'struct sctp_sched_ops' is not modified in these drivers.
Constifying this structure moves some data to a read-only section, so
increases overall security, especially when the structure holds some
function pointers.
On a x86_64, with allmodconfig, as an example:
Before:
======
text data bss dec hex filename
8019 568 0 8587 218b net/sctp/stream_sched_fc.o
After:
=====
text data bss dec hex filename
8275 312 0 8587 218b net/sctp/stream_sched_fc.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://patch.msgid.link/dce03527eb7b7cc8a3c26d5cdac12bafe3350135.1761377890.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Convert SCTP cookies to use HMAC-SHA256, instead of the previous choice
of the legacy algorithms HMAC-MD5 and HMAC-SHA1. Simplify and optimize
the code by using the HMAC-SHA256 library instead of crypto_shash, and
by preparing the HMAC key when it is generated instead of per-operation.
This doesn't break compatibility, since the cookie format is an
implementation detail, not part of the SCTP protocol itself.
Note that the cookie size doesn't change either. The HMAC field was
already 32 bytes, even though previously at most 20 bytes were actually
compared. 32 bytes exactly fits an untruncated HMAC-SHA256 value. So,
although we could safely truncate the MAC to something slightly shorter,
for now just keep the cookie size the same.
I also considered SipHash, but that would generate only 8-byte MACs. An
8-byte MAC *might* suffice here. However, there's quite a lot of
information in the SCTP cookies: more than in TCP SYN cookies. So
absent an analysis that occasional forgeries of all that information is
okay in SCTP, I errored on the side of caution.
Remove HMAC-MD5 and HMAC-SHA1 as options, since the new HMAC-SHA256
option is just better. It's faster as well as more secure. For
example, benchmarking on x86_64, cookie authentication is now nearly 3x
as fast as the previous default choice and implementation of HMAC-MD5.
Also just make the kernel always support cookie authentication if SCTP
is supported at all, rather than making it optional in the build. (It
was sort of optional before, but it didn't really work properly. E.g.,
a kernel with CONFIG_SCTP_COOKIE_HMAC_MD5=n still supported HMAC-MD5
cookie authentication if CONFIG_CRYPTO_HMAC and CONFIG_CRYPTO_MD5
happened to be enabled in the kconfig for other reasons.)
Acked-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20250818205426.30222-5-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For SCTP chunk authentication, use the HMAC-SHA1 and HMAC-SHA256 library
functions instead of crypto_shash. This is simpler and faster. There's
no longer any need to pre-allocate 'crypto_shash' objects; the SCTP code
now simply calls into the HMAC code directly.
As part of this, make SCTP always support both HMAC-SHA1 and
HMAC-SHA256. Previously, it only guaranteed support for HMAC-SHA1.
However, HMAC-SHA256 tended to be supported too anyway, as it was
supported if CONFIG_CRYPTO_SHA256 was enabled elsewhere in the kconfig.
Acked-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20250818205426.30222-4-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As part of the removal of the variably-sized sockaddr for kernel
internals, replace struct sockaddr with sockaddr_inet in the sctp_addr
union.
No binary changes; the union size remains unchanged due to sockaddr_inet
matching the size of sockaddr_in6.
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20250722171836.1078436-3-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sctp_sendmsg() re-uses associations and transports when possible by
doing a lookup based on the socket endpoint and the message destination
address, and then sctp_sendmsg_to_asoc() sets the selected transport in
all the message chunks to be sent.
There's a possible race condition if another thread triggers the removal
of that selected transport, for instance, by explicitly unbinding an
address with setsockopt(SCTP_SOCKOPT_BINDX_REM), after the chunks have
been set up and before the message is sent. This can happen if the send
buffer is full, during the period when the sender thread temporarily
releases the socket lock in sctp_wait_for_sndbuf().
This causes the access to the transport data in
sctp_outq_select_transport(), when the association outqueue is flushed,
to result in a use-after-free read.
This change avoids this scenario by having sctp_transport_free() signal
the freeing of the transport, tagging it as "dead". In order to do this,
the patch restores the "dead" bit in struct sctp_transport, which was
removed in
commit 47faa1e4c5 ("sctp: remove the dead field of sctp_transport").
Then, in the scenario where the sender thread has released the socket
lock in sctp_wait_for_sndbuf(), the bit is checked again after
re-acquiring the socket lock to detect the deletion. This is done while
holding a reference to the transport to prevent it from being freed in
the process.
If the transport was deleted while the socket lock was relinquished,
sctp_sendmsg_to_asoc() will return -EAGAIN to let userspace retry the
send.
The bug was found by a private syzbot instance (see the error report [1]
and the C reproducer that triggers it [2]).
