[PATCH] Exclude messages by message type

- Add a new, 5th filter called "exclude".
    - And add a new field AUDIT_MSGTYPE.
    - Define a new function audit_filter_exclude() that takes a message type
      as input and examines all rules in the filter.  It returns '1' if the
      message is to be excluded, and '0' otherwise.
    - Call the audit_filter_exclude() function near the top of
      audit_log_start() just after asserting audit_initialized.  If the
      message type is not to be audited, return NULL very early, before
      doing a lot of work.
[combined with followup fix for bug in original patch, Nov 4, same author]
[combined with later renaming AUDIT_FILTER_EXCLUDE->AUDIT_FILTER_TYPE
and audit_filter_exclude() -> audit_filter_type()]

Signed-off-by: Dustin Kirkland <dustin.kirkland@us.ibm.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dustin Kirkland 2005-11-03 16:12:36 +00:00 committed by Al Viro
parent 73241ccca0
commit c8edc80c8b
3 changed files with 41 additions and 2 deletions

View file

@ -92,8 +92,9 @@
#define AUDIT_FILTER_ENTRY 0x02 /* Apply rule at syscall entry */
#define AUDIT_FILTER_WATCH 0x03 /* Apply rule to file system watches */
#define AUDIT_FILTER_EXIT 0x04 /* Apply rule at syscall exit */
#define AUDIT_FILTER_TYPE 0x05 /* Apply rule at audit_log_start */
#define AUDIT_NR_FILTERS 5
#define AUDIT_NR_FILTERS 6
#define AUDIT_FILTER_PREPEND 0x10 /* Prepend to front of list */
@ -132,6 +133,7 @@
#define AUDIT_LOGINUID 9
#define AUDIT_PERS 10
#define AUDIT_ARCH 11
#define AUDIT_MSGTYPE 12
/* These are ONLY useful when checking
* at syscall exit time (AUDIT_AT_EXIT). */
@ -289,6 +291,7 @@ extern int audit_sockaddr(int len, void *addr);
extern int audit_avc_path(struct dentry *dentry, struct vfsmount *mnt);
extern void audit_signal_info(int sig, struct task_struct *t);
extern int audit_filter_user(struct netlink_skb_parms *cb, int type);
extern int audit_filter_type(int type);
#else
#define audit_alloc(t) ({ 0; })
#define audit_free(t) do { ; } while (0)

View file

@ -702,6 +702,9 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
if (!audit_initialized)
return NULL;
if (unlikely(audit_filter_type(type)))
return NULL;
if (gfp_mask & __GFP_WAIT)
reserve = 0;
else

View file

@ -187,7 +187,8 @@ static struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
LIST_HEAD_INIT(audit_filter_list[2]),
LIST_HEAD_INIT(audit_filter_list[3]),
LIST_HEAD_INIT(audit_filter_list[4]),
#if AUDIT_NR_FILTERS != 5
LIST_HEAD_INIT(audit_filter_list[5]),
#if AUDIT_NR_FILTERS != 6
#error Fix audit_filter_list initialiser
#endif
};
@ -663,6 +664,38 @@ int audit_filter_user(struct netlink_skb_parms *cb, int type)
return ret; /* Audit by default */
}
int audit_filter_type(int type)
{
struct audit_entry *e;
int result = 0;
rcu_read_lock();
if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
goto unlock_and_return;
list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
list) {
struct audit_rule *rule = &e->rule;
int i;
for (i = 0; i < rule->field_count; i++) {
u32 field = rule->fields[i] & ~AUDIT_OPERATORS;
u32 op = rule->fields[i] & AUDIT_OPERATORS;
u32 value = rule->values[i];
if ( field == AUDIT_MSGTYPE ) {
result = audit_comparator(type, op, value);
if (!result)
break;
}
}
if (result)
goto unlock_and_return;
}
unlock_and_return:
rcu_read_unlock();
return result;
}
/* This should be called with task_lock() held. */
static inline struct audit_context *audit_get_context(struct task_struct *tsk,
int return_valid,