This patch is to delay the endpoint free by calling call_rcu() to fix
another use-after-free issue in sctp_sock_dump():

  BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20
  Call Trace:
    __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218
    lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
    __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
    _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168
    spin_lock_bh include/linux/spinlock.h:334 [inline]
    __lock_sock+0x203/0x350 net/core/sock.c:2253
    lock_sock_nested+0xfe/0x120 net/core/sock.c:2774
    lock_sock include/net/sock.h:1492 [inline]
    sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324
    sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091
    sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527
    __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049
    inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065
    netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244
    __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352
    netlink_dump_start include/linux/netlink.h:216 [inline]
    inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170
    __sock_diag_cmd net/core/sock_diag.c:232 [inline]
    sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263
    netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
    sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274

This issue occurs when asoc is peeled off and the old sk is freed after
getting it by asoc->base.sk and before calling lock_sock(sk).

To prevent the sk free, as a holder of the sk, ep should be alive when
calling lock_sock(). This patch uses call_rcu() and moves sock_put and
ep free into sctp_endpoint_destroy_rcu(), so that it's safe to try to
hold the ep under rcu_read_lock in sctp_transport_traverse_process().

If sctp_endpoint_hold() returns true, it means this ep is still alive
and we have held it and can continue to dump it; If it returns false,
it means this ep is dead and can be freed after rcu_read_unlock, and
we should skip it.

In sctp_sock_dump(), after locking the sk, if this ep is different from
tsp->asoc->ep, it means during this dumping, this asoc was peeled off
before calling lock_sock(), and the sk should be skipped; If this ep is
the same with tsp->asoc->ep, it means no peeloff happens on this asoc,
and due to lock_sock, no peeloff will happen either until release_sock.

Note that delaying endpoint free won't delay the port release, as the
port release happens in sctp_endpoint_destroy() before calling call_rcu().
Also, freeing endpoint by call_rcu() makes it safe to access the sk by
asoc->base.sk in sctp_assocs_seq_show() and sctp_rcv().

Thanks Jones to bring this issue up.

v1->v2:
  - improve the changelog.
  - add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed.

Reported-by: syzbot+9276d76e83e3bcde6c99@syzkaller.appspotmail.com
Reported-by: NLee Jones <lee.jones@linaro.org>
Fixes: d25adbeb ("sctp: fix an use-after-free issue in sctp_sock_dump")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch reverts two prior patches, e7310c94
("security: implement sctp_assoc_established hook in selinux") and
7c2ef024 ("security: add sctp_assoc_established hook"), which
create the security_sctp_assoc_established() LSM hook and provide a
SELinux implementation.  Unfortunately these two patches were merged
without proper review (the Reviewed-by and Tested-by tags from
Richard Haines were for previous revisions of these patches that
were significantly different) and there are outstanding objections
from the SELinux maintainers regarding these patches.

Work is currently ongoing to correct the problems identified in the
reverted patches, as well as others that have come up during review,
but it is unclear at this point in time when that work will be ready
for inclusion in the mainline kernel.  In the interest of not keeping
objectionable code in the kernel for multiple weeks, and potentially
a kernel release, we are reverting the two problematic patches.
Signed-off-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch reverts two prior patches, e7310c94
("security: implement sctp_assoc_established hook in selinux") and
7c2ef024 ("security: add sctp_assoc_established hook"), which
create the security_sctp_assoc_established() LSM hook and provide a
SELinux implementation.  Unfortunately these two patches were merged
without proper review (the Reviewed-by and Tested-by tags from
Richard Haines were for previous revisions of these patches that
were significantly different) and there are outstanding objections
from the SELinux maintainers regarding these patches.

Work is currently ongoing to correct the problems identified in the
reverted patches, as well as others that have come up during review,
but it is unclear at this point in time when that work will be ready
for inclusion in the mainline kernel.  In the interest of not keeping
objectionable code in the kernel for multiple weeks, and potentially
a kernel release, we are reverting the two problematic patches.
Signed-off-by: NPaul Moore <paul@paul-moore.com>

sctp_sf_violation_chunk() is not called with asoc argument equal to NULL,
but if that happens it would lead to NULL pointer dereference
in sctp_vtag_verify().

The patch removes code that handles NULL asoc in sctp_sf_violation_chunk().

