Allow specifying segment size in the send call.

The new control message performs the same function as socket option
UDP_SEGMENT while avoiding the extra system call.

[ Export udp_cmsg_send for ipv6. -DaveM ]
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When sending large datagrams that are later segmented, store data in
page frags to avoid copying from linear in skb_segment.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb_segment by default transfers allocated wmem from the gso skb
to the tail of the segment list. This underreports real truesize
of the list, especially if the tail might be dropped.

Similar to tcp_gso_segment, update wmem_alloc with the aggregate
list truesize and make each segment responsible for its own
share by setting skb->destructor.

Clear gso_skb->destructor prior to calling skb_segment to skip
the default assignment to tail.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Support generic segmentation offload for udp datagrams. Callers can
concatenate and send at once the payload of multiple datagrams with
the same destination.

To set segment size, the caller sets socket option UDP_SEGMENT to the
length of each discrete payload. This value must be smaller than or
equal to the relevant MTU.

A follow-up patch adds cmsg UDP_SEGMENT to specify segment size on a
per send call basis.

Total byte length may then exceed MTU. If not an exact multiple of
segment size, the last segment will be shorter.

The implementation adds a gso_size field to the udp socket, ip(v6)
cmsg cookie and inet_cork structure to be able to set the value at
setsockopt or cmsg time and to work with both lockless and corked
paths.

Initial benchmark numbers show UDP GSO about as expensive as TCP GSO.

    tcp tso
     3197 MB/s 54232 msg/s 54232 calls/s
         6,457,754,262      cycles

    tcp gso
     1765 MB/s 29939 msg/s 29939 calls/s
        11,203,021,806      cycles

    tcp without tso/gso *
      739 MB/s 12548 msg/s 12548 calls/s
        11,205,483,630      cycles

    udp
      876 MB/s 14873 msg/s 624666 calls/s
        11,205,777,429      cycles

    udp gso
     2139 MB/s 36282 msg/s 36282 calls/s
        11,204,374,561      cycles

   [*] after reverting commit 0a6b2a1d
       ("tcp: switch to GSO being always on")

Measured total system cycles ('-a') for one core while pinning both
the network receive path and benchmark process to that core:

  perf stat -a -C 12 -e cycles \
    ./udpgso_bench_tx -C 12 -4 -D "$DST" -l 4

Note the reduction in calls/s with GSO. Bytes per syscall drops
increases from 1470 to 61818.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement generic segmentation offload support for udp datagrams. A
follow-up patch adds support to the protocol stack to generate such
packets.

UDP GSO is not UFO. UFO fragments a single large datagram. GSO splits
a large payload into a number of discrete UDP datagrams.

The implementation adds a GSO type SKB_UDP_GSO_L4 to differentiate it
from UFO (SKB_UDP_GSO).

IPPROTO_UDPLITE is excluded, as that protocol has no gso handler
registered.

[ Export __udp_gso_segment for ipv6. -DaveM ]
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

UDP segmentation offload needs access to inet_cork in the udp layer.
Pass the struct to ip(6)_make_skb instead of allocating it on the
stack in that function itself.

This patch is a noop otherwise.
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The function rds_ib_setup_qp is calling rds_ib_get_client_data and
should correspondingly call rds_ib_dev_put. This call was lost in
the non-error path with the introduction of error handling done in
commit 3b12f73a ("rds: ib: add error handle")
Signed-off-by: NDag Moxnes <dag.moxnes@oracle.com>
Reviewed-by: NHåkon Bugge <haakon.bugge@oracle.com>
Acked-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The internal CLC socket should exist till the SMC-socket is released.
Function tcp_listen_worker() releases the internal CLC socket of a
listen socket, if an smc_close_active() is called. This function
is called for the final release(), but it is called for shutdown
SHUT_RDWR as well. This opens a door for protection faults, if
socket calls using the internal CLC socket are called for a
shutdown listen socket.

With the changes of
commit 3d502067 ("net/smc: simplify wait when closing listen socket")
there is no need anymore to release the internal CLC socket in
function tcp_listen_worker((). It is sufficient to release it in
smc_release().

Fixes: 127f4970 ("net/smc: release clcsock from tcp_listen_worker")
Signed-off-by: NUrsula Braun <ubraun@linux.ibm.com>
Reported-by: syzbot+9045fc589fcd196ef522@syzkaller.appspotmail.com
Reported-by: syzbot+28a2c86cf19c81d871fa@syzkaller.appspotmail.com
Reported-by: syzbot+9605e6cace1b5efd4a0a@syzkaller.appspotmail.com
Reported-by: syzbot+cf9012c597c8379d535c@syzkaller.appspotmail.com
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After Commit 4f008781 ("sctp: apply rhashtable api to send/recv
path"), there's no place using sctp_assoc_is_match, so remove it.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the check on FRA_L3MDEV attribute to helper to improve the
readability of fib_nl2rule. Update the extack messages to be
clear when the configuration option is disabled versus an invalid
value has been passed.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It's currently written as:

if (!tchunk->tsn_gap_acked) {   [1]
	tchunk->tsn_gap_acked = 1;
	...
}

if (TSN_lte(tsn, sack_ctsn)) {
	if (!tchunk->tsn_gap_acked) {
		/* SFR-CACC processing */
		...
	}
}

Which causes the SFR-CACC processing on ack reception to never process,
as tchunk->tsn_gap_acked is always true by then. Block [1] was
moved to that position by the commit marked below.

This patch fixes it by doing SFR-CACC processing earlier, before
tsn_gap_acked is set to true.

Fixes: 31b02e15 ("sctp: Failover transmitted list on transport delete")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_make_sack() make changes to the asoc and this cast is just
bypassing the const attribute. As there is no need to have the const
there, just remove it and fix the violation.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch extends NTF_EXT_LEARNED support to the neighbour system.
Example use-case: An Ethernet VPN implementation (eg in FRR routing suite)
can use this flag to add dynamic reachable external neigh entires
learned via control plane. The use of neigh NTF_EXT_LEARNED in this
patch is consistent with its use with bridge and vxlan fdb entries.
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The addrconf_ifdown() evaluates keep_addr_on_down state twice. There
is no need to do it.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: NIvan Vecera <cera@cera.cz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ECMP (equal-cost multipath) hashes are typically computed on the packets'
5-tuple(src IP, dst IP, src port, dst port, L4 proto).

For encapsulated packets, the L4 data is not readily available and ECMP
hashing will often revert to (src IP, dst IP). This will lead to traffic
polarization on a single ECMP path, causing congestion and waste of network
capacity.

In IPv6, the 20-bit flow label field is also used as part of the ECMP hash.
In the lack of L4 data, the hashing will be on (src IP, dst IP, flow
label). Having a non-zero flow label is thus important for proper traffic
load balancing when L4 data is unavailable (i.e., when packets are
encapsulated).

Currently, the seg6_do_srh_encap() function extracts the original packet's
flow label and set it as the outer IPv6 flow label. There are two issues
with this behaviour:

a) There is no guarantee that the inner flow label is set by the source.
b) If the original packet is not IPv6, the flow label will be set to
zero (e.g., IPv4 or L2 encap).

This patch adds a function, named seg6_make_flowlabel(), that computes a
flow label from a given skb. It supports IPv6, IPv4 and L2 payloads, and
leverages the per namespace 'seg6_flowlabel" sysctl value.

The currently support behaviours are as follows:
-1 set flowlabel to zero.
0 copy flowlabel from Inner paceket in case of Inner IPv6
(Set flowlabel to 0 in case IPv4/L2)
1 Compute the flowlabel using seg6_make_flowlabel()

This patch has been tested for IPv6, IPv4, and L2 traffic.
Signed-off-by: NAhmed Abdelsalam <amsalam20@gmail.com>
Acked-by: NDavid Lebrun <dlebrun@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The percpu metadata_dst might carry the stale ip_tunnel_info
and cause incorrect behavior.  When mixing tests using ipv4/ipv6
bpf vxlan and geneve tunnel, the ipv6 tunnel info incorrectly uses
ipv4's src ip addr as its ipv6 src address, because the previous
tunnel info does not clean up.  The patch zeros the fields in
ip_tunnel_info.
Signed-off-by: NWilliam Tu <u9012063@gmail.com>
Reported-by: NYifeng Sun <pkusunyifeng@gmail.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>

rt6_remove_exception_rt() is called under rcu_read_lock() only.

