Extract "Protocol" field decompression code from transport protocols to
PPP generic layer, where it actually belongs. As a consequence, this
patch fixes incorrect place of PFC decompression in L2TP driver (when
it's not PPPOX_BOUND) and also enables this decompression for other
protocols, like PPPoE.
Protocol field decompression also happens in PPP Multilink Protocol
code and in PPP compression protocols implementations (bsd, deflate,
mppe). It looks like there is no easy way to get rid of that, so it was
decided to leave it as is, but provide those cases with appropriate
comments instead.
Changes in v2:
- Fix the order of checking skb data room and proto decompression
- Remove "inline" keyword from ppp_decompress_proto()
- Don't split line before function name
- Prefix ppp_decompress_proto() function with "__"
- Add ppp_decompress_proto() function with skb data room checks
- Add description for introduced functions
- Fix comments (as per review on mailing list)
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
The PPPIOCDETACH ioctl effectively tries to "close" the given ppp file
before f_count has reached 0, which is fundamentally a bad idea. It
does check 'f_count < 2', which excludes concurrent operations on the
file since they would only be possible with a shared fd table, in which
case each fdget() would take a file reference. However, it fails to
account for the fact that even with 'f_count == 1' the file can still be
linked into epoll instances. As reported by syzbot, this can trivially
be used to cause a use-after-free.
Yet, the only known user of PPPIOCDETACH is pppd versions older than
ppp-2.4.2, which was released almost 15 years ago (November 2003).
Also, PPPIOCDETACH apparently stopped working reliably at around the
same time, when the f_count check was added to the kernel, e.g. see
https://lkml.org/lkml/2002/12/31/83. Also, the current 'f_count < 2'
check makes PPPIOCDETACH only work in single-threaded applications; it
always fails if called from a multithreaded application.
All pppd versions released in the last 15 years just close() the file
descriptor instead.
Therefore, instead of hacking around this bug by exporting epoll
internals to modules, and probably missing other related bugs, just
remove the PPPIOCDETACH ioctl and see if anyone actually notices. Leave
a stub in place that prints a one-time warning and returns EINVAL.
Reported-by: syzbot+16363c99d4134717c05b@syzkaller.appspotmail.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Guillaume Nault <g.nault@alphalink.fr>
Tested-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Synchronous pernet_operations are not allowed anymore.
All are asynchronous. So, drop the structure member.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Prefer the direct use of octal for permissions.
Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.
Miscellanea:
o Whitespace neatening around these conversions.
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fun set of conflict resolutions here...
For the mac80211 stuff, these were fortunately just parallel
adds. Trivially resolved.
In drivers/net/phy/phy.c we had a bug fix in 'net' that moved the
function phy_disable_interrupts() earlier in the file, whilst in
'net-next' the phy_error() call from this function was removed.
In net/ipv4/xfrm4_policy.c, David Ahern's changes to remove the
'rt_table_id' member of rtable collided with a bug fix in 'net' that
added a new struct member "rt_mtu_locked" which needs to be copied
over here.
The mlxsw driver conflict consisted of net-next separating
the span code and definitions into separate files, whilst
a 'net' bug fix made some changes to that moved code.
The mlx5 infiniband conflict resolution was quite non-trivial,
the RDMA tree's merge commit was used as a guide here, and
here are their notes:
====================
Due to bug fixes found by the syzkaller bot and taken into the for-rc
branch after development for the 4.17 merge window had already started
being taken into the for-next branch, there were fairly non-trivial
merge issues that would need to be resolved between the for-rc branch
and the for-next branch. This merge resolves those conflicts and
provides a unified base upon which ongoing development for 4.17 can
be based.
Conflicts:
drivers/infiniband/hw/mlx5/main.c - Commit 42cea83f95
(IB/mlx5: Fix cleanup order on unload) added to for-rc and
commit b5ca15ad7e (IB/mlx5: Add proper representors support)
add as part of the devel cycle both needed to modify the
init/de-init functions used by mlx5. To support the new
representors, the new functions added by the cleanup patch
needed to be made non-static, and the init/de-init list
added by the representors patch needed to be modified to
match the init/de-init list changes made by the cleanup
patch.
