CVE-2026-64025: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

bpf, skmsg: fix verdict sk_data_ready racing with ktls rx

sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and
defers to psock->saved_data_ready when a TLS RX context is present,
avoiding a conflict with the TLS strparser's ownership of the receive
queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types
with ktls").

sk_psock_verdict_data_ready() has no equivalent guard.  When a socket
is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is
configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready
as rx_ctx->saved_data_ready.  On data arrival:

  tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready
    -> saved_data_ready() = sk_psock_verdict_data_ready()
      -> tcp_read_skb() drains sk_receive_queue via __skb_unlink()
         without calling tcp_eat_skb(), so copied_seq is not advanced.

tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls
tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and
returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned
(potentially freed) skb.  tls_decrypt_sg() subsequently walks that
frag_list: use-after-free.

Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context
is present, call psock->saved_data_ready (sock_def_readable) to wake
recv() waiters and return immediately, leaving the receive queue
untouched.  TLS retains sole ownership of the queue and decrypts the
record normally through tls_sw_recvmsg().

The Linux kernel CVE team has assigned CVE-2026-64025 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.10 with commit ef5659280eb13e8ac31c296f58cfdfa1684ac06b and fixed in 6.6.142 with commit c9ea01768903ae47f210cd457af1dead6de7a9c3
	Issue introduced in 5.10 with commit ef5659280eb13e8ac31c296f58cfdfa1684ac06b and fixed in 6.12.92 with commit 7c8cf21bc4efb4af18d6096db3f8bd06d622251c
	Issue introduced in 5.10 with commit ef5659280eb13e8ac31c296f58cfdfa1684ac06b and fixed in 6.18.34 with commit 1861d369efd62d67796563bf3e01fc22e5626f8b
	Issue introduced in 5.10 with commit ef5659280eb13e8ac31c296f58cfdfa1684ac06b and fixed in 7.0.11 with commit 8a52139560f833c3975032e1f5762611e3a36d71
	Issue introduced in 5.10 with commit ef5659280eb13e8ac31c296f58cfdfa1684ac06b and fixed in 7.1 with commit ddf8029623a1af20e984c040e89ff918158397ab

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-64025
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/core/skmsg.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/c9ea01768903ae47f210cd457af1dead6de7a9c3
	https://git.kernel.org/stable/c/7c8cf21bc4efb4af18d6096db3f8bd06d622251c
	https://git.kernel.org/stable/c/1861d369efd62d67796563bf3e01fc22e5626f8b
	https://git.kernel.org/stable/c/8a52139560f833c3975032e1f5762611e3a36d71
	https://git.kernel.org/stable/c/ddf8029623a1af20e984c040e89ff918158397ab