Link: https://people.igalia.com/rcn/kernel_logs/20250402__KASAN_slab-use-after-free_Read_in_sctp_outq_select_transport.txt [1]
Link: https://people.igalia.com/rcn/kernel_logs/20250402__KASAN_slab-use-after-free_Read_in_sctp_outq_select_transport__repro.c [2]
Cc: stable@vger.kernel.org
Fixes: df132eff46 ("sctp: clear the transport of some out_chunk_list chunks in sctp_assoc_rm_peer")
Suggested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Ricardo Cañuelo Navarro <rcn@igalia.com>
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20250404-kasan_slab-use-after-free_read_in_sctp_outq_select_transport__20250404-v1-1-5ce4a0b78ef2@igalia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This patch deletes the flexible-array peer_init[] from the structure
sctp_cookie to avoid some sparse warnings:
# make C=2 CF="-Wflexible-array-nested" M=./net/sctp/
net/sctp/sm_make_chunk.c: note: in included file (through include/net/sctp/sctp.h):
./include/net/sctp/structs.h:1588:28: warning: nested flexible array
./include/net/sctp/structs.h:343:28: warning: nested flexible array
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In the latest RFC9260, the Host Name Address param has been deprecated.
For INIT chunk:
Note 3: An INIT chunk MUST NOT contain the Host Name Address
parameter. The receiver of an INIT chunk containing a Host Name
Address parameter MUST send an ABORT chunk and MAY include an
"Unresolvable Address" error cause.
For Supported Address Types:
The value indicating the Host Name Address parameter MUST NOT be
used when sending this parameter and MUST be ignored when receiving
this parameter.
Currently Linux SCTP doesn't really support Host Name Address param,
but only saves some flag and print debug info, which actually won't
even be triggered due to the verification in sctp_verify_param().
This patch is to delete those dead code.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As it says in rfc8260#section-3.6 about the weighted fair queueing
scheduler:
A Weighted Fair Queueing scheduler between the streams is used. The
weight is configurable per outgoing SCTP stream. This scheduler
considers the lengths of the messages of each stream and schedules
them in a specific way to use the capacity according to the given
weights. If the weight of stream S1 is n times the weight of stream
S2, the scheduler should assign to stream S1 n times the capacity it
assigns to stream S2. The details are implementation dependent.
Interleaving user messages allows for a better realization of the
capacity usage according to the given weights.
This patch adds Weighted Fair Queueing Scheduler actually based on
the code of Fair Capacity Scheduler by adding fc_weight into struct
sctp_stream_out_ext and taking it into account when sorting stream->
fc_list in sctp_sched_fc_sched() and sctp_sched_fc_dequeue_done().
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
As it says in rfc8260#section-3.5 about the fair capacity scheduler:
A fair capacity distribution between the streams is used. This
scheduler considers the lengths of the messages of each stream and
schedules them in a specific way to maintain an equal capacity for
all streams. The details are implementation dependent. interleaving
user messages allows for a better realization of the fair capacity
usage.
This patch adds Fair Capacity Scheduler based on the foundations added
by commit 5bbbbe32a4 ("sctp: introduce stream scheduler foundations"):
A fc_list and a fc_length are added into struct sctp_stream_out_ext and
a fc_list is added into struct sctp_stream. In .enqueue, when there are
chunks enqueued into a stream, this stream will be linked into stream->
fc_list by its fc_list ordered by its fc_length. In .dequeue, it always
picks up the 1st skb from stream->fc_list. In .dequeue_done, fc_length
is increased by chunk's len and update its location in stream->fc_list
according to the its new fc_length.
Note that when the new fc_length overflows in .dequeue_done, instead of
resetting all fc_lengths to 0, we only reduced them by U32_MAX / 4 to
avoid a moment of imbalance in the scheduling, as Marcelo suggested.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
With this refcnt added in sctp_stream_priorities, we don't need to
traverse all streams to check if the prio is used by other streams
when freeing one stream's prio in sctp_sched_prio_free_sid(). This
can avoid a nested loop (up to 65535 * 65535), which may cause a
stuck as Ying reported:
watchdog: BUG: soft lockup - CPU#23 stuck for 26s! [ksoftirqd/23:136]
Call Trace:
<TASK>
sctp_sched_prio_free_sid+0xab/0x100 [sctp]
sctp_stream_free_ext+0x64/0xa0 [sctp]
sctp_stream_free+0x31/0x50 [sctp]
sctp_association_free+0xa5/0x200 [sctp]
Note that it doesn't need to use refcount_t type for this counter,
as its accessing is always protected under the sock lock.
v1->v2:
- add a check in sctp_sched_prio_set to avoid the possible prio_head
refcnt overflow.
