(analysis) Re: ipv6 causing panic?

[Matthew Dillon]

    Ok, I think I found the problem but more eyes would not hurt.

    netinet/in_gif.c/in_gif_input() is using:

	    gifp = (struct ifnet *)encap_getarg(m);
	    ...

    But encap_getarg() does this:

	    void *
	    encap_getarg(m)
		    struct mbuf *m;
	    {
		    void *p = NULL;
		    struct m_tag *tag;

		    tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
		    if (tag != NULL) {
			    p = (void *)(tag + 1);
			    m_tag_delete(m, tag);
		    }
		    return p;
	    }

    As far as I can tell, encap_getarg() is returning a pointer to
    data that it has already free()'d.  I think it has to return
    *(void **)(tag+ 1) rather then (void *)(tag + 1).

    Peter and Simon, please try the patch enclosed below.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>

Index: netinet/ip_encap.c
===================================================================
RCS file: /cvs/src/sys/netinet/ip_encap.c,v
retrieving revision 1.10
diff -u -r1.10 ip_encap.c
--- netinet/ip_encap.c	6 Jan 2005 09:14:13 -0000	1.10
+++ netinet/ip_encap.c	31 Jan 2005 19:54:13 -0000
@@ -512,7 +512,7 @@
 
 	tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
 	if (tag != NULL) {
-		p = (void *)(tag + 1);
+		p = *(void **)(tag + 1);
 		m_tag_delete(m, tag);
 	}
 	return p;