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avc.h
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/* * Access vector cache interface for object managers. * * Author : Eamon Walsh <ewalsh@epoch.ncsc.mil> */ #ifndef _SELINUX_AVC_H_ #define _SELINUX_AVC_H_ #include <stdint.h> #include <errno.h> #include <stdlib.h> #include <selinux/selinux.h> #ifdef __cplusplus extern "C" { #endif /* * SID format and operations */ struct security_id { char * ctx; unsigned int refcnt; }; typedef struct security_id *security_id_t; #define SECSID_WILD ((security_id_t)NULL) /* unspecified SID */ /** * avc_sid_to_context - get copy of context corresponding to SID. * @sid: input SID * @ctx: pointer to context reference * * Return a copy of the security context corresponding to the input * @sid in the memory referenced by @ctx. The caller is expected to * free the context with freecon(). Return %0 on success, -%1 on * failure, with @errno set to %ENOMEM if insufficient memory was * available to make the copy, or %EINVAL if the input SID is invalid. */ extern int avc_sid_to_context(security_id_t sid, char ** ctx); extern int avc_sid_to_context_raw(security_id_t sid, char ** ctx); /** * avc_context_to_sid - get SID for context. * @ctx: input security context * @sid: pointer to SID reference * * Look up security context @ctx in SID table, making * a new entry if @ctx is not found. Increment the * reference counter for the SID. Store a pointer * to the SID structure into the memory referenced by @sid, * returning %0 on success or -%1 on error with @errno set. */ extern int avc_context_to_sid(const char * ctx, security_id_t * sid); extern int avc_context_to_sid_raw(const char * ctx, security_id_t * sid); /** * sidget - increment SID reference counter. * @sid: SID reference * * Increment the reference counter for @sid, indicating that * @sid is in use by an (additional) object. Return the * new reference count, or zero if @sid is invalid (has zero * reference count). Note that avc_context_to_sid() also * increments reference counts. */ extern int sidget(security_id_t sid) #ifdef __GNUC__ __attribute__ ((deprecated)) #endif ; /** * sidput - decrement SID reference counter. * @sid: SID reference * * Decrement the reference counter for @sid, indicating that * a reference to @sid is no longer in use. Return the * new reference count. When the reference count reaches * zero, the SID is invalid, and avc_context_to_sid() must * be called to obtain a new SID for the security context. */ extern int sidput(security_id_t sid) #ifdef __GNUC__ __attribute__ ((deprecated)) #endif ; /** * avc_get_initial_sid - get SID for an initial kernel security identifier * @name: input name of initial kernel security identifier * @sid: pointer to a SID reference * * Get the context for an initial kernel security identifier specified by * @name using security_get_initial_context() and then call * avc_context_to_sid() to get the corresponding SID. */ extern int avc_get_initial_sid(const char *name, security_id_t * sid); /* * AVC entry */ struct avc_entry; struct avc_entry_ref { struct avc_entry *ae; }; /** * avc_entry_ref_init - initialize an AVC entry reference. * @aeref: pointer to avc entry reference structure * * Use this macro to initialize an avc entry reference structure * before first use. These structures are passed to avc_has_perm(), * which stores cache entry references in them. They can increase * performance on repeated queries. */ #define avc_entry_ref_init(aeref) ((aeref)->ae = NULL) /* * User-provided callbacks for memory, auditing, and locking */ /* These structures are passed by reference to avc_init(). Passing * a NULL reference will cause the AVC to use a default. The default * memory callbacks are malloc() and free(). The default logging method * is to print on stderr. If no thread callbacks are passed, a separate * listening thread won't be started for kernel policy change messages. * If no locking callbacks are passed, no locking will take place. */ struct avc_memory_callback { /* malloc() equivalent. */ void *(*func_malloc) (size_t size); /* free() equivalent. */ void (*func_free) (void *ptr); /* Note that these functions should set errno on failure. If not, some avc routines may return -1 without errno set. */ }; struct avc_log_callback { /* log the printf-style format and arguments. */ void #ifdef __GNUC__ __attribute__ ((format(printf, 1, 2))) #endif (*func_log) (const char *fmt, ...); /* store a string representation of auditdata (corresponding to the given security class) into msgbuf. */ void (*func_audit) (void *auditdata, security_class_t cls, char *msgbuf, size_t msgbufsize); }; struct avc_thread_callback { /* create and start a thread, returning an opaque pointer to it; the thread should run the given function. */ void *(*func_create_thread) (void (*run) (void)); /* cancel a given thread and free its resources. */ void (*func_stop_thread) (void *thread); }; struct avc_lock_callback { /* create a lock and return an opaque pointer to it. */ void *(*func_alloc_lock) (void); /* obtain a given lock, blocking if necessary. */ void (*func_get_lock) (void *lock); /* release a given lock. */ void (*func_release_lock) (void *lock); /* destroy a given lock (free memory, etc.) */ void (*func_free_lock) (void *lock); }; /* * Available options */ /* no-op option, useful for unused slots in an