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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no 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 0C05CC76191 for ; Mon, 15 Jul 2019 20:50:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7DED2171F for ; Mon, 15 Jul 2019 20:50:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=networkplumber-org.20150623.gappssmtp.com header.i=@networkplumber-org.20150623.gappssmtp.com header.b="O7zrLW6h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732743AbfGOUuA (ORCPT ); Mon, 15 Jul 2019 16:50:00 -0400 Received: from mail-pl1-f174.google.com ([209.85.214.174]:33085 "EHLO mail-pl1-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732750AbfGOUt7 (ORCPT ); Mon, 15 Jul 2019 16:49:59 -0400 Received: by mail-pl1-f174.google.com with SMTP id c14so8883090plo.0 for ; Mon, 15 Jul 2019 13:49:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Mc+jizhnLlSmQoVOvYZGx7SYSpOs2DGRrAIp2HmZQWI=; b=O7zrLW6hNGBHMzdw3Q8MQFhj8IeS/OeJ180IWkSFGfRQqimn2khazAqptt3GWtRIfa FWvZZVY/hPluV3Ybjiltg9Q9XNWHjZIHC/9kWbxCyPLK0efQuPhC7ZGXpVGiPSEk1QOo LKknoMfH6WOtB27dPcqEHybUrUp2x0CiSRi7hxdvXkf5HYw9TqRpSe7/xoJo6xkfSDty UGflk+TxP3PTSNBvN30N9onhoEP6p+06wpU+W4bkScg5KBZodTZ+uDA2qzcE7SYHHj2P eWBgrP98WdOLdfKJh2X5U4dqBrP5HM/pwsVln42T7f222JYmlAMpEFk2uTSbGYQrsHhE YAXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Mc+jizhnLlSmQoVOvYZGx7SYSpOs2DGRrAIp2HmZQWI=; b=qH3jbiAOr3w5HhX9JFirOyCu2yi+D4kbmbmqyeJYYLnidhI3rCPIuPU9cVlJIaD3lV gw3ed4iNfCIf16AyiXM3pnsJBWZiywtmX8OwCAuAsBTKHndmIATzvoea/BOFRNnGTsUx U1phuxPpeDYSbbJXsdPHjhHI3g5ppYD4ytXFtCtM7wm/1LrQ0UHPgCJPxAEVJZpX+dqh do4SCi6T9Czd/0WE0ykB4joYgcmC7pKoEnJwXvoUEZXmwPrLzXIMWEFiQI6e0SSLwfKa sxqgOQC4DQDWRss+B6wVRK4QFFqyodjcVR8Kkb5wRMpsKt3iumfYwfME7AZnu5nmfyQS BaDg== X-Gm-Message-State: APjAAAX4ExStek6w3HTOQXJoNOIW2z47DL764+Gr0iY6TMLlwhiYDJH0 8c3mEso7cG+LSErD525XYvY= X-Google-Smtp-Source: APXvYqy9UKdcrcWBCQPjIzySQ0kUxf9d9tZRsexxzx8aDq5kMM1d7hJg2ICTXO4y4a6kum+CzlLBLg== X-Received: by 2002:a17:902:b20c:: with SMTP id t12mr30781878plr.285.1563223798408; Mon, 15 Jul 2019 13:49:58 -0700 (PDT) Received: from hermes.lan (204-195-22-127.wavecable.com. [204.195.22.127]) by smtp.gmail.com with ESMTPSA id c98sm18369830pje.1.2019.07.15.13.49.58 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 15 Jul 2019 13:49:58 -0700 (PDT) Date: Mon, 15 Jul 2019 13:49:56 -0700 From: Stephen Hemminger To: Matteo Croce Cc: netdev@vger.kernel.org, David Ahern Subject: Re: [PATCH iproute2 v2] utils: don't match empty strings as prefixes Message-ID: <20190715134956.1e7af534@hermes.lan> In-Reply-To: <20190715180430.19902-1-mcroce@redhat.com> References: <20190715180430.19902-1-mcroce@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, 15 Jul 2019 20:04:30 +0200 Matteo Croce wrote: > iproute has an utility function which checks if a string is a prefix for > another one, to allow use of abbreviated commands, e.g. 'addr' or 'a' > instead of 'address'. > > This routine unfortunately considers an empty string as prefix > of any pattern, leading to undefined behaviour when an empty > argument is passed to ip: > > # ip '' > 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 > link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 > inet 127.0.0.1/8 scope host lo > valid_lft forever preferred_lft forever > inet6 ::1/128 scope host > valid_lft forever preferred_lft forever > > # tc '' > qdisc noqueue 0: dev lo root refcnt 2 > > # ip address add 192.0.2.0/24 '' 198.51.100.1 dev dummy0 > # ip addr show dev dummy0 > 6: dummy0: mtu 1500 qdisc noop state DOWN group default qlen 1000 > link/ether 02:9d:5e:e9:3f:c0 brd ff:ff:ff:ff:ff:ff > inet 192.0.2.0/24 brd 198.51.100.1 scope global dummy0 > valid_lft forever preferred_lft forever > > Rewrite matches() so it takes care of an empty input, and doesn't > scan the input strings three times: the actual implementation > does 2 strlen and a memcpy to accomplish the same task. > > Signed-off-by: Matteo Croce Thanks for following up. Applied