Rename mac_cred_mmapped_drop_perms(), which revokes access to virtual

memory mappings when the MAC label on a process changes, to
mac_proc_vm_revoke(),

It now also acquires its own credential reference directly from the
affected process rather than accepting one passed by the the caller,
simplifying the API and consumer code.

Obtained from:	TrustedBSD Project

3 files changed, 14 insertions, 16 deletions

diff --git a/sys/security/mac/mac_framework.h b/sys/security/mac/mac_framework.h
index 411fddb..4cb5262 100644
--- a/sys/security/mac/mac_framework.h
+++ b/sys/security/mac/mac_framework.h
@@ -259,6 +259,7 @@ int	mac_proc_check_signal(struct ucred *cred, struct proc *p,
 int	mac_proc_check_wait(struct ucred *cred, struct proc *p);
 void	mac_proc_destroy(struct proc *);
 void	mac_proc_init(struct proc *);
+void	mac_proc_vm_revoke(struct thread *td);
 int	mac_execve_enter(struct image_params *imgp, struct mac *mac_p);
 void	mac_execve_exit(struct image_params *imgp);
 void	mac_execve_interpreter_enter(struct vnode *interpvp,
@@ -434,8 +435,6 @@ int	mac_vnode_execve_will_transition(struct ucred *cred,
 void	mac_vnode_relabel(struct ucred *cred, struct vnode *vp,
 	    struct label *newlabel);
 
-void	mac_cred_mmapped_drop_perms(struct thread *td, struct ucred *cred);
-
 /*
  * Calls to help various file systems implement labeling functionality using
  * their existing EA implementation.
diff --git a/sys/security/mac/mac_process.c b/sys/security/mac/mac_process.c
index 98ee6cf..bb29aaa 100644
--- a/sys/security/mac/mac_process.c
+++ b/sys/security/mac/mac_process.c
@@ -81,7 +81,7 @@ SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
     &mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
     "copy-on-write semantics, or by removing all write access");
 
-static void	mac_cred_mmapped_drop_perms_recurse(struct thread *td,
+static void	mac_proc_vm_revoke_recurse(struct thread *td,
 		    struct ucred *cred, struct vm_map *map);
 
 struct label *
@@ -314,13 +314,20 @@ mac_execve_interpreter_exit(struct label *interpvplabel)
  * The process lock is not held here.
  */
 void
-mac_cred_mmapped_drop_perms(struct thread *td, struct ucred *cred)
+mac_proc_vm_revoke(struct thread *td)
 {
+	struct ucred *cred;
+
+	PROC_LOCK(td->td_proc);
+	cred = crhold(td->td_proc->p_ucred);
+	PROC_UNLOCK(td->td_proc);
 
 	/* XXX freeze all other threads */
-	mac_cred_mmapped_drop_perms_recurse(td, cred,
+	mac_proc_vm_revoke_recurse(td, cred,
 	    &td->td_proc->p_vmspace->vm_map);
 	/* XXX allow other threads to continue */
+
+	crfree(cred);
 }
 
 static __inline const char *
@@ -348,7 +355,7 @@ prot2str(vm_prot_t prot)
 }
 
 static void
-mac_cred_mmapped_drop_perms_recurse(struct thread *td, struct ucred *cred,
+mac_proc_vm_revoke_recurse(struct thread *td, struct ucred *cred,
     struct vm_map *map)
 {
 	struct vm_map_entry *vme;
@@ -365,7 +372,7 @@ mac_cred_mmapped_drop_perms_recurse(struct thread *td, struct ucred *cred,
 	vm_map_lock_read(map);
 	for (vme = map->header.next; vme != &map->header; vme = vme->next) {
 		if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
-			mac_cred_mmapped_drop_perms_recurse(td, cred,
+			mac_proc_vm_revoke_recurse(td, cred,
 			    vme->object.sub_map);
 			continue;
 		}
diff --git a/sys/security/mac/mac_syscalls.c b/sys/security/mac/mac_syscalls.c
index 5cff185..c4b0606 100644
--- a/sys/security/mac/mac_syscalls.c
+++ b/sys/security/mac/mac_syscalls.c
@@ -203,17 +203,9 @@ __mac_set_proc(struct thread *td, struct __mac_set_proc_args *uap)
 	mac_cred_relabel(newcred, intlabel);
 	p->p_ucred = newcred;
 
-	/*
-	 * Grab additional reference for use while revoking mmaps, prior to
-	 * releasing the proc lock and sharing the cred.
-	 */
-	crhold(newcred);
 	PROC_UNLOCK(p);
-
-	mac_cred_mmapped_drop_perms(td, newcred);
-
-	crfree(newcred);	/* Free revocation reference. */
 	crfree(oldcred);
+	mac_proc_vm_revoke(td);
 
 out:
 	mac_cred_label_free(intlabel);