Updates:
drivers/infiniband/hw/mlx5/mlx5_ib.h - Update function
prototypes added by representors patch to reflect new function
names as changed by cleanup patch
drivers/infiniband/hw/mlx5/ib_rep.c - Update init/de-init
stage list to match new order from cleanup patch
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
We already detect situations where a PPP channel sends packets back to
its upper PPP device. While this is enough to avoid deadlocking on xmit
locks, this doesn't prevent packets from looping between the channel
and the unit.
The problem is that ppp_start_xmit() enqueues packets in ppp->file.xq
before checking for xmit recursion. Therefore, __ppp_xmit_process()
might dequeue a packet from ppp->file.xq and send it on the channel
which, in turn, loops it back on the unit. Then ppp_start_xmit()
queues the packet back to ppp->file.xq and __ppp_xmit_process() picks
it up and sends it again through the channel. Therefore, the packet
will loop between __ppp_xmit_process() and ppp_start_xmit() until some
other part of the xmit path drops it.
For L2TP, we rapidly fill the skb's headroom and pppol2tp_xmit() drops
the packet after a few iterations. But PPTP reallocates the headroom
if necessary, letting the loop run and exhaust the machine resources
(as reported in https://bugzilla.kernel.org/show_bug.cgi?id=199109).
Fix this by letting __ppp_xmit_process() enqueue the skb to
ppp->file.xq, so that we can check for recursion before adding it to
the queue. Now ppp_xmit_process() can drop the packet when recursion is
detected.
__ppp_channel_push() is a bit special. It calls __ppp_xmit_process()
without having any actual packet to send. This is used by
ppp_output_wakeup() to re-enable transmission on the parent unit (for
implementations like ppp_async.c, where the .start_xmit() function
might not consume the skb, leaving it in ppp->xmit_pending and
disabling transmission).
Therefore, __ppp_xmit_process() needs to handle the case where skb is
NULL, dequeuing as many packets as possible from ppp->file.xq.
Reported-by: xu heng <xuheng333@zoho.com>
Fixes: 55454a5658 ("ppp: avoid dealock on recursive xmit")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
All of the conflicts were cases of overlapping changes.
In net/core/devlink.c, we have to make care that the
resouce size_params have become a struct member rather
than a pointer to such an object.
Signed-off-by: David S. Miller <davem@davemloft.net>
PPP units don't hold any reference on the channels connected to it.
It is the channel's responsibility to ensure that it disconnects from
its unit before being destroyed.
In practice, this is ensured by ppp_unregister_channel() disconnecting
the channel from the unit before dropping a reference on the channel.
However, it is possible for an unregistered channel to connect to a PPP
unit: register a channel with ppp_register_net_channel(), attach a
/dev/ppp file to it with ioctl(PPPIOCATTCHAN), unregister the channel
with ppp_unregister_channel() and finally connect the /dev/ppp file to
a PPP unit with ioctl(PPPIOCCONNECT).
Once in this situation, the channel is only held by the /dev/ppp file,
which can be released at anytime and free the channel without letting
the parent PPP unit know. Then the ppp structure ends up with dangling
pointers in its ->channels list.
Prevent this scenario by forbidding unregistered channels from
connecting to PPP units. This maintains the code logic by keeping
ppp_unregister_channel() responsible from disconnecting the channel if
necessary and avoids modification on the reference counting mechanism.
This issue seems to predate git history (successfully reproduced on
Linux 2.6.26 and earlier PPP commits are unrelated).
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
These pernet_operations are similar to bond_net_ops. Exit method
unregisters all net ppp devices, and it looks like another
pernet_operations are not interested in foreign net ppp list.
So, it's possible to mark them async.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:
for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
for f in $L; do sed -i "-es/^\([^\"]*\)\(\<POLL$V\>\)/\\1E\\2/" $f; done
done
with de-mangling cleanups yet to come.
NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do. But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.
The next patch from Al will sort out the final differences, and we
should be all done.
Scripted-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull poll annotations from Al Viro:
"This introduces a __bitwise type for POLL### bitmap, and propagates
the annotations through the tree. Most of that stuff is as simple as
'make ->poll() instances return __poll_t and do the same to local
variables used to hold the future return value'.
Some of the obvious brainos found in process are fixed (e.g. POLLIN
misspelled as POLL_IN). At that point the amount of sparse warnings is
low and most of them are for genuine bugs - e.g. ->poll() instance
deciding to return -EINVAL instead of a bitmap. I hadn't touched those
in this series - it's large enough as it is.
Another problem it has caught was eventpoll() ABI mess; select.c and
eventpoll.c assumed that corresponding POLL### and EPOLL### were
equal. That's true for some, but not all of them - EPOLL### are
arch-independent, but POLL### are not.
The last commit in this series separates userland POLL### values from
the (now arch-independent) kernel-side ones, converting between them
in the few places where they are copied to/from userland. AFAICS, this
is the least disruptive fix preserving poll(2) ABI and making epoll()
work on all architectures.
As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and
it will trigger only on what would've triggered EPOLLWRBAND on other
architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered
at all on sparc. With this patch they should work consistently on all
architectures"
* 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
make kernel-side POLL... arch-independent
eventpoll: no need to mask the result of epi_item_poll() again
eventpoll: constify struct epoll_event pointers
debugging printk in sg_poll() uses %x to print POLL... bitmap
annotate poll(2) guts
9p: untangle ->poll() mess
->si_band gets POLL... bitmap stored into a user-visible long field
ring_buffer_poll_wait() return value used as return value of ->poll()
the rest of drivers/*: annotate ->poll() instances
media: annotate ->poll() instances
fs: annotate ->poll() instances
ipc, kernel, mm: annotate ->poll() instances
net: annotate ->poll() instances
apparmor: annotate ->poll() instances
tomoyo: annotate ->poll() instances
sound: annotate ->poll() instances
acpi: annotate ->poll() instances
crypto: annotate ->poll() instances
block: annotate ->poll() instances
x86: annotate ->poll() instances
...
ppp_dev_uninit(), which is the .ndo_uninit() handler of PPP devices,
needs to lock pn->all_ppp_mutex. Therefore we mustn't call
register_netdevice() with pn->all_ppp_mutex already locked, or we'd
deadlock in case register_netdevice() fails and calls .ndo_uninit().
Fortunately, we can unlock pn->all_ppp_mutex before calling
register_netdevice(). This lock protects pn->units_idr, which isn't
used in the device registration process.
However, keeping pn->all_ppp_mutex locked during device registration
did ensure that no device in transient state would be published in
pn->units_idr. In practice, unlocking it before calling
register_netdevice() doesn't change this property: ppp_unit_register()
is called with 'ppp_mutex' locked and all searches done in
pn->units_idr hold this lock too.
Fixes: 8cb775bc0a ("ppp: fix device unregistration upon netns deletion")
Reported-and-tested-by: syzbot+367889b9c9e279219175@syzkaller.appspotmail.com
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Be sure that lists initialized in net_init hook were return
to initial state.
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The mutex_destroy only makes sense when enable DEBUG_MUTEX. For the
good readbility, it's better to invoke it in exit func when the init
func invokes mutex_init.
Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Check for CAP_NET_ADMIN with ns_capable() instead of capable()
to allow usage of ppp in user namespace other than the init one.
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable ppp_file.refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ppp_release() tries to ensure that netdevices are unregistered before
decrementing the unit refcount and running ppp_destroy_interface().
This is all fine as long as the the device is unregistered by
ppp_release(): the unregister_netdevice() call, followed by
rtnl_unlock(), guarantee that the unregistration process completes
before rtnl_unlock() returns.
However, the device may be unregistered by other means (like
ppp_nl_dellink()). If this happens right before ppp_release() calling
rtnl_lock(), then ppp_release() has to wait for the concurrent
unregistration code to release the lock.
