kern/95277: [netinet] IP Encapsulation mask_match() returns wrong results

[Bruce M Simpson]

The following reply was made to PR kern/95277; it has been noted by GNATS.

From: Bruce M Simpson <bms at incunabulum.net>
To: freebsd-gnats-submit at FreeBSD.org
Cc:  
Subject: Re: kern/95277: [netinet] IP Encapsulation mask_match() returns wrong
 results
Date: Thu, 28 Sep 2006 18:22:46 +0100

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 I guess a patch for the desired behaviour would look something like this?
 More detail needed...
 
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 ==== //depot/user/bms/nethead/sys/netinet/ip_encap.c#1 - /home/bms/fp4/nethead/sys/netinet/ip_encap.c ====
 --- /tmp/tmp.41786.0	Thu Sep 28 18:21:51 2006
 +++ /home/bms/fp4/nethead/sys/netinet/ip_encap.c	Thu Sep 28 18:21:09 2006
 @@ -403,6 +403,7 @@
  	const struct sockaddr *sp;
  	const struct sockaddr *dp;
  {
 +	const int hdrlen = offsetof(struct sockaddr, sa_data);
  	struct sockaddr_storage s;
  	struct sockaddr_storage d;
  	int i;
 @@ -419,32 +420,28 @@
  
  	matchlen = 0;
  
 -	p = (const u_int8_t *)sp;
 -	q = (const u_int8_t *)&ep->srcmask;
 -	r = (u_int8_t *)&s;
 -	for (i = 0 ; i < sp->sa_len; i++) {
 +	p = (const u_int8_t *)&sp->sa_data;
 +	q = (const u_int8_t *)&ep->srcmask + hdrlen;
 +	r = (u_int8_t *)&s + hdrlen;
 +	for (i = 0 ; i < sp->sa_len - hdrlen; i++) {
  		r[i] = p[i] & q[i];
  		/* XXX estimate */
  		matchlen += (q[i] ? 8 : 0);
  	}
  
 -	p = (const u_int8_t *)dp;
 -	q = (const u_int8_t *)&ep->dstmask;
 -	r = (u_int8_t *)&d;
 -	for (i = 0 ; i < dp->sa_len; i++) {
 +	p = (const u_int8_t *)&dp->sa_data;
 +	q = (const u_int8_t *)&ep->dstmask + hdrlen;
 +	r = (u_int8_t *)&d + hdrlen;
 +	for (i = 0 ; i < dp->sa_len - hdrlen; i++) {
  		r[i] = p[i] & q[i];
  		/* XXX rough estimate */
  		matchlen += (q[i] ? 8 : 0);
  	}
  
 -	/* need to overwrite len/family portion as we don't compare them */
 -	s.ss_len = sp->sa_len;
 -	s.ss_family = sp->sa_family;
 -	d.ss_len = dp->sa_len;
 -	d.ss_family = dp->sa_family;
 -
 -	if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
 -	    bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
 +	if (bcmp((u_int8_t *)&s + hdrlen, (const u_int8_t *)&ep->src + hdrlen,
 +	    ep->src.ss_len - hdrlen) == 0 &&
 +	    bcmp((u_int8_t *)&d + hdrlen, (const u_int8_t *)&ep->dst + hdrlen,
 +	    ep->dst.ss_len - hdrlen) == 0) {
  		return matchlen;
  	} else
  		return 0;
 
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