Integrate a devfs/MAC fix from the MAC tree: avoid a race condition during

devfs VOP symlink creation by introducing a new entry point to determine
the label of the devfs_dirent prior to allocation of a vnode for the
symlink.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories

14 files changed, 132 insertions, 4 deletions

diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index da09f0d..5f7775c 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -868,12 +868,11 @@ devfs_symlink(ap)
 	MALLOC(de->de_symlink, char *, i, M_DEVFS, M_WAITOK);
 	bcopy(ap->a_target, de->de_symlink, i);
 	lockmgr(&dmp->dm_lock, LK_EXCLUSIVE, 0, curthread);
+#ifdef MAC
+	mac_create_devfs_symlink(ap->a_cnp->cn_cred, dd, de);
+#endif
 	TAILQ_INSERT_TAIL(&dd->de_dlist, de, de_list);
 	devfs_allocv(de, ap->a_dvp->v_mount, ap->a_vpp, 0);
-#ifdef MAC
-	mac_create_vnode(ap->a_cnp->cn_cred, ap->a_dvp, *ap->a_vpp);
-	mac_update_devfsdirent(de, *ap->a_vpp);
-#endif /* MAC */
 	lockmgr(&dmp->dm_lock, LK_RELEASE, 0, curthread);
 	return (0);
 }
diff --git a/sys/kern/kern_mac.c b/sys/kern/kern_mac.c
index 5719b01f..8a9de01 100644
--- a/sys/kern/kern_mac.c
+++ b/sys/kern/kern_mac.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_framework.c b/sys/security/mac/mac_framework.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_framework.c
+++ b/sys/security/mac/mac_framework.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_framework.h b/sys/security/mac/mac_framework.h
index a646ad3..b0d0468 100644
--- a/sys/security/mac/mac_framework.h
+++ b/sys/security/mac/mac_framework.h
@@ -244,6 +244,8 @@ void	mac_create_devfs_device(dev_t dev, struct devfs_dirent *de);
 void	mac_create_devfs_directory(char *dirname, int dirnamelen,
 	    struct devfs_dirent *de);
 void	mac_create_devfs_vnode(struct devfs_dirent *de, struct vnode *vp);
+void	mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+	    struct devfs_dirent *de);
 void	mac_create_vnode(struct ucred *cred, struct vnode *parent,
 	    struct vnode *child);
 void	mac_create_mount(struct ucred *cred, struct mount *mp);
diff --git a/sys/security/mac/mac_internal.h b/sys/security/mac/mac_internal.h
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_internal.h
+++ b/sys/security/mac/mac_internal.h
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_net.c b/sys/security/mac/mac_net.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_net.c
+++ b/sys/security/mac/mac_net.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_pipe.c b/sys/security/mac/mac_pipe.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_pipe.c
+++ b/sys/security/mac/mac_pipe.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_policy.h b/sys/security/mac/mac_policy.h
index d9f1a8e..d455d3c 100644
--- a/sys/security/mac/mac_policy.h
+++ b/sys/security/mac/mac_policy.h
@@ -110,6 +110,9 @@ struct mac_policy_ops {
 		    struct label *label);
 	void	(*mpo_create_devfs_directory)(char *dirname, int dirnamelen,
 		    struct devfs_dirent *de, struct label *label);
+	void	(*mpo_create_devfs_symlink)(struct ucred *cred,
+		    struct devfs_dirent *dd, struct label *ddlabel,
+		    struct devfs_dirent *de, struct label *delabel);
 	void	(*mpo_create_devfs_vnode)(struct devfs_dirent *de,
 		    struct label *direntlabel, struct vnode *vp,
 		    struct label *vnodelabel);
@@ -387,6 +390,7 @@ enum mac_op_constant {
 	MAC_INTERNALIZE,
 	MAC_CREATE_DEVFS_DEVICE,
 	MAC_CREATE_DEVFS_DIRECTORY,
+	MAC_CREATE_DEVFS_SYMLINK,
 	MAC_CREATE_DEVFS_VNODE,
 	MAC_CREATE_VNODE,
 	MAC_CREATE_MOUNT,
diff --git a/sys/security/mac/mac_process.c b/sys/security/mac/mac_process.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_process.c
+++ b/sys/security/mac/mac_process.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_syscalls.c b/sys/security/mac/mac_syscalls.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_syscalls.c
+++ b/sys/security/mac/mac_syscalls.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_system.c b/sys/security/mac/mac_system.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_system.c
+++ b/sys/security/mac/mac_system.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/security/mac/mac_vfs.c b/sys/security/mac/mac_vfs.c
index 5719b01f..8a9de01 100644
--- a/sys/security/mac/mac_vfs.c
+++ b/sys/security/mac/mac_vfs.c
@@ -519,6 +519,10 @@ mac_policy_register(struct mac_policy_conf *mpc)
 			mpc->mpc_ops->mpo_create_devfs_directory =
 			    mpe->mpe_function;
 			break;
+		case MAC_CREATE_DEVFS_SYMLINK:
+			mpc->mpc_ops->mpo_create_devfs_symlink =
+			    mpe->mpe_function;
+			break;
 		case MAC_CREATE_DEVFS_VNODE:
 			mpc->mpc_ops->mpo_create_devfs_vnode =
 			    mpe->mpe_function;
@@ -2946,6 +2950,15 @@ mac_create_devfs_device(dev_t dev, struct devfs_dirent *de)
 	MAC_PERFORM(create_devfs_device, dev, de, &de->de_label);
 }
 
