linux-stable.git/net/rxrpc, branch linux-3.16.y

rxrpc: Fix several cases where a padded len isn't checked in ticket decode

2017-07-02T16:13:03+00:00

commit 5f2f97656ada8d811d3c1bef503ced266fcd53a0 upstream.

This fixes CVE-2017-7482.

When a kerberos 5 ticket is being decoded so that it can be loaded into an
rxrpc-type key, there are several places in which the length of a
variable-length field is checked to make sure that it's not going to
overrun the available data - but the data is padded to the nearest
four-byte boundary and the code doesn't check for this extra.  This could
lead to the size-remaining variable wrapping and the data pointer going
over the end of the buffer.

Fix this by making the various variable-length data checks use the padded
length.

Reported-by: 石磊 
Signed-off-by: David Howells 
Reviewed-by: Marc Dionne 
Reviewed-by: Dan Carpenter 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16: adjust filename, context]
Signed-off-by: Ben Hutchings

rxrpc: bogus MSG_PEEK test in rxrpc_recvmsg()

2015-03-24T10:31:10+00:00

commit 7d985ed1dca5c90535d67ce92ef6ca520302340a upstream.

[I would really like an ACK on that one from dhowells; it appears to be
quite straightforward, but...]

MSG_PEEK isn't passed to ->recvmsg() via msg->msg_flags; as the matter of
fact, neither the kernel users of rxrpc, nor the syscalls ever set that bit
in there.  It gets passed via flags; in fact, another such check in the same
function is done correctly - as flags & MSG_PEEK.

It had been that way (effectively disabled) for 8 years, though, so the patch
needs beating up - that case had never been tested.  If it is correct, it's
-stable fodder.

Signed-off-by: Al Viro 
Signed-off-by: David S. Miller 
Signed-off-by: Luis Henriques

af_rxrpc: Fix XDR length check in rxrpc key demarshalling.

2014-05-16T19:24:47+00:00

There may be padding on the ticket contained in the key payload, so just ensure
that the claimed token length is large enough, rather than exactly the right
size.

Signed-off-by: Nathaniel Wesley Filardo 
Signed-off-by: David Howells 
Signed-off-by: David S. Miller

net: Fix use after free by removing length arg from sk_data_ready callbacks.

2014-04-11T20:15:36+00:00

Several spots in the kernel perform a sequence like:

	skb_queue_tail(&sk->s_receive_queue, skb);
	sk->sk_data_ready(sk, skb->len);

But at the moment we place the SKB onto the socket receive queue it
can be consumed and freed up.  So this skb->len access is potentially
to freed up memory.

Furthermore, the skb->len can be modified by the consumer so it is
possible that the value isn't accurate.

And finally, no actual implementation of this callback actually uses
the length argument.  And since nobody actually cared about it's
value, lots of call sites pass arbitrary values in such as '0' and
even '1'.

So just remove the length argument from the callback, that way there
is no confusion whatsoever and all of these use-after-free cases get
fixed as a side effect.

Based upon a patch by Eric Dumazet and his suggestion to audit this
issue tree-wide.

Signed-off-by: David S. Miller

af_rxrpc: Keep rxrpc_call pointers in a hashtable

2014-03-04T10:36:53+00:00

Keep track of rxrpc_call structures in a hashtable so they can be
found directly from the network parameters which define the call.

This allows incoming packets to be routed directly to a call without walking
through hierarchy of peer -> transport -> connection -> call and all the
spinlocks that that entailed.

Signed-off-by: Tim Smith 
Signed-off-by: David Howells

af_rxrpc: Request an ACK for every alternate DATA packet

2014-02-26T17:25:07+00:00

Set the RxRPC header flag to request an ACK packet for every odd-numbered DATA
packet unless it's the last one (which implicitly requests an ACK anyway).
This is similar to how librx appears to work.

If we don't do this, we'll send out a full window of packets and then just sit
there until the other side gets bored and sends an ACK to indicate that it's
been idle for a while and has received no new packets.

Requesting a lot of ACKs shouldn't be a problem as ACKs should be merged when
possible.

As AF_RXRPC currently works, it will schedule an ACK to be generated upon
receipt of a DATA packet with the ACK-request packet set - and in the time
taken to schedule this in a work queue, several other packets are likely to
arrive and then all get ACK'd together.

Signed-off-by: David Howells

af_rxrpc: Expose more RxRPC parameters via sysctls

2014-02-26T17:25:07+00:00

Expose RxRPC parameters via sysctls to control the Rx window size, the Rx MTU
maximum size and the number of packets that can be glued into a jumbo packet.

More info added to Documentation/networking/rxrpc.txt.

Signed-off-by: David Howells

af_rxrpc: Improve ACK production

2014-02-26T17:25:07+00:00

Improve ACK production by the following means:

 (1) Don't send an ACK_REQUESTED ack immediately even if the RXRPC_MORE_PACKETS
     flag isn't set on a data packet that has also has RXRPC_REQUEST_ACK set.

     MORE_PACKETS just means that the sender just emptied its Tx data buffer.
     More data will be forthcoming unless RXRPC_LAST_PACKET is also flagged.

     It is possible to see runs of DATA packets with MORE_PACKETS unset that
     aren't waiting for an ACK.

     It is therefore better to wait a small instant to see if we can combine an
     ACK for several packets.

 (2) Don't send an ACK_IDLE ack immediately unless we're responding to the
     terminal data packet of a call.

     Whilst sending an ACK_IDLE mid-call serves to let the other side know
     that we won't be asking it to resend certain Tx buffers and that it can
     discard them, spamming it with loads of acks just because we've
     temporarily run out of data just distracts it.

 (3) Put the ACK_IDLE ack generation timeout up to half a second rather than a
     single jiffy.  Just because we haven't been given more data immediately
     doesn't mean that more isn't forthcoming.  The other side may be busily
     finding the data to send to us.

Signed-off-by: David Howells

af_rxrpc: Add sysctls for configuring RxRPC parameters

2014-02-26T17:25:06+00:00

Add sysctls for configuring RxRPC protocol handling, specifically controls on
delays before ack generation, the delay before resending a packet, the maximum
lifetime of a call and the expiration times of calls, connections and
transports that haven't been recently used.

More info added in Documentation/networking/rxrpc.txt.

Signed-off-by: David Howells

af_rxrpc: Fix UDP MTU calculation from ICMP_FRAG_NEEDED

2014-02-26T17:25:01+00:00

AF_RXRPC sends UDP packets with the "Don't Fragment" bit set in an attempt to
determine the maximum packet size between the local socket and the peer by
invoking the generation of ICMP_FRAG_NEEDED packets.

Once a packet is sent with the "Don't Fragment" bit set, it is then
inconvenient to break it up as that requires recalculating all the rxrpc serial
and sequence numbers and reencrypting all the fragments, so we switch off the
"Don't Fragment" service temporarily and send the bounced packet again.  Future
packets then use the new MTU.

That's all fine.  The problem lies in rxrpc_UDP_error_report() where the code
that deals with ICMP_FRAG_NEEDED packets lives.  Packets of this type have a
field (ee_info) to indicate the maximum packet size at the reporting node - but
sometimes ee_info isn't filled in and is just left as 0 and the code must allow
for this.

When ee_info is 0, the code should take the MTU size we're currently using and
reduce it for the next packet we want to send.  However, it takes ee_info
(which is known to be 0) and tries to reduce that instead.

This was discovered by Coverity.

Reported-by: Dave Jones 
Signed-off-by: David Howells