From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753498AbdEESdf (ORCPT ); Fri, 5 May 2017 14:33:35 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58516 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751716AbdEESda (ORCPT ); Fri, 5 May 2017 14:33:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , Andrey Konovalov , "David S. Miller" , Amit Pundir Subject: [PATCH 3.18 42/68] net: avoid signed overflows for SO_{SND|RCV}BUFFORCE Date: Fri, 5 May 2017 11:32:27 -0700 Message-Id: <20170505183214.284152762@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170505183212.587141964@linuxfoundation.org> References: <20170505183212.587141964@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet commit b98b0bc8c431e3ceb4b26b0dfc8db509518fb290 upstream. CAP_NET_ADMIN users should not be allowed to set negative sk_sndbuf or sk_rcvbuf values, as it can lead to various memory corruptions, crashes, OOM... Note that before commit 82981930125a ("net: cleanups in sock_setsockopt()"), the bug was even more serious, since SO_SNDBUF and SO_RCVBUF were vulnerable. This needs to be backported to all known linux kernels. Again, many thanks to syzkaller team for discovering this gem. Signed-off-by: Eric Dumazet Reported-by: Andrey Konovalov Signed-off-by: David S. Miller Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman --- net/core/sock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/core/sock.c +++ b/net/core/sock.c @@ -733,7 +733,7 @@ int sock_setsockopt(struct socket *sock, val = min_t(u32, val, sysctl_wmem_max); set_sndbuf: sk->sk_userlocks |= SOCK_SNDBUF_LOCK; - sk->sk_sndbuf = max_t(u32, val * 2, SOCK_MIN_SNDBUF); + sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF); /* Wake up sending tasks if we upped the value. */ sk->sk_write_space(sk); break; @@ -769,7 +769,7 @@ set_rcvbuf: * returning the value we actually used in getsockopt * is the most desirable behavior. */ - sk->sk_rcvbuf = max_t(u32, val * 2, SOCK_MIN_RCVBUF); + sk->sk_rcvbuf = max_t(int, val * 2, SOCK_MIN_RCVBUF); break; case SO_RCVBUFFORCE: