As reported by Mark Dowd <Mark_Dowd@McAfee.com>, ip6_tables is susceptible
to a fragmentation attack causing false negatives on extension header
matches.

When extension headers occur in the non-first fragment after the fragment
header (possibly with an incorrect nexthdr value in the fragment header)
a rule looking for this extension header will never match.

Drop fragments that are at offset 0 and don't contain the final protocol
header regardless of the ruleset, since this should not happen normally.
Since all extension headers are before the protocol header this makes sure
an extension header is either not present or in the first fragment, where
we can properly parse it.

With help from Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

As reported by Mark Dowd <Mark_Dowd@McAfee.com>, ip6_tables is susceptible
to a fragmentation attack causing false negatives on protocol matches.

When the protocol header doesn't follow the fragment header immediately,
the fragment header contains the protocol number of the next extension
header. When the extension header and the protocol header are sent in
a second fragment a rule like "ip6tables .. -p udp -j DROP" will never
match.

Drop fragments that are at offset 0 and don't contain the final protocol
header regardless of the ruleset, since this should not happen normally.

With help from Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

This is a long standing bug that seems to have only recently become
apparent, presumably due to increasing use of NFS over TCP - many
distros seem to be making it the default.

The SK_CONN bit gets set when a listening socket may be ready
for an accept, just as SK_DATA is set when data may be available.

It is entirely possible for svc_tcp_accept to be called with neither
of these set.  It doesn't happen often but there is a small race in
svc_sock_enqueue as SK_CONN and SK_DATA are tested outside the
spin_lock.  They could be cleared immediately after the test and
before the lock is gained.

This normally shouldn't be a problem.  The sockets are non-blocking so
trying to read() or accept() when ther is nothing to do is not a problem.

However: svc_tcp_recvfrom makes the decision "Should I accept() or
should I read()" based on whether SK_CONN is set or not.  This usually
works but is not safe.  The decision should be based on whether it is
a TCP_LISTEN socket or a TCP_CONNECTED socket.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

The integer divisions in the timer accounting code can round the result
down to 0.  Adding 0 is without effect and the signal delivery stops.

Clamp the division result to minimum 1 to avoid this.

Problem was reported by Seongbae Park <spark@google.com>, who provided
also an inital patch.

Roland sayeth:

  I have had some more time to think about the problem, and to reproduce it
  using Toyo's test case.  For the record, if my understanding of the problem
  is correct, this happens only in one very particular case.  First, the
  expiry time has to be so soon that in cputime_t units (usually 1s/HZ ticks)
  it's < nthreads so the division yields zero.  Second, it only affects each
  thread that is so new that its CPU time accumulation is zero so now+0 is
  still zero and ->it_*_expires winds up staying zero.  For the VIRT and PROF
  clocks when cputime_t is tick granularity (or the SCHED clock on
  configurations where sched_clock's value only advances on clock ticks), this
  is not hard to arrange with new threads starting up and blocking before they
  accumulate a whole tick of CPU time.  That's what happens in Toyo's test
  case.

  Note that in general it is fine for that division to round down to zero,
  and set each thread's expiry time to its "now" time.  The problem only
  arises with thread's whose "now" value is still zero, so that now+0 winds up
  0 and is interpreted as "not set" instead of ">= now".  So it would be a
  sufficient and more precise fix to just use max(ticks, 1) inside the loop
  when setting each it_*_expires value.

  But, it does no harm to round the division up to one and always advance
  every thread's expiry time.  If the thread didn't already fire timers for
  the expiry time of "now", there is no expectation that it will do so before
  the next tick anyway.  So I followed Thomas's patch in lifting the max out
  of the loops.

  This patch also covers the reload cases, which are harder to write a test
  for (and I didn't try).  I've tested it with Toyo's case and it fixes that.

[toyoa@mvista.com: fix: min_t -> max_t]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

There's a bug in the seqfile handling for /proc/net/ip6_flowlabel, where,
after finding a flowlabel, the code will loop forever not finding any
further flowlabels, first traversing the rest of the hash bucket then just
looping.

This patch fixes the problem by breaking after the hash bucket has been
traversed.

Note that this bug can cause lockups and oopses, and is trivially invoked
by an unpriveleged user.

Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

http://bugzilla.kernel.org/show_bug.cgi?id=5653

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

memcpy 4 bytes to address of auto unsigned long variable followed
by comparison with u32 is a bloody bad idea.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

The previous patch to correct the copy_from_user padding is quite
broken. The execute instruction needs to be done via the register %r4,
not via %r2 and 31 bit doesn't know the instructions lgr and ahji.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>