Don't sort gids that are already sorted

kern_prot.patch

--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -2045,12 +2045,22 @@ crsetgroups_locked(struct ucred *cr, int ngrp, gid_t *groups)
        int i;
        int j;
        gid_t g;
+       unsigned int sorted = 0;
        
        KASSERT(cr->cr_agroups >= ngrp, ("cr_ngroups is too small"));
 
        bcopy(groups, cr->cr_groups, ngrp * sizeof(gid_t));
        cr->cr_ngroups = ngrp;
 
+       /* If the groups are already sorted, don't sort again */
+       for (i = 0; i < ngrp-1; i++) {
+               sorted += (cr->cr_groups[i] > cr->cr_groups[i+1]);
+       }
+
+        if (sorted==0) {
+                return;
+        }
+
        /*
         * Sort all groups except cr_groups[0] to allow groupmember to
         * perform a binary search.