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 B7A5C2210C2; Thu, 12 Dec 2024 15:51:47 +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=1734018707; cv=none; b=ICIsnHLwXO5q88E+DDgGt4ppQnYaHpDmI/eq+Vbst6z1mZO3qnLlvGbWmWU4cl2+gyBNZ3bEsEbPqb2gI7gu9rmLg5oB6S+/qrR2+fDIcDfeOYYgm5xdC5TEAdJBsqFAHudgvW8rwROCUmjhOykpkrlIQ+QLm25mOHkNwLTch+w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734018707; c=relaxed/simple; bh=OeQInyXXhRzDUPQOlDUg/lpyFcQ8eHyo1BHuVZJkBU0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Wf85hzEmCtT97Ryk2RWUPw5DFMFF1AKONXTwOqfSQU2LpnYV17zq26F9QiGTyeo3HeQf707dk+YK+0g4jWAXnISupd4gyz3DLunLKnZ0rPwnQiPME2HV6YEOF5Qlolw0SZ/wt5Dmwdp3c6W2QJPB/n0NIwL1aTSIUBgCFqnH4II= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KGWcItv7; 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="KGWcItv7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25890C4CECE; Thu, 12 Dec 2024 15:51:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734018707; bh=OeQInyXXhRzDUPQOlDUg/lpyFcQ8eHyo1BHuVZJkBU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KGWcItv7SWgk19UfC06N3pzQI1LeVhpekN6hEvBlOE/XulrA7TKOy2LXMpXEQDecN 0TlSk+lNJiG28GxBVFFaFi/falFR3ZDzodrzsExFBR+4G/kBM0X9mL1RL448NdVqh3 //R0X8ZkO8zuBVScgHnk+LOQJ8a2AAW+K3w7fD+k= 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 6.1 010/772] bpf: fix filed access without lock Date: Thu, 12 Dec 2024 15:49:15 +0100 Message-ID: <20241212144350.375931609@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144349.797589255@linuxfoundation.org> References: <20241212144349.797589255@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 6.1-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 07a896685d0d3..f67e4c9f8d40e 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -216,11 +216,11 @@ 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); @@ -233,7 +233,8 @@ 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