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Date:      Wed, 27 Nov 2013 18:56:36 +1100 (EST)
From:      Ian Smith <smithi@nimnet.asn.au>
To:        Ben Morrow <ben@morrow.me.uk>
Cc:        "Alexander V.Chernikov" <melifaro@freebsd.org>, Ian Lepore <ian@freebsd.org>, freebsd-ipfw@freebsd.org, freebsd-stable@freebsd.org, Luigi Rizzo <rizzo@iet.unipi.it>, =?ISO-8859-1?Q?=D6zkan_KIRIK?= <ozkan.kirik@gmail.com>
Subject:   Re: ipfw table add problem
Message-ID:  <20131127011442.P78756@sola.nimnet.asn.au>
In-Reply-To: <20131126124757.GA9974@anubis.morrow.me.uk>
References:  <CAAcX-AGDZbFn5RmhLBBn2PPWRPcsFUnea5MgTc7nuXGD8Ge53A@mail.gmail.com> <52911993.8010108@ipfw.ru> <CAAcX-AEt_i8RUfmMy6WLnER0X=uLk5A1=oj911k-nyMJEghRLw@mail.gmail.com> <529259DE.2040701@FreeBSD.org> <20131125152238.S78756@sola.nimnet.asn.au> <1385391778.1220.4.camel@revolution.hippie.lan> <20131126001806.27951AD3DBF@rock.dv.isc.org> <20131126124757.GA9974@anubis.morrow.me.uk>
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On Tue, 26 Nov 2013 12:48:01 +0000, Ben Morrow wrote:
 > To: freebsd-stable@freebsd.org

Restoring cc ipfw@ and others after the inet_pton side?thread in 
stable@.  grepping /usr/src for inet_pton suggests that a behavioural 
change in inet_pton at this stage seems rather unlikely :)
 
 > Quoth Michael Butler <imb@protected-networks.net>:
 > > 
 > > Misinterpreting "10.2.3.01" as "0.0.0.10/32" without so much as a
 > > warning from either inet_pton() or ipfw is an egregious breach of POLA,
 > 
 > That's not a bug in inet_pton, though, that's a bug in ipfw. It's
 > blindly passing the string to atoi or some such when inet_pton fails,
 > and ignoring the fact it doesn't consume the whole string.

Indeed it is; strtol actually, which quits at the first (here decimal) 
non-digit.  It does return a pointer to it though, and a check for that 
character being '.' seems like a fair indicator of a failed dotted quad?

http://svnweb.freebsd.org/base/head/sbin/ipfw/ipfw2.c?revision=250759&view=co

	if (ishexnumber(*arg) != 0 || *arg == ':') {
		/* Remove / if exists */
		if ((p = strchr(arg, '/')) != NULL) {
			*p = '\0';
			mask = atoi(p + 1);
		}

		if (inet_pton(AF_INET, arg, paddr) == 1) {
			...
		} else if (inet_pton(AF_INET6, arg, paddr) == 1) {
			...
		} else {
			/* Port or any other key */
			key = strtol(arg, &p, 10);
			/* Skip non-base 10 entries like 'fa1' */
			if (p != arg) {
				pkey = (uint32_t *)paddr;
				*pkey = htonl(key);
				type = IPFW_TABLE_CIDR;
				addrlen = sizeof(uint32_t);
			}
		}
	}

	if (type == 0 && strchr(arg, '.') == NULL) {
		/* Assume interface name. Copy significant data only */
		...
	}

	if (type == 0) {
		if (lookup_host(arg, (struct in_addr *)paddr) != 0)
			errx(EX_NOHOST, "hostname ``%s'' unknown", arg);
		...
	}
	...
}

I'm mostly a pascal programmer (oh, the shame! :) so I can easily misuse 
C pointers, but my reading of strtol(3) leads to suggest something like:

		} else {
			/* Port or any other key */
			key = strtol(arg, &p, 10);
			/* Skip non-base 10 entries like 'fa1' */
			if (p != arg) {
+				/* IPv4 address that failed inet_pton */
+				if (*p == '.') {
+					errx(EX_DATAERR, "bad IPv4 address");
+				}
				pkey = (uint32_t *)paddr;
				*pkey = htonl(key);
				type = IPFW_TABLE_CIDR;
				addrlen = sizeof(uint32_t);
			}
		}

cheers, Ian

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