From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7817F27FD4A; Tue, 11 Nov 2025 01:19:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762823949; cv=none; b=LXxNFjD+0MXCT0SrlHfcdh2pc9aqyjE+Y7CntFSnVUZ6y6AGFkBhEmt0EUlMCE7WJcnBrSZpG6Mj4xwmROPinVWVs7Zo4hKcv8+NipxDkuFEGAVDAZrbf3VXsQ9i/DrXYAm96ttL4Gt8ycwjt1577Brn1/v/CkmFoU7SJmJztf4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762823949; c=relaxed/simple; bh=ABnkS29oGZ1Of76JlllobGcJwllOE9dCTfmbdPp64Jw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KuJj9FuxG57B6Hbes1eb7JWRwSwIt6Zy6pIqFAs+GPULYQOKWjcVYytcaO/uY+yVOnuvA/HqvtJh7+6Ku9rDiWR0avLIw0yQ7HFLa0R+Bt4hMR07w1kAYaGdtasgkkgQencw8TSSIC0a0oIjXHLgXHssE5WWi+2cJjsT+uUq8Q0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lOH06Trz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lOH06Trz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17A15C4CEF5; Tue, 11 Nov 2025 01:19:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1762823949; bh=ABnkS29oGZ1Of76JlllobGcJwllOE9dCTfmbdPp64Jw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lOH06TrzAMR7lQyIGqPfE0nbs5UeKyl08Rzed+zk1kE/PkXQe+uErDlSWW8CgaOh5 LEK88tdtk/M9Wz56PeboAKjQ3eMxw/G0L5xJJFWvUHnt4/eguj5G/rBiIRddYjaP/V W9b3GF+zDPDDWOi7j2cwImg91YWjhqA3WfC/0QTc= 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 6.17 403/849] tcp: use dst_dev_rcu() in tcp_fastopen_active_disable_ofo_check() Date: Tue, 11 Nov 2025 09:39:33 +0900 Message-ID: <20251111004546.182165484@linuxfoundation.org> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20251111004536.460310036@linuxfoundation.org> References: <20251111004536.460310036@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 6.17-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 f1884f0c9e523..7d945a527daf0 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -576,11 +576,12 @@ 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(); } } -- 2.51.0