[PATCH 1/2] libsepol: Move the PERMISSION_MASK macro to private.h

[PATCH 1/2] libsepol: Move the PERMISSION_MASK macro to private.h

[James Carter]

Move the PERMISSION_MASK macro from policydb_validate.c to
private.h so that it can be used in other places.

Signed-off-by: James Carter <jwcart2@gmail.com>
---
 libsepol/src/policydb_validate.c | 3 ---
 libsepol/src/private.h           | 4 ++++
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
index 7d9ae3fd..99d27f88 100644
--- a/libsepol/src/policydb_validate.c
+++ b/libsepol/src/policydb_validate.c
@@ -18,9 +18,6 @@
  * Check that at least one permission bit is valid.
  * Older compilers might set invalid bits for the wildcard permission.
  */
-#define PERMISSION_MASK(nprim)                          \
-	((nprim) == PERM_SYMTAB_SIZE ? (~UINT32_C(0)) : \
-				       ((UINT32_C(1) << (nprim)) - 1))
 #define NO_VALID_PERMS(av, nprim) (!((av) & PERMISSION_MASK(nprim)))
 
 typedef struct validate {
diff --git a/libsepol/src/private.h b/libsepol/src/private.h
index 6fc5fa2d..7f7344a8 100644
--- a/libsepol/src/private.h
+++ b/libsepol/src/private.h
@@ -45,6 +45,10 @@
 
 #define MAX_ALIAS_REPEATS 32
 
+#define PERMISSION_MASK(nprim)                          \
+	((nprim) == PERM_SYMTAB_SIZE ? (~UINT32_C(0)) : \
+				       ((UINT32_C(1) << (nprim)) - 1))
+
 static inline int exceeds_available_bytes(const struct policy_file *fp,
 					  size_t x, size_t req_elem_size)
 {
-- 
2.55.0

[PATCH 2/2] libsepol: Remove junk permissions before optimzing the policy

[James Carter]

In older policy compilers, a wildcard or complement would cause
all the bits higher than those corresponding to the class's declared
permissions to be set. These junk bits must be removed before
optimization is done to avoid a situation where the only bits left
for an access vector are one or more of these junk bits. If a policy
does not have at least one actual permission bit set, it will fail
validation.

Signed-off-by: James Carter <jwcart2@gmail.com>
---
 libsepol/src/optimize.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/libsepol/src/optimize.c b/libsepol/src/optimize.c
index eeffee7d..1efd3832 100644
--- a/libsepol/src/optimize.c
+++ b/libsepol/src/optimize.c
@@ -446,6 +446,32 @@ static void optimize_cond_avtab(policydb_t *p, const struct type_vec *type_map)
 	}
 }
 
+/*
+ * Older policy compilers could set bits higher than any of the permissions
+ * in the class. These junk bits must be removed before optimization to keep
+ * redundant rules from being kept because of junk bits and to prevent the
+ * failure of policy validation because no actual permission bit is set. 
+ */
+static int remove_junk_permissions(avtab_key_t *k, avtab_datum_t *d, void *args)
+{
+	const policydb_t *p = args;
+	const class_datum_t *tclass;
+	uint32_t mask;
+
+	if (!(k->specified & AVTAB_AV))
+		return 0;
+
+	tclass = p->class_val_to_struct[k->target_class - 1];
+	mask = PERMISSION_MASK(tclass->permissions.nprim);
+
+	if ((k->specified & ~AVTAB_ENABLED) == AVTAB_AUDITDENY)
+		d->data |= ~mask;
+	else
+		d->data &= mask;
+
+	return 0;
+}
+
 int policydb_optimize(policydb_t *p)
 {
 	struct type_vec *type_map;
@@ -453,6 +479,9 @@ int policydb_optimize(policydb_t *p)
 	if (p->policy_type != POLICY_KERN)
 		return -1;
 
+	avtab_map(&p->te_avtab, remove_junk_permissions, p);
+	avtab_map(&p->te_cond_avtab, remove_junk_permissions, p);
+
 	type_map = build_type_map(p);
 	if (!type_map)
 		return -1;
-- 
2.55.0

Re: [PATCH 1/2] libsepol: Move the PERMISSION_MASK macro to private.h

[Stephen Smalley]

On Tue, Aug 25, 2026 at 3:41 PM James Carter <jwcart2@gmail.com> wrote:
>
> Move the PERMISSION_MASK macro from policydb_validate.c to
> private.h so that it can be used in other places.
>
> Signed-off-by: James Carter <jwcart2@gmail.com>

Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

Re: [PATCH 2/2] libsepol: Remove junk permissions before optimzing the policy

[Stephen Smalley]

On Tue, Aug 25, 2026 at 3:41 PM James Carter <jwcart2@gmail.com> wrote:
>
> In older policy compilers, a wildcard or complement would cause
> all the bits higher than those corresponding to the class's declared
> permissions to be set. These junk bits must be removed before
> optimization is done to avoid a situation where the only bits left
> for an access vector are one or more of these junk bits. If a policy
> does not have at least one actual permission bit set, it will fail
> validation.
>
> Signed-off-by: James Carter <jwcart2@gmail.com>

Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

Re: [PATCH 1/2] libsepol: Move the PERMISSION_MASK macro to private.h

[Stephen Smalley]

On Tue, Aug 25, 2026 at 4:13 PM Stephen Smalley
<stephen.smalley.work@gmail.com> wrote:
>
> On Tue, Aug 25, 2026 at 3:41 PM James Carter <jwcart2@gmail.com> wrote:
> >
> > Move the PERMISSION_MASK macro from policydb_validate.c to
> > private.h so that it can be used in other places.
> >
> > Signed-off-by: James Carter <jwcart2@gmail.com>
>
> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>

Both merged.