We lock rt6_exception_lock a bit later, so we do not hold
rt6_exception_lock yet.

Fixes: 8a14e46f ("net/ipv6: Fix missing rcu dereferences on from")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Cc: David Ahern <dsahern@gmail.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A duplicated null check on sgout is redundant as it is known to be
already true because of the identical earlier check. Remove it.
Detected by cppcheck:

net/tls/tls_sw.c:696: (warning) Identical inner 'if' condition is always
true.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Distributed filesystems are most effective when the server and client
clocks are synchronised. Embedded devices often use NFS for their
root filesystem but typically do not contain an RTC, so the clocks of
the NFS server and the embedded device will be out-of-sync when the root
filesystem is mounted (and may not be synchronised until late in the
boot process).

Extend ipconfig with the ability to export IP addresses of NTP servers
it discovers to /proc/net/ipconfig/ntp_servers. They can be supplied as
follows:

 - If ipconfig is configured manually via the "ip=" or "nfsaddrs="
   kernel command line parameters, one NTP server can be specified in
   the new "<ntp0-ip>" parameter.
 - If ipconfig is autoconfigured via DHCP, request DHCP option 42 in
   the DHCPDISCOVER message, and record the IP addresses of up to three
   NTP servers sent by the responding DHCP server in the subsequent
   DHCPOFFER message.

ipconfig will only write the NTP server IP addresses it discovers to
/proc/net/ipconfig/ntp_servers, one per line (in the order received from
the DHCP server, if DHCP autoconfiguration is used); making use of these
NTP servers is the responsibility of a user space process (e.g. an
initrd/initram script that invokes an NTP client before mounting an NFS
root filesystem).
Signed-off-by: NChris Novakovic <chris@chrisn.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To allow ipconfig to report IP configuration details to user space
processes without cluttering /proc/net, create a new subdirectory
/proc/net/ipconfig. All files containing IP configuration details should
be written to this directory.
Signed-off-by: NChris Novakovic <chris@chrisn.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ic_nameservers, which stores the list of name servers discovered by
ipconfig, is initialised (i.e. has all of its elements set to NONE, or
0xffffffff) by ic_nameservers_predef() in the following scenarios:

 - before the "ip=" and "nfsaddrs=" kernel command line parameters are
   parsed (in ip_auto_config_setup());
 - before autoconfiguring via DHCP or BOOTP (in ic_bootp_init()), in
   order to clear any values that may have been set after parsing "ip="
   or "nfsaddrs=" and are no longer needed.

This means that ic_nameservers_predef() is not called when neither "ip="
nor "nfsaddrs=" is specified on the kernel command line. In this
scenario, every element in ic_nameservers remains set to 0x00000000,
which is indistinguishable from ANY and causes pnp_seq_show() to write
the following (bogus) information to /proc/net/pnp:

  #MANUAL
  nameserver 0.0.0.0
  nameserver 0.0.0.0
  nameserver 0.0.0.0

This is potentially problematic for systems that blindly link
/etc/resolv.conf to /proc/net/pnp.

Ensure that ic_nameservers is also initialised when neither "ip=" nor
"nfsaddrs=" are specified by calling ic_nameservers_predef() in
ip_auto_config(), but only when ip_auto_config_setup() was not called
earlier. This causes the following to be written to /proc/net/pnp, and
is consistent with what gets written when ipconfig is configured
manually but no name servers are specified on the kernel command line:

  #MANUAL
Signed-off-by: NChris Novakovic <chris@chrisn.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() always allocates 8 bytes for the name
server option, limiting the BOOTP server to responding with at most 2
name servers even though ipconfig in fact supports an arbitrary number
of name servers (as defined by CONF_NAMESERVERS_MAX, which is currently
3).

Only request name servers in the request packet if CONF_NAMESERVERS_MAX
is positive (to comply with [1, §3.8]), and allocate enough space in the
packet for CONF_NAMESERVERS_MAX name servers to indicate the maximum
number we can accept in response.

