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Commit 62062cf8 authored by Eric Paris's avatar Eric Paris
Browse files

audit: allow checking the type of audit message in the user filter 



When userspace sends messages to the audit system it includes a type.
We want to be able to filter messages based on that type without have to
do the all or nothing option currently available on the
AUDIT_FILTER_TYPE filter list.  Instead we should be able to use the
AUDIT_FILTER_USER filter list and just use the message type as one part
of the matching decision.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent 34c474de

include/linux/audit.h

+1 −1
Original line number Diff line number Diff line
@@ -438,7 +438,7 @@ static inline void audit_log_secctx(struct audit_buffer *ab, u32 secid) 
extern int		    audit_update_lsm_rules(void);



				/* Private API (for audit.c only) */

extern int audit_filter_user(void);

extern int audit_filter_user(int type);

extern int audit_filter_type(int type);

extern int  audit_receive_filter(int type, int pid, int seq,

				void *data, size_t datasz, kuid_t loginuid,

kernel/audit.c

+1 −1
Original line number Diff line number Diff line
@@ -737,7 +737,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 
		if (!audit_enabled && msg_type != AUDIT_USER_AVC)

			return 0;



		err = audit_filter_user();

		err = audit_filter_user(msg_type);

		if (err == 1) {

			err = 0;

			if (msg_type == AUDIT_USER_TTY) {

kernel/auditfilter.c

+25 −3
Original line number Diff line number Diff line
@@ -310,6 +310,18 @@ static u32 audit_to_op(u32 op) 
	return n;

}



/* check if a field is valid for a given list */

static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)

{

	switch(f->type) {

	case AUDIT_MSGTYPE:

		if (entry->rule.listnr != AUDIT_FILTER_TYPE &&

		    entry->rule.listnr != AUDIT_FILTER_USER)

			return -EINVAL;

		break;

	};

	return 0;

}



/* Translate struct audit_rule to kernel's rule respresentation.

 * Exists for backward compatibility with userspace. */
@@ -459,6 +471,13 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, 
		f->gid = INVALID_GID;

		f->lsm_str = NULL;

		f->lsm_rule = NULL;



		err = audit_field_valid(entry, f);

		if (err)

			goto exit_free;



		err = -EINVAL;



		switch(f->type) {

		case AUDIT_UID:

		case AUDIT_EUID:
@@ -1354,7 +1373,7 @@ int audit_compare_dname_path(const char *dname, const char *path, int parentlen) 
	return strncmp(p, dname, dlen);

}



static int audit_filter_user_rules(struct audit_krule *rule,

static int audit_filter_user_rules(struct audit_krule *rule, int type,

				   enum audit_state *state)

{

	int i;
@@ -1378,6 +1397,9 @@ static int audit_filter_user_rules(struct audit_krule *rule, 
			result = audit_uid_comparator(audit_get_loginuid(current),

						  f->op, f->uid);

			break;

		case AUDIT_MSGTYPE:

			result = audit_comparator(type, f->op, f->val);

			break;

		case AUDIT_SUBJ_USER:

		case AUDIT_SUBJ_ROLE:

		case AUDIT_SUBJ_TYPE:
@@ -1404,7 +1426,7 @@ static int audit_filter_user_rules(struct audit_krule *rule, 
	return 1;

}



int audit_filter_user(void)

int audit_filter_user(int type)

{

	enum audit_state state = AUDIT_DISABLED;

	struct audit_entry *e;
@@ -1412,7 +1434,7 @@ int audit_filter_user(void) 


	rcu_read_lock();

	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {

		if (audit_filter_user_rules(&e->rule, &state)) {

		if (audit_filter_user_rules(&e->rule, type, &state)) {

			if (state == AUDIT_DISABLED)

				ret = 0;

			break;