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

sctp: trim optlen when it's a huge value in sctp_setsockopt

2021-07-18T16:47:29+00:00

After commit ca84bd058dae ("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: ca84bd058dae ("sctp: copy the optval from user space in sctp_setsockopt")
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller

sctp: enable PLPMTUD when the transport is ready

2021-06-22T18:28:52+00:00

sctp_transport_pl_reset() is called whenever any of these 3 members in
transport is changed:

  - probe_interval
  - param_flags & SPP_PMTUD_ENABLE
  - state == ACTIVE

If all are true, start the PLPMTUD when it's not yet started. If any of
these is false, stop the PLPMTUD when it's already running.

sctp_transport_pl_update() is called when the transport dst has changed.
It will restart the PLPMTUD probe. Again, the pathmtu won't change but
use the dst's mtu until the Search phase is done.

Note that after using PLPMTUD, the pathmtu is only initialized with the
dst mtu when the transport dst changes. At other time it is updated by
pl.pmtu. So sctp_transport_pmtu_check() will be called only when PLPMTUD
is disabled in sctp_packet_config().

After this patch, the PLPMTUD feature from RFC8899 will be activated
and can be used by users.

Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

sctp: add SCTP_PLPMTUD_PROBE_INTERVAL sockopt for sock/asoc/transport

2021-06-22T18:28:51+00:00

With this socket option, users can change probe_interval for
a transport, asoc or sock after it's created.

Note that if the change is for an asoc, also apply the change
to each transport in this asoc.

Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

sctp: add probe_interval in sysctl and sock/asoc/transport

2021-06-22T18:28:51+00:00

PLPMTUD can be enabled by doing 'sysctl -w net.sctp.probe_interval=n'.
'n' is the interval for PLPMTUD probe timer in milliseconds, and it
can't be less than 5000 if it's not 0.

All asoc/transport's PLPMTUD in a new socket will be enabled by default.

Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

sctp: add the missing setting for asoc encap_port

2021-05-25T22:17:26+00:00

This patch is to add the missing setting back for asoc encap_port.

Fixes: 8dba29603b5c ("sctp: add SCTP_REMOTE_UDP_ENCAPS_PORT sockopt")
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller

sctp: delay auto_asconf init until binding the first addr

2021-05-03T20:36:21+00:00

As Or Cohen described:

  If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock
  held and sp->do_auto_asconf is true, then an element is removed
  from the auto_asconf_splist without any proper locking.

  This can happen in the following functions:
  1. In sctp_accept, if sctp_sock_migrate fails.
  2. In inet_create or inet6_create, if there is a bpf program
     attached to BPF_CGROUP_INET_SOCK_CREATE which denies
     creation of the sctp socket.

This patch is to fix it by moving the auto_asconf init out of
sctp_init_sock(), by which inet_create()/inet6_create() won't
need to operate it in sctp_destroy_sock() when calling
sk_common_release().

It also makes more sense to do auto_asconf init while binding the
first addr, as auto_asconf actually requires an ANY addr bind,
see it in sctp_addr_wq_timeout_handler().

This addresses CVE-2021-23133.

Fixes: 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications")
Reported-by: Or Cohen 
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller

Revert "net/sctp: fix race condition in sctp_destroy_sock"

2021-05-03T20:36:21+00:00

This reverts commit b166a20b07382b8bc1dcee2a448715c9c2c81b5b.

This one has to be reverted as it introduced a dead lock, as
syzbot reported:

       CPU0                    CPU1
       ----                    ----
  lock(&net->sctp.addr_wq_lock);
                               lock(slock-AF_INET6);
                               lock(&net->sctp.addr_wq_lock);
  lock(slock-AF_INET6);

CPU0 is the thread of sctp_addr_wq_timeout_handler(), and CPU1
is that of sctp_close().

The original issue this commit fixed will be fixed in the next
patch.

Reported-by: syzbot+959223586843e69a2674@syzkaller.appspotmail.com
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-04-17T18:08:07+00:00

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
 - keep the ZC code, drop the code related to reinit
net/bridge/netfilter/ebtables.c
 - fix build after move to net_generic

Signed-off-by: Jakub Kicinski

net/sctp: fix race condition in sctp_destroy_sock

2021-04-13T21:59:46+00:00

If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock
held and sp->do_auto_asconf is true, then an element is removed
from the auto_asconf_splist without any proper locking.

This can happen in the following functions:
1. In sctp_accept, if sctp_sock_migrate fails.
2. In inet_create or inet6_create, if there is a bpf program
   attached to BPF_CGROUP_INET_SOCK_CREATE which denies
   creation of the sctp socket.

The bug is fixed by acquiring addr_wq_lock in sctp_destroy_sock
instead of sctp_close.

This addresses CVE-2021-23133.

Reported-by: Or Cohen 
Reviewed-by: Xin Long 
Fixes: 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications")
Signed-off-by: Or Cohen 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

net: sctp: Fix some typos

2021-03-29T00:52:50+00:00

Modify "unkown" to "unknown" in net/sctp/sm_make_chunk.c and
Modify "orginal" to "original" in net/sctp/socket.c.

Reported-by: Hulk Robot 
Signed-off-by: Lu Wei 
Signed-off-by: David S. Miller