ipfw table add problem

[Ian Smith]

On Tue, 26 Nov 2013 12:48:01 +0000, Ben Morrow wrote:
 > To: freebsd-stable at freebsd.org

Restoring cc ipfw@ and others after the inet_pton side?thread in 
stable at .  grepping /usr/src for inet_pton suggests that a behavioural 
change in inet_pton at this stage seems rather unlikely :)
 
 > Quoth Michael Butler <imb at 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