linux.git/net/ipv6/udp.c, branch v5.0

udpv6: fix possible user after free in error handler

2019-02-23T00:05:11+00:00

Before derefencing the encap pointer, commit e7cc082455cb ("udp: Support
for error handlers of tunnels with arbitrary destination port") checks
for a NULL value, but the two fetch operation can race with removal.
Fix the above using a single access.
Also fix a couple of type annotations, to make sparse happy.

Fixes: e7cc082455cb ("udp: Support for error handlers of tunnels with arbitrary destination port")
Signed-off-by: Paolo Abeni 
Acked-by: Stefano Brivio 
Signed-off-by: David S. Miller

udpv6: add the required annotation to mib type

2019-02-23T00:05:11+00:00

In commit 029a37434880 ("udp6: cleanup stats accounting in recvmsg()")
I forgot to add the percpu annotation for the mib pointer. Add it, and
make sparse happy.

Fixes: 029a37434880 ("udp6: cleanup stats accounting in recvmsg()")
Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller

udp6: add missing rehash callback to udplite

2019-01-17T23:01:08+00:00

After commit 23b0269e58ae ("net: udp6: prefer listeners bound to an
address"), UDP-Lite only works when specifying a local address for
the sockets.

This is related to the problem addressed in the commit 719f835853a9
("udp: add rehash on connect()"). Moreover, __udp6_lib_lookup() now
looks for a socket immediately in the secondary hash table.

And this issue was found with LTP/network tests as well.

Fixes: 23b0269e58ae ("net: udp6: prefer listeners bound to an address")
Signed-off-by: Alexey Kodanev 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller

udp: with udp_segment release on error path

2019-01-16T23:48:11+00:00

Failure __ip_append_data triggers udp_flush_pending_frames, but these
tests happen later. The skb must be freed directly.

Fixes: bec1f6f697362 ("udp: generate gso with UDP_SEGMENT")
Reported-by: Eric Dumazet 
Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller

bpf: Fix [::] -> [::1] rewrite in sys_sendmsg

2019-01-05T04:23:33+00:00

sys_sendmsg has supported unspecified destination IPv6 (wildcard) for
unconnected UDP sockets since 876c7f41. When [::] is passed by user as
destination, sys_sendmsg rewrites it with [::1] to be consistent with
BSD (see "BSD'ism" comment in the code).

This didn't work when cgroup-bpf was enabled though since the rewrite
[::] -> [::1] happened before passing control to cgroup-bpf block where
fl6.daddr was updated with passed by user sockaddr_in6.sin6_addr (that
might or might not be changed by BPF program). That way if user passed
[::] as dst IPv6 it was first rewritten with [::1] by original code from
876c7f41, but then rewritten back with [::] by cgroup-bpf block.

It happened even when BPF_CGROUP_UDP6_SENDMSG program was not present
(CONFIG_CGROUP_BPF=y was enough).

The fix is to apply BSD'ism after cgroup-bpf block so that [::] is
replaced with [::1] no matter where it came from: passed by user to
sys_sendmsg or set by BPF_CGROUP_UDP6_SENDMSG program.

Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg")
Reported-by: Nitin Rawat 
Signed-off-by: Andrey Ignatov 
Signed-off-by: Alexei Starovoitov

net: udp6: prefer listeners bound to an address

2018-12-14T23:55:20+00:00

A relatively common use case is to have several IPs configured
on a host, and have different listeners for each of them. We would
like to add a "catch all" listener on addr_any, to match incoming
connections not served by any of the listeners bound to a specific
address.

However, port-only lookups can match addr_any sockets when sockets
listening on specific addresses are present if so_reuseport flag
is set. This patch eliminates lookups into port-only hashtable,
as lookups by (addr,port) tuple are easily available.

In addition, compute_score() is tweaked to _not_ match
addr_any sockets to specific addresses, as hash collisions
could result in the unwanted behavior described above.

Tested: the patch compiles; full test in the last patch in this
patchset. Existing reuseport_* selftests also pass.

Suggested-by: Eric Dumazet 
Signed-off-by: Peter Oskolkov 
Signed-off-by: David S. Miller

udp: fix jump label misuse

2018-11-17T07:01:56+00:00

The commit 60fb9567bf30 ("udp: implement complete book-keeping for
encap_needed") introduced a severe misuse of jump label APIs, which
syzbot, as reported by Eric, was able to exploit.

When multiple sockets/process can concurrently request (and than
disable) the udp encap, we need to track the activation counter with
*_inc()/*_dec() jump label variants, or we can experience bad things
at disable time.

Fixes: 60fb9567bf30 ("udp: implement complete book-keeping for encap_needed")
Reported-by: Eric Dumazet 
Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller

udp6: cleanup stats accounting in recvmsg()

2018-11-10T04:07:05+00:00

In the udp6 code path, we needed multiple tests to select the correct
mib to be updated. Since we touch at least a counter at each iteration,
it's convenient to use the recently introduced __UDPX_MIB() helper once
and remove some code duplication.

Signed-off-by: Paolo Abeni 
Signed-off-by: David S. Miller

udp: Support for error handlers of tunnels with arbitrary destination port

2018-11-09T01:13:08+00:00

ICMP error handling is currently not possible for UDP tunnels not
employing a receiving socket with local destination port matching the
remote one, because we have no way to look them up.

Add an err_handler tunnel encapsulation operation that can be exported by
tunnels in order to pass the error to the protocol implementing the
encapsulation. We can't easily use a lookup function as we did for VXLAN
and GENEVE, as protocol error handlers, which would be in turn called by
implementations of this new operation, handle the errors themselves,
together with the tunnel lookup.

Without a socket, we can't be sure which encapsulation error handler is
the appropriate one: encapsulation handlers (the ones for FoU and GUE
introduced in the next patch, e.g.) will need to check the new error codes
returned by protocol handlers to figure out if errors match the given
encapsulation, and, in turn, report this error back, so that we can try
all of them in __udp{4,6}_lib_err_encap_no_sk() until we have a match.

v2:
- Name all arguments in err_handler prototypes (David Miller)

Signed-off-by: Stefano Brivio 
Reviewed-by: Sabrina Dubroca 
Signed-off-by: David S. Miller

net: Convert protocol error handlers from void to int

2018-11-09T01:13:08+00:00

We'll need this to handle ICMP errors for tunnels without a sending socket
(i.e. FoU and GUE). There, we might have to look up different types of IP
tunnels, registered as network protocols, before we get a match, so we
want this for the error handlers of IPPROTO_IPIP and IPPROTO_IPV6 in both
inet_protos and inet6_protos. These error codes will be used in the next
patch.

For consistency, return sensible error codes in protocol error handlers
whenever handlers can't handle errors because, even if valid, they don't
match a protocol or any of its states.

This has no effect on existing error handling paths.

Signed-off-by: Stefano Brivio 
Reviewed-by: Sabrina Dubroca 
Signed-off-by: David S. Miller