users++;
|
|
|
|
/*
|
|
|
|
* Save function pointer under lock, to protect against ->proc_fops
|
|
|
|
* NULL'ifying right after ->pde_unload_lock is dropped.
|
|
|
|
*/
|
|
|
|
llseek = pde->proc_fops->llseek;
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (!llseek)
|
|
|
|
llseek = default_llseek;
|
|
|
|
rv = llseek(file, offset, whence);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
|
|
|
ssize_t rv = -EIO;
|
|
|
|
ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
|
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
read = pde->proc_fops->read;
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (read)
|
|
|
|
rv = read(file, buf, count, ppos);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
|
|
|
ssize_t rv = -EIO;
|
|
|
|
ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
|
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
write = pde->proc_fops->write;
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (write)
|
|
|
|
rv = write(file, buf, count, ppos);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static unsigned int proc_reg_poll(struct file *file, struct poll_table_struct *pts)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
2007-09-12 06:23:55 +08:00
|
|
|
unsigned int rv = DEFAULT_POLLMASK;
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
unsigned int (*poll)(struct file *, struct poll_table_struct *);
|
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
poll = pde->proc_fops->poll;
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (poll)
|
|
|
|
rv = poll(file, pts);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
|
|
|
long rv = -ENOTTY;
|
2010-07-04 06:15:10 +08:00
|
|
|
long (*ioctl)(struct file *, unsigned int, unsigned long);
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
2010-07-04 06:15:10 +08:00
|
|
|
ioctl = pde->proc_fops->unlocked_ioctl;
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
2010-07-04 06:15:10 +08:00
|
|
|
if (ioctl)
|
|
|
|
rv = ioctl(file, cmd, arg);
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
|
|
|
long rv = -ENOTTY;
|
|
|
|
long (*compat_ioctl)(struct file *, unsigned int, unsigned long);
|
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
compat_ioctl = pde->proc_fops->compat_ioctl;
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (compat_ioctl)
|
|
|
|
rv = compat_ioctl(file, cmd, arg);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
|
|
|
|
int rv = -EIO;
|
|
|
|
int (*mmap)(struct file *, struct vm_area_struct *);
|
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
mmap = pde->proc_fops->mmap;
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (mmap)
|
|
|
|
rv = mmap(file, vma);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int proc_reg_open(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(inode);
|
|
|
|
int rv = 0;
|
|
|
|
int (*open)(struct inode *, struct file *);
|
2008-07-25 16:48:29 +08:00
|
|
|
int (*release)(struct inode *, struct file *);
|
|
|
|
struct pde_opener *pdeo;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* What for, you ask? Well, we can have open, rmmod, remove_proc_entry
|
|
|
|
* sequence. ->release won't be called because ->proc_fops will be
|
|
|
|
* cleared. Depending on complexity of ->release, consequences vary.
|
|
|
|
*
|
|
|
|
* We can't wait for mercy when close will be done for real, it's
|
|
|
|
* deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
|
|
|
|
* by hand in remove_proc_entry(). For this, save opener's credentials
|
|
|
|
* for later.
|
|
|
|
*/
|
|
|
|
pdeo = kmalloc(sizeof(struct pde_opener), GFP_KERNEL);
|
|
|
|
if (!pdeo)
|
|
|
|
return -ENOMEM;
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (!pde->proc_fops) {
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
2008-07-25 16:48:29 +08:00
|
|
|
kfree(pdeo);
|
2011-07-27 07:08:37 +08:00
|
|
|
return -ENOENT;
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
open = pde->proc_fops->open;
|
2008-07-25 16:48:29 +08:00
|
|
|
release = pde->proc_fops->release;
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (open)
|
|
|
|
rv = open(inode, file);
|
|
|
|
|
2008-07-25 16:48:29 +08:00
|
|
|
spin_lock(&pde->pde_unload_lock);
|
|
|
|
if (rv == 0 && release) {
|
|
|
|
/* To know what to release. */
|
|
|
|
pdeo->inode = inode;
|
|
|
|
pdeo->file = file;
|
|
|
|
/* Strictly for "too late" ->release in proc_reg_release(). */
|
|
|
|
pdeo->release = release;
|
|
|
|
list_add(&pdeo->lh, &pde->pde_openers);
|
|
|
|
} else
|
|
|
|
kfree(pdeo);
|
|
|
|
__pde_users_dec(pde);
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
2008-07-25 16:48:29 +08:00
|
|
|
static struct pde_opener *find_pde_opener(struct proc_dir_entry *pde,
|
|
|
|
struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct pde_opener *pdeo;
|
|
|
|
|
|
|
|
list_for_each_entry(pdeo, &pde->pde_openers, lh) {
|
|
|
|
if (pdeo->inode == inode && pdeo->file == file)
|
|
|
|
return pdeo;
|
|
|
|
}
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
static int proc_reg_release(struct inode *inode, struct file *file)
|
|
|
|
{
|
|
|
|
struct proc_dir_entry *pde = PDE(inode);
|
|
|
|
int rv = 0;
|
|
|
|
int (*release)(struct inode *, struct file *);
|
2008-07-25 16:48:29 +08:00
|
|
|
struct pde_opener *pdeo;
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
|
|
|
|
spin_lock(&pde->pde_unload_lock);
|
2008-07-25 16:48:29 +08:00
|
|
|
pdeo = find_pde_opener(pde, inode, file);
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
if (!pde->proc_fops) {
|
2008-07-25 16:48:29 +08:00
|
|
|
/*
|
|
|
|
* Can't simply exit, __fput() will think that everything is OK,
|
|
|
|
* and move on to freeing struct file. remove_proc_entry() will
|
|
|
|
* find slacker in opener's list and will try to do non-trivial
|
|
|
|
* things with struct file. Therefore, remove opener from list.
|
|
|
|
*
|
|
|
|
* But if opener is removed from list, who will ->release it?
|
|
|
|
*/
|
|
|
|
if (pdeo) {
|
|
|
|
list_del(&pdeo->lh);
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
rv = pdeo->release(inode, file);
|
|
|
|
kfree(pdeo);
|
|
|
|
} else
|
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
pde->pde_users++;
|
|
|
|
release = pde->proc_fops->release;
|
2008-07-25 16:48:29 +08:00
|
|
|
if (pdeo) {
|
|
|
|
list_del(&pdeo->lh);
|
|
|
|
kfree(pdeo);
|
|
|
|
}
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
spin_unlock(&pde->pde_unload_lock);
|
|
|
|
|
|
|
|
if (release)
|
|
|
|
rv = release(inode, file);
|
|
|
|
|
|
|
|
pde_users_dec(pde);
|
|
|
|
return rv;
|
|
|
|
}
|
|
|
|
|
|
|
|
static const struct file_operations proc_reg_file_ops = {
|
|
|
|
.llseek = proc_reg_llseek,
|
|
|
|
.read = proc_reg_read,
|
|
|
|
.write = proc_reg_write,
|
|
|
|
.poll = proc_reg_poll,
|
|
|
|
.unlocked_ioctl = proc_reg_unlocked_ioctl,
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
.compat_ioctl = proc_reg_compat_ioctl,
|
|
|
|
#endif