[1] RFC 2132, "DHCP Options and BOOTP Vendor Extensions":
    https://tools.ietf.org/rfc/rfc2132.txtSigned-off-by: NChris Novakovic <chris@chrisn.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When ipconfig is autoconfigured via BOOTP, the request packet
initialised by ic_bootp_init_ext() allocates 8 bytes for tag 5 ("Name
Server" [1, §3.7]), but tag 5 in the response isn't processed by
ic_do_bootp_ext(). Instead, allocate the 8 bytes to tag 6 ("Domain Name
Server" [1, §3.8]), which is processed by ic_do_bootp_ext(), and appears
to have been the intended tag to request.

This won't cause any breakage for existing users, as tag 5 responses
provided by BOOTP servers weren't being processed anyway.

[1] RFC 2132, "DHCP Options and BOOTP Vendor Extensions":
    https://tools.ietf.org/rfc/rfc2132.txtSigned-off-by: NChris Novakovic <chris@chrisn.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 5e953778 ("ipconfig: add
nameserver IPs to kernel-parameter ip=") adds the IP addresses of
discovered name servers to the summary printed by ipconfig when
configuration is complete. It appears the intention in ip_auto_config()
was to print the name servers on a new line (especially given the
spacing and lack of comma before "nameserver0="), but they're actually
printed on the same line as the NFS root filesystem configuration
summary:

  [    0.686186] IP-Config: Complete:
  [    0.686226]      device=eth0, hwaddr=xx:xx:xx:xx:xx:xx, ipaddr=10.0.0.2, mask=255.255.255.0, gw=10.0.0.1
  [    0.686328]      host=test, domain=example.com, nis-domain=(none)
  [    0.686386]      bootserver=10.0.0.1, rootserver=10.0.0.1, rootpath=     nameserver0=10.0.0.1

This makes it harder to read and parse ipconfig's output. Instead, print
the name servers on a separate line:

  [    0.791250] IP-Config: Complete:
  [    0.791289]      device=eth0, hwaddr=xx:xx:xx:xx:xx:xx, ipaddr=10.0.0.2, mask=255.255.255.0, gw=10.0.0.1
  [    0.791407]      host=test, domain=example.com, nis-domain=(none)
  [    0.791475]      bootserver=10.0.0.1, rootserver=10.0.0.1, rootpath=
  [    0.791476]      nameserver0=10.0.0.1
Signed-off-by: NChris Novakovic <chris@chrisn.me.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RETPOLINE made calls to tp->af_specific->md5_lookup() quite expensive,
given they have no result.
We can omit the calls for sockets that have no md5 keys.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Updates to the bitfields in struct packet_sock are not atomic.
Serialize these read-modify-write cycles.

Move po->running into a separate variable. Its writes are protected by
po->bind_lock (except for one startup case at packet_create). Also
replace a textual precondition warning with lockdep annotation.

All others are set only in packet_setsockopt. Serialize these
updates by holding the socket lock. Analogous to other field updates,
also hold the lock when testing whether a ring is active (pg_vec).

Fixes: 8dc41944 ("[PACKET]: Add optional checksum computation for recvmsg")
Reported-by: NDaeRyong Jeong <threeearcat@gmail.com>
Reported-by: NByoungyoung Lee <byoungyoung@purdue.edu>
Signed-off-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit <c6849a3a> ("net: init sk_cookie for inet socket")

Per discussion with Eric, when update sock_net(sk)->cookie_gen, the
whole cache cache line will be invalidated, as this cache line is shared
with all cpus, that may cause great performace hit.

Bellow is the data form Eric.
"Performance is reduced from ~5 Mpps to ~3.8 Mpps with 16 RX queues on
my host" when running synflood test.

Have to revert it to prevent from cache line false sharing.
Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: b16fb418 ("net: fib_rules: add extack support")
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Check sockaddr_len before dereferencing sp->sa_protocol, to ensure that
it actually points to valid data.

Fixes: fd558d18 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Reported-by: syzbot+a70ac890b23b1bf29f5c@syzkaller.appspotmail.com
Signed-off-by: NGuillaume Nault <g.nault@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

kbuild test robot reported 2 uses of rt->from not properly accessed
using rcu_dereference:
1. add rcu_dereference_protected to rt6_remove_exception_rt and make
   sure it is always called with rcu lock held.

