svn commit: r270085 - stable/10/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Sun Aug 17 06:54:49 2014
New Revision: 270085
URL: http://svnweb.freebsd.org/changeset/base/270085

Log:
  MFC r268087:
  
  Don't call crcopysafe or uifind unnecessarily in execve.

Modified:
  stable/10/sys/kern/kern_exec.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/kern/kern_exec.c
==============================================================================
--- stable/10/sys/kern/kern_exec.c	Sun Aug 17 06:52:35 2014	(r270084)
+++ stable/10/sys/kern/kern_exec.c	Sun Aug 17 06:54:49 2014	(r270085)
@@ -339,7 +339,7 @@ do_execve(td, args, mac_p)
 	struct proc *p = td->td_proc;
 	struct nameidata nd;
 	struct ucred *newcred = NULL, *oldcred;
-	struct uidinfo *euip;
+	struct uidinfo *euip = NULL;
 	register_t *stack_base;
 	int error, i;
 	struct image_params image_params, *imgp;
@@ -604,8 +604,6 @@ interpret:
 	/*
 	 * Malloc things before we need locks.
 	 */
-	newcred = crget();
-	euip = uifind(attr.va_uid);
 	i = imgp->args->begin_envv - imgp->args->begin_argv;
 	/* Cache arguments if they fit inside our allowance */
 	if (ps_arg_cache_limit >= i + sizeof(struct pargs)) {
@@ -634,7 +632,7 @@ interpret:
 	PROC_LOCK(p);
 	if (oldsigacts)
 		p->p_sigacts = newsigacts;
-	oldcred = crcopysafe(p, newcred);
+	oldcred = p->p_ucred;
 	/* Stop profiling */
 	stopprofclock(p);
 
@@ -724,6 +722,8 @@ interpret:
 		vn_lock(imgp->vp, LK_SHARED | LK_RETRY);
 		if (error != 0)
 			goto done1;
+		newcred = crdup(oldcred);
+		euip = uifind(attr.va_uid);
 		PROC_LOCK(p);
 		/*
 		 * Set the new credentials.
@@ -748,7 +748,6 @@ interpret:
 		change_svuid(newcred, newcred->cr_uid);
 		change_svgid(newcred, newcred->cr_gid);
 		p->p_ucred = newcred;
-		newcred = NULL;
 	} else {
 		if (oldcred->cr_uid == oldcred->cr_ruid &&
 		    oldcred->cr_gid == oldcred->cr_rgid)
@@ -767,10 +766,12 @@ interpret:
 		 */
 		if (oldcred->cr_svuid != oldcred->cr_uid ||
 		    oldcred->cr_svgid != oldcred->cr_gid) {
+			PROC_UNLOCK(p);
+			newcred = crdup(oldcred);
+			PROC_LOCK(p);
 			change_svuid(newcred, newcred->cr_uid);
 			change_svgid(newcred, newcred->cr_gid);
 			p->p_ucred = newcred;
-			newcred = NULL;
 		}
 	}
 
@@ -847,11 +848,10 @@ done1:
 	/*
 	 * Free any resources malloc'd earlier that we didn't use.
 	 */
-	uifree(euip);
-	if (newcred == NULL)
+	if (euip != NULL)
+		uifree(euip);
+	if (newcred != NULL)
 		crfree(oldcred);
-	else
-		crfree(newcred);
 	VOP_UNLOCK(imgp->vp, 0);
 
 	/*