Rework the credential code to support larger values of NGROUPS and

NGROUPS_MAX, eliminate ABI dependencies on them, and raise the to 1024
and 1023 respectively.  (Previously they were equal, but under a close
reading of POSIX, NGROUPS_MAX was defined to be too large by 1 since it
is the number of supplemental groups, not total number of groups.)

The bulk of the change consists of converting the struct ucred member
cr_groups from a static array to a pointer.  Do the equivalent in
kinfo_proc.

Introduce new interfaces crcopysafe() and crsetgroups() for duplicating
a process credential before modifying it and for setting group lists
respectively.  Both interfaces take care for the details of allocating
groups array. crsetgroups() takes care of truncating the group list
to the current maximum (NGROUPS) if necessary.  In the future,
crsetgroups() may be responsible for insuring invariants such as sorting
the supplemental groups to allow groupmember() to be implemented as a
binary search.

Because we can not change struct xucred without breaking application
ABIs, we leave it alone and introduce a new XU_NGROUPS value which is
always 16 and is to be used or NGRPS as appropriate for things such as
NFS which need to use no more than 16 groups.  When feasible, truncate
the group list rather than generating an error.

Minor changes:
  - Reduce the number of hand rolled versions of groupmember().
  - Do not assign to both cr_gid and cr_groups[0].
  - Modify ipfw to cache ucreds instead of part of their contents since
    they are immutable once referenced by more than one entity.

Submitted by:	Isilon Systems (initial implementation)
X-MFC after:	never
PR:		bin/113398 kern/133867

3 files changed, 6 insertions, 12 deletions

diff --git a/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c b/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c
index 9653c91..13fcce9 100644
--- a/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c
+++ b/sys/rpc/rpcsec_gss/svc_rpcsec_gss.c
@@ -449,11 +449,7 @@ rpc_gss_svc_getcred(struct svc_req *req, struct ucred **crp, int *flavorp)
 	cr = client->cl_cred = crget();
 	cr->cr_uid = cr->cr_ruid = cr->cr_svuid = uc->uid;
 	cr->cr_rgid = cr->cr_svgid = uc->gid;
-	cr->cr_ngroups = uc->gidlen;
-	if (cr->cr_ngroups > NGROUPS)
-		cr->cr_ngroups = NGROUPS;
-	for (i = 0; i < cr->cr_ngroups; i++)
-		cr->cr_groups[i] = uc->gidlist[i];
+	crsetgroups(cr, uc->gidlen, uc->gidlist);
 	*crp = crhold(cr);
 
 	return (TRUE);
diff --git a/sys/rpc/svc_auth.c b/sys/rpc/svc_auth.c
index 2d2b73d..5d83c8d 100644
--- a/sys/rpc/svc_auth.c
+++ b/sys/rpc/svc_auth.c
@@ -166,7 +166,7 @@ int
 svc_getcred(struct svc_req *rqst, struct ucred **crp, int *flavorp)
 {
 	struct ucred *cr = NULL;
-	int flavor, i;
+	int flavor;
 	struct xucred *xcr;
 
 	flavor = rqst->rq_cred.oa_flavor;
@@ -178,9 +178,7 @@ svc_getcred(struct svc_req *rqst, struct ucred **crp, int *flavorp)
 		xcr = (struct xucred *) rqst->rq_clntcred;
 		cr = crget();
 		cr->cr_uid = cr->cr_ruid = cr->cr_svuid = xcr->cr_uid;
-		cr->cr_ngroups = xcr->cr_ngroups;
-		for (i = 0; i < xcr->cr_ngroups; i++)
-			cr->cr_groups[i] = xcr->cr_groups[i];
+		crsetgroups(cr, xcr->cr_ngroups, xcr->cr_groups);
 		cr->cr_rgid = cr->cr_svgid = cr->cr_groups[0];
 		cr->cr_prison = &prison0;
 		prison_hold(cr->cr_prison);
diff --git a/sys/rpc/svc_auth_unix.c b/sys/rpc/svc_auth_unix.c
index 0c11a4a..19ff40a 100644
--- a/sys/rpc/svc_auth_unix.c
+++ b/sys/rpc/svc_auth_unix.c
@@ -95,13 +95,13 @@ _svcauth_unix(struct svc_req *rqst, struct rpc_msg *msg)
 			goto done;
 		}
 		for (i = 0; i < gid_len; i++) {
-			if (i + 1 < NGROUPS)
+			if (i + 1 < XU_NGROUPS)
 				xcr->cr_groups[i + 1] = IXDR_GET_INT32(buf);
 			else
 				buf++;
 		}
-		if (gid_len + 1 > NGROUPS)
-			xcr->cr_ngroups = NGROUPS;
+		if (gid_len + 1 > XU_NGROUPS)
+			xcr->cr_ngroups = XU_NGROUPS;
 		else
 			xcr->cr_ngroups = gid_len + 1;