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path: root/fs/proc/proc_net.c
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2008-02-08proc: fix ->open'less usage due to ->proc_fops flipAlexey Dobriyan
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>
2008-01-28[ATM]: Oops reading net/atm/arpDenis V. Lunev
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 <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NET]: Consolidate net namespace related proc files creation.Denis V. Lunev
Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-12-02[NETNS]: Fix /proc/net breakageEric W. Biederman
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 <ebiederm@xmission.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2007-11-13[NET]: Move unneeded data to initdata section.Denis V. Lunev
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 <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-07[NET]: Kill proc_net_create()David S. Miller
There are no more users. Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-26[NET]: Marking struct pernet_operations __net_initdata was inappropriateEric W. Biederman
It is not safe to to place struct pernet_operations in a special section. We need struct pernet_operations to last until we call unregister_pernet_subsys. Which doesn't happen until module unload. So marking struct pernet_operations is a disaster for modules in two ways. - We discard it before we call the exit method it points to. - Because I keep struct pernet_operations on a linked list discarding it for compiled in code removes elements in the middle of a linked list and does horrible things for linked insert. So this looks safe assuming __exit_refok is not discarded for modules. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-26[NET] fs/proc/proc_net.c: make a struct staticAdrian Bunk
Struct proc_net_ns_ops can become static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NETNS]: Move some code into __init section when CONFIG_NET_NS=nPavel Emelyanov
With the net namespaces many code leaved the __init section, thus making the kernel occupy more memory than it did before. Since we have a config option that prohibits the namespace creation, the functions that initialize/finalize some netns stuff are simply not needed and can be freed after the boot. Currently, this is almost not noticeable, since few calls are no longer in __init, but when the namespaces will be merged it will be possible to free more code. I propose to use the __net_init, __net_exit and __net_initdata "attributes" for functions/variables that are not used if the CONFIG_NET_NS is not set to save more space in memory. The exiting functions cannot just reside in the __exit section, as noticed by David, since the init section will have references on it and the compilation will fail due to modpost checks. These references can exist, since the init namespace never dies and the exit callbacks are never called. So I introduce the __exit_refok attribute just like it is already done with the __init_refok. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET]: Fix race when opening a proc file while a network namespace is exiting.Eric W. Biederman
The problem: proc_net files remember which network namespace the are against but do not remember hold a reference count (as that would pin the network namespace). So we currently have a small window where the reference count on a network namespace may be incremented when opening a /proc file when it has already gone to zero. To fix this introduce maybe_get_net and get_proc_net. maybe_get_net increments the network namespace reference count only if it is greater then zero, ensuring we don't increment a reference count after it has gone to zero. get_proc_net handles all of the magic to go from a proc inode to the network namespace instance and call maybe_get_net on it. PROC_NET the old accessor is removed so that we don't get confused and use the wrong helper function. Then I fix up the callers to use get_proc_net and handle the case case where get_proc_net returns NULL. In that case I return -ENXIO because effectively the network namespace has already gone away so the files we are trying to access don't exist anymore. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NETNS]: Fix export symbols.Daniel Lezcano
Add the appropriate EXPORT_SYMBOLS for proc_net_create, proc_net_fops_create and proc_net_remove to fix errors when compiling allmodconfig Signed-off-by: Mark Nelson <markn@au1.ibm.com> Acked-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET]: Fix missed addition of fs/proc/proc_net.cDavid S. Miller
My bad. Signed-off-by: David S. Miller <davem@davemloft.net>