From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52378 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753971AbeDYKl0 (ORCPT ); Wed, 25 Apr 2018 06:41:26 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Gustavo A. R. Silva" , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 104/183] tcp_nv: fix potential integer overflow in tcpnv_acked Date: Wed, 25 Apr 2018 12:35:24 +0200 Message-Id: <20180425103246.634702642@linuxfoundation.org> In-Reply-To: <20180425103242.532713678@linuxfoundation.org> References: <20180425103242.532713678@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Gustavo A. R. Silva" [ Upstream commit e4823fbd229bfbba368b40cdadb8f4eeb20604cc ] Add suffix ULL to constant 80000 in order to avoid a potential integer overflow and give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64. The current cast to u64 effectively applies to the whole expression as an argument of type u64 to be passed to div64_u64, but it does not prevent it from being evaluated using 32-bit arithmetic instead of 64-bit arithmetic. Also, once the expression is properly evaluated using 64-bit arithmentic, there is no need for the parentheses and the external cast to u64. Addresses-Coverity-ID: 1357588 ("Unintentional integer overflow") Signed-off-by: Gustavo A. R. Silva Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_nv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/tcp_nv.c +++ b/net/ipv4/tcp_nv.c @@ -327,7 +327,7 @@ static void tcpnv_acked(struct sock *sk, */ cwnd_by_slope = (u32) div64_u64(((u64)ca->nv_rtt_max_rate) * ca->nv_min_rtt, - (u64)(80000 * tp->mss_cache)); + 80000ULL * tp->mss_cache); max_win = cwnd_by_slope + nv_pad; /* If cwnd > max_win, decrease cwnd