From patchwork Fri Sep 25 15:01:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Coly Li X-Patchwork-Id: 11800047 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C037D618 for ; Fri, 25 Sep 2020 15:02:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A92E722B2D for ; Fri, 25 Sep 2020 15:02:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729365AbgIYPBx (ORCPT ); Fri, 25 Sep 2020 11:01:53 -0400 Received: from mx2.suse.de ([195.135.220.15]:34140 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728693AbgIYPBx (ORCPT ); Fri, 25 Sep 2020 11:01:53 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 45629AD72; Fri, 25 Sep 2020 15:01:51 +0000 (UTC) From: Coly Li To: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, netdev@vger.kernel.org, open-iscsi@googlegroups.com, linux-scsi@vger.kernel.org, ceph-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Coly Li , Cong Wang , Christoph Hellwig , "David S . Miller" , Sridhar Samudrala Subject: [PATCH v8 2/7] net: add WARN_ONCE in kernel_sendpage() for improper zero-copy send Date: Fri, 25 Sep 2020 23:01:14 +0800 Message-Id: <20200925150119.112016-3-colyli@suse.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200925150119.112016-1-colyli@suse.de> References: <20200925150119.112016-1-colyli@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org If a page sent into kernel_sendpage() is a slab page or it doesn't have ref_count, this page is improper to send by the zero copy sendpage() method. Otherwise such page might be unexpected released in network code path and causes impredictable panic due to kernel memory management data structure corruption. This path adds a WARN_ON() on the sending page before sends it into the concrete zero-copy sendpage() method, if the page is improper for the zero-copy sendpage() method, a warning message can be observed before the consequential unpredictable kernel panic. This patch does not change existing kernel_sendpage() behavior for the improper page zero-copy send, it just provides hint warning message for following potential panic due the kernel memory heap corruption. Signed-off-by: Coly Li Cc: Cong Wang Cc: Christoph Hellwig Cc: David S. Miller Cc: Sridhar Samudrala --- net/socket.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/socket.c b/net/socket.c index 0c0144604f81..771456a1d947 100644 --- a/net/socket.c +++ b/net/socket.c @@ -3638,9 +3638,11 @@ EXPORT_SYMBOL(kernel_getpeername); int kernel_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags) { - if (sock->ops->sendpage) + if (sock->ops->sendpage) { + /* Warn in case the improper page to zero-copy send */ + WARN_ONCE(!sendpage_ok(page)); return sock->ops->sendpage(sock, page, offset, size, flags); - + } return sock_no_sendpage(sock, page, offset, size, flags); } EXPORT_SYMBOL(kernel_sendpage);