Re: [PATCH 1/2] audit: move processing of "audit" boot param to audit_init()
On Thu, Feb 22, 2018 at 7:22 PM, Greg Edwards <gedwards(a)ddn.com> wrote:
The processing of the "audit" boot parameter is handled
before the
console has been initialized. We therefore miss any panic messages if
we fail to verify the boot parameter or set the audit state, unless we
also enable earlyprintk.
Instead, have the boot parameter function just save the parameter value
and process it later from audit_init(), which is a postcore_initcall()
function.
Signed-off-by: Greg Edwards <gedwards(a)ddn.com>
---
kernel/audit.c | 48 +++++++++++++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 17 deletions(-)
In the process of trying to explain things a bit further (see the
discussion thread in 0/2), I realized that some example code might
speak better than I could. Below is what I was thinking for a fix; I
haven't tested it, so it may blow up badly, but hopefully it makes
things a bit more clear.
One thing of note, I did away with the kstrtol() altogether, when we
are only looking for zero and one it seems easier to just compare the
strings.
diff --git a/kernel/audit.c b/kernel/audit.c
index 1a3e75d9a66c..5dd63f60ef90 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -61,6 +61,7 @@
#include <linux/gfp.h>
#include <linux/pid.h>
#include <linux/slab.h>
+#include <linux/string.h>
#include <linux/audit.h>
@@ -86,6 +87,7 @@ static int audit_initialized;
#define AUDIT_OFF 0
#define AUDIT_ON 1
#define AUDIT_LOCKED 2
+#define AUDIT_ARGERR 3 /* indicate a "audit=X" syntax error at boot */
u32 audit_enabled = AUDIT_OFF;
bool audit_ever_enabled = !!AUDIT_OFF;
@@ -1581,6 +1583,12 @@ static int __init audit_init(void)
if (audit_initialized == AUDIT_DISABLED)
return 0;
+ /* handle any delayed error reporting from audit_enable() */
+ if (audit_default == AUDIT_ARGERR) {
+ pr_err("invalid 'audit' parameter value, use 0 or
1\n");
+ audit_default = AUDIT_ON;
+ }
+
audit_buffer_cache = kmem_cache_create("audit_buffer",
sizeof(struct audit_buffer),
0, SLAB_PANIC, NULL);
@@ -1618,19 +1626,23 @@ postcore_initcall(audit_init);
/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
static int __init audit_enable(char *str)
{
- long val;
+ /* NOTE: we can't reliably send any messages to the console here */
- if (kstrtol(str, 0, &val))
- panic("audit: invalid 'audit' parameter value (%s)\n",
str);
- audit_default = (val ? AUDIT_ON : AUDIT_OFF);
+ if (!strcasecmp(str, "off") || !strcmp(str, "0"))
+ audit_default = AUDIT_OFF;
+ else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
+ audit_default = AUDIT_ON;
+ else
+ audit_default = AUDIT_ARGERR;
- if (audit_default == AUDIT_OFF)
+ if (audit_default) {
+ audit_enabled = AUDIT_ON;
+ audit_ever_enabled = AUDIT_ON;
+ } else {
+ audit_enabled = AUDIT_OFF;
+ audit_ever_enabled = AUDIT_OFF;
audit_initialized = AUDIT_DISABLED;
- if (audit_set_enabled(audit_default))
- panic("audit: error setting audit state (%d)\n",
audit_default);
-
- pr_info("%s\n", audit_default ?
- "enabled (after initialization)" : "disabled (until
reboot)");
+ }
return 1;
}
--
paul moore
www.paul-moore.com