From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ganesha.gnumonks.org (ganesha.gnumonks.org [213.95.27.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B03CC1ABECC for ; Thu, 26 Sep 2024 10:33:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.27.120 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727346789; cv=none; b=I+zZgcZ/prFTnpZ5XVbdZY8IHXd/OirZVDAnZzqLzziKVLzpa9CKDxo2fne8b5tyRKtKZYTf5W10ReIXDGRzQ026h7pnur7x9mDb+QTfZ6I18mLiYY4vUG5A5+dTAIjcPWXEu0u0ASj91axhrKCIYxfebQNvO8aa5kcl1/AZu70= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727346789; c=relaxed/simple; bh=gXgdcxG9u0CzcJKxI9HTfbJPD+kSo2xnJposMGoB2OM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=klud3ixlJw0F28unL0PZbXGsQ8NWR3UgG8GuzyzzaQ3iqQkf49elyphppw1YeAc6SSn2hv67YBaO6qD0TwYD9GEuhrMjvBeKH/kvLCn5YX/N19jYchCO5ndQCbb9zzj4LqeCUbdP+ExskQLKggb1XEhrZFzC0sXGP/bb+TC3aBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=gnumonks.org; arc=none smtp.client-ip=213.95.27.120 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gnumonks.org Received: from [78.30.37.63] (port=54696 helo=gnumonks.org) by ganesha.gnumonks.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1stlnu-001PQE-BL; Thu, 26 Sep 2024 12:33:00 +0200 Date: Thu, 26 Sep 2024 12:32:56 +0200 From: Pablo Neira Ayuso To: =?utf-8?B?0L3QsNCx?= Cc: netfilter-devel@vger.kernel.org Subject: Re: [PATCH] conntrack: -L doesn't take a value, so don't discard one (same for -IUDGEFA) Message-ID: References: <2pdkunyljqasunwbqeofqdetpda2xfdqtyrqg6sqr4efwuwzlq@tarta.nabijaczleweli.xyz> Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2pdkunyljqasunwbqeofqdetpda2xfdqtyrqg6sqr4efwuwzlq@tarta.nabijaczleweli.xyz> X-Spam-Score: -1.9 (-) On Thu, Sep 26, 2024 at 10:28:58AM +0200, наб wrote: > On Wed, Sep 25, 2024 at 10:32:59PM +0200, Pablo Neira Ayuso wrote: > > On Wed, Sep 25, 2024 at 05:11:01PM +0200, Ahelenia Ziemiańska wrote: > > > On Wed, Sep 25, 2024 at 04:53:49PM +0200, Pablo Neira Ayuso wrote: > > > > On Tue, Sep 03, 2024 at 04:53:46PM +0200, Ahelenia Ziemiańska wrote: > > > > > On Tue, Sep 03, 2024 at 10:22:09AM +0200, Pablo Neira Ayuso wrote: > > > > > > On Tue, Sep 03, 2024 at 04:16:21AM +0200, Ahelenia Ziemiańska wrote: > > > > > > > The manual says > > > > > > > COMMANDS > > > > > > > These options specify the particular operation to perform. > > > > > > > Only one of them can be specified at any given time. > > > > > > > > > > > > > > -L --dump > > > > > > > List connection tracking or expectation table > > > > > > > > > > > > > > So, naturally, "conntrack -Lo extended" should work, > > > > > > > but it doesn't, it's equivalent to "conntrack -L", > > > > > > > and you need "conntrack -L -o extended". > > > > > > > This violates user expectations (borne of the Utility Syntax Guidelines) > > > > > > > and contradicts the manual. > > > > > > > > > > > > > > optarg is unused, anyway. Unclear why any of these were :: at all? > > > > > > Because this supports: > > > > > > -L > > > > > > -L conntrack > > > > > > -L expect > > > > > Well that's not what :: does, though; we realise this, right? > > > > > > > > > > "L::" means that getopt() will return > > > > > "-L", "conntrack" -> 'L',optarg=NULL > > > > > "-Lconntrack" -> 'L',optarg="conntrack" > > > > > and the parser for -L (&c.) doesn't... use optarg. > > > > Are you sure it does not use optarg? > > > > > > > > static unsigned int check_type(int argc, char *argv[]) > > > > { > > > > const char *table = get_optional_arg(argc, argv); > > > > > > > > and get_optional_arg() uses optarg. > > > This I've missed, but actually my diagnosis still holds: > > > static unsigned int check_type(int argc, char *argv[]) > > > { > > > const char *table = get_optional_arg(argc, argv); > > > > > > /* default to conntrack subsystem if nothing has been specified. */ > > > if (table == NULL) > > > return CT_TABLE_CONNTRACK; > > > > > > static char *get_optional_arg(int argc, char *argv[]) > > > { > > > char *arg = NULL; > > > > > > /* Nasty bug or feature in getopt_long ? > > > * It seems that it behaves badly with optional arguments. > > > * Fortunately, I just stole the fix from iptables ;) */ > > > if (optarg) > > > return arg; > > > > > > So, if you say -Lanything, then > > > optarg=anything > > > get_optional_arg=(null) > > > (notice that it says "return arg;", not "return optarg;", > > > i.e. this is "return NULL"). > > > > > > It /doesn't/ use optarg, because it explicitly treats an optarg as no optarg. > > > > > > It's unclear to me what the comment is referencing, > > > but I'm assuming some sort of confusion with what :: does? > > > Anyway, that if(){ can be removed now, since it can never be taken now. > > Then, this breaks: > > # conntrack -Lexpect > > conntrack v1.4.9 (conntrack-tools): Bad parameter `xpect' > > Try `conntrack -h' or 'conntrack --help' for more information. > > > > Maybe your patch needs an extension to deal with this case too? > > This doesn't "break", this is equivalent to conntrack -L -e xpect. > It's now correct. This was the crux of the patch, actually. > > Compare the manual: > SYNOPSIS > conntrack -L [table] [options] [-z] > COMMANDS > -L --dump List connection tracking or expectation table > PARAMETERS > -e, --event-mask [ALL|NEW|UPDATES|DESTROY][,...] > Set the bitmask of events that are to be generated by the in-kernel ctnetlink event code. Using this parameter, you can reduce the event messages generated > by the kernel to the types that you are actually interested in. This option can only be used in conjunction with "-E, --event". > > Previously, it /was/ broken: conntrack -Lexpect was as-if --dump=expect > (also not legal since --dump doesn't take an argument), > and the "expect" was ignored, so it was equivalent to conntrack -L. > You can trivially validate this by running an older version. > > (Well, --dump=expect /is/ accepted. And ignored. > So fix that too with s/optional_argument/no_argument/ (or s/2/0/). > I didn't actually look at the longopts before.) > > > The issue that I'm observing is that > > # conntrack -Lconntrack > > now optarg is NULL after your patch, so 'conntrack' is ignored, so it > > falls back to list the conntrack table. > > What do you mean "now". That shit was always ignored. > You can read trace the calls yourself if you don't believe my analysis. > Now it behaves as-documented (-L -c onntrack). > > And, per > case 'c': > options |= opt2type[c]; > nfct_set_attr_u32(tmpl->ct, > opt2attr[c], > strtoul(optarg, NULL, 0)); > break; > -c onntrack is equivalent to -c 0. > This is also obviously wrong. > > I will repeat this and you can confirm this once more > (or refer back to my analysis above): > for all of -LIUDGEFA, an optional parameter was accepted, and always discarded. > It now isn't, and behaves as-expected per the USG > ("the USG" is an annoying way to say "how getopt() works". > > > Regarding your question, this parser is old and I shamelessly took it > > from the original iptables to make syntax similar. > So you have someone to blame it on when it turns out to be dysfunctional. > But you also have a huge parser that doesn't work. > Win some/lose some, I suppose. Your stuff breaks existing behaviour. I will revert and leave it as is. There is a risk of breaking existing applications. You can use the word shit, dysfunctional, and keep augment your wording as many times as you want, but that does not change my point.