net: Allow driver to limit number of GSO segments per skb

[ Upstream commit 30b678d844af3305cda5953467005cebb5d7b687 ]

A peer (or local user) may cause TCP to use a nominal MSS of as little
as 88 (actual MSS of 76 with timestamps).  Given that we have a
sufficiently prodigious local sender and the peer ACKs quickly enough,
it is nevertheless possible to grow the window for such a connection
to the point that we will try to send just under 64K at once.  This
results in a single skb that expands to 861 segments.

In some drivers with TSO support, such an skb will require hundreds of
DMA descriptors; a substantial fraction of a TX ring or even more than
a full ring.  The TX queue selected for the skb may stall and trigger
the TX watchdog repeatedly (since the problem skb will be retried
after the TX reset).  This particularly affects sfc, for which the
issue is designated as CVE-2012-3412.

Therefore:
1. Add the field net_device::gso_max_segs holding the device-specific
   limit.
2. In netif_skb_features(), if the number of segments is too high then
   mask out GSO features to force fall back to software GSO.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sfc: Fix maximum number of TSO segments and minimum TX queue size

[ Upstream commit 7e6d06f0de3f74ca929441add094518ae332257c ]

Currently an skb requiring TSO may not fit within a minimum-size TX
queue.  The TX queue selected for the skb may stall and trigger the TX
watchdog repeatedly (since the problem skb will be retried after the
TX reset).  This issue is designated as CVE-2012-3412.

Set the maximum number of TSO segments for our devices to 100.  This
should make no difference to behaviour unless the actual MSS is less
than about 700.  Increase the minimum TX queue size accordingly to
allow for 2 worst-case skbs, so that there will definitely be space
to add an skb after we wake a queue.

To avoid invalidating existing configurations, change
efx_ethtool_set_ringparam() to fix up values that are too small rather
than returning -EINVAL.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcp: Apply device TSO segment limit earlier

[ Upstream commit 1485348d2424e1131ea42efc033cbd9366462b01 ]

Cache the device gso_max_segs in sock::sk_gso_max_segs and use it to
limit the size of TSO skbs.  This avoids the need to fall back to
software GSO for local TCP senders.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net_sched: gact: Fix potential panic in tcf_gact().

[ Upstream commit 696ecdc10622d86541f2e35cc16e15b6b3b1b67e ]

gact_rand array is accessed by gact->tcfg_ptype whose value
is assumed to less than MAX_RAND, but any range checks are
not performed.

So add a check in tcf_gact_init(). And in tcf_gact(), we can
reduce a branch.

Signed-off-by: Hiroaki SHIMODA <shimoda.hiroaki@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
isdnloop: fix and simplify isdnloop_init()

[ Upstream commit 77f00f6324cb97cf1df6f9c4aaeea6ada23abdb2 ]

Fix a buffer overflow bug by removing the revision and printk.

[   22.016214] isdnloop-ISDN-driver Rev 1.11.6.7
[   22.097508] isdnloop: (loop0) virtual card added
[   22.174400] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff83244972
[   22.174400]
[   22.436157] Pid: 1, comm: swapper Not tainted 3.5.0-bisect-00018-gfa8bbb1-dirty #129
[   22.624071] Call Trace:
[   22.720558]  [<ffffffff832448c3>] ? CallcNew+0x56/0x56
[   22.815248]  [<ffffffff8222b623>] panic+0x110/0x329
[   22.914330]  [<ffffffff83244972>] ? isdnloop_init+0xaf/0xb1
[   23.014800]  [<ffffffff832448c3>] ? CallcNew+0x56/0x56
[   23.090763]  [<ffffffff8108e24b>] __stack_chk_fail+0x2b/0x30
[   23.185748]  [<ffffffff83244972>] isdnloop_init+0xaf/0xb1

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pptp: lookup route with the proper net namespace

[ Upstream commit 08252b32311c3fa84219ad794d640af7399b5485 ]

pptp always use init_net as the net namespace to lookup
route, this will cause route lookup failed in container.

because we already set the correct net namespace to struct
sock in pptp_create,so fix this by using sock_net(sk) to
replace &init_net.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/core: Fix potential memory leak in dev_set_alias()

[ Upstream commit 7364e445f62825758fa61195d237a5b8ecdd06ec ]

Do not leak memory by updating pointer with potentially NULL realloc return value.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
af_packet: remove BUG statement in tpacket_destruct_skb

[ Upstream commit 7f5c3e3a80e6654cf48dfba7cf94f88c6b505467 ]

Here's a quote of the comment about the BUG macro from asm-generic/bug.h:

 Don't use BUG() or BUG_ON() unless there's really no way out; one
 example might be detecting data structure corruption in the middle
 of an operation that can't be backed out of.  If the (sub)system
 can somehow continue operating, perhaps with reduced functionality,
 it's probably not BUG-worthy.

 If you're tempted to BUG(), think again:  is completely giving up
 really the *only* solution?  There are usually better options, where
 users don't need to reboot ASAP and can mostly shut down cleanly.

In our case, the status flag of a ring buffer slot is managed from both sides,
the kernel space and the user space. This means that even though the kernel
side might work as expected, the user space screws up and changes this flag
right between the send(2) is triggered when the flag is changed to
TP_STATUS_SENDING and a given skb is destructed after some time. Then, this
will hit the BUG macro. As David suggested, the best solution is to simply
remove this statement since it cannot be used for kernel side internal
consistency checks. I've tested it and the system still behaves /stable/ in
this case, so in accordance with the above comment, we should rather remove it.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert "jiffies conversions: Use compile time constants when possible"

This reverts commit 3bc1f0a50f12e2b9ecd0fbcf569b7524a8ef50d8.