Fixes: 9ed7bfc795 ("sctp: fix memory leak in sctp_stream_outq_migrate()")
Reported-by: Ying Xu <yinxu@redhat.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/825eb0c905cb864991eba335f4a2b780e543f06b.1677085641.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch at first adds a pernet global l3mdev_accept to decide if it
accepts the packets from a l3mdev when a SCTP socket doesn't bind to
any interface. It's set to 1 to avoid any possible incompatible issue,
and in next patch, a sysctl will be introduced to allow to change it.
Then similar to inet/udp_sk_bound_dev_eq(), sctp_sk_bound_dev_eq() is
added to check either dif or sdif is equal to sk_bound_dev_if, and to
check sid is 0 or l3mdev_accept is 1 if sk_bound_dev_if is not set.
This function is used to match a association or a endpoint, namely
called by sctp_addrs_lookup_transport() and sctp_endpoint_is_match().
All functions that needs updating are:
sctp_rcv():
asoc:
__sctp_rcv_lookup()
__sctp_lookup_association() -> sctp_addrs_lookup_transport()
__sctp_rcv_lookup_harder()
__sctp_rcv_init_lookup()
__sctp_lookup_association() -> sctp_addrs_lookup_transport()
__sctp_rcv_walk_lookup()
__sctp_rcv_asconf_lookup()
__sctp_lookup_association() -> sctp_addrs_lookup_transport()
ep:
__sctp_rcv_lookup_endpoint() -> sctp_endpoint_is_match()
sctp_connect():
sctp_endpoint_is_peeled_off()
__sctp_lookup_association()
sctp_has_association()
sctp_lookup_association()
__sctp_lookup_association() -> sctp_addrs_lookup_transport()
sctp_diag_dump_one():
sctp_transport_lookup_process() -> sctp_addrs_lookup_transport()
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add skb_sdif function in struct sctp_af to get the enslaved device
for both ipv4 and ipv6 when adding SCTP VRF support in sctp_rcv in
the next patch.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
commit 077cdda764 ("net/mlx5e: TC, Fix memory leak with rules with internal port")
commit 31108d142f ("net/mlx5: Fix some error handling paths in 'mlx5e_tc_add_fdb_flow()'")
commit 4390c6edc0 ("net/mlx5: Fix some error handling paths in 'mlx5e_tc_add_fdb_flow()'")
https://lore.kernel.org/all/20211229065352.30178-1-saeed@kernel.org/
net/smc/smc_wr.c
commit 49dc9013e3 ("net/smc: Use the bitmap API when applicable")
commit 349d43127d ("net/smc: fix kernel panic caused by race of smc_sock")
bitmap_zero()/memset() is removed by the fix
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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: Lee Jones <lee.jones@linaro.org>
Fixes: d25adbeb0c ("sctp: fix an use-after-free issue in sctp_sock_dump")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Struct sctp_ep_common is included in both asoc and ep, but hlist_node
and hashent are only needed by ep after asoc_hashtable was dropped by
Commit b5eff71283 ("sctp: drop the old assoc hashtable of sctp").
So it is better to move hlist_node and hashent from sctp_ep_common to
sctp_endpoint, and it saves some space for each asoc.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the probe timer is reused as the raise timer when PLPMTUD is in
the Search Complete state. raise_count was introduced to count how many
times the probe timer has timed out. When raise_count reaches to 30, the
raise timer handler will be triggered.
During the whole processing above, the timer keeps timing out every probe_
interval. It is a waste for the Search Complete state, as the raise timer
only needs to time out after 30 * probe_interval.
Since the raise timer and probe timer are never used at the same time, it
is no need to keep probe timer 'alive' in the Search Complete state. This
patch to introduce sctp_transport_reset_raise_timer() to start the timer
as the raise timer when entering the Search Complete state. When entering
the other states, sctp_transport_reset_probe_timer() will still be called
to reset the timer to the probe timer.
raise_count can be removed from sctp_transport as no need to count probe
timer timeout for raise timer timeout. last_rtx_chunks can be removed as
sctp_transport_reset_probe_timer() can be called in the place where asoc
rtx_data_chunks is changed.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/edb0e48988ea85997488478b705b11ddc1ba724a.1637781974.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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: 72e89f5008 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: Richard Haines <richard_c_haines@btinternet.com>
Tested-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David 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: 0dac127c05 ("sctp: do black hole detection in search complete state")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David 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: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Kuniyuki Iwashima
Christophe JAILLET
Eric Biggers
Kees Cook
Dr. David Alan Gilbert
Ricardo Cañuelo Navarro
Simon Horman
Eric Dumazet
Yue Haibing
Xin Long
Jakub Kicinski