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Proposed-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nr_free_buffer_pages could be exposed through mm.h instead of swap.h.
The advantage of this change is that it can reduce the obsolete
includes.  For example, net/ipv4/tcp.c wouldn't need swap.h any more
since it has already included mm.h.  Similarly, after checking all the
other files, it comes that tcp.c, udp.c meter.c ,...  follow the same
rule, so these files can have swap.h removed too.

Moreover, after preprocessing all the files that use
nr_free_buffer_pages, it turns out that those files have already
included mm.h.Thus, we can move nr_free_buffer_pages from swap.h to mm.h
safely.  This change will not affect the compilation of other files.

Link: https://lkml.kernel.org/r/20210912133640.1624-1-liumh1@shanghaitech.edu.cnSigned-off-by: NMianhan Liu <liumh1@shanghaitech.edu.cn>
Cc: Jakub Kicinski <kuba@kernel.org>
CC: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "David S . Miller" <davem@davemloft.net>
Cc: Simon Horman <horms@verge.net.au>
Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

security_sctp_assoc_established() is added to replace
security_inet_conn_established() called in
sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security
subsystem and save the peer secid to asoc->peer_secid.

v1->v2:
  - fix the return value of security_sctp_assoc_established() in
    security.h, found by kernel test robot and Ondrej.

Fixes: 72e89f50 ("security: Add support for SCTP security hooks")
Reported-by: NPrashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: NRichard Haines <richard_c_haines@btinternet.com>
Tested-by: NRichard Haines <richard_c_haines@btinternet.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The asoc created when receives the INIT chunk is a temporary one, it
will be deleted after INIT_ACK chunk is replied. So for the real asoc
created in sctp_sf_do_5_1D_ce() when the COOKIE_ECHO chunk is received,
security_sctp_assoc_request() should also be called.

v1->v2:
  - fix some typo and grammar errors, noticed by Ondrej.

Fixes: 72e89f50 ("security: Add support for SCTP security hooks")
Reported-by: NPrashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: NRichard Haines <richard_c_haines@btinternet.com>
Tested-by: NRichard Haines <richard_c_haines@btinternet.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to move secid and peer_secid from endpoint to association,
and pass asoc to sctp_assoc_request and sctp_sk_clone instead of ep. As
ep is the local endpoint and asoc represents a connection, and in SCTP
one sk/ep could have multiple asoc/connection, saving secid/peer_secid
for new asoc will overwrite the old asoc's.

Note that since asoc can be passed as NULL, security_sctp_assoc_request()
is moved to the place right after the new_asoc is created in
sctp_sf_do_5_1B_init() and sctp_sf_do_unexpected_init().

v1->v2:
  - fix the description of selinux_netlbl_skbuff_setsid(), as Jakub noticed.
  - fix the annotation in selinux_sctp_assoc_request(), as Richard Noticed.

Fixes: 72e89f50 ("security: Add support for SCTP security hooks")
Reported-by: NPrashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: NRichard Haines <richard_c_haines@btinternet.com>
Tested-by: NRichard Haines <richard_c_haines@btinternet.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_transport_pl_toobig() supposes to return true only if there's
pathmtu update, so that in sctp_icmp_frag_needed() it would call
sctp_assoc_sync_pmtu() and sctp_retransmit(). This patch is to fix
these return places in sctp_transport_pl_toobig().

Fixes: 83696408 ("sctp: do state transition when receiving an icmp TOOBIG packet")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently when PLPMTUD enters Error state, transport pathmtu will be set
to MIN_PLPMTU(512) while probe is continuing with BASE_PLPMTU(1200). It
will cause pathmtu to stay in a very small value, even if the real pmtu
is some value like 1000.

RFC8899 doesn't clearly say how to set the value in Error state. But one
possibility could be keep using BASE_PLPMTU for the real pmtu, but allow
to do IP fragmentation when it's in Error state.

As it says in rfc8899#section-5.4:

   Some paths could be unable to sustain packets of the BASE_PLPMTU
   size.  The Error State could be implemented to provide robustness to
   such paths.  This allows fallback to a smaller than desired PLPMTU
   rather than suffer connectivity failure.  This could utilize methods
   such as endpoint IP fragmentation to enable the PL sender to
   communicate using packets smaller than the BASE_PLPMTU.

This patch is to set pmtu to BASE_PLPMTU instead of MIN_PLPMTU for Error
state in sctp_transport_pl_send/toobig(), and set packet ipfragok for
non-probe packets when it's in Error state.

Fixes: 1dc68c19 ("sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path")
Reported-by: NYing Xu <yinxu@redhat.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_sf_ootb() is called when processing DATA chunk in closed state,
and many other places are also using it.

