linux.git/net/sctp, branch master

sctp: properly validate chunk size in sctp_sf_ootb()

2024-11-03T19:03:23+00:00

A size validation fix similar to that in Commit 50619dbf8db7 ("sctp: add
size validation when walking chunks") is also required in sctp_sf_ootb()
to address a crash reported by syzbot:

  BUG: KMSAN: uninit-value in sctp_sf_ootb+0x7f5/0xce0 net/sctp/sm_statefuns.c:3712
  sctp_sf_ootb+0x7f5/0xce0 net/sctp/sm_statefuns.c:3712
  sctp_do_sm+0x181/0x93d0 net/sctp/sm_sideeffect.c:1166
  sctp_endpoint_bh_rcv+0xc38/0xf90 net/sctp/endpointola.c:407
  sctp_inq_push+0x2ef/0x380 net/sctp/inqueue.c:88
  sctp_rcv+0x3831/0x3b20 net/sctp/input.c:243
  sctp4_rcv+0x42/0x50 net/sctp/protocol.c:1159
  ip_protocol_deliver_rcu+0xb51/0x13d0 net/ipv4/ip_input.c:205
  ip_local_deliver_finish+0x336/0x500 net/ipv4/ip_input.c:233

Reported-by: syzbot+f0cbb34d39392f2746ca@syzkaller.appspotmail.com
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Xin Long 
Link: https://patch.msgid.link/a29ebb6d8b9f8affd0f9abb296faafafe10c17d8.1730223981.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski

sctp: ensure sk_state is set to CLOSED if hashing fails in sctp_listen_start

2024-10-09T12:36:32+00:00

If hashing fails in sctp_listen_start(), the socket remains in the
LISTENING state, even though it was not added to the hash table.
This can lead to a scenario where a socket appears to be listening
without actually being accessible.

This patch ensures that if the hashing operation fails, the sk_state
is set back to CLOSED before returning an error.

Note that there is no need to undo the autobind operation if hashing
fails, as the bind port can still be used for next listen() call on
the same socket.

Fixes: 76c6d988aeb3 ("sctp: add sock_reuseport for the sock in __sctp_hash_endpoint")
Reported-by: Marcelo Ricardo Leitner 
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Signed-off-by: David S. Miller

sctp: set sk_state back to CLOSED if autobind fails in sctp_listen_start

2024-10-03T10:18:29+00:00

In sctp_listen_start() invoked by sctp_inet_listen(), it should set the
sk_state back to CLOSED if sctp_autobind() fails due to whatever reason.

Otherwise, next time when calling sctp_inet_listen(), if sctp_sk(sk)->reuse
is already set via setsockopt(SCTP_REUSE_PORT), sctp_sk(sk)->bind_hash will
be dereferenced as sk_state is LISTENING, which causes a crash as bind_hash
is NULL.

  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:sctp_inet_listen+0x7f0/0xa20 net/sctp/socket.c:8617
  Call Trace:
   
   __sys_listen_socket net/socket.c:1883 [inline]
   __sys_listen+0x1b7/0x230 net/socket.c:1894
   __do_sys_listen net/socket.c:1902 [inline]

Fixes: 5e8f3f703ae4 ("sctp: simplify sctp listening code")
Reported-by: syzbot+f4e0f821e3a3b7cee51d@syzkaller.appspotmail.com
Signed-off-by: Xin Long 
Acked-by: Marcelo Ricardo Leitner 
Link: https://patch.msgid.link/a93e655b3c153dc8945d7a812e6d8ab0d52b7aa0.1727729391.git.lucien.xin@gmail.com
Signed-off-by: Paolo Abeni

sctp: Unmask upper DSCP bits in sctp_v4_get_dst()

2024-09-09T13:14:53+00:00

Unmask the upper DSCP bits when calling ip_route_output_key() so that in
the future it could perform the FIB lookup according to the full DSCP
value.

Note that the 'tos' variable holds the full DS field.

Signed-off-by: Ido Schimmel 
Reviewed-by: Guillaume Nault 
Reviewed-by: Xin Long 
Signed-off-by: David S. Miller

sctp: fix association labeling in the duplicate COOKIE-ECHO case

2024-08-27T23:07:12+00:00

sctp_sf_do_5_2_4_dupcook() currently calls security_sctp_assoc_request()
on new_asoc, but as it turns out, this association is always discarded
and the LSM labels never get into the final association (asoc).

This can be reproduced by having two SCTP endpoints try to initiate an
association with each other at approximately the same time and then peel
off the association into a new socket, which exposes the unitialized
labels and triggers SELinux denials.

