From 65cddd50980be8c9c27ad7518a0dc812eccb25d5 Mon Sep 17 00:00:00 2001 From: Ondrej Mosnacek Date: Tue, 7 Jan 2020 14:31:53 +0100 Subject: selinux: treat atomic flags more carefully The disabled/enforcing/initialized flags are all accessed concurrently by threads so use the appropriate accessors that ensure atomicity and document that it is expected. Use smp_load/acquire...() helpers (with memory barriers) for the initialized flag, since it gates access to the rest of the state structures. Note that the disabled flag is currently not used for anything other than avoiding double disable, but it will be used for bailing out of hooks once security_delete_hooks() is removed. Signed-off-by: Ondrej Mosnacek Acked-by: Stephen Smalley Reviewed-by: Kees Cook Reviewed-by: James Morris Signed-off-by: Paul Moore --- security/selinux/include/security.h | 33 +++++++++++++++++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-) (limited to 'security/selinux/include') diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h index ecdd610e6449..a39f9565d80b 100644 --- a/security/selinux/include/security.h +++ b/security/selinux/include/security.h @@ -117,15 +117,27 @@ void selinux_avc_init(struct selinux_avc **avc); extern struct selinux_state selinux_state; +static inline bool selinux_initialized(const struct selinux_state *state) +{ + /* do a synchronized load to avoid race conditions */ + return smp_load_acquire(&state->initialized); +} + +static inline void selinux_mark_initialized(struct selinux_state *state) +{ + /* do a synchronized write to avoid race conditions */ + smp_store_release(&state->initialized, true); +} + #ifdef CONFIG_SECURITY_SELINUX_DEVELOP static inline bool enforcing_enabled(struct selinux_state *state) { - return state->enforcing; + return READ_ONCE(state->enforcing); } static inline void enforcing_set(struct selinux_state *state, bool value) { - state->enforcing = value; + WRITE_ONCE(state->enforcing, value); } #else static inline bool enforcing_enabled(struct selinux_state *state) @@ -138,6 +150,23 @@ static inline void enforcing_set(struct selinux_state *state, bool value) } #endif +#ifdef CONFIG_SECURITY_SELINUX_DISABLE +static inline bool selinux_disabled(struct selinux_state *state) +{ + return READ_ONCE(state->disabled); +} + +static inline void selinux_mark_disabled(struct selinux_state *state) +{ + WRITE_ONCE(state->disabled, true); +} +#else +static inline bool selinux_disabled(struct selinux_state *state) +{ + return false; +} +#endif + static inline bool selinux_policycap_netpeer(void) { struct selinux_state *state = &selinux_state; -- cgit v1.2.3