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 123757E for ; Wed, 2 Nov 2022 02:54:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23221C433D7; Wed, 2 Nov 2022 02:54:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667357695; bh=q0H/7X9ErSl/dS/in7cW+7g1yipU1biWpSHKBoi+YYU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rU1+6whF0DLl7g3OWDjqeeJDKpJUNJ5sNSk5mznekEeNo/IilDbwmq4n59toqaMEz xUUMjFFtE1l5EBX/1hd0oOMMW7kK6K7dVdJKIM/bVlZEYXfu15rQhBnJOe9EHJhwjz t7rdlrDrHhJKj4PuFMOTKYTHK5a+Q49OjvGNR61I= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lu Wei , Eric Dumazet , Kuniyuki Iwashima , "David S. Miller" , Sasha Levin Subject: [PATCH 6.0 187/240] tcp: fix a signed-integer-overflow bug in tcp_add_backlog() Date: Wed, 2 Nov 2022 03:32:42 +0100 Message-Id: <20221102022115.620001811@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221102022111.398283374@linuxfoundation.org> References: <20221102022111.398283374@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Lu Wei [ Upstream commit ec791d8149ff60c40ad2074af3b92a39c916a03f ] The type of sk_rcvbuf and sk_sndbuf in struct sock is int, and in tcp_add_backlog(), the variable limit is caculated by adding sk_rcvbuf, sk_sndbuf and 64 * 1024, it may exceed the max value of int and overflow. This patch reduces the limit budget by halving the sndbuf to solve this issue since ACK packets are much smaller than the payload. Fixes: c9c3321257e1 ("tcp: add tcp_add_backlog()") Signed-off-by: Lu Wei Reviewed-by: Eric Dumazet Acked-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv4/tcp_ipv4.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 5b019ba2b9d2..fe9a6022db66 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1853,11 +1853,13 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, __skb_push(skb, hdrlen); no_coalesce: + limit = (u32)READ_ONCE(sk->sk_rcvbuf) + (u32)(READ_ONCE(sk->sk_sndbuf) >> 1); + /* Only socket owner can try to collapse/prune rx queues * to reduce memory overhead, so add a little headroom here. * Few sockets backlog are possibly concurrently non empty. */ - limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf) + 64*1024; + limit += 64 * 1024; if (unlikely(sk_add_backlog(sk, skb, limit))) { bh_unlock_sock(sk); -- 2.35.1