audit: ensure that 'audit=1' actually enables audit for PID 1

BugLink: http://bugs.launchpad.net/bugs/1745047

[ Upstream commit 173743dd ]

Prior to this patch we enabled audit in audit_init(), which is too
late for PID 1 as the standard initcalls are run after the PID 1 task
is forked.  This means that we never allocate an audit_context (see
audit_alloc()) for PID 1 and therefore miss a lot of audit events
generated by PID 1.

This patch enables audit as early as possible to help ensure that when
PID 1 is forked it can allocate an audit_context if required.
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

kernel/audit.c

@@ -80,13 +80,13 @@ static int	audit_initialized;
 #define AUDIT_OFF	0
 #define AUDIT_ON	1
 #define AUDIT_LOCKED	2
-u32		audit_enabled;
-u32		audit_ever_enabled;
+u32		audit_enabled = AUDIT_OFF;
+u32		audit_ever_enabled = !!AUDIT_OFF;
 
 EXPORT_SYMBOL_GPL(audit_enabled);
 
 /* Default state when kernel boots without any parameters. */
-static u32	audit_default;
+static u32	audit_default = AUDIT_OFF;
 
 /* If auditing cannot proceed, audit_failure selects what happens. */
 static u32	audit_failure = AUDIT_FAIL_PRINTK;
@@ -1193,8 +1193,6 @@ static int __init audit_init(void)
 	skb_queue_head_init(&audit_skb_queue);
 	skb_queue_head_init(&audit_skb_hold_queue);
 	audit_initialized = AUDIT_INITIALIZED;
-	audit_enabled = audit_default;
-	audit_ever_enabled |= !!audit_default;
 
 	audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
 
@@ -1211,6 +1209,8 @@ static int __init audit_enable(char *str)
 	audit_default = !!simple_strtol(str, NULL, 0);
 	if (!audit_default)
 		audit_initialized = AUDIT_DISABLED;
+	audit_enabled = audit_default;
+	audit_ever_enabled = !!audit_enabled;
 
 	pr_info("%s\n", audit_default ?
 		"enabled (after initialization)" : "disabled (until reboot)");