- Catch up to the new ucred API.

- Add proc locking to the jail() syscall.  This mostly involved shuffling
  a few things around so that blockable things like malloc and copyin
  were performed before acquiring the lock and checking the existing
  ucred and then updating the ucred as one "atomic" change under the proc
  lock.

1 files changed, 24 insertions, 18 deletions

diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c
index 12da38c..2dd432c 100644
--- a/sys/kern/kern_jail.c
+++ b/sys/kern/kern_jail.c
@@ -29,6 +29,8 @@ MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
 SYSCTL_NODE(, OID_AUTO, jail, CTLFLAG_RW, 0,
     "Jail rules");
 
+mp_fixme("these variables need a lock")
+
 int	jail_set_hostname_allowed = 1;
 SYSCTL_INT(_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
     &jail_set_hostname_allowed, 0,
@@ -59,41 +61,45 @@ jail(td, uap)
 	struct prison *pr;
 	struct jail j;
 	struct chroot_args ca;
+	struct ucred *newcred = NULL, *oldcred;
 
-	mtx_lock(&Giant);
-
-	/* Implicitly fail if already in jail.  */
-	error = suser(p);
-	if (error)
-		goto done2;
 	error = copyin(uap->jail, &j, sizeof j);
 	if (error)
-		goto done2;
-	if (j.version != 0) {
-		error = EINVAL;
-		goto done2;
-	}
+		return (error);
+	if (j.version != 0)
+		return (EINVAL);
+
+	mtx_lock(&Giant);
 	MALLOC(pr, struct prison *, sizeof *pr , M_PRISON, M_WAITOK | M_ZERO);
 	pr->pr_securelevel = securelevel;
 	error = copyinstr(j.hostname, &pr->pr_host, sizeof pr->pr_host, 0);
-	if (error) 
+	if (error)
 		goto bail;
-	pr->pr_ip = j.ip_number;
-
 	ca.path = j.path;
 	error = chroot(td, &ca);
 	if (error)
 		goto bail;
-
-	p->p_ucred = crcopy(p->p_ucred);
+	newcred = crget();
+	pr->pr_ip = j.ip_number;
+	PROC_LOCK(p);
+	/* Implicitly fail if already in jail.  */
+	error = suser(p);
+	if (error)
+		goto badcred;
+	oldcred = p->p_ucred;
+	crcopy(newcred, oldcred);
+	p->p_ucred = newcred;
 	p->p_ucred->cr_prison = pr;
 	pr->pr_ref = 1;
+	PROC_UNLOCK(p);
+	crfree(oldcred);
 	mtx_unlock(&Giant);
 	return (0);
-
+badcred:
+	PROC_UNLOCK(p);
+	crfree(newcred);
 bail:
 	FREE(pr, M_PRISON);
-done2:
 	mtx_unlock(&Giant);
 	return (error);
 }