The vtag in the chunk's sctphdr should be verified, otherwise, as
later in chunk length check, it may send abort with the existent
asoc's vtag, which can be exploited by one to cook a malicious
chunk to terminate a SCTP asoc.

When fails to verify the vtag from the chunk, this patch sets asoc
to NULL, so that the abort will be made with the vtag from the
received chunk later.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

sctp_sf_do_8_5_1_E_sa() is called when processing SHUTDOWN_ACK chunk
in cookie_wait and cookie_echoed state.

The vtag in the chunk's sctphdr should be verified, otherwise, as
later in chunk length check, it may send abort with the existent
asoc's vtag, which can be exploited by one to cook a malicious
chunk to terminate a SCTP asoc.

Note that when fails to verify the vtag from SHUTDOWN-ACK chunk,
SHUTDOWN COMPLETE message will still be sent back to peer, but
with the vtag from SHUTDOWN-ACK chunk, as said in 5) of
rfc4960#section-8.4.

While at it, also remove the unnecessary chunk length check from
sctp_sf_shut_8_4_5(), as it's already done in both places where
it calls sctp_sf_shut_8_4_5().

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

sctp_sf_violation() is called when processing HEARTBEAT_ACK chunk
in cookie_wait state, and some other places are also using it.

The vtag in the chunk's sctphdr should be verified, otherwise, as
later in chunk length check, it may send abort with the existent
asoc's vtag, which can be exploited by one to cook a malicious
chunk to terminate a SCTP asoc.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

1. In closed state: in sctp_sf_do_5_1D_ce():

  When asoc is NULL, making packet for abort will use chunk's vtag
  in sctp_ootb_pkt_new(). But when asoc exists, vtag from the chunk
  should be verified before using peer.i.init_tag to make packet
  for abort in sctp_ootb_pkt_new(), and just discard it if vtag is
  not correct.

2. In the other states: in sctp_sf_do_5_2_4_dupcook():

  asoc always exists, but duplicate cookie_echo's vtag will be
  handled by sctp_tietags_compare() and then take actions, so before
  that we only verify the vtag for the abort sent for invalid chunk
  length.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Currently INIT_ACK chunk in non-cookie_echoed state is processed in
sctp_sf_discard_chunk() to send an abort with the existent asoc's
vtag if the chunk length is not valid. But the vtag in the chunk's
sctphdr is not verified, which may be exploited by one to cook a
malicious chunk to terminal a SCTP asoc.

sctp_sf_discard_chunk() also is called in many other places to send
an abort, and most of those have this problem. This patch is to fix
it by sending abort with the existent asoc's vtag only if the vtag
from the chunk's sctphdr is verified in sctp_sf_discard_chunk().

Note on sctp_sf_do_9_1_abort() and sctp_sf_shutdown_pending_abort(),
the chunk length has been verified before sctp_sf_discard_chunk(),
so replace it with sctp_sf_discard(). On sctp_sf_do_asconf_ack() and
sctp_sf_do_asconf(), move the sctp_chunk_length_valid check ahead of
sctp_sf_discard_chunk(), then replace it with sctp_sf_discard().

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

This patch fixes the problems below:

1. In non-shutdown_ack_sent states: in sctp_sf_do_5_1B_init() and
   sctp_sf_do_5_2_2_dupinit():

  chunk length check should be done before any checks that may cause
  to send abort, as making packet for abort will access the init_tag
  from init_hdr in sctp_ootb_pkt_new().

2. In shutdown_ack_sent state: in sctp_sf_do_9_2_reshutack():

  The same checks as does in sctp_sf_do_5_2_2_dupinit() is needed
  for sctp_sf_do_9_2_reshutack().

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Currently Linux SCTP uses the verification tag of the existing SCTP
asoc when failing to process and sending the packet with the ABORT
chunk. This will result in the peer accepting the ABORT chunk and
removing the SCTP asoc. One could exploit this to terminate a SCTP
asoc.

This patch is to fix it by always using the initiate tag of the
received INIT chunk for the ABORT chunk to be sent.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

sctp_make_strreset_req() makes repeated calls to sctp_addto_chunk()
which will automatically account for padding on each call. inreq and
outreq are already 4 bytes aligned, but the payload is not and doing
SCTP_PAD4(a + b) (which _sctp_make_chunk() did implicitly here) is
different from SCTP_PAD4(a) + SCTP_PAD4(b) and not enough. It led to
possible attempt to use more buffer than it was allocated and triggered
a BUG_ON.

Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Fixes: cc16f00f ("sctp: add support for generating stream reconf ssn reset request chunk")
Reported-by: NEiichi Tsukata <eiichi.tsukata@nutanix.com>
Signed-off-by: NEiichi Tsukata <eiichi.tsukata@nutanix.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NMarcelo Ricardo Leitner <mleitner@redhat.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/b97c1f8b0c7ff79ac4ed206fc2c49d3612e0850c.1634156849.git.mleitner@redhat.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

We should always check if skb_header_pointer's return is NULL before
using it, otherwise it may cause null-ptr-deref, as syzbot reported:

  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:sctp_rcv_ootb net/sctp/input.c:705 [inline]
  RIP: 0010:sctp_rcv+0x1d84/0x3220 net/sctp/input.c:196
  Call Trace:
  <IRQ>
   sctp6_rcv+0x38/0x60 net/sctp/ipv6.c:1109
   ip6_protocol_deliver_rcu+0x2e9/0x1ca0 net/ipv6/ip6_input.c:422
   ip6_input_finish+0x62/0x170 net/ipv6/ip6_input.c:463
   NF_HOOK include/linux/netfilter.h:307 [inline]
   NF_HOOK include/linux/netfilter.h:301 [inline]
   ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:472
   dst_input include/net/dst.h:460 [inline]
   ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
   NF_HOOK include/linux/netfilter.h:307 [inline]
   NF_HOOK include/linux/netfilter.h:301 [inline]
   ipv6_rcv+0x28c/0x3c0 net/ipv6/ip6_input.c:297

Fixes: 3acb50c1 ("sctp: delay as much as possible skb_linearize")
Reported-by: syzbot+581aff2ae6b860625116@syzkaller.appspotmail.com
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit 58acd100 ("sctp: update active_key for asoc when old key is
being replaced"), sctp_auth_asoc_init_active_key() is called to update
the active_key right after the old key is deleted and before the new key
is added, and it caused that the active_key could be found with the key_id.

In Ying Xu's testing, the BUG_ON in sctp_auth_asoc_init_active_key() was
triggered:

  [ ] kernel BUG at net/sctp/auth.c:416!
  [ ] RIP: 0010:sctp_auth_asoc_init_active_key.part.8+0xe7/0xf0 [sctp]
  [ ] Call Trace:
  [ ]  sctp_auth_set_key+0x16d/0x1b0 [sctp]
  [ ]  sctp_setsockopt.part.33+0x1ba9/0x2bd0 [sctp]
  [ ]  __sys_setsockopt+0xd6/0x1d0
  [ ]  __x64_sys_setsockopt+0x20/0x30
  [ ]  do_syscall_64+0x5b/0x1a0

So fix it by moving the active_key update after sh_keys is added.

Fixes: 58acd100 ("sctp: update active_key for asoc when old key is being replaced")
Reported-by: NYing Xu <yinxu@redhat.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As Ben Hutchings noticed, this check should have been inverted: the call
returns true in case of success.
Reported-by: NBen Hutchings <ben@decadent.org.uk>
Fixes: 0c5dc070 ("sctp: validate from_addr_param return")
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_inet6addr_event deletes 'addr' from 'local_addr_list' when setting
netdev down, but it is possible to delete the incorrect entry (match
the first one with the same ipaddr, but the different 'ifindex'), if
there are some netdevs with the same 'local-link' ipaddr added already.
It should delete the entry depending on 'sin6_addr' and 'sin6_scope_id'
both. otherwise, the endpoint will call 'sctp_sf_ootb' if it can't find
the according association when receives 'heartbeat', and finally will
reply 'abort'.

For example:
1.when linux startup
the entries in local_addr_list:
ifindex:35 addr:fe80::40:43ff:fe80:0 (eths0.201)
ifindex:36 addr:fe80::40:43ff:fe80:0 (eths0.209)
ifindex:37 addr:fe80::40:43ff:fe80:0 (eths0.210)

the route table:
local fe80::40:43ff:fe80:0 dev eths0.201
local fe80::40:43ff:fe80:0 dev eths0.209
local fe80::40:43ff:fe80:0 dev eths0.210

2.after 'ifconfig eths0.209 down'
the entries in local_addr_list:
ifindex:36 addr:fe80::40:43ff:fe80:0 (eths0.209)
ifindex:37 addr:fe80::40:43ff:fe80:0 (eths0.210)

the route table:
local fe80::40:43ff:fe80:0 dev eths0.201
local fe80::40:43ff:fe80:0 dev eths0.210

3.asoc not found for src:[fe80::40:43ff:fe80:0]:37381 dst:[:1]:53335
::1->fe80::40:43ff:fe80:0 HEARTBEAT
fe80::40:43ff:fe80:0->::1 ABORT
Signed-off-by: NChen Shen <peterchenshen@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to introduce last_rtx_chunks into sctp_transport to detect
if there's any packet retransmission/loss happened by checking against
asoc's rtx_data_chunks in sctp_transport_pl_send().

If there is, namely, transport->last_rtx_chunks != asoc->rtx_data_chunks,
the pmtu probe will be sent out. Otherwise, increment the pl.raise_count
and return when it's in Search Complete state.

With this patch, if in Search Complete state, which is a long period, it
doesn't need to keep probing the current pmtu unless there's data packet
loss. This will save quite some traffic.

v1->v2:
  - add the missing Fixes tag.

Fixes: 0dac127c ("sctp: do black hole detection in search complete state")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch does 3 things:

  - make sctp_transport_pl_send() and sctp_transport_pl_recv()
    return bool type to decide if more probe is needed to send.

  - pr_debug() only when probe is really needed to send.

  - count pl.raise_count in sctp_transport_pl_send() instead of
    sctp_transport_pl_recv(), and it's only incremented for the
    1st probe for the same size.

These are preparations for the next patch to make probes happen
only when there's packet loss in Search Complete state.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, in sctp_packet_config(), sctp_transport_pmtu_check() is
called to update transport pathmtu with dst's mtu when dst's mtu
has been changed by non sctp stack like xfrm.

However, this should only happen when SPP_PMTUD_ENABLE is set, no
matter where dst's mtu changed. This patch is to fix by checking
SPP_PMTUD_ENABLE flag before calling sctp_transport_pmtu_check().

Thanks Jacek for reporting and looking into this issue.

v1->v2:
  - add the missing "{" to fix the build error.

Fixes: 69fec325 ('Revert "sctp: remove sctp_transport_pmtu_check"')
Reported-by: NJacek Szafraniec <jacek.szafraniec@nokia.com>
Tested-by: NJacek Szafraniec <jacek.szafraniec@nokia.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzbot reported a call trace:

  BUG: KASAN: use-after-free in sctp_auth_shkey_hold+0x22/0xa0 net/sctp/auth.c:112
  Call Trace:
   sctp_auth_shkey_hold+0x22/0xa0 net/sctp/auth.c:112
   sctp_set_owner_w net/sctp/socket.c:131 [inline]
   sctp_sendmsg_to_asoc+0x152e/0x2180 net/sctp/socket.c:1865
   sctp_sendmsg+0x103b/0x1d30 net/sctp/socket.c:2027
   inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821
   sock_sendmsg_nosec net/socket.c:703 [inline]
   sock_sendmsg+0xcf/0x120 net/socket.c:723

This is an use-after-free issue caused by not updating asoc->shkey after
it was replaced in the key list asoc->endpoint_shared_keys, and the old
key was freed.

This patch is to fix by also updating active_key for asoc when old key is
being replaced with a new one. Note that this issue doesn't exist in
sctp_auth_del_key_id(), as it's not allowed to delete the active_key
from the asoc.

Fixes: 1b1e0bc9 ("sctp: add refcnt support for sh_key")
Reported-by: syzbot+b774577370208727d12b@syzkaller.appspotmail.com
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit ca84bd05 ("sctp: copy the optval from user space in
sctp_setsockopt"), it does memory allocation in sctp_setsockopt with
the optlen, and it would fail the allocation and return error if the
optlen from user space is a huge value.

This breaks some sockopts, like SCTP_HMAC_IDENT, SCTP_RESET_STREAMS and
SCTP_AUTH_KEY, as when processing these sockopts before, optlen would
be trimmed to a biggest value it needs when optlen is a huge value,
instead of failing the allocation and returning error.

This patch is to fix the allocation failure when it's a huge optlen from
user space by trimming it to the biggest size sctp sockopt may need when
necessary, and this biggest size is from sctp_setsockopt_reset_streams()
for SCTP_RESET_STREAMS, which is bigger than those for SCTP_HMAC_IDENT
and SCTP_AUTH_KEY.