But rtnl_unlock() releases the lock before completing the device
unregistration process. This allows ppp_release() to proceed and
eventually call ppp_destroy_interface() before the unregistration
process completes. Calling free_netdev() on this partially unregistered
device will BUG():
------------[ cut here ]------------
kernel BUG at net/core/dev.c:8141!
invalid opcode: 0000 [#1] SMP
CPU: 1 PID: 1557 Comm: pppd Not tainted 4.14.0-rc2+ #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc26 04/01/2014
Call Trace:
ppp_destroy_interface+0xd8/0xe0 [ppp_generic]
ppp_disconnect_channel+0xda/0x110 [ppp_generic]
ppp_unregister_channel+0x5e/0x110 [ppp_generic]
pppox_unbind_sock+0x23/0x30 [pppox]
pppoe_connect+0x130/0x440 [pppoe]
SYSC_connect+0x98/0x110
? do_fcntl+0x2c0/0x5d0
SyS_connect+0xe/0x10
entry_SYSCALL_64_fastpath+0x1a/0xa5
RIP: free_netdev+0x107/0x110 RSP: ffffc28a40573d88
---[ end trace ed294ff0cc40eeff ]---
We could set the ->needs_free_netdev flag on PPP devices and move the
ppp_destroy_interface() logic in the ->priv_destructor() callback. But
that'd be quite intrusive as we'd first need to unlink from the other
channels and units that depend on the device (the ones that used the
PPPIOCCONNECT and PPPIOCATTACH ioctls).
Instead, we can just let the netdevice hold a reference on its
ppp_file. This reference is dropped in ->priv_destructor(), at the very
end of the unregistration process, so that neither ppp_release() nor
ppp_disconnect_channel() can call ppp_destroy_interface() in the interim.
Reported-by: Beniamino Galvani <bgalvani@redhat.com>
Fixes: 8cb775bc0a ("ppp: fix device unregistration upon netns deletion")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit e5dadc65f9 ("ppp: Fix false xmit recursion detect with two ppp
devices") dropped the xmit_recursion counter incrementation in
ppp_channel_push() and relied on ppp_xmit_process() for this task.
But __ppp_channel_push() can also send packets directly (using the
.start_xmit() channel callback), in which case the xmit_recursion
counter isn't incremented anymore. If such packets get routed back to
the parent ppp unit, ppp_xmit_process() won't notice the recursion and
will call ppp_channel_push() on the same channel, effectively creating
the deadlock situation that the xmit_recursion mechanism was supposed
to prevent.
This patch re-introduces the xmit_recursion counter incrementation in
ppp_channel_push(). Since the xmit_recursion variable is now part of
the parent ppp unit, incrementation is skipped if the channel doesn't
have any. This is fine because only packets routed through the parent
unit may enter the channel recursively.
Finally, we have to ensure that pch->ppp is not going to be modified
while executing ppp_channel_push(). Instead of taking this lock only
while calling ppp_xmit_process(), we now have to hold it for the full
ppp_channel_push() execution. This respects the ppp locks ordering
which requires locking ->upl before ->downl.
Fixes: e5dadc65f9 ("ppp: Fix false xmit recursion detect with two ppp devices")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
The global percpu variable ppp_xmit_recursion is used to detect the ppp
xmit recursion to avoid the deadlock, which is caused by one CPU tries to
lock the xmit lock twice. But it would report false recursion when one CPU
wants to send the skb from two different PPP devices, like one L2TP on the
PPPoE. It is a normal case actually.
Now use one percpu member of struct ppp instead of the gloable variable to
detect the xmit recursion of one ppp device.
Fixes: 55454a5658 ("ppp: avoid dealock on recursive xmit")
Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Signed-off-by: Liu Jianying <jianying.liu@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for extended error reporting.
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for extended error reporting.
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.
Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:
@@
expression SKB, LEN;
typedef u8;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
@@
- *(fn(SKB, LEN))
+ *(u8 *)fn(SKB, LEN)
@@
expression E, SKB, LEN;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
type T;
@@
- E = ((T *)(fn(SKB, LEN)))
+ E = fn(SKB, LEN)
@@
expression SKB, LEN;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
@@
- fn(SKB, LEN)[0]
+ *(u8 *)fn(SKB, LEN)
Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since the commit 55454a5658 ("ppp: avoid dealock on recursive xmit"),
the PPP xmit path is protected by wrapper functions which disable the
bh already. So it is unnecessary to disable the bh again in the real
xmit path.
Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Acked-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix up affected files that include this signal functionality via sched.h.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The network device operation for reading statistics is only called
in one place, and it ignores the return value. Having a structure
return value is potentially confusing because some future driver could
incorrectly assume that the return value was used.
Fix all drivers with ndo_get_stats64 to have a void function.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Make struct pernet_operations::id unsigned.
There are 2 reasons to do so:
1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.
2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.
"int" being used as an array index needs to be sign-extended
to 64-bit before being used.
void f(long *p, int i)
{
g(p[i]);
}
roughly translates to
movsx rsi, esi
mov rdi, [rsi+...]
call g
MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.
Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:
static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}
And this function is used a lot, so those sign extensions add up.
Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]
However, overall balance is in negative direction:
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In case of misconfiguration, a virtual PPP channel might send packets
back to their parent PPP interface. This typically happens in
misconfigured L2TP setups, where PPP's peer IP address is set with the
IP of the L2TP peer.
When that happens the system hangs due to PPP trying to recursively
lock its xmit path.
[ 243.332155] BUG: spinlock recursion on CPU#1, accel-pppd/926
[ 243.333272] lock: 0xffff880033d90f18, .magic: dead4ead, .owner: accel-pppd/926, .owner_cpu: 1
[ 243.334859] CPU: 1 PID: 926 Comm: accel-pppd Not tainted 4.8.0-rc2 #1
[ 243.336010] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[ 243.336018] ffff7fffffffffff ffff8800319a77a0 ffffffff8128de85 ffff880033d90f18
[ 243.336018] ffff880033ad8000 ffff8800319a77d8 ffffffff810ad7c0 ffffffff0000039e
[ 243.336018] ffff880033d90f18 ffff880033d90f60 ffff880033d90f18 ffff880033d90f28
[ 243.336018] Call Trace:
[ 243.336018] [<ffffffff8128de85>] dump_stack+0x4f/0x65
[ 243.336018] [<ffffffff810ad7c0>] spin_dump+0xe1/0xeb
[ 243.336018] [<ffffffff810ad7f0>] spin_bug+0x26/0x28
[ 243.336018] [<ffffffff810ad8b9>] do_raw_spin_lock+0x5c/0x160
[ 243.336018] [<ffffffff815522aa>] _raw_spin_lock_bh+0x35/0x3c
[ 243.336018] [<ffffffffa01a88e2>] ? ppp_push+0xa7/0x82d [ppp_generic]
[ 243.336018] [<ffffffffa01a88e2>] ppp_push+0xa7/0x82d [ppp_generic]
