linux.git/net/dccp/feat.c, branch master

net: Retire DCCP socket.

2025-04-12T01:58:10+00:00

DCCP was orphaned in 2021 by commit 054c4610bd05 ("MAINTAINERS: dccp:
move Gerrit Renker to CREDITS"), which noted that the last maintainer
had been inactive for five years.

In recent years, it has become a playground for syzbot, and most changes
to DCCP have been odd bug fixes triggered by syzbot. Apart from that,
the only changes have been driven by treewide or networking API updates
or adjustments related to TCP.

Thus, in 2023, we announced we would remove DCCP in 2025 via commit
b144fcaf46d4 ("dccp: Print deprecation notice.").

Since then, only one individual has contacted the netdev mailing list. [0]

There is ongoing research for Multipath DCCP. The repository is hosted
on GitHub [1], and development is not taking place through the upstream
community. While the repository is published under the GPLv2 license,
the scheduling part remains proprietary, with a LICENSE file [2] stating:

"This is not Open Source software."

The researcher mentioned a plan to address the licensing issue, upstream
the patches, and step up as a maintainer, but there has been no further
communication since then.

Maintaining DCCP for a decade without any real users has become a burden.

Therefore, it's time to remove it.

Removing DCCP will also provide significant benefits to TCP. It allows
us to freely reorganize the layout of struct inet_connection_sock, which
is currently shared with DCCP, and optimize it to reduce the number of
cachelines accessed in the TCP fast path.

Note that we keep DCCP netfilter modules as requested. [3]

Link: https://lore.kernel.org/netdev/20230710182253.81446-1-kuniyu@amazon.com/T/#u #[0]
Link: https://github.com/telekom/mp-dccp #[1]
Link: https://github.com/telekom/mp-dccp/blob/mpdccp_v03_k5.10/net/dccp/non_gpl_scheduler/LICENSE #[2]
Link: https://lore.kernel.org/netdev/Z_VQ0KlCRkqYWXa-@calendula/ #[3]
Signed-off-by: Kuniyuki Iwashima
Acked-by: Paul Moore (LSM and SELinux)
Acked-by: Casey Schaufler
Link: https://patch.msgid.link/20250410023921.11307-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

dccp: Fix memory leak in dccp_feat_change_recv

2024-12-03T08:50:21+00:00

If dccp_feat_push_confirm() fails after new value for SP feature was accepted
without reconciliation ('entry == NULL' branch), memory allocated for that value
with dccp_feat_clone_sp_val() is never freed.

Here is the kmemleak stack for this:

unreferenced object 0xffff88801d4ab488 (size 8):
  comm "syz-executor310", pid 1127, jiffies 4295085598 (age 41.666s)
  hex dump (first 8 bytes):
    01 b4 4a 1d 80 88 ff ff                          ..J.....
  backtrace:
    [<00000000db7cabfe>] kmemdup+0x23/0x50 mm/util.c:128
    [<0000000019b38405>] kmemdup include/linux/string.h:465 [inline]
    [<0000000019b38405>] dccp_feat_clone_sp_val net/dccp/feat.c:371 [inline]
    [<0000000019b38405>] dccp_feat_clone_sp_val net/dccp/feat.c:367 [inline]
    [<0000000019b38405>] dccp_feat_change_recv net/dccp/feat.c:1145 [inline]
    [<0000000019b38405>] dccp_feat_parse_options+0x1196/0x2180 net/dccp/feat.c:1416
    [<00000000b1f6d94a>] dccp_parse_options+0xa2a/0x1260 net/dccp/options.c:125
    [<0000000030d7b621>] dccp_rcv_state_process+0x197/0x13d0 net/dccp/input.c:650
    [<000000001f74c72e>] dccp_v4_do_rcv+0xf9/0x1a0 net/dccp/ipv4.c:688
    [<00000000a6c24128>] sk_backlog_rcv include/net/sock.h:1041 [inline]
    [<00000000a6c24128>] __release_sock+0x139/0x3b0 net/core/sock.c:2570
    [<00000000cf1f3a53>] release_sock+0x54/0x1b0 net/core/sock.c:3111
    [<000000008422fa23>] inet_wait_for_connect net/ipv4/af_inet.c:603 [inline]
    [<000000008422fa23>] __inet_stream_connect+0x5d0/0xf70 net/ipv4/af_inet.c:696
    [<0000000015b6f64d>] inet_stream_connect+0x53/0xa0 net/ipv4/af_inet.c:735
    [<0000000010122488>] __sys_connect_file+0x15c/0x1a0 net/socket.c:1865
    [<00000000b4b70023>] __sys_connect+0x165/0x1a0 net/socket.c:1882
    [<00000000f4cb3815>] __do_sys_connect net/socket.c:1892 [inline]
    [<00000000f4cb3815>] __se_sys_connect net/socket.c:1889 [inline]
    [<00000000f4cb3815>] __x64_sys_connect+0x6e/0xb0 net/socket.c:1889
    [<00000000e7b1e839>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
    [<0000000055e91434>] entry_SYSCALL_64_after_hwframe+0x67/0xd1

Clean up the allocated memory in case of dccp_feat_push_confirm() failure
and bail out with an error reset code.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: e77b8363b2ea ("dccp: Process incoming Change feature-negotiation options")
Signed-off-by: Ivan Solodovnikov 
Link: https://patch.msgid.link/20241126143902.190853-1-solodovnikov.ia@phystech.edu
Signed-off-by: Paolo Abeni

dccp: Return the correct errno code

2021-02-06T19:15:28+00:00

When kalloc or kmemdup failed, should return ENOMEM rather than ENOBUF.

