[PATCH AUTOSEL 5.9 068/147] selinux: access policycaps with READ_ONCE/WRITE_ONCE

Sasha Levin
2020-10-27T00:41:41Z

From: Stephen Smalley <stephen.smalley.work@gmail.com>

[ Upstream commit e8ba53d0023a76ba0f50e6ee3e6288c5442f9d33 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
security/selinux/include/security.h | 14 +++++++-------
security/selinux/ss/services.c | 3 ++-
2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index b0e02cfe3ce14..8a432f646967e 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -177,49 +177,49 @@ 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 1caf4e6033096..c55b3063753ab 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2103,7 +2103,8 @@ static void security_load_policycaps(struct selinux_state *state)
struct ebitmap_node *node;

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",
--
2.25.1