From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 519A439934B; Sat, 17 Oct 2026 17:30:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258236; cv=none; b=utaGHl9rPAFKweEBz4qRo1WGpA72Ej1/Q2MmyYA6IAXxSjFTEyw9QerN9o4tKYXMLkuNhYgi9+MYg2YFa5/M+Jq85oCGQj3ObjV51mGNfwkkinXui4+GHtEopbNCt9sef8IrC/mXHUKqavAbW9kzZzta45m4VmsmqbveVoGRm78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258236; c=relaxed/simple; bh=ImigujwoPHsQJ9UfC2fF1nmIpLS5uMKl18K+VpvIzLA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kq4kVCe/8r69ygo5MVZXzt93n8B0yEaNy5Bt2OG2rED+DiZ099KacjCY1sqqaTqU+5rFHUvDS5SHrSs7g2xnrI3c5dde77+yJZEh/BqRro0tJ4Bmzws7GfhYQl75OnnFMwTMH1W2DuKJodksJiifFhvOoNWwkK7RdKwMq5u93+Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ef0SmtC1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ef0SmtC1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FFE41F000C4; Sat, 17 Oct 2026 17:30:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258234; bh=RjKp2bjHOCSTluVK5+sFgvtvwhnXdoIPK0JqTu19VyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ef0SmtC1KQfwa2n+CsxfCb96QdJ/Lmh3n0lN06P7Y2WCxQvUZ3obrB9ykW4vqsZAA Y8Ju2JP3WYTOVMKVJFMmRr5kBEx2qBWhvi0sTNfvRbC9TIN7XryYR50wEw6f+sBQV2 5IauFy0hacYbfYl8NS8fK4TpgIZE+V6nxsipXM5k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , David Ahern , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 0817/1674] tcp: use dst_dev_rcu() in tcp_fastopen_active_disable_ofo_check() Date: Sat, 17 Oct 2026 17:51:29 +0200 Message-ID: <20261017160452.093970431@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit b62a59c18b692f892dcb8109c1c2e653b2abc95c ] Use RCU to avoid a pair of atomic operations and a potential UAF on dst_dev()->flags. Signed-off-by: Eric Dumazet Reviewed-by: David Ahern Link: https://patch.msgid.link/20250828195823.3958522-8-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/tcp_fastopen.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index e874ec597014d..d36a1ceb75101 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -575,11 +575,12 @@ void tcp_fastopen_active_disable_ofo_check(struct sock *sk) } } else if (tp->syn_fastopen_ch && atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times)) { - dst = sk_dst_get(sk); - dev = dst ? dst_dev(dst) : NULL; + rcu_read_lock(); + dst = __sk_dst_get(sk); + dev = dst ? dst_dev_rcu(dst) : NULL; if (!(dev && (dev->flags & IFF_LOOPBACK))) atomic_set(&sock_net(sk)->ipv4.tfo_active_disable_times, 0); - dst_release(dst); + rcu_read_unlock(); } } -- 2.53.0