|
|
|
|
.mmap = proc_reg_mmap,
|
|
|
|
.open = proc_reg_open,
|
|
|
|
.release = proc_reg_release,
|
|
|
|
};
|
|
|
|
|
2007-07-28 13:58:37 +08:00
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
static const struct file_operations proc_reg_file_ops_no_compat = {
|
|
|
|
.llseek = proc_reg_llseek,
|
|
|
|
.read = proc_reg_read,
|
|
|
|
.write = proc_reg_write,
|
|
|
|
.poll = proc_reg_poll,
|
|
|
|
.unlocked_ioctl = proc_reg_unlocked_ioctl,
|
|
|
|
.mmap = proc_reg_mmap,
|
|
|
|
.open = proc_reg_open,
|
|
|
|
.release = proc_reg_release,
|
|
|
|
};
|
|
|
|
#endif
|
|
|
|
|
2011-01-13 09:00:33 +08:00
|
|
|
struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
struct inode * inode;
|
|
|
|
|
2011-01-13 09:00:33 +08:00
|
|
|
inode = iget_locked(sb, de->low_ino);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!inode)
|
2009-03-26 03:48:06 +08:00
|
|
|
return NULL;
|
2008-02-07 16:15:45 +08:00
|
|
|
if (inode->i_state & I_NEW) {
|
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
|
|
|
|
PROC_I(inode)->fd = 0;
|
|
|
|
PROC_I(inode)->pde = de;
|
2008-04-29 16:01:41 +08:00
|
|
|
|
|
|
|
if (de->mode) {
|
|
|
|
inode->i_mode = de->mode;
|
|
|
|
inode->i_uid = de->uid;
|
|
|
|
inode->i_gid = de->gid;
|
|
|
|
}
|
|
|
|
if (de->size)
|
|
|
|
inode->i_size = de->size;
|
|
|
|
if (de->nlink)
|
2011-10-28 20:13:29 +08:00
|
|
|
set_nlink(inode, de->nlink);
|
2008-04-29 16:01:41 +08:00
|
|
|
if (de->proc_iops)
|
|
|
|
inode->i_op = de->proc_iops;
|
|
|
|
if (de->proc_fops) {
|
|
|
|
if (S_ISREG(inode->i_mode)) {
|
2007-07-28 13:58:37 +08:00
|
|
|
#ifdef CONFIG_COMPAT
|
2008-04-29 16:01:41 +08:00
|
|
|
if (!de->proc_fops->compat_ioctl)
|
|
|
|
inode->i_fop =
|
|
|
|
&proc_reg_file_ops_no_compat;
|
|
|
|
else
|
2007-07-28 13:58:37 +08:00
|
|
|
#endif
|
2008-04-29 16:01:41 +08:00
|
|
|
inode->i_fop = &proc_reg_file_ops;
|
|
|
|
} else {
|
|
|
|
inode->i_fop = de->proc_fops;
|
2007-07-28 13:58:37 +08:00
|
|
|
}
|
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>
2007-07-16 14:39:00 +08:00
|
|
|
}
|
2008-02-07 16:15:45 +08:00
|
|
|
unlock_new_inode(inode);
|
2009-03-26 03:48:06 +08:00
|
|
|
} else
|
2009-12-16 08:45:39 +08:00
|
|
|
pde_put(de);
|
2005-04-17 06:20:36 +08:00
|
|
|
return inode;
|
|
|
|
}
|
|
|
|
|
2007-10-19 14:40:08 +08:00
|
|
|
int proc_fill_super(struct super_block *s)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
struct inode * root_inode;
|
|
|
|
|
2006-07-16 03:20:05 +08:00
|
|
|
s->s_flags |= MS_NODIRATIME | MS_NOSUID | MS_NOEXEC;
|
2005-04-17 06:20:36 +08:00
|
|
|
s->s_blocksize = 1024;
|
|
|
|
s->s_blocksize_bits = 10;
|
|
|
|
s->s_magic = PROC_SUPER_MAGIC;
|
|
|
|
s->s_op = &proc_sops;
|
|
|
|
s->s_time_gran = 1;
|
|
|
|
|
2009-12-16 08:45:39 +08:00
|
|
|
pde_get(&proc_root);
|
2011-01-13 09:00:33 +08:00
|
|
|
root_inode = proc_get_inode(s, &proc_root);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!root_inode)
|
|
|
|
goto out_no_root;
|
|
|
|
root_inode->i_uid = 0;
|
|
|
|
root_inode->i_gid = 0;
|
|
|
|
s->s_root = d_alloc_root(root_inode);
|
|
|
|
if (!s->s_root)
|
|
|
|
goto out_no_root;
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
out_no_root:
|
|
|
|
printk("proc_read_super: get root inode failed\n");
|
|
|
|
iput(root_inode);
|
2009-12-16 08:45:39 +08:00
|
|
|
pde_put(&proc_root);
|
2005-04-17 06:20:36 +08:00
|
|
|
return -ENOMEM;
|
|
|
|
}
|