[ 243.336018] [<ffffffff810adada>] ? do_raw_spin_unlock+0xc2/0xcc
[ 243.336018] [<ffffffff81084962>] ? preempt_count_sub+0x13/0xc7
[ 243.336018] [<ffffffff81552438>] ? _raw_spin_unlock_irqrestore+0x34/0x49
[ 243.336018] [<ffffffffa01ac657>] ppp_xmit_process+0x48/0x877 [ppp_generic]
[ 243.336018] [<ffffffff81084962>] ? preempt_count_sub+0x13/0xc7
[ 243.336018] [<ffffffff81408cd3>] ? skb_queue_tail+0x71/0x7c
[ 243.336018] [<ffffffffa01ad1c5>] ppp_start_xmit+0x21b/0x22a [ppp_generic]
[ 243.336018] [<ffffffff81426af1>] dev_hard_start_xmit+0x15e/0x32c
[ 243.336018] [<ffffffff81454ed7>] sch_direct_xmit+0xd6/0x221
[ 243.336018] [<ffffffff814273a8>] __dev_queue_xmit+0x52a/0x820
[ 243.336018] [<ffffffff814276a9>] dev_queue_xmit+0xb/0xd
[ 243.336018] [<ffffffff81430a3c>] neigh_direct_output+0xc/0xe
[ 243.336018] [<ffffffff8146b5d7>] ip_finish_output2+0x4d2/0x548
[ 243.336018] [<ffffffff8146a8e6>] ? dst_mtu+0x29/0x2e
[ 243.336018] [<ffffffff8146d49c>] ip_finish_output+0x152/0x15e
[ 243.336018] [<ffffffff8146df84>] ? ip_output+0x74/0x96
[ 243.336018] [<ffffffff8146df9c>] ip_output+0x8c/0x96
[ 243.336018] [<ffffffff8146d55e>] ip_local_out+0x41/0x4a
[ 243.336018] [<ffffffff8146dd15>] ip_queue_xmit+0x531/0x5c5
[ 243.336018] [<ffffffff814a82cd>] ? udp_set_csum+0x207/0x21e
[ 243.336018] [<ffffffffa01f2f04>] l2tp_xmit_skb+0x582/0x5d7 [l2tp_core]
[ 243.336018] [<ffffffffa01ea458>] pppol2tp_xmit+0x1eb/0x257 [l2tp_ppp]
[ 243.336018] [<ffffffffa01acf17>] ppp_channel_push+0x91/0x102 [ppp_generic]
[ 243.336018] [<ffffffffa01ad2d8>] ppp_write+0x104/0x11c [ppp_generic]
[ 243.336018] [<ffffffff811a3c1e>] __vfs_write+0x56/0x120
[ 243.336018] [<ffffffff81239801>] ? fsnotify_perm+0x27/0x95
[ 243.336018] [<ffffffff8123ab01>] ? security_file_permission+0x4d/0x54
[ 243.336018] [<ffffffff811a4ca4>] vfs_write+0xbd/0x11b
[ 243.336018] [<ffffffff811a5a0a>] SyS_write+0x5e/0x96
[ 243.336018] [<ffffffff81552a1b>] entry_SYSCALL_64_fastpath+0x13/0x94
The main entry points for sending packets over a PPP unit are the
.write() and .ndo_start_xmit() callbacks (simplified view):
.write(unit fd) or .ndo_start_xmit()
\
CALL ppp_xmit_process()
\
LOCK unit's xmit path (ppp->wlock)
|
CALL ppp_push()
\
LOCK channel's xmit path (chan->downl)
|
CALL lower layer's .start_xmit() callback
\
... might recursively call .ndo_start_xmit() ...
/
RETURN from .start_xmit()
|
UNLOCK channel's xmit path
/
RETURN from ppp_push()
|
UNLOCK unit's xmit path
/
RETURN from ppp_xmit_process()
Packets can also be directly sent on channels (e.g. LCP packets):
.write(channel fd) or ppp_output_wakeup()
\
CALL ppp_channel_push()
\
LOCK channel's xmit path (chan->downl)
|
CALL lower layer's .start_xmit() callback
\
... might call .ndo_start_xmit() ...
/
RETURN from .start_xmit()
|
UNLOCK channel's xmit path
/
RETURN from ppp_channel_push()
Key points about the lower layer's .start_xmit() callback:
* It can be called directly by a channel fd .write() or by
ppp_output_wakeup() or indirectly by a unit fd .write() or by
.ndo_start_xmit().
* In any case, it's always called with chan->downl held.
* It might route the packet back to its parent unit using
.ndo_start_xmit() as entry point.
This patch detects and breaks recursion in ppp_xmit_process(). This
function is a good candidate for the task because it's called early
enough after .ndo_start_xmit(), it's always part of the recursion
loop and it's on the path of whatever entry point is used to send
a packet on a PPP unit.
