selinux: declare data arrays const

The arrays for the policy capability names, the initial sid identifiers
and the class and permission names are not changed at runtime.  Declare
them const to avoid accidental modification.

Do not override the classmap and the initial sid list in the build time
script genheaders.

Check flose(3) is successful in genheaders.c, otherwise the written data
might be corrupted or incomplete.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: manual merge due to fuzz, minor style tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>

9 files changed, 24 insertions, 26 deletions

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 874c1c6fe10b..9a43af0ebd7d 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -668,7 +668,7 @@ static void avc_audit_pre_callback(struct audit_buffer *ab, void *a)
 	struct common_audit_data *ad = a;
 	struct selinux_audit_data *sad = ad->selinux_audit_data;
 	u32 av = sad->audited;
-	const char **perms;
+	const char *const *perms;
 	int i, perm;
 
 	audit_log_format(ab, "avc:  %s ", sad->denied ? "denied" : "granted");
diff --git a/security/selinux/include/avc_ss.h b/security/selinux/include/avc_ss.h
index 66a87559b788..42912c917fd4 100644
--- a/security/selinux/include/avc_ss.h
+++ b/security/selinux/include/avc_ss.h
@@ -18,7 +18,7 @@ struct security_class_mapping {
 	const char *perms[sizeof(u32) * 8 + 1];
 };
 
-extern struct security_class_mapping secclass_map[];
+extern const struct security_class_mapping secclass_map[];
 
 #endif /* _SELINUX_AVC_SS_H_ */
 
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 35aac62a662e..ff757ae5f253 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -38,7 +38,7 @@
  * Note: The name for any socket class should be suffixed by "socket",
  *	 and doesn't contain more than one substr of "socket".
  */
-struct security_class_mapping secclass_map[] = {
+const struct security_class_mapping secclass_map[] = {
 	{ "security",
 	  { "compute_av", "compute_create", "compute_member",
 	    "check_context", "load_policy", "compute_relabel",
diff --git a/security/selinux/include/initial_sid_to_string.h b/security/selinux/include/initial_sid_to_string.h
index 9683f0ddecbc..60820517aa43 100644
--- a/security/selinux/include/initial_sid_to_string.h
+++ b/security/selinux/include/initial_sid_to_string.h
@@ -1,5 +1,5 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-static const char *initial_sid_to_string[] = {
+static const char *const initial_sid_to_string[] = {
 	NULL,
 	"kernel",
 	"security",
diff --git a/security/selinux/include/policycap.h b/security/selinux/include/policycap.h
index 2680aa21205c..f35d3458e71d 100644
--- a/security/selinux/include/policycap.h
+++ b/security/selinux/include/policycap.h
@@ -16,6 +16,6 @@ enum {
 };
 #define POLICYDB_CAP_MAX (__POLICYDB_CAP_MAX - 1)
 
-extern const char *selinux_policycap_names[__POLICYDB_CAP_MAX];
+extern const char *const selinux_policycap_names[__POLICYDB_CAP_MAX];
 
 #endif /* _SELINUX_POLICYCAP_H_ */
diff --git a/security/selinux/include/policycap_names.h b/security/selinux/include/policycap_names.h
index 100da7d043db..2a87fc3702b8 100644
--- a/security/selinux/include/policycap_names.h
+++ b/security/selinux/include/policycap_names.h
@@ -5,7 +5,7 @@
 #include "policycap.h"
 
 /* Policy capability names */
-const char *selinux_policycap_names[__POLICYDB_CAP_MAX] = {
+const char *const selinux_policycap_names[__POLICYDB_CAP_MAX] = {
 	"network_peer_controls",
 	"open_perms",
 	"extended_socket_class",
diff --git a/security/selinux/ss/avtab.c b/security/selinux/ss/avtab.c
index ea9fc69568e3..8480ec6c6e75 100644
--- a/security/selinux/ss/avtab.c
+++ b/security/selinux/ss/avtab.c
@@ -385,7 +385,7 @@ void avtab_hash_eval(struct avtab *h, char *tag)
 	       chain2_len_sum);
 }
 
-static uint16_t spec_order[] = {
+static const uint16_t spec_order[] = {
 	AVTAB_ALLOWED,
 	AVTAB_AUDITDENY,
 	AVTAB_AUDITALLOW,
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 3d50dfb0211b..adcfb63b3550 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -61,7 +61,7 @@ struct policydb_compat_info {
 };
 
