From patchwork Mon Mar 29 07:58:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 412607 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT 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 6E4D9C433DB for ; Mon, 29 Mar 2021 08:24:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 369A1619A7 for ; Mon, 29 Mar 2021 08:24:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232959AbhC2IYJ (ORCPT ); Mon, 29 Mar 2021 04:24:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:40608 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233106AbhC2IXX (ORCPT ); Mon, 29 Mar 2021 04:23:23 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5451861554; Mon, 29 Mar 2021 08:23:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617006202; bh=OccUCev7wftWWMxIJL7xbKd2olf2arqmEU/Kp+ISNkU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m2SE8ff/tFXqL95yhWzcUn07B5YSoHj3Bs2DZDogO11g/Dtp3Pp+NaHsoLHsXYKXM QMxeq7WNGBUt26jz1Av15i2OSNyNTl9DrCEQi7084LO9s2pLj0gIesbirgqmOGlL/T 49wqdetH0z6bgs4F4puV92ZEyejSAmbB8QrtnjgE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Bohac , Jiri Pirko , "David S. Miller" , Sasha Levin Subject: [PATCH 5.10 156/221] net: check all name nodes in __dev_alloc_name Date: Mon, 29 Mar 2021 09:58:07 +0200 Message-Id: <20210329075634.365237903@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210329075629.172032742@linuxfoundation.org> References: <20210329075629.172032742@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jiri Bohac [ Upstream commit 6c015a2256801597fadcbc11d287774c9c512fa5 ] __dev_alloc_name(), when supplied with a name containing '%d', will search for the first available device number to generate a unique device name. Since commit ff92741270bf8b6e78aa885f166b68c7a67ab13a ("net: introduce name_node struct to be used in hashlist") network devices may have alternate names. __dev_alloc_name() does take these alternate names into account, possibly generating a name that is already taken and failing with -ENFILE as a result. This demonstrates the bug: # rmmod dummy 2>/dev/null # ip link property add dev lo altname dummy0 # modprobe dummy numdummies=1 modprobe: ERROR: could not insert 'dummy': Too many open files in system Instead of creating a device named dummy1, modprobe fails. Fix this by checking all the names in the d->name_node list, not just d->name. Signed-off-by: Jiri Bohac Fixes: ff92741270bf ("net: introduce name_node struct to be used in hashlist") Reviewed-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/dev.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 75ca6c6d01d6..dbc286fd2047 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1195,6 +1195,18 @@ static int __dev_alloc_name(struct net *net, const char *name, char *buf) return -ENOMEM; for_each_netdev(net, d) { + struct netdev_name_node *name_node; + list_for_each_entry(name_node, &d->name_node->list, list) { + if (!sscanf(name_node->name, name, &i)) + continue; + if (i < 0 || i >= max_netdevices) + continue; + + /* avoid cases where sscanf is not exact inverse of printf */ + snprintf(buf, IFNAMSIZ, name, i); + if (!strncmp(buf, name_node->name, IFNAMSIZ)) + set_bit(i, inuse); + } if (!sscanf(d->name, name, &i)) continue; if (i < 0 || i >= max_netdevices)