RFE: add additional fields for use in audit filter exclude rules
https://github.com/linux-audit/audit-kernel/issues/5
Re-factor and combine audit_filter_type() with audit_filter_user() to
use audit_filter_user_rules() to enable the exclude filter to
additionally filter on PID, UID, GID, AUID, LOGINUID_SET, SUBJ_*.
The process of combining the similar audit_filter_user() and
audit_filter_type() functions, required inverting the meaning and
including the ALWAYS action of the latter.
Include audit_filter_user_rules() into audit_filter(), removing unneeded
logic in the process.
Keep the check to quit early if the list is empty.
Signed-off-by: Richard Guy Briggs <r...@redhat.com>
---
v3: pull audit_filter_user_rules() into audit_filter() and simplify
logic.
v2: combine audit_filter_user() and audit_filter_type() into
audit_filter().
---
include/linux/audit.h | 2 -
kernel/audit.c | 4 +-
kernel/audit.h | 2 +
kernel/auditfilter.c | 147 ++++++++++++++++++-------------------------------
4 files changed, 57 insertions(+), 98 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 32cdafb..539c1d9 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -160,8 +160,6 @@ extern void audit_log_task_info(struct audit_buffer *ab,
extern int audit_update_lsm_rules(void);
/* Private API (for audit.c only) */
-extern int audit_filter_user(int type);
-extern int audit_filter_type(int type);
extern int audit_rule_change(int type, __u32 portid, int seq,
void *data, size_t datasz);
extern int audit_list_rules_send(struct sk_buff *request_skb, int seq);
diff --git a/kernel/audit.c b/kernel/audit.c
index 384374a..2dfaa19 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -914,7 +914,7 @@ 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(msg_type);
+ err = audit_filter(msg_type, AUDIT_FILTER_USER);
if (err == 1) { /* match or error */
err = 0;
if (msg_type == AUDIT_USER_TTY) {
@@ -1362,7 +1362,7 @@ struct audit_buffer *audit_log_start(struct audit_context
*ctx, gfp_t gfp_mask,
if (audit_initialized != AUDIT_INITIALIZED)
return NULL;
- if (unlikely(audit_filter_type(type)))
+ if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
return NULL;
if (gfp_mask & __GFP_DIRECT_RECLAIM) {
diff --git a/kernel/audit.h b/kernel/audit.h
index cbbe6bb..1879f02 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -327,6 +327,8 @@ extern pid_t audit_sig_pid;
extern kuid_t audit_sig_uid;
extern u32 audit_sig_sid;
+extern int audit_filter(int msgtype, unsigned int listtype);
+
#ifdef CONFIG_AUDITSYSCALL
extern int __audit_signal_info(int sig, struct task_struct *t);
static inline int audit_signal_info(int sig, struct task_struct *t)
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 96c9a1b..60579ec 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1290,113 +1290,72 @@ 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, int type,
- enum audit_state *state)
+int audit_filter(int msgtype, unsigned int listtype)
{
- int i;
-
- for (i = 0; i < rule->field_count; i++) {
- struct audit_field *f = &rule->fields[i];
- pid_t pid;
- int result = 0;
- u32 sid;
-
- switch (f->type) {
- case AUDIT_PID:
- pid = task_pid_nr(current);
- result = audit_comparator(pid, f->op, f->val);
- break;
- case AUDIT_UID:
- result = audit_uid_comparator(current_uid(), f->op,
f->uid);
- break;
- case AUDIT_GID:
- result = audit_gid_comparator(current_gid(), f->op,
f->gid);
- break;
- case AUDIT_LOGINUID:
- result =
audit_uid_comparator(audit_get_loginuid(current),
- f->op, f->uid);
- break;
- case AUDIT_LOGINUID_SET:
- result = audit_comparator(audit_loginuid_set(current),
- f->op, f->val);
- 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:
- case AUDIT_SUBJ_SEN:
- case AUDIT_SUBJ_CLR:
- if (f->lsm_rule) {
- security_task_getsecid(current, &sid);
- result = security_audit_rule_match(sid,
- f->type,
- f->op,
- f->lsm_rule,
- NULL);
- }
- break;
- }
-
- if (result <= 0)
- return result;
- }
- switch (rule->action) {
- case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
- case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
- }
- return 1;
-}
-
-int audit_filter_user(int type)
-{
- enum audit_state state = AUDIT_DISABLED;
struct audit_entry *e;
- int rc, ret;
-
- ret = 1; /* Audit by default */
-
- rcu_read_lock();
- list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list)
{
- rc = audit_filter_user_rules(&e->rule, type, &state);
- if (rc) {
- if (rc > 0 && state == AUDIT_DISABLED)
- ret = 0;
- break;
- }
- }
- rcu_read_unlock();
-
- return ret;
-}
-
-int audit_filter_type(int type)
-{
- struct audit_entry *e;
- int result = 0;
+ int ret = 1; /* Audit by default */
rcu_read_lock();
- if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
+ if (list_empty(&audit_filter_list[listtype]))
goto unlock_and_return;
+ list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) {
+ int i, result = 0;
- list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
- list) {
- int i;
for (i = 0; i < e->rule.field_count; i++) {
struct audit_field *f = &e->rule.fields[i];
- if (f->type == AUDIT_MSGTYPE) {
- result = audit_comparator(type, f->op, f->val);
- if (!result)
- break;
+ pid_t pid;
+ u32 sid;
+
+ switch (f->type) {
+ case AUDIT_PID:
+ pid = task_pid_nr(current);
+ result = audit_comparator(pid, f->op, f->val);
+ break;
+ case AUDIT_UID:
+ result = audit_uid_comparator(current_uid(),
f->op, f->uid);
+ break;
+ case AUDIT_GID:
+ result = audit_gid_comparator(current_gid(),
f->op, f->gid);
+ break;
+ case AUDIT_LOGINUID:
+ result =
audit_uid_comparator(audit_get_loginuid(current),
+ f->op, f->uid);
+ break;
+ case AUDIT_LOGINUID_SET:
+ result =
audit_comparator(audit_loginuid_set(current),
+ f->op, f->val);
+ break;
+ case AUDIT_MSGTYPE:
+ result = audit_comparator(msgtype, f->op,
f->val);
+ break;
+ case AUDIT_SUBJ_USER:
+ case AUDIT_SUBJ_ROLE:
+ case AUDIT_SUBJ_TYPE:
+ case AUDIT_SUBJ_SEN:
+ case AUDIT_SUBJ_CLR:
+ if (f->lsm_rule) {
+ security_task_getsecid(current, &sid);
+ result = security_audit_rule_match(sid,
+ f->type, f->op,
f->lsm_rule, NULL);
+ }
+ break;
+ default:
+ goto unlock_and_return;
}
+ if (result < 0) /* error */
+ goto unlock_and_return;
+ if (!result)
+ break;
+ }
+ if (result > 0) {
+ if (e->rule.action == AUDIT_NEVER || listtype ==
AUDIT_FILTER_TYPE)
+ ret = 0;
+ break;
}
- if (result)
- goto unlock_and_return;
}
unlock_and_return:
rcu_read_unlock();
- return result;
+ return ret;
}
static int update_lsm_rule(struct audit_krule *r)
--
1.7.1
