Re: [PATCH 6/9] LSM/Audit: Introduce generic Audit LSM hooks

Paul Moore
2008-03-03T23:36:15Z

On Saturday 01 March 2008 3:00:05 pm Ahmed S. Darwish wrote:
> Introduce a generic Audit interface for security modules
> by adding the following new LSM hooks:
>
> audit_rule_init(field, op, rulestr, lsmrule)
> audit_rule_known(krule)
> audit_rule_match(secid, field, op, rule, actx)
> audit_rule_free(rule)
>
> Those hooks are only available if CONFIG_AUDIT is enabled.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>

Reviewed-by: Paul Moore <paul.moore@hp.com>

> ---
>
> include/linux/security.h | 72
> +++++++++++++++++++++++++++++++++++++++++++++++ security/dummy.c
> | 31 +++++++++++++++++++-
> security/security.c | 25 ++++++++++++++++
> 3 files changed, 127 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index b5d1ad7..eb663e5 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -43,6 +43,7 @@
> extern unsigned securebits;
>
> struct ctl_table;
> +struct audit_krule;
>
> /*
> * These functions are in security/capability.c and are used
> @@ -1227,6 +1228,37 @@ struct request_sock;
> * @secdata contains the security context.
> * @seclen contains the length of the security context.
> *
> + * Security hooks for Audit
> + *
> + * @audit_rule_init:
> + * Allocate and initialize an LSM audit rule structure.
> + * @field contains the required Audit action. Fields flags are
> defined in include/linux/audit.h + * @op contains the operator the
> rule uses.
> + * @rulestr contains the context where the rule will be applied to.
> + * @lsmrule contains a pointer to receive the result.
> + * Return 0 if @lsmrule has been successfully set,
> + * -EINVAL in case of an invalid rule.
> + *
> + * @audit_rule_known:
> + * Specifies whether given @rule contains any fields related to
> current LSM. + * @rule contains the audit rule of interest.
> + * Return 1 in case of relation found, 0 otherwise.
> + *
> + * @audit_rule_match:
> + * Determine if given @secid matches a rule previously approved
> + * by @audit_rule_known.
> + * @secid contains the security id in question.
> + * @field contains the field which relates to current LSM.
> + * @op contains the operator that will be used for matching.
> + * @rule points to the audit rule that will be checked against.
> + * @actx points to the audit context associated with the check.
> + * Return 1 if secid matches the rule, 0 if it does not, -ERRNO on
> failure. + *
> + * @audit_rule_free:
> + * Deallocate the LSM audit rule structure previously allocated by
> + * audit_rule_init.
> + * @rule contains the allocated rule
> + *
> * This is the main security structure.
> */
> struct security_operations {
> @@ -1487,6 +1519,13 @@ struct security_operations {
> int (*key_getsecurity)(struct key *key, char **_buffer);
> #endif /* CONFIG_KEYS */
>
> +#ifdef CONFIG_AUDIT
> + int (*audit_rule_init)(u32 field, u32 op, char *rulestr, void
> **lsmrule); + int (*audit_rule_known)(struct audit_krule *krule);
> + int (*audit_rule_match)(u32 secid, u32 field, u32 op, void
> *lsmrule, + struct audit_context *actx);
> + void (*audit_rule_free)(void *lsmrule);
> +#endif /* CONFIG_AUDIT */
> };
>
> /* prototypes */
> @@ -2670,5 +2709,38 @@ static inline int
> security_key_getsecurity(struct key *key, char **_buffer) #endif
> #endif /* CONFIG_KEYS */
>
> +#ifdef CONFIG_AUDIT
> +#ifdef CONFIG_SECURITY
> +int security_audit_rule_init(u32 field, u32 op, char *rulestr, void
> **lsmrule); +int security_audit_rule_known(struct audit_krule
> *krule);
> +int security_audit_rule_match(u32 secid, u32 field, u32 op, void
> *lsmrule, + struct audit_context *actx);
> +void security_audit_rule_free(void *lsmrule);
> +
> +#else
> +
> +static inline int security_audit_rule_init(u32 field, u32 op, char
> *rulestr, + void **lsmrule)
> +{
> + return 0;
> +}
> +
> +static inline int security_audit_rule_known(struct audit_krule
> *krule) +{
> + return 0;
> +}
> +
> +static inline int security_audit_rule_match(u32 secid, u32 field,
> u32 op, + void *lsmrule, struct audit_context *actx)
> +{
> + return 0;
> +}
> +
> +static inline void security_audit_rule_free(void *lsmrule)
> +{ }
> +
> +#endif /* CONFIG_SECURITY */
> +#endif /* CONFIG_AUDIT */
> +
> #endif /* ! __LINUX_SECURITY_H */
>
> diff --git a/security/dummy.c b/security/dummy.c
> index b4967f4..241ab20 100644
> --- a/security/dummy.c
> +++ b/security/dummy.c
> @@ -998,6 +998,30 @@ static int dummy_key_getsecurity(struct key
> *key, char **_buffer)
>
> #endif /* CONFIG_KEYS */
>
> +#ifdef CONFIG_AUDIT
> +static inline int dummy_audit_rule_init(u32 field, u32 op, char
> *rulestr, + void **lsmrule)
> +{
> + return 0;
> +}
> +
> +static inline int dummy_audit_rule_known(struct audit_krule *krule)
> +{
> + return 0;
> +}
> +
> +static inline int dummy_audit_rule_match(u32 secid, u32 field, u32
> op, + void *lsmrule,
> + struct audit_context *actx)
> +{
> + return 0;
> +}
> +
> +static inline void dummy_audit_rule_free(void *lsmrule)
> +{ }
> +
> +#endif /* CONFIG_AUDIT */
> +
> struct security_operations dummy_security_ops;
>
> #define set_to_dummy_if_null(ops, function) \
> @@ -1187,6 +1211,11 @@ void security_fixup_ops (struct
> security_operations *ops) set_to_dummy_if_null(ops, key_permission);
> set_to_dummy_if_null(ops, key_getsecurity);
> #endif /* CONFIG_KEYS */
> -
> +#ifdef CONFIG_AUDIT
> + set_to_dummy_if_null(ops, audit_rule_init);
> + set_to_dummy_if_null(ops, audit_rule_known);
> + set_to_dummy_if_null(ops, audit_rule_match);
> + set_to_dummy_if_null(ops, audit_rule_free);
> +#endif
> }
>
> diff --git a/security/security.c b/security/security.c
> index 1748329..1bf2ee4 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1118,3 +1118,28 @@ int security_key_getsecurity(struct key *key,
> char **_buffer) }
>
> #endif /* CONFIG_KEYS */
> +
> +#ifdef CONFIG_AUDIT
> +
> +int security_audit_rule_init(u32 field, u32 op, char *rulestr, void
> **lsmrule) +{
> + return security_ops->audit_rule_init(field, op, rulestr, lsmrule);
> +}
> +
> +int security_audit_rule_known(struct audit_krule *krule)
> +{
> + return security_ops->audit_rule_known(krule);
> +}
> +
> +void security_audit_rule_free(void *lsmrule)
> +{
> + security_ops->audit_rule_free(lsmrule);
> +}
> +
> +int security_audit_rule_match(u32 secid, u32 field, u32 op, void
> *lsmrule, + struct audit_context *actx)
> +{
> + return security_ops->audit_rule_match(secid, field, op, lsmrule,
> actx); +}
> +
> +#endif /* CONFIG_AUDIT */

--
paul moore
linux security @ hp