From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Bryam Vargas <hexlabsecurity@proton.me>,
	Stephen Smalley <stephen.smalley.work@gmail.com>,
	Paul Moore <paul@paul-moore.com>
Subject: [PATCH 5.10 004/235] selinux: require every boolean value to be defined
Date: Thu, 20 Aug 2026 16:54:00 +0200
Message-ID: <20260820145216.571778224@linuxfoundation.org>
In-Reply-To: <20260820145216.426568665@linuxfoundation.org>
References: <20260820145216.426568665@linuxfoundation.org>
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5.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bryam Vargas <hexlabsecurity@proton.me>

commit a93d37a09b863810653f93d371fb197457d59deb upstream.

p_bools.nprim comes from the policy image independently of how many
booleans follow it, and cond_index_bool() fills bool_val_to_struct[] at
value - 1, so a count larger than the values present leaves NULL entries.
Every user of that array then walks it by index and dereferences each
entry: cond_evaluate_expr() on the access-vector path,
security_get_bools() and security_get_bool_value() behind selinuxfs, and
security_set_bools(). A sparse class value is absorbed by
policydb_class_isvalid() and its siblings; booleans have no such
predicate, and no consumer that could use one.

Reject a boolean value that no boolean defines, once, where the array is
built. Conforming policies define every boolean they declare and are
unaffected.

Cc: stable@vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 security/selinux/ss/policydb.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -718,6 +718,7 @@ static inline void hash_eval(struct hash
 static int policydb_index(struct policydb *p)
 {
 	int i, rc;
+	u32 v;
 
 	if (p->mls_enabled)
 		pr_debug("SELinux:  %d users, %d roles, %d types, %d bools, %d sens, %d cats\n",
@@ -775,6 +776,24 @@ static int policydb_index(struct policyd
 		if (rc)
 			goto out;
 	}
+
+	/*
+	 * A sparse class value is absorbed by policydb_class_isvalid() and
+	 * its siblings, but no such predicate exists for booleans: every
+	 * user of bool_val_to_struct[] walks it by index and dereferences
+	 * each entry -- cond_evaluate_expr(), the two getters and
+	 * security_set_bools() -- so an unclaimed one has no consumer that
+	 * can tolerate it.
+	 */
+	for (v = 0; v < p->p_bools.nprim; v++) {
+		if (!p->bool_val_to_struct[v]) {
+			pr_err("SELinux:  boolean %u is declared but not defined\n",
+			       v + 1);
+			rc = -EINVAL;
+			goto out;
+		}
+	}
+
 	rc = 0;
 out:
 	return rc;