2020-04-28 03:47:33

by Tianjia Zhang

Subject: [PATCH] module: Allow to disable modsign in kernel cmdline

This change allows to disable modsign completely at the beginning,
and turn off by set the kernel cmdline `no_modsig_enforce` when
CONFIG_MODULE_SIG_FORCE is enabled.

Yet another change allows to always show the current status of
modsign through `/sys/module/module/parameters/sig_enforce`.

Signed-off-by: Jia Zhang <[email protected]>
Signed-off-by: Tianjia Zhang <[email protected]>
---
kernel/module.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/kernel/module.c b/kernel/module.c
index 646f1e2330d2..0e68e1286377 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -269,6 +269,14 @@ static void module_assert_mutex_or_preempt(void)

static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
module_param(sig_enforce, bool_enable_only, 0644);
+#ifdef CONFIG_MODULE_SIG_FORCE
+static int __init set_no_modsig_enforce(char *str)
+{
+ sig_enforce = false;
+ return 1;
+}
+__setup("no_modsig_enforce", set_no_modsig_enforce);
+#endif /* !CONFIG_MODULE_SIG_FORCE */

/*
* Export sig_enforce kernel cmdline parameter to allow other subsystems rely
--
2.17.1

2020-04-28 03:49:31

by Randy Dunlap

Subject: Re: [PATCH] module: Allow to disable modsign in kernel cmdline

On 4/27/20 8:43 PM, Tianjia Zhang wrote:
> This change allows to disable modsign completely at the beginning,
> and turn off by set the kernel cmdline `no_modsig_enforce` when
> CONFIG_MODULE_SIG_FORCE is enabled.
>
> Yet another change allows to always show the current status of
> modsign through `/sys/module/module/parameters/sig_enforce`.
>
> Signed-off-by: Jia Zhang <[email protected]>
> Signed-off-by: Tianjia Zhang <[email protected]>
> ---
> kernel/module.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 646f1e2330d2..0e68e1286377 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -269,6 +269,14 @@ static void module_assert_mutex_or_preempt(void)
>
> static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
> module_param(sig_enforce, bool_enable_only, 0644);
> +#ifdef CONFIG_MODULE_SIG_FORCE
> +static int __init set_no_modsig_enforce(char *str)
> +{
> + sig_enforce = false;
> + return 1;
> +}
> +__setup("no_modsig_enforce", set_no_modsig_enforce);
> +#endif /* !CONFIG_MODULE_SIG_FORCE */
>
> /*
> * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
>

Hi,
Please document this cmdline option, probably in
Documentation/admin-guide/kernel-parameters.txt.

thanks.

--
~Randy

2020-04-28 05:08:37

by Tianjia Zhang

Subject: Re: [PATCH] module: Allow to disable modsign in kernel cmdline

On 2020/4/28 11:47, Randy Dunlap wrote:
> On 4/27/20 8:43 PM, Tianjia Zhang wrote:
>> This change allows to disable modsign completely at the beginning,
>> and turn off by set the kernel cmdline `no_modsig_enforce` when
>> CONFIG_MODULE_SIG_FORCE is enabled.
>>
>> Yet another change allows to always show the current status of
>> modsign through `/sys/module/module/parameters/sig_enforce`.
>>
>> Signed-off-by: Jia Zhang <[email protected]>
>> Signed-off-by: Tianjia Zhang <[email protected]>
>> ---
>> kernel/module.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/kernel/module.c b/kernel/module.c
>> index 646f1e2330d2..0e68e1286377 100644
>> --- a/kernel/module.c
>> +++ b/kernel/module.c
>> @@ -269,6 +269,14 @@ static void module_assert_mutex_or_preempt(void)
>>
>> static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
>> module_param(sig_enforce, bool_enable_only, 0644);
>> +#ifdef CONFIG_MODULE_SIG_FORCE
>> +static int __init set_no_modsig_enforce(char *str)
>> +{
>> + sig_enforce = false;
>> + return 1;
>> +}
>> +__setup("no_modsig_enforce", set_no_modsig_enforce);
>> +#endif /* !CONFIG_MODULE_SIG_FORCE */
>>
>> /*
>> * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
>>
>
> Hi,
> Please document this cmdline option, probably in
> Documentation/admin-guide/kernel-parameters.txt.
>
> thanks.
>

Thanks for your information, I will submit a v2 patch.

Thanks and best,
Tianjia