AUDIT: Clean up user message filtering
Don't look up the task by its pid and then use the syscall filtering
helper. Just implement our own filter helper which operates solely on
the information in the netlink_skb_parms.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 7b123f0..34a99022 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -40,6 +40,7 @@
#include <linux/personality.h>
#include <linux/time.h>
#include <linux/kthread.h>
+#include <linux/netlink.h>
#include <asm/unistd.h>
/* 0 = no checking
@@ -530,35 +531,62 @@
return AUDIT_BUILD_CONTEXT;
}
-int audit_filter_user(int pid, int type)
+static int audit_filter_user_rules(struct netlink_skb_parms *cb,
+ struct audit_rule *rule,
+ enum audit_state *state)
{
- struct task_struct *tsk;
+ int i;
+
+ for (i = 0; i < rule->field_count; i++) {
+ u32 field = rule->fields[i] & ~AUDIT_NEGATE;
+ u32 value = rule->values[i];
+ int result = 0;
+
+ switch (field) {
+ case AUDIT_PID:
+ result = (cb->creds.pid == value);
+ break;
+ case AUDIT_UID:
+ result = (cb->creds.uid == value);
+ break;
+ case AUDIT_GID:
+ result = (cb->creds.gid == value);
+ break;
+ case AUDIT_LOGINUID:
+ result = (cb->loginuid == value);
+ break;
+ }
+
+ if (rule->fields[i] & AUDIT_NEGATE)
+ result = !result;
+ if (!result)
+ return 0;
+ }
+ switch (rule->action) {
+ case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
+ case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break;
+ case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
+ }
+ return 1;
+}
+
+int audit_filter_user(struct netlink_skb_parms *cb, int type)
+{
struct audit_entry *e;
enum audit_state state;
int ret = 1;
- read_lock(&tasklist_lock);
- tsk = find_task_by_pid(pid);
- if (tsk)
- get_task_struct(tsk);
- read_unlock(&tasklist_lock);
-
- if (!tsk)
- return -ESRCH;
-
rcu_read_lock();
list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
- if (audit_filter_rules(tsk, &e->rule, NULL, &state)) {
+ if (audit_filter_user_rules(cb, &e->rule, &state)) {
if (state == AUDIT_DISABLED)
ret = 0;
break;
}
}
rcu_read_unlock();
- put_task_struct(tsk);
return ret; /* Audit by default */
-
}
/* This should be called with task_lock() held. */
