xnu-792.6.76.tar.gz

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

diff --git a/bsd/kern/ubc_subr.c b/bsd/kern/ubc_subr.c
index 1660c5b7a33f9e6be05724e7ec95fea1c7dda591..2cbd623647e6bf23e8a381d5ee3a1368e6eb090a 100644 (file)
--- a/bsd/kern/ubc_subr.c
+++ b/bsd/kern/ubc_subr.c
@@ -45,6 +45,7 @@
 #include <sys/proc_internal.h>
 #include <sys/kauth.h>
 #include <sys/buf.h>
+#include <sys/user.h>
 
 #include <mach/mach_types.h>
 #include <mach/memory_object_types.h>
@@ -54,6 +55,7 @@
 
 #include <kern/kern_types.h>
 #include <kern/zalloc.h>
+#include <kern/thread.h>
 #include <vm/vm_kern.h>
 #include <vm/vm_protos.h> /* last */
 
@@ -346,6 +348,35 @@ ubc_getcred(struct vnode *vp)
        return (NOCRED);
 }
 
+int
+ubc_setthreadcred(struct vnode *vp, struct proc *p, thread_t thread)
+{
+       struct ubc_info *uip;
+       kauth_cred_t credp;
+       struct uthread *uthread = get_bsdthread_info(thread);
+
+       if (!UBCINFOEXISTS(vp))
+               return (1);
+
+       vnode_lock(vp);
+
+       uip = vp->v_ubcinfo;
+       credp = uip->ui_ucred;
+
+       if (credp == NOCRED) {
+               /* use per-thread cred, if assumed identity, else proc cred */
+               if (uthread == NULL || (uthread->uu_flag & UT_SETUID) == 0) {
+                       uip->ui_ucred = kauth_cred_proc_ref(p);
+               } else {
+                       uip->ui_ucred = uthread->uu_ucred;
+                       kauth_cred_ref(uip->ui_ucred);
+               }
+       }
+       vnode_unlock(vp);
+
+       return (0);
+}
+
 /*
  * Set the credentials
  * existing credentials are not changed