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 cbdd3c7..0ce2ef6 100644 (file)
--- 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 8dc111f..9704c8a 100644 (file)
--- 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",