SELinux: Update policy version to support constraints info

Update the policy version (POLICYDB_VERSION_CONSTRAINT_NAMES) to allow
holding of policy source info for constraints.

Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <pmoore@redhat.com>

3 files changed, 99 insertions, 9 deletions

diff --git a/security/selinux/ss/constraint.h b/security/selinux/ss/constraint.h
index 149dda731fd3..96fd947c494b 100644
--- a/security/selinux/ss/constraint.h
+++ b/security/selinux/ss/constraint.h
@@ -48,6 +48,7 @@ struct constraint_expr {
         u32 op;                 /* operator */
 
         struct ebitmap names;   /* names */
+        struct type_set *type_names;
 
         struct constraint_expr *next;   /* next expression */
 };
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index f6195ebde3c9..dc4011643b55 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -143,6 +143,11 @@ static struct policydb_compat_info policydb_compat[] = {
                 .sym_num        = SYM_NUM,
                 .ocon_num       = OCON_NUM,
         },
+        {
+                .version        = POLICYDB_VERSION_CONSTRAINT_NAMES,
+                .sym_num        = SYM_NUM,
+                .ocon_num       = OCON_NUM,
+        },
 };
 
 static struct policydb_compat_info *policydb_lookup_compat(int version)
@@ -613,6 +618,19 @@ static int common_destroy(void *key, void *datum, void *p)
         return 0;
 }
 
+static void constraint_expr_destroy(struct constraint_expr *expr)
+{
+        if (expr) {
+                ebitmap_destroy(&expr->names);
+                if (expr->type_names) {
+                        ebitmap_destroy(&expr->type_names->types);
+                        ebitmap_destroy(&expr->type_names->negset);
+                        kfree(expr->type_names);
+                }
+                kfree(expr);
+        }
+}
+
 static int cls_destroy(void *key, void *datum, void *p)
 {
         struct class_datum *cladatum;
@@ -628,10 +646,9 @@ static int cls_destroy(void *key, void *datum, void *p)
                 while (constraint) {
                         e = constraint->expr;
                         while (e) {
-                                ebitmap_destroy(&e->names);
                                 etmp = e;
                                 e = e->next;
-                                kfree(etmp);
+                                constraint_expr_destroy(etmp);
                         }
                         ctemp = constraint;
                         constraint = constraint->next;
@@ -642,16 +659,14 @@ static int cls_destroy(void *key, void *datum, void *p)
                 while (constraint) {
                         e = constraint->expr;
                         while (e) {
-                                ebitmap_destroy(&e->names);
                                 etmp = e;
                                 e = e->next;
-                                kfree(etmp);
+                                constraint_expr_destroy(etmp);
                         }
                         ctemp = constraint;
                         constraint = constraint->next;
                         kfree(ctemp);
                 }
-
                 kfree(cladatum->comkey);
         }
         kfree(datum);
@@ -1156,8 +1171,34 @@ bad:
         return rc;
 }
 
-static int read_cons_helper(struct constraint_node **nodep, int ncons,
-                            int allowxtarget, void *fp)
+static void type_set_init(struct type_set *t)
+{
+        ebitmap_init(&t->types);
+        ebitmap_init(&t->negset);
+}
+
+static int type_set_read(struct type_set *t, void *fp)
+{
+        __le32 buf[1];
+        int rc;
+
+        if (ebitmap_read(&t->types, fp))
+                return -EINVAL;
+        if (ebitmap_read(&t->negset, fp))
+                return -EINVAL;
+
+        rc = next_entry(buf, fp, sizeof(u32));
+        if (rc < 0)
+                return -EINVAL;
+        t->flags = le32_to_cpu(buf[0]);
+
+        return 0;
+}
+
+
+static int read_cons_helper(struct policydb *p,
+                                struct constraint_node **nodep,
+                                int ncons, int allowxtarget, void *fp)
 {
         struct constraint_node *c, *lc;
         struct constraint_expr *e, *le;
@@ -1225,6 +1266,18 @@ static int read_cons_helper(struct constraint_node **nodep, int ncons,
                                 rc = ebitmap_read(&e->names, fp);
                                 if (rc)
                                         return rc;
+                                if (p->policyvers >=
+                                        POLICYDB_VERSION_CONSTRAINT_NAMES) {
+                                                e->type_names = kzalloc(sizeof
+                                                (*e->type_names),
+                                                GFP_KERNEL);
+                                        if (!e->type_names)
+                                                return -ENOMEM;
+                                        type_set_init(e->type_names);
+                                        rc = type_set_read(e->type_names, fp);
+                                        if (rc)
+                                                return rc;
+                                }
                                 break;
                         default:
                                 return -EINVAL;
@@ -1301,7 +1354,7 @@ static int class_read(struct policydb *p, struct hashtab *h, void *fp)
                         goto bad;
         }
 
-        rc = read_cons_helper(&cladatum->constraints, ncons, 0, fp);
+        rc = read_cons_helper(p, &cladatum->constraints, ncons, 0, fp);
         if (rc)
                 goto bad;
 
@@ -1311,7 +1364,8 @@ static int class_read(struct policydb *p, struct hashtab *h, void *fp)
                 if (rc)
                         goto bad;
                 ncons = le32_to_cpu(buf[0]);
-                rc = read_cons_helper(&cladatum->validatetrans, ncons, 1, fp);
+                rc = read_cons_helper(p, &cladatum->validatetrans,
+                                ncons, 1, fp);
                 if (rc)
                         goto bad;
         }
@@ -2753,6 +2807,24 @@ static int common_write(void *vkey, void *datum, void *ptr)
         return 0;
 }
 
+static int type_set_write(struct type_set *t, void *fp)
+{
+        int rc;
+        __le32 buf[1];
+
+        if (ebitmap_write(&t->types, fp))
+                return -EINVAL;
+        if (ebitmap_write(&t->negset, fp))
+                return -EINVAL;
+
+        buf[0] = cpu_to_le32(t->flags);
+        rc = put_entry(buf, sizeof(u32), 1, fp);
+        if (rc)
+                return -EINVAL;
+
+        return 0;
+}
+
 static int write_cons_helper(struct policydb *p, struct constraint_node *node,
                              void *fp)
 {
@@ -2784,6 +2856,12 @@ static int write_cons_helper(struct policydb *p, struct constraint_node *node,
                                 rc = ebitmap_write(&e->names, fp);
                                 if (rc)
                                         return rc;
+                                if (p->policyvers >=
+                                        POLICYDB_VERSION_CONSTRAINT_NAMES) {
+                                        rc = type_set_write(e->type_names, fp);
+                                        if (rc)
+                                                return rc;
+                                }
                                 break;
                         default:
                                 break;
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index da637471d4ce..725d5945a97e 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -154,6 +154,17 @@ struct cond_bool_datum {
 struct cond_node;
 
 /*
+ * type set preserves data needed to determine constraint info from
+ * policy source. This is not used by the kernel policy but allows
+ * utilities such as audit2allow to determine constraint denials.
+ */
+struct type_set {
+        struct ebitmap types;
+        struct ebitmap negset;
+        u32 flags;
+};
+
+/*
  * The configuration data includes security contexts for
  * initial SIDs, unlabeled file systems, TCP and UDP port numbers,
  * network interfaces, and nodes.  This structure stores the