Fix it by calling security_sctp_assoc_request() on asoc instead of
new_asoc. Xin Long also suggested limit calling the hook only to cases
A, B, and D, since in cases C and E the COOKIE ECHO chunk is discarded
and the association doesn't enter the ESTABLISHED state, so rectify that
as well.

One related caveat with SELinux and peer labeling: When an SCTP
connection is set up simultaneously in this way, we will end up with an
association that is initialized with security_sctp_assoc_request() on
both sides, so the MLS component of the security context of the
association will get swapped between the peers, instead of just one side
setting it to the other's MLS component. However, at that point
security_sctp_assoc_request() had already been called on both sides in
sctp_sf_do_unexpected_init() (on a temporary association) and thus if
the exchange didn't fail before due to MLS, it won't fail now either
(most likely both endpoints have the same MLS range).

Tested by:
 - reproducer from https://src.fedoraproject.org/tests/selinux/pull-request/530
 - selinux-testsuite (https://github.com/SELinuxProject/selinux-testsuite/)
 - sctp-tests (https://github.com/sctp/sctp-tests) - no tests failed
   that wouldn't fail also without the patch applied

Fixes: c081d53f97a1 ("security: pass asoc to sctp_assoc_request and sctp_sk_clone")
Suggested-by: Xin Long 
Signed-off-by: Ondrej Mosnacek 
Acked-by: Xin Long 
Acked-by: Paul Moore  (LSM/SELinux)
Link: https://patch.msgid.link/20240826130711.141271-1-omosnace@redhat.com
Signed-off-by: Jakub Kicinski

sctp: Fix null-ptr-deref in reuseport_add_sock().

2024-08-02T23:25:06+00:00

syzbot reported a null-ptr-deref while accessing sk2->sk_reuseport_cb in
reuseport_add_sock(). [0]

The repro first creates a listener with SO_REUSEPORT.  Then, it creates
another listener on the same port and concurrently closes the first
listener.

The second listen() calls reuseport_add_sock() with the first listener as
sk2, where sk2->sk_reuseport_cb is not expected to be cleared concurrently,
but the close() does clear it by reuseport_detach_sock().

The problem is SCTP does not properly synchronise reuseport_alloc(),
reuseport_add_sock(), and reuseport_detach_sock().

The caller of reuseport_alloc() and reuseport_{add,detach}_sock() must
provide synchronisation for sockets that are classified into the same
reuseport group.

Otherwise, such sockets form multiple identical reuseport groups, and
all groups except one would be silently dead.

  1. Two sockets call listen() concurrently
  2. No socket in the same group found in sctp_ep_hashtable[]
  3. Two sockets call reuseport_alloc() and form two reuseport groups
  4. Only one group hit first in __sctp_rcv_lookup_endpoint() receives
      incoming packets

Also, the reported null-ptr-deref could occur.

TCP/UDP guarantees that would not happen by holding the hash bucket lock.

Let's apply the locking strategy to __sctp_hash_endpoint() and
__sctp_unhash_endpoint().

[0]:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 1 UID: 0 PID: 10230 Comm: syz-executor119 Not tainted 6.10.0-syzkaller-12585-g301927d2d2eb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:reuseport_add_sock+0x27e/0x5e0 net/core/sock_reuseport.c:350
Code: 00 0f b7 5d 00 bf 01 00 00 00 89 de e8 1b a4 ff f7 83 fb 01 0f 85 a3 01 00 00 e8 6d a0 ff f7 49 8d 7e 12 48 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 4b 02 00 00 41 0f b7 5e 12 49 8d 7e 14
RSP: 0018:ffffc9000b947c98 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff8880252ddf98 RCX: ffff888079478000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000012
RBP: 0000000000000001 R08: ffffffff8993e18d R09: 1ffffffff1fef385
R10: dffffc0000000000 R11: fffffbfff1fef386 R12: ffff8880252ddac0
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f24e45b96c0(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcced5f7b8 CR3: 00000000241be000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 
 __sctp_hash_endpoint net/sctp/input.c:762 [inline]
 sctp_hash_endpoint+0x52a/0x600 net/sctp/input.c:790
 sctp_listen_start net/sctp/socket.c:8570 [inline]
 sctp_inet_listen+0x767/0xa20 net/sctp/socket.c:8625
 __sys_listen_socket net/socket.c:1883 [inline]
 __sys_listen+0x1b7/0x230 net/socket.c:1894
 __do_sys_listen net/socket.c:1902 [inline]
 __se_sys_listen net/socket.c:1900 [inline]
 __x64_sys_listen+0x5a/0x70 net/socket.c:1900
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f24e46039b9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 1a 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f24e45b9228 EFLAGS: 00000246 ORIG_RAX: 0000000000000032
RAX: ffffffffffffffda RBX: 00007f24e468e428 RCX: 00007f24e46039b9
RDX: 00007f24e46039b9 RSI: 0000000000000003 RDI: 0000000000000004
RBP: 00007f24e468e420 R08: 00007f24e45b96c0 R09: 00007f24e45b96c0
R10: 00007f24e45b96c0 R11: 0000000000000246 R12: 00007f24e468e42c
R13: 00007f24e465a5dc R14: 0020000000000001 R15: 00007ffcced5f7d8
 
Modules linked in:

Fixes: 6ba845740267 ("sctp: process sk_reuseport in sctp_get_port_local")
Reported-by: syzbot+e6979a5d2f10ecb700e4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e6979a5d2f10ecb700e4
Tested-by: syzbot+e6979a5d2f10ecb700e4@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Xin Long 
Link: https://patch.msgid.link/20240731234624.94055-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

sysctl: treewide: constify the ctl_table argument of proc_handlers

2024-07-24T18:59:29+00:00

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
  virtual patch

  @r1@
  identifier ctl, write, buffer, lenp, ppos;
  identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

  @r2@
  identifier func, ctl, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int write, void *buffer, size_t *lenp, loff_t *ppos)
  { ... }

  @r3@
  identifier func;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int , void *, size_t *, loff_t *);

  @r4@
  identifier func, ctl;
  @@

  int func(
  - struct ctl_table *ctl
  + const struct ctl_table *ctl
    ,int , void *, size_t *, loff_t *);

  @r5@
  identifier func, write, buffer, lenp, ppos;
  @@

  int func(
  - struct ctl_table *
  + const struct ctl_table *
    ,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
  conventions. The xfs_stats_clear_proc_handler,
  xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
  adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
  This is called from a proc_handler itself and is calling back into
  another proc_handler, making it necessary to change it as part of the
  proc_handler migration.

Co-developed-by: Thomas Weißschuh 
Signed-off-by: Thomas Weißschuh 
Co-developed-by: Joel Granados 
Signed-off-by: Joel Granados

sctp: cancel a blocking accept when shutdown a listen socket

2024-07-03T08:45:39+00:00

As David Laight noticed,

"In a multithreaded program it is reasonable to have a thread blocked in
 accept(). With TCP a subsequent shutdown(listen_fd, SHUT_RDWR) causes
 the accept to fail. But nothing happens for SCTP."

sctp_disconnect() is eventually called when shutdown a listen socket,
but nothing is done in this function. This patch sets RCV_SHUTDOWN
flag in sk->sk_shutdown there, and adds the check (sk->sk_shutdown &
RCV_SHUTDOWN) to break and return in sctp_accept().

Note that shutdown() is only supported on TCP-style SCTP socket.

Reported-by: David Laight 
Signed-off-by: Xin Long 
Signed-off-by: David S. Miller

net: change proto and proto_ops accept type

2024-05-14T00:19:09+00:00

Rather than pass in flags, error pointer, and whether this is a kernel
invocation or not, add a struct proto_accept_arg struct as the argument.
This then holds all of these arguments, and prepares accept for being
able to pass back more information.

No functional changes in this patch.

Acked-by: Jakub Kicinski 
Signed-off-by: Jens Axboe

net: Remove ctl_table sentinel elements from several networking subsystems

2024-05-03T12:29:42+00:00

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

To avoid lots of small commits, this commit brings together network
changes from (as they appear in MAINTAINERS) LLC, MPTCP, NETROM NETWORK
LAYER, PHONET PROTOCOL, ROSE NETWORK LAYER, RXRPC SOCKETS, SCTP
PROTOCOL, SHARED MEMORY COMMUNICATIONS (SMC), TIPC NETWORK LAYER and
NETWORKING [IPSEC]

* Remove sentinel element from ctl_table structs.
* Replace empty array registration with the register_net_sysctl_sz call
  in llc_sysctl_init
* Replace the for loop stop condition that tests for procname == NULL
  with one that depends on array size in sctp_sysctl_net_register
* Remove instances where an array element is zeroed out to make it look
  like a sentinel in xfrm_sysctl_init. This is not longer needed and is
  safe after commit c899710fe7f9 ("networking: Update to
  register_net_sysctl_sz") added the array size to the ctl_table
  registration
* Use a table_size variable to keep the value of ARRAY_SIZE

Signed-off-by: Joel Granados 
Signed-off-by: David S. Miller