2. change rt6_do_redirect to take a reference on 'from' when accessed
   the first time so it can be used the sceond time outside of the lock

Fixes: a68886a6 ("net/ipv6: Make from in rt6_info rcu protected")
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reported a suspicious rcu_dereference_check:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1b9/0x294 lib/dump_stack.c:113
  lockdep_rcu_suspicious+0x14a/0x153 kernel/locking/lockdep.c:4592
  rt6_check_expired+0x38b/0x3e0 net/ipv6/route.c:410
  ip6_negative_advice+0x67/0xc0 net/ipv6/route.c:2204
  dst_negative_advice include/net/sock.h:1786 [inline]
  sock_setsockopt+0x138f/0x1fe0 net/core/sock.c:1051
  __sys_setsockopt+0x2df/0x390 net/socket.c:1899
  SYSC_setsockopt net/socket.c:1914 [inline]
  SyS_setsockopt+0x34/0x50 net/socket.c:1911

Add rcu locking around call to rt6_check_expired in
ip6_negative_advice.

Fixes: a68886a6 ("net/ipv6: Make from in rt6_info rcu protected")
Reported-by: syzbot+2422c9e35796659d2273@syzkaller.appspotmail.com
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

KMSAN reported use of uninit-value that I tracked to lack
of proper size check on RTA_TABLE attribute.

I also believe RTA_PREFSRC lacks a similar check.

Fixes: 86872cb5 ("[IPv6] route: FIB6 configuration using struct fib6_config")
Fixes: c3968a85 ("ipv6: RTA_PREFSRC support for ipv6 route source address selection")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Acked-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With sk_cookie we can identify a socket, that is very helpful for
traceing and statistic, i.e. tcp tracepiont and ebpf.
So we'd better init it by default for inet socket.
When using it, we just need call atomic64_read(&sk->sk_cookie).
Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reduces code duplication in the fib rule add and del paths.
Get rid of validate_rulemsg. This became obvious when adding duplicate
extack support in fib newrule/delrule error paths.
Signed-off-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

tcp_rcv_space_adjust is called every time data is copied to user space,
introducing a tcp tracepoint for which could show us when the packet is
copied to user.

When a tcp packet arrives, tcp_rcv_established() will be called and with
the existed tracepoint tcp_probe we could get the time when this packet
arrives.
Then this packet will be copied to user, and tcp_rcv_space_adjust will
be called and with this new introduced tracepoint we could get the time
when this packet is copied to user.
With these two tracepoints, we could figure out whether the user program
processes this packet immediately or there's latency.

Hence in the printk message, sk_cookie is printed as a key to relate
tcp_rcv_space_adjust with tcp_probe.

Maybe we could export sockfd in this new tracepoint as well, then we
could relate this new tracepoint with epoll/read/recv* tracepoints, and
finally that could show us the whole lifespan of this packet. But we
could also implement that with pid as these functions are executed in
process context.
Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The old code reads the "opsize" variable from out-of-bounds memory (first
byte behind the segment) if a broken TCP segment ends directly after an
opcode that is neither EOL nor NOP.

The result of the read isn't used for anything, so the worst thing that
could theoretically happen is a pagefault; and since the physmap is usually
mostly contiguous, even that seems pretty unlikely.

The following C reproducer triggers the uninitialized read - however, you
can't actually see anything happen unless you put something like a
pr_warn() in tcp_parse_md5sig_option() to print the opsize.

====================================
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <stdlib.h>
#include <errno.h>
#include <stdarg.h>
#include <net/if.h>
#include <linux/if.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/in.h>
#include <linux/if_tun.h>
#include <err.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <assert.h>

void systemf(const char *command, ...) {
  char *full_command;
  va_list ap;
  va_start(ap, command);
  if (vasprintf(&full_command, command, ap) == -1)
    err(1, "vasprintf");
  va_end(ap);
  printf("systemf: <<<%s>>>\n", full_command);
  system(full_command);
}

char *devname;

int tun_alloc(char *name) {
  int fd = open("/dev/net/tun", O_RDWR);
  if (fd == -1)
    err(1, "open tun dev");
  static struct ifreq req = { .ifr_flags = IFF_TUN|IFF_NO_PI };
  strcpy(req.ifr_name, name);
  if (ioctl(fd, TUNSETIFF, &req))
    err(1, "TUNSETIFF");
  devname = req.ifr_name;
  printf("device name: %s\n", devname);
  return fd;
}