array of options */ #define AVC_OPT_UNUSED 0 /* override kernel enforcing mode (boolean value) */ #define AVC_OPT_SETENFORCE 1 /* * AVC operations */ /** * avc_init - Initialize the AVC. * @msgprefix: prefix for log messages * @mem_callbacks: user-supplied memory callbacks * @log_callbacks: user-supplied logging callbacks * @thread_callbacks: user-supplied threading callbacks * @lock_callbacks: user-supplied locking callbacks * * Initialize the access vector cache. Return %0 on * success or -%1 with @errno set on failure. * If @msgprefix is NULL, use "uavc". If any callback * structure references are NULL, use default methods * for those callbacks (see the definition of the callback * structures above). */ extern int avc_init(const char *msgprefix, const struct avc_memory_callback *mem_callbacks, const struct avc_log_callback *log_callbacks, const struct avc_thread_callback *thread_callbacks, const struct avc_lock_callback *lock_callbacks) #ifdef __GNUC__ __attribute__ ((deprecated("Use avc_open and selinux_set_callback"))) #endif ; /** * avc_open - Initialize the AVC. * @opts: array of selabel_opt structures specifying AVC options or NULL. * @nopts: number of elements in opts array or zero for no options. * * This function is identical to avc_init(), except the message prefix * is set to "avc" and any callbacks desired should be specified via * selinux_set_callback(). Available options are listed above. */ extern int avc_open(struct selinux_opt *opts, unsigned nopts); /** * avc_cleanup - Remove unused SIDs and AVC entries. * * Search the SID table for SID structures with zero * reference counts, and remove them along with all * AVC entries that reference them. This can be used * to return memory to the system. */ extern void avc_cleanup(void); /** * avc_reset - Flush the cache and reset statistics. * * Remove all entries from the cache and reset all access * statistics (as returned by avc_cache_stats()) to zero. * The SID mapping is not affected. Return %0 on success, * -%1 with @errno set on error. */ extern int avc_reset(void); /** * avc_destroy - Free all AVC structures. * * Destroy all AVC structures and free all allocated * memory. User-supplied locking, memory, and audit * callbacks will be retained, but security-event * callbacks will not. All SID's will be invalidated. * User must call avc_init() if further use of AVC is desired. */ extern void avc_destroy(void); /** * avc_has_perm_noaudit - Check permissions but perform no auditing. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions, interpreted based on @tclass * @aeref: AVC entry reference * @avd: access vector decisions * * Check the AVC to determine whether the @requested permissions are granted * for the SID pair (@ssid, @tsid), interpreting the permissions * based on @tclass, and call the security server on a cache miss to obtain * a new decision and add it to the cache. Update @aeref to refer to an AVC * entry with the resulting decisions, and return a copy of the decisions * in @avd. Return %0 if all @requested permissions are granted, -%1 with * @errno set to %EACCES if any permissions are denied, or to another value * upon other errors. This function is typically called by avc_has_perm(), * but may also be called directly to separate permission checking from * auditing, e.g. in cases where a lock must be held for the check but * should be released for the auditing. */ extern int avc_has_perm_noaudit(security_id_t ssid, security_id_t tsid, security_class_t tclass, access_vector_t requested, struct avc_entry_ref *aeref, struct av_decision *avd); /** * avc_has_perm - Check permissions and perform any appropriate auditing. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions, interpreted based on @tclass * @aeref: AVC entry reference * @auditdata: auxiliary audit data * * Check the AVC to determine whether the @requested permissions are granted * for the SID pair (@ssid, @tsid), interpreting the permissions * based on @tclass, and call the security server on a cache miss to obtain * a new decision and add it to the cache. Update @aeref to refer to an AVC * entry with the resulting decisions. Audit the granting or denial of * permissions in accordance with the policy. Return %0 if all @requested * permissions are granted, -%1 with @errno set to %EACCES if any permissions * are denied or to another value upon other errors. */ extern int avc_has_perm(security_id_t ssid, security_id_t tsid, security_class_t tclass, access_vector_t requested, struct avc_entry_ref *aeref, void *auditdata); /** * avc_audit - Audit the granting or denial of permissions. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @requested: requested permissions * @avd: access vector decisions * @result: result from avc_has_perm_noaudit * @auditdata: auxiliary audit data * * Audit the granting or denial of permissions in accordance * with the policy. This function is typically called by * avc_has_perm() after a permission check, but can also be * called directly by callers who use avc_has_perm_noaudit() * in order to separate the permission check from the auditing. * For example, this separation is useful when the permission check must * be performed under a lock, to allow the lock to be released * before calling the auditing code. */ extern void avc_audit(security_id_t ssid, security_id_t tsid, security_class_t tclass, access_vector_t requested, struct av_decision *avd, int result, void *auditdata); /** * avc_compute_create - Compute SID for labeling a new object. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @newsid: pointer to SID reference * * Call the security server to obtain a context for labeling a * new object. Look up the context in the SID table, making * a new entry if not found. Increment the reference counter * for the SID. Store a pointer to the SID structure into the * memory referenced by @newsid, returning %0 on success or -%1 on * error with @errno set. */ extern int avc_compute_create(security_id_t ssid, security_id_t tsid, security_class_t tclass, security_id_t * newsid); /** * avc_compute_member - Compute SID for polyinstantation. * @ssid: source security identifier * @tsid: target security identifier * @tclass: target security class * @newsid: pointer to SID reference * * Call the security server to obtain a context for labeling an * object instance. Look up the context in the SID table, making * a new entry if not found. Increment the reference counter * for the SID. Store a pointer to the SID structure into the * memory referenced by @newsid, returning %0 on success or -%1 on * error with @errno set. */ extern int avc_compute_member(security_id_t ssid, security_id_t tsid, security_class_t tclass, security_id_t * newsid); /* * security event callback facility */ /* security events */ #define AVC_CALLBACK_GRANT 1 #define AVC_CALLBACK_TRY_REVOKE 2 #define AVC_CALLBACK_REVOKE 4 #define AVC_CALLBACK_RESET 8 #define AVC_CALLBACK_AUDITALLOW_ENABLE 16 #define AVC_CALLBACK_AUDITALLOW_DISABLE 32 #define AVC_CALLBACK_AUDITDENY_ENABLE 64 #define AVC_CALLBACK_AUDITDENY_DISABLE 128 /** * avc_add_callback - Register a callback for security events. * @callback: callback function * @events: bitwise OR of desired security events * @ssid: source security identifier or %SECSID_WILD * @tsid: target security identifier or %SECSID_WILD * @tclass: target security class * @perms: permissions * * Register a callback function for events in the set @events * related to the SID pair (@ssid, @tsid) and * and the permissions @perms, interpreting * @perms based on @tclass. Returns %0 on success or * -%1 if insufficient memory exists to add the callback. */ extern int avc_add_callback(int (*callback) (uint32_t event, security_id_t ssid, security_id_t tsid, security_class_t tclass, access_vector_t perms, access_vector_t * out_retained), uint32_t events, security_id_t ssid, security_id_t tsid, security_class_t tclass, access_vector_t perms); /* * AVC statistics */ /* If set, cache statistics are tracked. This may * become a compile-time option in the future. */ #define AVC_CACHE_STATS 1 struct avc_cache_stats { unsigned entry_lookups; unsigned entry_hits; unsigned entry_misses; unsigned entry_discards; unsigned cav_lookups; unsigned cav_hits; unsigned cav_probes; unsigned cav_misses; }; /** * avc_cache_stats - get cache access statistics. * @stats: reference to statistics structure * * Fill the supplied structure with information about AVC * activity since the last call to avc_init() or * avc_reset(). See the structure definition for * details. */ extern void avc_cache_stats(struct avc_cache_stats *stats); /** * avc_av_stats - log av table statistics. * * Log a message with information about the size and * distribution of the access vector table. The audit * callback is used to print the message. */ extern void avc_av_stats(void); /** * avc_sid_stats - log SID table statistics. * * Log a message with information about the size and * distribution of the SID table. The audit callback * is used to print the message. */ extern void avc_sid_stats(void); /** * avc_netlink_open - Create a netlink socket and connect to the kernel. */ extern int avc_netlink_open(int blocking); /** * avc_netlink_loop - Wait for netlink messages from the kernel */ extern void avc_netlink_loop(void); /** * avc_netlink_close - Close the netlink socket */ extern void avc_netlink_close(void); /** * avc_netlink_acquire_fd - Acquire netlink socket fd. * * Allows the application to manage messages from the netlink socket in * its own main loop. */ extern int avc_netlink_acquire_fd(void); /** * avc_netlink_release_fd - Release netlink socket fd. * * Returns ownership of the netlink socket to the library. */ extern void avc_netlink_release_fd(void); /** * avc_netlink_check_nb - Check netlink socket for new messages. * * Called by the application when using avc_netlink_acquire_fd() to * process kernel netlink events. */ extern int avc_netlink_check_nb(void); /** * selinux_status_open - Open and map SELinux kernel status page * */ extern int selinux_status_open(int fallback); /** * selinux_status_close - Unmap and close SELinux kernel status page * */ extern void selinux_status_close(void); /** * selinux_status_updated - Inform us whether the kernel status has been updated * */ extern int selinux_status_updated(void); /** * selinux_status_getenforce - Get the enforce flag value * */ extern int selinux_status_getenforce(void); /** * selinux_status_policyload - Get the number of policy reloaded * */ extern int selinux_status_policyload(void); /** * selinux_status_deny_unknown - Get the behavior for undefined classes/permissions * */ extern int selinux_status_deny_unknown(void); #ifdef __cplusplus } #endif #endif /* _SELINUX_AVC_H_ */