[PATCH] audit: do not panic on invalid boot parameter
Richard Guy Briggs
rgb at redhat.com
Wed Mar 7 04:13:59 UTC 2018
On 2018-03-06 13:53, Paul Moore wrote:
> On Tue, Mar 6, 2018 at 9:38 AM, Paul Moore <paul at paul-moore.com> wrote:
> > On Mon, Mar 5, 2018 at 10:24 PM, Richard Guy Briggs <rgb at redhat.com> wrote:
> >> On 2018-03-05 15:05, Greg Edwards wrote:
> >>> If you pass in an invalid audit boot parameter value, e.g. "audit=off",
> >>> the kernel panics very early in boot before the regular console is
> >>> initialized. Unless you have earlyprintk enabled, there is no
> >>> indication of what the problem is on the console.
> >>>
> >>> Convert the panic() calls to pr_err(), and leave auditing enabled if an
> >>> invalid parameter value was passed in.
> >>>
> >>> Modify the parameter to also accept "on" or "off" as valid values, and
> >>> update the documentation accordingly.
> >>>
> >>> Signed-off-by: Greg Edwards <gedwards at ddn.com>
> >>> ---
> >>> Changes v2 -> v3:
> >>> - convert panic() calls to pr_err()
> >>> - add handling of "on"/"off" as valid values
> >>> - update documentation
> >>>
> >>> Changes v1 -> v2:
> >>> - default to auditing enabled for the error case
> >>>
> >>> Documentation/admin-guide/kernel-parameters.txt | 14 +++++++-------
> >>> kernel/audit.c | 21 ++++++++++++++-------
> >>> 2 files changed, 21 insertions(+), 14 deletions(-)
> >>>
> >>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> >>> index 1d1d53f85ddd..0b926779315c 100644
> >>> --- a/Documentation/admin-guide/kernel-parameters.txt
> >>> +++ b/Documentation/admin-guide/kernel-parameters.txt
> >>> @@ -389,15 +389,15 @@
> >>> Use software keyboard repeat
> >>>
> >>> audit= [KNL] Enable the audit sub-system
> >>> - Format: { "0" | "1" } (0 = disabled, 1 = enabled)
> >>> - 0 - kernel audit is disabled and can not be enabled
> >>> - until the next reboot
> >>> + Format: { "0" | "1" | "off" | "on" }
> >>> + 0 | off - kernel audit is disabled and can not be
> >>> + enabled until the next reboot
> >>> unset - kernel audit is initialized but disabled and
> >>> will be fully enabled by the userspace auditd.
> >>> - 1 - kernel audit is initialized and partially enabled,
> >>> - storing at most audit_backlog_limit messages in
> >>> - RAM until it is fully enabled by the userspace
> >>> - auditd.
> >>> + 1 | on - kernel audit is initialized and partially
> >>> + enabled, storing at most audit_backlog_limit
> >>> + messages in RAM until it is fully enabled by the
> >>> + userspace auditd.
> >>> Default: unset
> >>>
> >>> audit_backlog_limit= [KNL] Set the audit queue size limit.
> >>> diff --git a/kernel/audit.c b/kernel/audit.c
> >>> index 227db99b0f19..8fccea5ded71 100644
> >>> --- a/kernel/audit.c
> >>> +++ b/kernel/audit.c
> >>> @@ -1567,19 +1567,26 @@ static int __init audit_init(void)
> >>> }
> >>> postcore_initcall(audit_init);
> >>>
> >>> -/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
> >>> +/*
> >>> + * Process kernel command-line parameter at boot time.
> >>> + * audit={0|off} or audit={1|on}.
> >>> + */
> >>> static int __init audit_enable(char *str)
> >>> {
> >>> - long val;
> >>> -
> >>> - 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 {
> >>> + pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
> >>> + audit_default = AUDIT_ON;
> >>> + }
> >>>
> >>> if (audit_default == AUDIT_OFF)
> >>> audit_initialized = AUDIT_DISABLED;
> >>> if (audit_set_enabled(audit_default))
> >>> - panic("audit: error setting audit state (%d)\n", audit_default);
> >>> + pr_err("audit: error setting audit state (%d)\n",
> >>> + audit_default);
> >>
> >> This patch looks good.
> >
> > On quick glance, I agree. I'll look at it a bit closer later today
> > and likely merge it.
> >
> > Thanks Greg.
>
> It's merge now. Thanks again everyone!
If you haven't already, please add my Reviewed-by:
> paul moore
- RGB
--
Richard Guy Briggs <rgb at redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
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