linux-stable.git/net/sctp, branch linux-5.14.y

sctp: return true only for pathmtu update in sctp_transport_pl_toobig

2021-11-17T10:04:18+00:00

[ Upstream commit 75cf662c64dd8543f56c329c69eba18141c8fd9f ]

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: 836964083177 ("sctp: do state transition when receiving an icmp TOOBIG packet")
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

sctp: allow IP fragmentation when PLPMTUD enters Error state

2021-11-17T10:04:17+00:00

[ Upstream commit 40171248bb8934537fec8fbaf718e57c8add187c ]

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: 1dc68c194571 ("sctp: do state transition when PROBE_COUNT == MAX_PROBES on HB send path")
Reported-by: Ying Xu 
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

sctp: add vtag check in sctp_sf_ootb

2021-11-02T18:51:00+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

2021-11-02T18:51:00+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

2021-11-02T18:51:00+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

2021-11-02T18:51:00+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

2021-11-02T18:51:00+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: fix the processing for INIT chunk

2021-11-02T18:51:00+00:00

[ Upstream commit eae5783908042a762c24e1bd11876edb91d314b1 ]

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: 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

2021-11-02T18:51:00+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

2021-10-20T09:57:54+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