Fixes: ca84bd05 ("sctp: copy the optval from user space in sctp_setsockopt")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It has 'if (err >0 )' statement in nlmsg_unicast(), so use nlmsg_unicast()
instead of netlink_unicast(), this looks more concise.

v2: remove the change in netfilter.
Signed-off-by: NYajun Deng <yajun.deng@linux.dev>
Reviewed-by: NDavid Ahern <dsahern@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The doc draft-stewart-tsvwg-sctp-ipv4-00 that restricts 198 addresses
was never published. These addresses as private addresses should be
allowed to use in SCTP.

As Michael Tuexen suggested, this patch is to move 198 addresses from
unusable to private scope.
Reported-by: NSérgio <surkamp@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As Marcelo's suggestion this will make code more clear to read.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The "hbinfo" struct has a 4 byte hole at the end so we have to zero it
out to prevent stack information from being disclosed.

Fixes: fe59379b ("sctp: do the basic send and recv for PLPMTUD probe")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces a function wrapper to call the sk_error_report
callback. That will prepare to add additional handling whenever
sk_error_report is called, for example to trace socket errors.
Signed-off-by: NAlexander Aring <aahringo@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When SCTP handles an INIT chunk, it calls for example:
sctp_sf_do_5_1B_init
  sctp_verify_init
    sctp_verify_param
  sctp_process_init
    sctp_process_param
      handling of SCTP_PARAM_SET_PRIMARY

sctp_verify_init() wasn't doing proper size validation and neither the
later handling, allowing it to work over the chunk itself, possibly being
uninitialized memory.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In one of the fallbacks that SCTP has for identifying an association for an
incoming packet, it looks for AddIp chunk (from ASCONF) and take a peek.
Thing is, at this stage nothing was validating that the chunk actually had
enough content for that, allowing the peek to happen over uninitialized
memory.

Similar check already exists in actual asconf handling in
sctp_verify_asconf().
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The first chunk in a packet is ensured to be present at the beginning of
sctp_rcv(), as a packet needs to have at least 1 chunk. But the second
one, may not be completely available and ch->length can be over
uninitialized memory.

Fix here is by only trying to walk on the next chunk if there is enough to
hold at least the header, and then proceed with the ch->length validation
that is already there.
Reported-by: NIlja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Ilja reported that, simply putting it, nothing was validating that
from_addr_param functions were operating on initialized memory. That is,
the parameter itself was being validated by sctp_walk_params, but it
doesn't check for types and their specific sizes and it could be a 0-length
one, causing from_addr_param to potentially work over the next parameter or
even uninitialized memory.

The fix here is to, in all calls to from_addr_param, check if enough space
is there for the wanted IP address type.
Reported-by: NIlja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These is no need to wait for 'interval' period for the next probe
if the last probe is already acked in search state. The 'interval'
period waiting should be only for probe failure timeout and the
current pmtu check when it's in search complete state.

This change will shorten the probe time a lot in search state, and
also fix the document accordingly.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently the PLPMUTD probe will stop for a long period (interval * 30)
after it enters search complete state. If there's a pmtu change on the
route path, it takes a long time to be aware if the ICMP TooBig packet
is lost or filtered.

As it says in rfc8899#section-4.3:

  "A DPLPMTUD method MUST NOT rely solely on this method."
  (ICMP PTB message).

This patch is to enable the other method for search complete state:

  "A PL can use the DPLPMTUD probing mechanism to periodically
   generate probe packets of the size of the current PLPMTU."

With this patch, the probe will continue with the current pmtu every
'interval' until the PMTU_RAISE_TIMER 'timeout', which we implement
by adding raise_count to raise the probe size when it counts to 30
and removing the SCTP_PL_COMPLETE check for PMTU_RAISE_TIMER.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Previously, sctp over udp was using udp tunnel's icmp err process, which
only does sk lookup on sctp side. However for sctp's icmp error process,
there are more things to do, like syncing assoc pmtu/retransmit packets
for toobig type err, and starting proto_unreach_timer for unreach type
err etc.

Now after adding PLPMTUD, which also requires to process toobig type err
on sctp side. This patch is to process icmp err on sctp side by parsing
the type/code/info in .encap_err_lookup and call sctp's icmp processing
functions. Note as the 'redirect' err process needs to know the outer
ip(v6) header's, we have to leave it to udp(v6)_err to handle it.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to extract sctp_v4_err_handle() from sctp_v4_err() to
only handle the icmp err after the sock lookup, and it also makes
the code clearer.

sctp_v4_err_handle() will be used in sctp over udp's err handling
in the following patch.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>