#define IPADDR(a,b,c,d) (((a)<<0)+((b)<<8)+((c)<<16)+((d)<<24))

void sum_accumulate(unsigned int *sum, void *data, int len) {
  assert((len&2)==0);
  for (int i=0; i<len/2; i++) {
    *sum += ntohs(((unsigned short *)data)[i]);
  }
}

unsigned short sum_final(unsigned int sum) {
  sum = (sum >> 16) + (sum & 0xffff);
  sum = (sum >> 16) + (sum & 0xffff);
  return htons(~sum);
}

void fix_ip_sum(struct iphdr *ip) {
  unsigned int sum = 0;
  sum_accumulate(&sum, ip, sizeof(*ip));
  ip->check = sum_final(sum);
}

void fix_tcp_sum(struct iphdr *ip, struct tcphdr *tcp) {
  unsigned int sum = 0;
  struct {
    unsigned int saddr;
    unsigned int daddr;
    unsigned char pad;
    unsigned char proto_num;
    unsigned short tcp_len;
  } fakehdr = {
    .saddr = ip->saddr,
    .daddr = ip->daddr,
    .proto_num = ip->protocol,
    .tcp_len = htons(ntohs(ip->tot_len) - ip->ihl*4)
  };
  sum_accumulate(&sum, &fakehdr, sizeof(fakehdr));
  sum_accumulate(&sum, tcp, tcp->doff*4);
  tcp->check = sum_final(sum);
}

int main(void) {
  int tun_fd = tun_alloc("inject_dev%d");
  systemf("ip link set %s up", devname);
  systemf("ip addr add 192.168.42.1/24 dev %s", devname);

  struct {
    struct iphdr ip;
    struct tcphdr tcp;
    unsigned char tcp_opts[20];
  } __attribute__((packed)) syn_packet = {
    .ip = {
      .ihl = sizeof(struct iphdr)/4,
      .version = 4,
      .tot_len = htons(sizeof(syn_packet)),
      .ttl = 30,
      .protocol = IPPROTO_TCP,
      /* FIXUP check */
      .saddr = IPADDR(192,168,42,2),
      .daddr = IPADDR(192,168,42,1)
    },
    .tcp = {
      .source = htons(1),
      .dest = htons(1337),
      .seq = 0x12345678,
      .doff = (sizeof(syn_packet.tcp)+sizeof(syn_packet.tcp_opts))/4,
      .syn = 1,
      .window = htons(64),
      .check = 0 /*FIXUP*/
    },
    .tcp_opts = {
      /* INVALID: trailing MD5SIG opcode after NOPs */
      1, 1, 1, 1, 1,
      1, 1, 1, 1, 1,
      1, 1, 1, 1, 1,
      1, 1, 1, 1, 19
    }
  };
  fix_ip_sum(&syn_packet.ip);
  fix_tcp_sum(&syn_packet.ip, &syn_packet.tcp);
  while (1) {
    int write_res = write(tun_fd, &syn_packet, sizeof(syn_packet));
    if (write_res != sizeof(syn_packet))
      err(1, "packet write failed");
  }
}
====================================

Fixes: cfb6eeb4 ("[TCP]: MD5 Signature Option (RFC2385) support.")
Signed-off-by: NJann Horn <jannh@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch checks if sk buffer is available to dererence ife header. If
not then NULL will returned to signal an malformed ife packet. This
avoids to crashing the kernel from outside.
Signed-off-by: NAlexander Aring <aring@mojatatu.com>
Reviewed-by: NYotam Gigi <yotam.gi@gmail.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is currently no handling to check on a invalid tlv length. This
patch adds such handling to avoid killing the kernel with a malformed
ife packet.
Signed-off-by: NAlexander Aring <aring@mojatatu.com>
Reviewed-by: NYotam Gigi <yotam.gi@gmail.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We need to record stats for received metadata that we dont know how
to process. Have find_decode_metaid() return -ENOENT to capture this.
Signed-off-by: NAlexander Aring <aring@mojatatu.com>
Reviewed-by: NYotam Gigi <yotam.gi@gmail.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>