linux/include/uapi
Eric Dumazet 3ba075278c tcp: be less liberal in TSEcr received while in SYN_RECV state
Yong-Hao Zou mentioned that linux was not strict as other OS in 3WHS,
for flows using TCP TS option (RFC 7323)

As hinted by an old comment in tcp_check_req(),
we can check the TSEcr value in the incoming packet corresponds
to one of the SYNACK TSval values we have sent.

In this patch, I record the oldest and most recent values
that SYNACK packets have used.

Send a challenge ACK if we receive a TSEcr outside
of this range, and increase a new SNMP counter.

nstat -az | grep TSEcrRejected
TcpExtTSEcrRejected            0                  0.0

Due to TCP fastopen implementation, do not apply yet these checks
for fastopen flows.

v2: No longer use req->num_timeout, but treq->snt_tsval_first
    to detect when first SYNACK is prepared. This means
    we make sure to not send an initial zero TSval.
    Make sure MPTCP and TCP selftests are passing.
    Change MIB name to TcpExtTSEcrRejected

v1: https://lore.kernel.org/netdev/CADVnQykD8i4ArpSZaPKaoNxLJ2if2ts9m4As+=Jvdkrgx1qMHw@mail.gmail.com/T/

Reported-by: Yong-Hao Zou <yonghaoz1994@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250225171048.3105061-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
History 2025-02-26 18:11:17 -08:00
..
asm-generic \n 2025-01-23 13:36:06 -08:00
drm drm/amdgpu: add a BO metadata flag to disable write compression for Vulkan 2025-02-03 12:11:36 -05:00
linux tcp: be less liberal in TSEcr received while in SYN_RECV state 2025-02-26 18:11:17 -08:00
misc Revert "misc: fastrpc: Restrict untrusted app to attach to privileged PD" 2024-08-15 16:59:14 +02:00
mtd ubi: Expose interface for detailed erase counters 2025-01-18 15:32:32 +01:00
rdma RDMA/nldev: Add IB device and net device rename events 2024-11-04 06:57:21 -05:00
regulator uapi: regulator: Fix typo 2024-01-04 13:22:24 +00:00
scsi scsi: mpi3mr: Add ioctl support for HDB 2024-06-26 23:30:09 -04:00
sound ASoC: Updates for v6.14 2025-01-20 16:15:07 +01:00
video License cleanup: add SPDX license identifier to uapi header files with a license 2017-11-02 11:20:11 +01:00
xen xen/privcmd: Add new syscall to get gsi from dev 2024-09-25 09:54:55 +02:00
Kbuild kbuild: re-implement Makefile.headersinst without recursion 2019-06-15 19:57:02 +09:00