 /* These need to be updated if SYM_NUM or OCON_NUM changes */
-static struct policydb_compat_info policydb_compat[] = {
+static const struct policydb_compat_info policydb_compat[] = {
 	{
 		.version	= POLICYDB_VERSION_BASE,
 		.sym_num	= SYM_NUM - 3,
@@ -159,18 +159,16 @@ static struct policydb_compat_info policydb_compat[] = {
 	},
 };
 
-static struct policydb_compat_info *policydb_lookup_compat(int version)
+static const struct policydb_compat_info *policydb_lookup_compat(int version)
 {
 	int i;
-	struct policydb_compat_info *info = NULL;
 
 	for (i = 0; i < ARRAY_SIZE(policydb_compat); i++) {
-		if (policydb_compat[i].version == version) {
-			info = &policydb_compat[i];
-			break;
-		}
+		if (policydb_compat[i].version == version)
+			return &policydb_compat[i];
 	}
-	return info;
+
+	return NULL;
 }
 
 /*
@@ -314,7 +312,7 @@ static int cat_destroy(void *key, void *datum, void *p)
 	return 0;
 }
 
-static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) = {
+static int (*const destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) = {
 	common_destroy,
 	cls_destroy,
 	role_destroy,
@@ -669,7 +667,7 @@ static int cat_index(void *key, void *datum, void *datap)
 	return 0;
 }
 
-static int (*index_f[SYM_NUM]) (void *key, void *datum, void *datap) = {
+static int (*const index_f[SYM_NUM]) (void *key, void *datum, void *datap) = {
 	common_index,
 	class_index,
 	role_index,
@@ -1637,7 +1635,8 @@ bad:
 	return rc;
 }
 
-static int (*read_f[SYM_NUM]) (struct policydb *p, struct symtab *s, void *fp) = {
+static int (*const read_f[SYM_NUM]) (struct policydb *p,
+				     struct symtab *s, void *fp) = {
 	common_read,
 	class_read,
 	role_read,
@@ -2208,7 +2207,7 @@ out:
 	return rc;
 }
 
-static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
+static int ocontext_read(struct policydb *p, const struct policydb_compat_info *info,
 			 void *fp)
 {
 	int i, j, rc;
@@ -2404,7 +2403,7 @@ int policydb_read(struct policydb *p, void *fp)
 	u32 len, nprim, nel, perm;
 
 	char *policydb_str;
-	struct policydb_compat_info *info;
+	const struct policydb_compat_info *info;
 
 	policydb_init(p);
 
@@ -3238,8 +3237,7 @@ static int user_write(void *vkey, void *datum, void *ptr)
 	return 0;
 }
 
-static int (*write_f[SYM_NUM]) (void *key, void *datum,
-				void *datap) = {
+static int (*const write_f[SYM_NUM]) (void *key, void *datum, void *datap) = {
 	common_write,
 	class_write,
 	role_write,
@@ -3250,7 +3248,7 @@ static int (*write_f[SYM_NUM]) (void *key, void *datum,
 	cat_write,
 };
 
-static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
+static int ocontext_write(struct policydb *p, const struct policydb_compat_info *info,
 			  void *fp)
 {
 	unsigned int i, j, rc;
@@ -3607,7 +3605,7 @@ int policydb_write(struct policydb *p, void *fp)
 	__le32 buf[4];
 	u32 config;
 	size_t len;
-	struct policydb_compat_info *info;
+	const struct policydb_compat_info *info;
 
 	/*
 	 * refuse to write policy older than compressed avtab
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index e62e04b1ec6c..69b2734311a6 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -99,7 +99,7 @@ static void context_struct_compute_av(struct policydb *policydb,
 				      struct extended_perms *xperms);
 
 static int selinux_set_mapping(struct policydb *pol,
-			       struct security_class_mapping *map,
+			       const struct security_class_mapping *map,
 			       struct selinux_map *out_map)
 {
 	u16 i, j;
@@ -121,7 +121,7 @@ static int selinux_set_mapping(struct policydb *pol,
 	/* Store the raw class and permission values */
 	j = 0;
 	while (map[j].name) {
-		struct security_class_mapping *p_in = map + (j++);
+		const struct security_class_mapping *p_in = map + (j++);
 		struct selinux_mapping *p_out = out_map->mapping + j;
 
 		/* An empty class string skips ahead */