From: Stephen Smalley <stephen.smalley.work@gmail.com>
Date: Thu, 10 Sep 2020 14:28:05 +0000 (-0400)
Subject: selinux: access policycaps with READ_ONCE/WRITE_ONCE
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e8ba53d0023a76ba0f50e6ee3e6288c5442f9d33;p=linux.git

selinux: access policycaps with READ_ONCE/WRITE_ONCE

Use READ_ONCE/WRITE_ONCE for all accesses to the
selinux_state.policycaps booleans to prevent compiler
mischief.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
---

diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index cbdd3c7aff8b2..0ce2ef684ed06 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -164,49 +164,49 @@ static inline bool selinux_policycap_netpeer(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_NETPEER];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_NETPEER]);
 }
 
 static inline bool selinux_policycap_openperm(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_OPENPERM];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_OPENPERM]);
 }
 
 static inline bool selinux_policycap_extsockclass(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_EXTSOCKCLASS];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_EXTSOCKCLASS]);
 }
 
 static inline bool selinux_policycap_alwaysnetwork(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_ALWAYSNETWORK];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_ALWAYSNETWORK]);
 }
 
 static inline bool selinux_policycap_cgroupseclabel(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_CGROUPSECLABEL];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_CGROUPSECLABEL]);
 }
 
 static inline bool selinux_policycap_nnp_nosuid_transition(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_NNP_NOSUID_TRANSITION]);
 }
 
 static inline bool selinux_policycap_genfs_seclabel_symlinks(void)
 {
 	struct selinux_state *state = &selinux_state;
 
-	return state->policycap[POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS];
+	return READ_ONCE(state->policycap[POLICYDB_CAPABILITY_GENFS_SECLABEL_SYMLINKS]);
 }
 
 int security_mls_enabled(struct selinux_state *state);
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 8dc111fbe23ab..9704c8a32303f 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2123,7 +2123,8 @@ static void security_load_policycaps(struct selinux_state *state,
 	p = &policy->policydb;
 
 	for (i = 0; i < ARRAY_SIZE(state->policycap); i++)
-		state->policycap[i] = ebitmap_get_bit(&p->policycaps, i);
+		WRITE_ONCE(state->policycap[i],
+			ebitmap_get_bit(&p->policycaps, i));
 
 	for (i = 0; i < ARRAY_SIZE(selinux_policycap_names); i++)
 		pr_info("SELinux:  policy capability %s=%d\n",