Merge implementation of mpo_check_vnode_link() for various appropriate

file-system aware MAC policies.  Sync to MAC tree.

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

1 files changed, 26 insertions, 0 deletions

diff --git a/sys/security/mac_biba/mac_biba.c b/sys/security/mac_biba/mac_biba.c
index 8d53cdb..eb1345f 100644
--- a/sys/security/mac_biba/mac_biba.c
+++ b/sys/security/mac_biba/mac_biba.c
@@ -1510,6 +1510,30 @@ mac_biba_check_vnode_getextattr(struct ucred *cred, struct vnode *vp,
 }
 
 static int
+mac_biba_check_vnode_link(struct ucred *cred, struct vnode *dvp,
+    struct label *dlabel, struct vnode *vp, struct label *label,
+    struct componentname *cnp)
+{
+	struct mac_biba *subj, *obj;
+
+	if (!mac_biba_enabled)
+		return (0);
+
+	subj = SLOT(&cred->cr_label);
+	obj = SLOT(dlabel);
+
+	if (!mac_biba_dominate_single(subj, obj))
+		return (EACCES);
+
+	obj = SLOT(label);
+
+	if (!mac_biba_dominate_single(subj, obj))
+		return (EACCES);
+
+	return (0);
+}
+
+static int
 mac_biba_check_vnode_lookup(struct ucred *cred, struct vnode *dvp,
     struct label *dlabel, struct componentname *cnp)
 {
@@ -2087,6 +2111,8 @@ static struct mac_policy_op_entry mac_biba_ops[] =
 	    (macop_t)mac_biba_check_vnode_getacl },
 	{ MAC_CHECK_VNODE_GETEXTATTR,
 	    (macop_t)mac_biba_check_vnode_getextattr },
+	{ MAC_CHECK_VNODE_LINK,
+	    (macop_t)mac_biba_check_vnode_link },
 	{ MAC_CHECK_VNODE_LOOKUP,
 	    (macop_t)mac_biba_check_vnode_lookup },
 	{ MAC_CHECK_VNODE_OPEN,