Commit 4a4cd633 authored by David Woodhouse's avatar David Woodhouse

AUDIT: Optimise the audit-disabled case for discarding user messages

Also exempt USER_AVC message from being discarded to preserve 
existing behaviour for SE Linux.
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent f6a789d1
......@@ -51,7 +51,8 @@
#define AUDIT_WATCH_LIST 1009 /* List all file/dir watches */
#define AUDIT_SIGNAL_INFO 1010 /* Get info about sender of signal to auditd */
#define AUDIT_FIRST_USER_MSG 1100 /* Userspace messages uninteresting to kernel */
#define AUDIT_FIRST_USER_MSG 1100 /* Userspace messages mostly uninteresting to kernel */
#define AUDIT_USER_AVC 1107 /* We filter this differently */
#define AUDIT_LAST_USER_MSG 1199
#define AUDIT_DAEMON_START 1200 /* Daemon startup record */
......@@ -235,7 +236,7 @@ extern int audit_socketcall(int nargs, unsigned long *args);
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 task_struct *tsk, int type);
extern int audit_filter_user(int pid, int type);
#else
#define audit_alloc(t) ({ 0; })
#define audit_free(t) do { ; } while (0)
......@@ -252,7 +253,7 @@ extern int audit_filter_user(struct task_struct *tsk, int type);
#define audit_sockaddr(len, addr) ({ 0; })
#define audit_avc_path(dentry, mnt) ({ 0; })
#define audit_signal_info(s,t) do { ; } while (0)
#define audit_filter_user(struct ({ 1; })
#define audit_filter_user(p,t) ({ 1; })
#endif
#ifdef CONFIG_AUDIT
......
......@@ -429,25 +429,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
break;
case AUDIT_USER:
case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
read_lock(&tasklist_lock);
tsk = find_task_by_pid(pid);
if (tsk)
get_task_struct(tsk);
read_unlock(&tasklist_lock);
if (!tsk)
return -ESRCH;
if (audit_enabled && audit_filter_user(tsk, msg_type)) {
ab = audit_log_start(NULL, msg_type);
if (ab) {
audit_log_format(ab,
"user pid=%d uid=%u auid=%u msg='%.1024s'",
pid, uid, loginuid, (char *)data);
audit_set_pid(ab, pid);
audit_log_end(ab);
}
if (!audit_enabled && msg_type != AUDIT_USER_AVC)
return 0;
err = audit_filter_user(pid, msg_type);
if (err == 1) {
err = 0;
ab = audit_log_start(NULL, msg_type);
if (ab) {
audit_log_format(ab,
"user pid=%d uid=%u auid=%u msg='%.1024s'",
pid, uid, loginuid, (char *)data);
audit_set_pid(ab, pid);
audit_log_end(ab);
}
}
put_task_struct(tsk);
break;
case AUDIT_ADD:
case AUDIT_DEL:
......
......@@ -530,22 +530,33 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk,
return AUDIT_BUILD_CONTEXT;
}
int audit_filter_user(struct task_struct *tsk, int type)
int audit_filter_user(int pid, int type)
{
struct task_struct *tsk;
struct audit_entry *e;
enum audit_state state;
int ret = 1;
if (audit_pid && tsk->pid == audit_pid)
return AUDIT_DISABLED;
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)) {
rcu_read_unlock();
return state != AUDIT_DISABLED;
if (state == AUDIT_DISABLED)
ret = 0;
break;
}
}
rcu_read_unlock();
put_task_struct(tsk);
return 1; /* Audit by default */
}
......
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