+void
+mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+    struct devfs_dirent *de)
+{
+
+	MAC_PERFORM(create_devfs_symlink, cred, dd, &dd->de_label, de,
+	    &de->de_label);
+}
+
 static int
 mac_stdcreatevnode_ea(struct vnode *vp)
 {
diff --git a/sys/sys/mac.h b/sys/sys/mac.h
index a646ad3..b0d0468 100644
--- a/sys/sys/mac.h
+++ b/sys/sys/mac.h
@@ -244,6 +244,8 @@ void	mac_create_devfs_device(dev_t dev, struct devfs_dirent *de);
 void	mac_create_devfs_directory(char *dirname, int dirnamelen,
 	    struct devfs_dirent *de);
 void	mac_create_devfs_vnode(struct devfs_dirent *de, struct vnode *vp);
+void	mac_create_devfs_symlink(struct ucred *cred, struct devfs_dirent *dd,
+	    struct devfs_dirent *de);
 void	mac_create_vnode(struct ucred *cred, struct vnode *parent,
 	    struct vnode *child);
 void	mac_create_mount(struct ucred *cred, struct mount *mp);
diff --git a/sys/sys/mac_policy.h b/sys/sys/mac_policy.h
index d9f1a8e..d455d3c 100644
--- a/sys/sys/mac_policy.h
+++ b/sys/sys/mac_policy.h
@@ -110,6 +110,9 @@ struct mac_policy_ops {
 		    struct label *label);
 	void	(*mpo_create_devfs_directory)(char *dirname, int dirnamelen,
 		    struct devfs_dirent *de, struct label *label);
+	void	(*mpo_create_devfs_symlink)(struct ucred *cred,
+		    struct devfs_dirent *dd, struct label *ddlabel,
+		    struct devfs_dirent *de, struct label *delabel);
 	void	(*mpo_create_devfs_vnode)(struct devfs_dirent *de,
 		    struct label *direntlabel, struct vnode *vp,
 		    struct label *vnodelabel);
@@ -387,6 +390,7 @@ enum mac_op_constant {
 	MAC_INTERNALIZE,
 	MAC_CREATE_DEVFS_DEVICE,
 	MAC_CREATE_DEVFS_DIRECTORY,
+	MAC_CREATE_DEVFS_SYMLINK,
 	MAC_CREATE_DEVFS_VNODE,
 	MAC_CREATE_VNODE,
 	MAC_CREATE_MOUNT,