From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D9A0C43381 for ; Wed, 20 Mar 2019 11:24:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB7822175B for ; Wed, 20 Mar 2019 11:24:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727914AbfCTLYn (ORCPT ); Wed, 20 Mar 2019 07:24:43 -0400 Received: from charlotte.tuxdriver.com ([70.61.120.58]:50639 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727154AbfCTLYn (ORCPT ); Wed, 20 Mar 2019 07:24:43 -0400 Received: from cpe-2606-a000-111b-405a-9816-2c85-c514-8f7a.dyn6.twc.com ([2606:a000:111b:405a:9816:2c85:c514:8f7a] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1h6ZKj-0003Ga-P4; Wed, 20 Mar 2019 07:24:40 -0400 Date: Wed, 20 Mar 2019 07:24:06 -0400 From: Neil Horman To: Xin Long Cc: network dev , linux-sctp@vger.kernel.org, davem@davemloft.net, Marcelo Ricardo Leitner , syzkaller@googlegroups.com Subject: Re: [PATCH net] sctp: use memdup_user instead of vmemdup_user Message-ID: <20190320112406.GA15855@hmswarspite.think-freely.org> References: <94e635135533b7469c84b0aa4df59ea7818a486a.1553064578.git.lucien.xin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <94e635135533b7469c84b0aa4df59ea7818a486a.1553064578.git.lucien.xin@gmail.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Mar 20, 2019 at 02:49:38PM +0800, Xin Long wrote: > In sctp_setsockopt_bindx()/__sctp_setsockopt_connectx(), it allocates > memory with addrs_size which is passed from userspace. We used flag > GFP_USER to put some more restrictions on it in Commit cacc06215271 > ("sctp: use GFP_USER for user-controlled kmalloc"). > > However, since Commit c981f254cc82 ("sctp: use vmemdup_user() rather > than badly open-coding memdup_user()"), vmemdup_user() has been used, > which doesn't check GFP_USER flag when goes to vmalloc_*(). So when > addrs_size is a huge value, it could exhaust memory and even trigger > oom killer. > > This patch is to use memdup_user() instead, in which GFP_USER would > work to limit the memory allocation with a huge addrs_size. > > Note we can't fix it by limiting 'addrs_size', as there's no demand > for it from RFC. > > Reported-by: syzbot+ec1b7575afef85a0e5ca@syzkaller.appspotmail.com > Fixes: c981f254cc82 ("sctp: use vmemdup_user() rather than badly open-coding memdup_user()") > Signed-off-by: Xin Long > --- > net/sctp/socket.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index 6140471..09ad5b2 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -999,7 +999,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > if (unlikely(addrs_size <= 0)) > return -EINVAL; > > - kaddrs = vmemdup_user(addrs, addrs_size); > + kaddrs = memdup_user(addrs, addrs_size); > if (unlikely(IS_ERR(kaddrs))) > return PTR_ERR(kaddrs); > > @@ -1007,7 +1007,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > addr_buf = kaddrs; > while (walk_size < addrs_size) { > if (walk_size + sizeof(sa_family_t) > addrs_size) { > - kvfree(kaddrs); > + kfree(kaddrs); > return -EINVAL; > } > > @@ -1018,7 +1018,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > * causes the address buffer to overflow return EINVAL. > */ > if (!af || (walk_size + af->sockaddr_len) > addrs_size) { > - kvfree(kaddrs); > + kfree(kaddrs); > return -EINVAL; > } > addrcnt++; > @@ -1054,7 +1054,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > } > > out: > - kvfree(kaddrs); > + kfree(kaddrs); > > return err; > } > @@ -1329,7 +1329,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk, > if (unlikely(addrs_size <= 0)) > return -EINVAL; > > - kaddrs = vmemdup_user(addrs, addrs_size); > + kaddrs = memdup_user(addrs, addrs_size); > if (unlikely(IS_ERR(kaddrs))) > return PTR_ERR(kaddrs); > > @@ -1349,7 +1349,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk, > err = __sctp_connect(sk, kaddrs, addrs_size, flags, assoc_id); > > out_free: > - kvfree(kaddrs); > + kfree(kaddrs); > > return err; > } > -- > 2.1.0 > > Acked-by: Neil Horman From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Date: Wed, 20 Mar 2019 11:24:06 +0000 Subject: Re: [PATCH net] sctp: use memdup_user instead of vmemdup_user Message-Id: <20190320112406.GA15855@hmswarspite.think-freely.org> List-Id: References: <94e635135533b7469c84b0aa4df59ea7818a486a.1553064578.git.lucien.xin@gmail.com> In-Reply-To: <94e635135533b7469c84b0aa4df59ea7818a486a.1553064578.git.lucien.xin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Xin Long Cc: network dev , linux-sctp@vger.kernel.org, davem@davemloft.net, Marcelo Ricardo Leitner , syzkaller@googlegroups.com On Wed, Mar 20, 2019 at 02:49:38PM +0800, Xin Long wrote: > In sctp_setsockopt_bindx()/__sctp_setsockopt_connectx(), it allocates > memory with addrs_size which is passed from userspace. We used flag > GFP_USER to put some more restrictions on it in Commit cacc06215271 > ("sctp: use GFP_USER for user-controlled kmalloc"). > > However, since Commit c981f254cc82 ("sctp: use vmemdup_user() rather > than badly open-coding memdup_user()"), vmemdup_user() has been used, > which doesn't check GFP_USER flag when goes to vmalloc_*(). So when > addrs_size is a huge value, it could exhaust memory and even trigger > oom killer. > > This patch is to use memdup_user() instead, in which GFP_USER would > work to limit the memory allocation with a huge addrs_size. > > Note we can't fix it by limiting 'addrs_size', as there's no demand > for it from RFC. > > Reported-by: syzbot+ec1b7575afef85a0e5ca@syzkaller.appspotmail.com > Fixes: c981f254cc82 ("sctp: use vmemdup_user() rather than badly open-coding memdup_user()") > Signed-off-by: Xin Long > --- > net/sctp/socket.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index 6140471..09ad5b2 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -999,7 +999,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > if (unlikely(addrs_size <= 0)) > return -EINVAL; > > - kaddrs = vmemdup_user(addrs, addrs_size); > + kaddrs = memdup_user(addrs, addrs_size); > if (unlikely(IS_ERR(kaddrs))) > return PTR_ERR(kaddrs); > > @@ -1007,7 +1007,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > addr_buf = kaddrs; > while (walk_size < addrs_size) { > if (walk_size + sizeof(sa_family_t) > addrs_size) { > - kvfree(kaddrs); > + kfree(kaddrs); > return -EINVAL; > } > > @@ -1018,7 +1018,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > * causes the address buffer to overflow return EINVAL. > */ > if (!af || (walk_size + af->sockaddr_len) > addrs_size) { > - kvfree(kaddrs); > + kfree(kaddrs); > return -EINVAL; > } > addrcnt++; > @@ -1054,7 +1054,7 @@ static int sctp_setsockopt_bindx(struct sock *sk, > } > > out: > - kvfree(kaddrs); > + kfree(kaddrs); > > return err; > } > @@ -1329,7 +1329,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk, > if (unlikely(addrs_size <= 0)) > return -EINVAL; > > - kaddrs = vmemdup_user(addrs, addrs_size); > + kaddrs = memdup_user(addrs, addrs_size); > if (unlikely(IS_ERR(kaddrs))) > return PTR_ERR(kaddrs); > > @@ -1349,7 +1349,7 @@ static int __sctp_setsockopt_connectx(struct sock *sk, > err = __sctp_connect(sk, kaddrs, addrs_size, flags, assoc_id); > > out_free: > - kvfree(kaddrs); > + kfree(kaddrs); > > return err; > } > -- > 2.1.0 > > Acked-by: Neil Horman