Signed-off-by: Zheng Yongjun 
Link: https://lore.kernel.org/r/20210204072820.17723-1-zhengyongjun3@huawei.com
Signed-off-by: Jakub Kicinski

net: dccp: Fix most of the kerneldoc warnings

2020-10-30T19:08:54+00:00

net/dccp/ccids/ccid2.c:190: warning: Function parameter or member 'hc' not described in 'ccid2_update_used_window'
net/dccp/ccids/ccid2.c:190: warning: Function parameter or member 'new_wnd' not described in 'ccid2_update_used_window'
net/dccp/ccids/ccid2.c:360: warning: Function parameter or member 'sk' not described in 'ccid2_rtt_estimator'
net/dccp/ccids/ccid3.c:112: warning: Function parameter or member 'sk' not described in 'ccid3_hc_tx_update_x'
net/dccp/ccids/ccid3.c:159: warning: Function parameter or member 'hc' not described in 'ccid3_hc_tx_update_s'
net/dccp/ccids/ccid3.c:268: warning: Function parameter or member 'sk' not described in 'ccid3_hc_tx_send_packet'
net/dccp/ccids/ccid3.c:667: warning: Function parameter or member 'sk' not described in 'ccid3_first_li'
net/dccp/ccids/ccid3.c:85: warning: Function parameter or member 'hc' not described in 'ccid3_update_send_interval'
net/dccp/ccids/lib/loss_interval.c:85: warning: Function parameter or member 'lh' not described in 'tfrc_lh_update_i_mean'
net/dccp/ccids/lib/loss_interval.c:85: warning: Function parameter or member 'skb' not described in 'tfrc_lh_update_i_mean'
net/dccp/ccids/lib/packet_history.c:392: warning: Function parameter or member 'h' not described in 'tfrc_rx_hist_sample_rtt'
net/dccp/ccids/lib/packet_history.c:392: warning: Function parameter or member 'skb' not described in 'tfrc_rx_hist_sample_rtt'
net/dccp/feat.c:1003: warning: Function parameter or member 'dreq' not described in 'dccp_feat_server_ccid_dependencies'
net/dccp/feat.c:1040: warning: Function parameter or member 'array_len' not described in 'dccp_feat_prefer'
net/dccp/feat.c:1040: warning: Function parameter or member 'array' not described in 'dccp_feat_prefer'
net/dccp/feat.c:1040: warning: Function parameter or member 'preferred_value' not described in 'dccp_feat_prefer'
net/dccp/output.c:151: warning: Function parameter or member 'dp' not described in 'dccp_determine_ccmps'
net/dccp/output.c:242: warning: Function parameter or member 'sk' not described in 'dccp_xmit_packet'
net/dccp/output.c:305: warning: Function parameter or member 'sk' not described in 'dccp_flush_write_queue'
net/dccp/output.c:305: warning: Function parameter or member 'time_budget' not described in 'dccp_flush_write_queue'
net/dccp/output.c:378: warning: Function parameter or member 'sk' not described in 'dccp_retransmit_skb'
net/dccp/qpolicy.c:88: warning: Function parameter or member '' not described in 'dccp_qpolicy_operations'
net/dccp/qpolicy.c:88: warning: Function parameter or member '{' not described in 'dccp_qpolicy_operations'
net/dccp/qpolicy.c:88: warning: Function parameter or member 'params' not described in 'dccp_qpolicy_operations'

Signed-off-by: Andrew Lunn 
Link: https://lore.kernel.org/r/20201028011412.931250-1-andrew@lunn.ch
Signed-off-by: Jakub Kicinski

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

net: dccp: kerneldoc fixes

2020-07-14T00:20:39+00:00

Simple fixes which require no deep knowledge of the code.

Cc: Gerrit Renker 
Signed-off-by: Andrew Lunn 
Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman

dccp: Fix memleak in __feat_register_sp

2019-04-02T01:15:10+00:00

If dccp_feat_push_change fails, we forget free the mem
which is alloced by kmemdup in dccp_feat_clone_sp_val.

Reported-by: Hulk Robot 
Fixes: e8ef967a54f4 ("dccp: Registration routines for changing feature values")
Reviewed-by: Mukesh Ojha 
Signed-off-by: YueHaibing 
Signed-off-by: David S. Miller

dccp: fix a memleak for dccp_feat_init err process

2017-07-27T07:01:05+00:00

In dccp_feat_init, when ccid_get_builtin_ccids failsto alloc
memory for rx.val, it should free tx.val before returning an
error.

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

dccp: kerneldoc warning fixes

2014-11-18T20:26:31+00:00

Signed-off-by: Fabian Frederick 
Signed-off-by: David S. Miller