linux-kernel - [RFC PATCH 21/22] selinux: check for simple types

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Message-ID: <20241115133619.114393-21-cgoettsche@seltendoof.de>
Date: Fri, 15 Nov 2024 14:35:40 +0100
From: Christian Göttsche <cgoettsche@...tendoof.de>
To: selinux@...r.kernel.org
Cc: Christian Göttsche <cgzones@...glemail.com>,
	Paul Moore <paul@...l-moore.com>,
	Stephen Smalley <stephen.smalley.work@...il.com>,
	Ondrej Mosnacek <omosnace@...hat.com>,
	Eric Suen <ericsu@...ux.microsoft.com>,
	Jacob Satterfield <jsatterfield.linux@...il.com>,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH 21/22] selinux: check for simple types

From: Christian Göttsche <cgzones@...glemail.com>

Validate that the target of AVTAB_TYPE rules and file transitions are
simple types and not attributes.

Signed-off-by: Christian Göttsche <cgzones@...glemail.com>
---
 security/selinux/ss/avtab.c    |  9 ++++++++-
 security/selinux/ss/policydb.c | 23 +++++++++++++++++++++--
 security/selinux/ss/policydb.h |  1 +
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c
index 002853dd3443..2aa16aa75aac 100644
--- a/security/selinux/ss/avtab.c
+++ b/security/selinux/ss/avtab.c
@@ -424,6 +424,13 @@ int avtab_read_item(struct avtab *a, struct policy_file *fp, struct policydb *po
 				}
 				key.specified = spec_order[i] | enabled;
 				datum.u.data = le32_to_cpu(buf32[items++]);
+
+				if ((key.specified & AVTAB_TYPE) &&
+				    !policydb_simpletype_isvalid(pol, datum.u.data)) {
+					pr_err("SELinux: avtab: invalid type\n");
+					return -EINVAL;
+				}
+
 				rc = insertf(a, &key, &datum, p);
 				if (rc)
 					return rc;
@@ -519,7 +526,7 @@ int avtab_read_item(struct avtab *a, struct policy_file *fp, struct policydb *po
 		datum.u.data = le32_to_cpu(*buf32);
 	}
 	if ((key.specified & AVTAB_TYPE) &&
-	    !policydb_type_isvalid(pol, datum.u.data)) {
+	    !policydb_simpletype_isvalid(pol, datum.u.data)) {
 		pr_err("SELinux: avtab: invalid type\n");
 		return -EINVAL;
 	}
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 17fbd145ba1b..917b468c5144 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -681,7 +681,7 @@ static int role_validate(void *key, void *datum, void *datap)
 	}
 
 	ebitmap_for_each_positive_bit(&role->types, node, i) {
-		if (!policydb_type_isvalid(p, i + 1))
+		if (!policydb_simpletype_isvalid(p, i + 1))
 			goto bad;
 	}
 
@@ -1042,6 +1042,23 @@ bool policydb_type_isvalid(const struct policydb *p, u32 type)
 	return true;
 }
 
+bool policydb_simpletype_isvalid(const struct policydb *p, u32 type)
+{
+	const struct type_datum *datum;
+
+	if (!type || type > p->p_types.nprim)
+		return false;
+
+	datum = p->type_val_to_struct[type - 1];
+	if (!datum)
+		return false;
+
+	if (datum->attribute)
+		return false;
+
+	return true;
+}
+
 bool policydb_boolean_isvalid(const struct policydb *p, u32 boolean)
 {
 	if (!boolean || boolean > p->p_bools.nprim)
@@ -2225,6 +2242,8 @@ static int filename_trans_read_helper_compat(struct policydb *p, struct policy_f
 	key.name = name;
 
 	otype = le32_to_cpu(buf[3]);
+	if (!policydb_simpletype_isvalid(p, otype))
+		goto out;
 
 	last = NULL;
 	datum = policydb_filenametr_search(p, &key);
@@ -2347,7 +2366,7 @@ static int filename_trans_read_helper(struct policydb *p, struct policy_file *fp
 		datum->otype = le32_to_cpu(buf[0]);
 
 		rc = -EINVAL;
-		if (!policydb_type_isvalid(p, datum->otype))
+		if (!policydb_simpletype_isvalid(p, datum->otype))
 			goto out;
 
 		dst = &datum->next;
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 28dd91a7427f..73a0b793354e 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -317,6 +317,7 @@ extern int policydb_load_isids(struct policydb *p, struct sidtab *s);
 extern bool policydb_context_isvalid(const struct policydb *p, const struct context *c);
 extern bool policydb_class_isvalid(const struct policydb *p, u16 class);
 extern bool policydb_type_isvalid(const struct policydb *p, u32 type);
+extern bool policydb_simpletype_isvalid(const struct policydb *p, u32 type);
 extern bool policydb_role_isvalid(const struct policydb *p, u32 role);
 extern bool policydb_user_isvalid(const struct policydb *p, u32 user);
 extern bool policydb_boolean_isvalid(const struct policydb *p, u32 boolean);
-- 
2.45.2