Recursion detection is done using the per-cpu ppp_xmit_recursion
variable.
Since ppp_channel_push() too locks the channel's xmit path and calls
the lower layer's .start_xmit() callback, we need to also increment
ppp_xmit_recursion there. However there's no need to check for
recursion, as it's out of the recursion loop.
Reported-by: Feng Gao <gfree.wind@gmail.com>
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Userspace programs generally need to know the name of the ppp devices
they create. Both ioctl and rtnl interfaces use the ppp<suffix> sheme
to name them. But although the suffix used by the ioctl interface can
be known by userspace (it's the PPP unit identifier returned by the
PPPIOCGUNIT ioctl), the one used by the rtnl is only known by the
kernel.
This patch brings more consistency between ioctl and rtnl based ppp
devices by generating device names using the PPP unit identifer as
suffix in both cases. This way, userspace can always infer the name of
the devices they create.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Matt reported that we have a NULL pointer dereference
in ppp_pernet() from ppp_connect_channel(),
i.e. pch->chan_net is NULL.
This is due to that a parallel ppp_unregister_channel()
could happen while we are in ppp_connect_channel(), during
which pch->chan_net set to NULL. Since we need a reference
to net per channel, it makes sense to sync the refcnt
with the life time of the channel, therefore we should
release this reference when we destroy it.
Fixes: 1f461dcdd2 ("ppp: take reference on channels netns")
Reported-by: Matt Bennett <Matt.Bennett@alliedtelesis.co.nz>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linux-ppp@vger.kernel.org
Cc: Guillaume Nault <g.nault@alphalink.fr>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is time to add netdev_lockdep_set_classes() helper
so that lockdep annotations per device type are easier to manage.
This removes a lot of copies and missing annotations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of using a single bit (__QDISC___STATE_RUNNING)
in sch->__state, use a seqcount.
This adds lockdep support, but more importantly it will allow us
to sample qdisc/class statistics without having to grab qdisc root lock.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Define PPP device handler for use with rtnetlink.
The only PPP specific attribute is IFLA_PPP_DEV_FD. It is mandatory and
contains the file descriptor of the associated /dev/ppp instance (the
file descriptor which would have been used for ioctl(PPPIOCNEWUNIT) in
the ioctl-based API). The PPP device is removed when this file
descriptor is released (same behaviour as with ioctl based PPP
devices).
PPP devices created with the rtnetlink API behave like the ones created
with ioctl(PPPIOCNEWUNIT). In particular existing ioctls work the same
way, no matter how the PPP device was created.
The rtnl callbacks are also assigned to ioctl based PPP devices. This
way, rtnl messages have the same effect on any PPP devices.
The immediate effect is that all PPP devices, even ioctl-based
ones, can now be removed with "ip link del".
A minor difference still exists between ioctl and rtnl based PPP
interfaces: in the device name, the number following the "ppp" prefix
corresponds to the PPP unit number for ioctl based devices, while it is
just an unrelated incrementing index for rtnl ones.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move PPP device initialisation and registration out of
ppp_create_interface().
This prepares code for device registration with rtnetlink.
While there, simplify the prototype of ppp_create_interface():
* Since ppp_dev_configure() takes care of setting file->private_data,
there's no need to return a ppp structure to ppp_unattached_ioctl()
anymore.
* The unit parameter is made read/write so that ppp_create_interface()
can tell which unit number has been assigned.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Locking ppp_mutex must be done before dereferencing file->private_data,
otherwise it could be modified before ppp_unattached_ioctl() takes the
lock. This could lead ppp_unattached_ioctl() to override ->private_data,
thus leaking reference to the ppp_file previously pointed to.
v2: lock all ppp_ioctl() instead of just checking private_data in
ppp_unattached_ioctl(), to avoid ambiguous behaviour.
Fixes: f3ff8a4d80 ("ppp: push BKL down into the driver")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Several cases of overlapping changes, as well as one instance
(vxlan) of a bug fix in 'net' overlapping with code movement
in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing rtnl_unlock() in the error path of ppp_create_interface().
