linux.git/net/sctp, branch v5.4.164

sctp: add vtag check in sctp_sf_ootb

2021-11-02T18:46:15+00:00

[ Upstream commit 9d02831e517aa36ee6bdb453a0eb47bd49923fe3 ]

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

sctp: add vtag check in sctp_sf_do_8_5_1_E_sa

2021-11-02T18:46:15+00:00

[ Upstream commit ef16b1734f0a176277b7bb9c71a6d977a6ef3998 ]

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

sctp: add vtag check in sctp_sf_violation

2021-11-02T18:46:15+00:00

[ Upstream commit aa0f697e45286a6b5f0ceca9418acf54b9099d99 ]

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

sctp: fix the processing for COOKIE_ECHO chunk

2021-11-02T18:46:15+00:00

[ Upstream commit a64b341b8695e1c744dd972b39868371b4f68f83 ]

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

sctp: fix the processing for INIT_ACK chunk

2021-11-02T18:46:15+00:00

[ Upstream commit 438b95a7c98f77d51cbf4db021f41b602d750a3f ]

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

sctp: use init_tag from inithdr for ABORT chunk

2021-11-02T18:46:14+00:00

[ Upstream commit 4f7019c7eb33967eb87766e0e4602b5576873680 ]

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: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

sctp: account stream padding length for reconf chunk

2021-10-20T09:40:15+00:00

commit a2d859e3fc97e79d907761550dbc03ff1b36479c upstream.

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 
Cc: Neil Horman 
Cc: Greg KH 
Fixes: cc16f00f6529 ("sctp: add support for generating stream reconf ssn reset request chunk")
Reported-by: Eiichi Tsukata 
Signed-off-by: Eiichi Tsukata 
Signed-off-by: Marcelo Ricardo Leitner 
Signed-off-by: Marcelo Ricardo Leitner 
Reviewed-by: Xin Long 
Link: https://lore.kernel.org/r/b97c1f8b0c7ff79ac4ed206fc2c49d3612e0850c.1634156849.git.mleitner@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

sctp: break out if skb_header_pointer returns NULL in sctp_rcv_ootb

2021-10-06T13:42:33+00:00

[ Upstream commit f7e745f8e94492a8ac0b0a26e25f2b19d342918f ]

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:
  
   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: 3acb50c18d8d ("sctp: delay as much as possible skb_linearize")
Reported-by: syzbot+581aff2ae6b860625116@syzkaller.appspotmail.com
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

sctp: add param size validation for SCTP_PARAM_SET_PRIMARY

2021-09-26T12:07:07+00:00

commit ef6c8d6ccf0c1dccdda092ebe8782777cd7803c9 upstream.

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: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sctp: validate chunk size in __rcv_asconf_lookup

2021-09-26T12:07:07+00:00

commit b6ffe7671b24689c09faa5675dd58f93758a97ae upstream.

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: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman