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 49F4315575F; Fri, 6 Dec 2024 14:49:34 +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=1733496574; cv=none; b=DoyNMaGulcchFEZ5X2qSEG7wfGTNSZC5IiPBY4f8FWOai3SYsjv1oK2y3HUjuow7C9sWnTis6uLnXACIWfYhll8vzWV1FvVaFkHhJ0r5nIHHKeyVO674vk5zax1BatYfKxaO7eQaWYn3agU+/ubciKTWIopbdu0TDjEi6M22BLA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733496574; c=relaxed/simple; bh=XEXw/KEtHuMxz9HhaLK9DDb+s2M11npcvYEqB8X8Y8s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dYrx2nl7EU2NmU2luyl+ddsEFbOXVdJmPYj+CpQKO99HJ1t65NEAsfxrlrLFNzLrpZZAsBdMIPbnaIBxvUmEk0034i6t8dPb2n4rTXzaajPgp2Nwi18i2dJEq/82j1tQXoV0c3hojWBTB9TNgiPWQYLKfSh/o9NMsa0L9lO5Nrk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DPTFZGa8; 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="DPTFZGa8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ACB03C4CED1; Fri, 6 Dec 2024 14:49:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733496574; bh=XEXw/KEtHuMxz9HhaLK9DDb+s2M11npcvYEqB8X8Y8s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DPTFZGa8eNWMASel8fvydqqEJPU9HryY7k5iExEMTRwECa4rnyvDrgjzUva8nhzN/ ljG7hRfb5tlEN+S3LcyD5pCYKOJdtaX24RmS6Yq6NPRfzMNlZWScgCNxAqa7P85w2V 1IWGTnLvJ4blD+dyLBYOKDzcQoO8IRI+eHPXTpKs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayuan Chen , Martin KaFai Lau , Sasha Levin Subject: [PATCH 6.6 013/676] bpf: fix filed access without lock Date: Fri, 6 Dec 2024 15:27:12 +0100 Message-ID: <20241206143653.876525531@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241206143653.344873888@linuxfoundation.org> References: <20241206143653.344873888@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org 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: Jiayuan Chen [ Upstream commit a32aee8f0d987a7cba7fcc28002553361a392048 ] The tcp_bpf_recvmsg_parser() function, running in user context, retrieves seq_copied from tcp_sk without holding the socket lock, and stores it in a local variable seq. However, the softirq context can modify tcp_sk->seq_copied concurrently, for example, n tcp_read_sock(). As a result, the seq value is stale when it is assigned back to tcp_sk->copied_seq at the end of tcp_bpf_recvmsg_parser(), leading to incorrect behavior. Due to concurrency, the copied_seq field in tcp_bpf_recvmsg_parser() might be set to an incorrect value (less than the actual copied_seq) at the end of function: 'WRITE_ONCE(tcp->copied_seq, seq)'. This causes the 'offset' to be negative in tcp_read_sock()->tcp_recv_skb() when processing new incoming packets (sk->copied_seq - skb->seq becomes less than 0), and all subsequent packets will be dropped. Signed-off-by: Jiayuan Chen Link: https://lore.kernel.org/r/20241028065226.35568-1-mrpre@163.com Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- net/ipv4/tcp_bpf.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index fe6178715ba05..915286c3615a2 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -221,11 +221,11 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk, int flags, int *addr_len) { - struct tcp_sock *tcp = tcp_sk(sk); int peek = flags & MSG_PEEK; - u32 seq = tcp->copied_seq; struct sk_psock *psock; + struct tcp_sock *tcp; int copied = 0; + u32 seq; if (unlikely(flags & MSG_ERRQUEUE)) return inet_recv_error(sk, msg, len, addr_len); @@ -238,7 +238,8 @@ static int tcp_bpf_recvmsg_parser(struct sock *sk, return tcp_recvmsg(sk, msg, len, flags, addr_len); lock_sock(sk); - + tcp = tcp_sk(sk); + seq = tcp->copied_seq; /* We may have received data on the sk_receive_queue pre-accept and * then we can not use read_skb in this context because we haven't * assigned a sk_socket yet so have no link to the ops. The work-around -- 2.43.0