Fixes: 58a89ecaca ("ppp: fix lockdep splat in ppp_dev_uninit()")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
ppp_read() and ppp_poll() can be called concurrently with ppp_ioctl().
In this case, ppp_ioctl() might call ppp_ccp_closed(), which may update
ppp->flags while ppp_read() or ppp_poll() is reading it.
The update done by ppp_ccp_closed() isn't atomic due to the bit mask
operation ('ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP)'), so concurrent
readers might get transient values.
Reading incorrect ppp->flags may disturb the 'ppp->flags & SC_LOOP_TRAFFIC'
test in ppp_read() and ppp_poll(), which in turn can lead to improper
decision on whether the PPP unit file is ready for reading or not.
Since ppp_ccp_closed() is protected by the Rx and Tx locks (with
ppp_lock()), taking the Rx lock is enough for ppp_read() and ppp_poll()
to guarantee that ppp_ccp_closed() won't update ppp->flags
concurrently.
The same reasoning applies to ppp->n_channels. The 'n_channels' field
can also be written to concurrently by ppp_ioctl() (through
ppp_connect_channel() or ppp_disconnect_channel()). These writes aren't
atomic (simple increment/decrement), but are protected by both the Rx
and Tx locks (like in the ppp->flags case). So holding the Rx lock
before reading ppp->n_channels also prevents concurrent writes.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
* Split big conditional statement.
* Check (data.length <= CCP_MAX_OPTION_LENGTH) only once.
* Don't read ccp_option[1] if not initialised.
Reading uninitialised ccp_option[1] was harmless, because this could
only happen when data.length was 0 or 1. So even then, we couldn't pass
the (ccp_option[1] < 2 || ccp_option[1] > data.length) test anyway.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Let user space be aware of the naming scheme used by ppp interfaces
(visible in /sys/class/net/<iface>/name_assign_type).
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Let PPP devices be identified as such in /sys/class/net/<iface>/uevent.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently slhc_init() treats out-of-range values of rslots and tslots
as equivalent to 0, except that if tslots is too large it will
dereference a null pointer (CVE-2015-7799).
Add a range-check at the top of the function and make it return an
ERR_PTR() on error instead of NULL. Change the callers accordingly.
Compile-tested only.
Reported-by: 郭永刚 <guoyonggang@360.cn>
References: http://article.gmane.org/gmane.comp.security.oss.general/17908
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Let packets move from one netns to the other at PPP encapsulation and
decapsulation time.
PPP units and channels remain in the netns in which they were
originally created. Only the net_device may move to a different
namespace. Cross netns handling is thus transparent to lower PPP
layers (PPPoE, L2TP, etc.).
PPP devices are automatically unregistered when their netns gets
removed. So read() and poll() on the unit file descriptor will
respectively receive EOF and POLLHUP. Channels aren't affected.
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
PPP devices may get automatically unregistered when their network
namespace is getting removed. This happens if the ppp control plane
daemon (e.g. pppd) exits while it is the last user of this namespace.
This leads to several races:
* ppp_exit_net() may destroy the per namespace idr (pn->units_idr)
before all file descriptors were released. Successive ppp_release()
calls may then cleanup PPP devices with ppp_shutdown_interface() and
try to use the already destroyed idr.
* Automatic device unregistration may also happen before the
ppp_release() call for that device gets executed. Once called on
the file owning the device, ppp_release() will then clean it up and
try to unregister it a second time.
To fix these issues, operations defined in ppp_shutdown_interface() are
moved to the PPP device's ndo_uninit() callback. This allows PPP
devices to be properly cleaned up by unregister_netdev() and friends.
So checking for ppp->owner is now an accurate test to decide if a PPP
device should be unregistered.
Setting ppp->owner is done in ppp_create_interface(), before device
registration, in order to avoid unprotected modification of this field.
Finally, ppp_exit_net() now starts by unregistering all remaining PPP
devices to ensure that none will get unregistered after the call to
idr_destroy().
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
