Author: bms
Date: Thu Nov 19 13:30:06 2009
New Revision: 199526
URL: http://svn.freebsd.org/changeset/base/199526

Log:
  Adapt r197132 to IPv6 stack:
    Tighten input checking in in6p_join_group():
     * Don't try to use the source address, when its family is unspecified.
     * If we get a join without a source, on an existing inclusive
       mode group, this is an error, as it would change the filter mode.
  
    Fix a problem with the handling of in6_mfilter for new memberships:
     * Do not rely on im6f being NULL; it is explicitly initialized to a
       non-NULL pointer when constructing a membership.
     * Explicitly initialize *im6f to EX mode when the source address
       is unspecified.
  
    This fixes a problem with in_mfilter slot recycling in the join path.
  
  MFC after:    1 day

Modified:
  head/sys/netinet6/in6_mcast.c

Modified: head/sys/netinet6/in6_mcast.c
==============================================================================
--- head/sys/netinet6/in6_mcast.c       Thu Nov 19 13:21:37 2009        
(r199525)
+++ head/sys/netinet6/in6_mcast.c       Thu Nov 19 13:30:06 2009        
(r199526)
@@ -1917,11 +1917,6 @@ in6p_join_group(struct inpcb *inp, struc
         */
        (void)in6_setscope(&gsa->sin6.sin6_addr, ifp, NULL);
 
-       /*
-        * MCAST_JOIN_SOURCE on an exclusive membership is an error.
-        * On an existing inclusive membership, it just adds the
-        * source to the filter list.
-        */
        imo = in6p_findmoptions(inp);
        idx = im6o_match_group(imo, ifp, &gsa->sa);
        if (idx == -1) {
@@ -1929,15 +1924,33 @@ in6p_join_group(struct inpcb *inp, struc
        } else {
                inm = imo->im6o_membership[idx];
                imf = &imo->im6o_mfilters[idx];
-               if (ssa->ss.ss_family != AF_UNSPEC &&
-                   imf->im6f_st[1] != MCAST_INCLUDE) {
-                       error = EINVAL;
-                       goto out_in6p_locked;
-               }
-               lims = im6o_match_source(imo, idx, &ssa->sa);
-               if (lims != NULL) {
-                       error = EADDRNOTAVAIL;
-                       goto out_in6p_locked;
+               if (ssa->ss.ss_family != AF_UNSPEC) {
+                       /*
+                        * MCAST_JOIN_SOURCE_GROUP on an exclusive membership
+                        * is an error. On an existing inclusive membership,
+                        * it just adds the source to the filter list.
+                        */
+                       if (imf->im6f_st[1] != MCAST_INCLUDE) {
+                               error = EINVAL;
+                               goto out_in6p_locked;
+                       }
+                       /* Throw out duplicates. */
+                       lims = im6o_match_source(imo, idx, &ssa->sa);
+                       if (lims != NULL) {
+                               error = EADDRNOTAVAIL;
+                               goto out_in6p_locked;
+                       }
+               } else {
+                       /*
+                        * MCAST_JOIN_GROUP on an existing inclusive
+                        * membership is an error; if you want to change
+                        * filter mode, you must use the userland API
+                        * setsourcefilter().
+                        */
+                       if (imf->im6f_st[1] == MCAST_INCLUDE) {
+                               error = EINVAL;
+                               goto out_in6p_locked;
+                       }
                }
        }
 
@@ -1970,7 +1983,8 @@ in6p_join_group(struct inpcb *inp, struc
        /*
         * Graft new source into filter list for this inpcb's
         * membership of the group. The in6_multi may not have
-        * been allocated yet if this is a new membership.
+        * been allocated yet if this is a new membership, however,
+        * the in_mfilter slot will be allocated and must be initialized.
         */
        if (ssa->ss.ss_family != AF_UNSPEC) {
                /* Membership starts in IN mode */
@@ -1987,6 +2001,12 @@ in6p_join_group(struct inpcb *inp, struc
                        error = ENOMEM;
                        goto out_im6o_free;
                }
+       } else {
+               /* No address specified; Membership starts in EX mode */
+               if (is_new) {
+                       CTR1(KTR_MLD, "%s: new join w/o source", __func__);
+                       im6f_init(imf, MCAST_UNDEFINED, MCAST_EXCLUDE);
+               }
        }
 
        /*
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