From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0117.outbound.protection.outlook.com ([104.47.42.117]:63840 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932084AbeDIAYh (ORCPT ); Sun, 8 Apr 2018 20:24:37 -0400 From: Sasha Levin To: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" CC: "Gustavo A. R. Silva" , "David S . Miller" , Sasha Levin Subject: [PATCH AUTOSEL for 4.14 092/161] tcp_nv: fix potential integer overflow in tcpnv_acked Date: Mon, 9 Apr 2018 00:21:03 +0000 Message-ID: <20180409001936.162706-92-alexander.levin@microsoft.com> References: <20180409001936.162706-1-alexander.levin@microsoft.com> In-Reply-To: <20180409001936.162706-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: 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 --- net/ipv4/tcp_nv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_nv.c b/net/ipv4/tcp_nv.c index 125fc1450b01..09f8773fd769 100644 --- a/net/ipv4/tcp_nv.c +++ b/net/ipv4/tcp_nv.c @@ -327,7 +327,7 @@ static void tcpnv_acked(struct sock *sk, const struct a= ck_sample *sample) */ cwnd_by_slope =3D (u32) div64_u64(((u64)ca->nv_rtt_max_rate) * ca->nv_min_rtt, - (u64)(80000 * tp->mss_cache)); + 80000ULL * tp->mss_cache); max_win =3D cwnd_by_slope + nv_pad; =20 /* If cwnd > max_win, decrease cwnd --=20 2.15.1