xnu-792.6.76.tar.gz

[apple/xnu.git] / bsd / kern / kern_prot.c

diff --git a/bsd/kern/kern_prot.c b/bsd/kern/kern_prot.c
index 1a963663be722a0f9ef7a3a75f79acabf99a269e..c7721f14d38249c7069659443779d57ca70c54d4 100644 (file)
--- a/bsd/kern/kern_prot.c
+++ b/bsd/kern/kern_prot.c
@@ -722,6 +722,7 @@ setgroups1(struct proc *p, u_int gidsetsize, user_addr_t gidset, uid_t gmuid, __
        gid_t   newgroups[NGROUPS] = { 0 };
        int     error;
        kauth_cred_t my_cred, my_new_cred;
+       struct uthread *uthread = get_bsdthread_info(current_thread());
 
        if ((error = suser(p->p_ucred, &p->p_acflag)))
                return (error);
@@ -740,39 +741,64 @@ setgroups1(struct proc *p, u_int gidsetsize, user_addr_t gidset, uid_t gmuid, __
                }
        }
 
-       /* get current credential and take a reference while we muck with it */
-       for (;;) {
-               my_cred = kauth_cred_proc_ref(p);
+       if ((uthread->uu_flag & UT_SETUID) != 0) {
+               /*
+                * If this thread is under an assumed identity, set the
+                * supplementary grouplist on the thread credential instead
+                * of the process one.  If we were the only reference holder,
+                * the credential is updated in place, otherwise, our reference
+                * is dropped and we get back a different cred with a reference
+                * already held on it.  Because this is per-thread, we don't
+                * need the referencing/locking/retry required for per-process.
+                *
+                * Hack: this opts into memberd to avoid needing to use a per
+                * thread credential initgroups() instead of setgroups() in
+                * AFP server to address <rdar://4561060>
+                */
+               my_cred = uthread->uu_ucred;
+               uthread->uu_ucred = kauth_cred_setgroups(my_cred, &newgroups[0], ngrp, my_cred->cr_gmuid);
+       } else {
 
-               /* 
-                * set the credential with new info.  If there is no change we get back 
-                * the same credential we passed in.
+               /*
+                * get current credential and take a reference while we muck
+                * with it
                 */
-               my_new_cred = kauth_cred_setgroups(p->p_ucred, &newgroups[0], ngrp, gmuid);
-               if (my_cred != my_new_cred) {
-                       proc_lock(p);
-                       /* need to protect for a race where another thread also changed
-                        * the credential after we took our reference.  If p_ucred has 
-                        * changed then we should restart this again with the new cred.
+               for (;;) {
+                       my_cred = kauth_cred_proc_ref(p);
+
+                       /* 
+                        * set the credential with new info.  If there is no
+                        * change we get back the same credential we passed in.
                         */
-                       if (p->p_ucred != my_cred) {
+                       my_new_cred = kauth_cred_setgroups(my_cred, &newgroups[0], ngrp, gmuid);
+                       if (my_cred != my_new_cred) {
+                               proc_lock(p);
+                               /*
+                                * need to protect for a race where another
+                                * thread also changed the credential after we
+                                * took our reference.  If p_ucred has 
+                                * changed then we should restart this again
+                                * with the new cred.
+                                */
+                               if (p->p_ucred != my_cred) {
+                                       proc_unlock(p);
+                                       kauth_cred_rele(my_cred);
+                                       kauth_cred_rele(my_new_cred);
+                                       /* try again */
+                                       continue;
+                               }
+                               p->p_ucred = my_new_cred;
+                               p->p_flag |= P_SUGID;
                                proc_unlock(p);
-                               kauth_cred_rele(my_cred);
-                               kauth_cred_rele(my_new_cred);
-                               /* try again */
-                               continue;
                        }
-                       p->p_ucred = my_new_cred;
-                       p->p_flag |= P_SUGID;
-                       proc_unlock(p);
+                       /* drop our extra reference */
+                       kauth_cred_rele(my_cred);
+                       break;
                }
-               /* drop our extra reference */
-               kauth_cred_rele(my_cred);
-               break;
-       }
 
-       AUDIT_ARG(groupset, p->p_ucred->cr_groups, ngrp);
-       set_security_token(p);
+               AUDIT_ARG(groupset, p->p_ucred->cr_groups, ngrp);
+               set_security_token(p);
+       }
 
        return (0);
 }