2021-11-16 00:20:07

by Eric Snowberg

Subject: [PATCH v7 11/17] KEYS: Introduce link restriction for machine keys

Introduce a new link restriction that includes the trusted builtin,
secondary and machine keys. The restriction is based on the key to be
added being vouched for by a key in any of these three keyrings.

Suggested-by: Mimi Zohar <[email protected]>
Signed-off-by: Eric Snowberg <[email protected]>
---
v3: Initial version
v4: moved code under CONFIG_INTEGRITY_MOK_KEYRING
v5: Rename to machine keyring
v6: Change subject name (suggested by Mimi)
Rename restrict_link_by_builtin_secondary_and_ca_trusted
to restrict_link_by_builtin_secondary_and_machine (suggested by
Mimi)
v7: Unmodified from v6
---
certs/system_keyring.c | 23 +++++++++++++++++++++++
include/keys/system_keyring.h | 6 ++++++
2 files changed, 29 insertions(+)

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index bc7e44fc82c2..71a00add9805 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -99,6 +99,29 @@ void __init set_machine_trusted_keys(struct key *keyring)
{
machine_trusted_keys = keyring;
}
+
+/**
+ * restrict_link_by_builtin_secondary_and_machine
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in, the secondary, or
+ * the machine keyrings.
+ */
+int restrict_link_by_builtin_secondary_and_machine(
+ struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *restrict_key)
+{
+ if (machine_trusted_keys && type == &key_type_keyring &&
+ dest_keyring == secondary_trusted_keys &&
+ payload == &machine_trusted_keys->payload)
+ /* Allow the machine keyring to be added to the secondary */
+ return 0;
+
+ return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
+ payload, restrict_key);
+}
#endif

/*
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 98c9b10cdc17..2419a735420f 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -39,8 +39,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
#endif

#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
+extern int restrict_link_by_builtin_secondary_and_machine(
+ struct key *dest_keyring,
+ const struct key_type *type,
+ const union key_payload *payload,
+ struct key *restrict_key);
extern void __init set_machine_trusted_keys(struct key *keyring);
#else
+#define restrict_link_by_builtin_secondary_and_machine restrict_link_by_builtin_trusted
static inline void __init set_machine_trusted_keys(struct key *keyring)
{
}
--
2.18.4

2021-11-19 00:20:38

by Mimi Zohar

Subject: Re: [PATCH v7 11/17] KEYS: Introduce link restriction for machine keys

Hi Eric,

On Mon, 2021-11-15 at 19:15 -0500, Eric Snowberg wrote:
> Introduce a new link restriction that includes the trusted builtin,
> secondary and machine keys. The restriction is based on the key to be
> added being vouched for by a key in any of these three keyrings.
>
> Suggested-by: Mimi Zohar <[email protected]>
> Signed-off-by: Eric Snowberg <[email protected]>
> ---
> v3: Initial version
> v4: moved code under CONFIG_INTEGRITY_MOK_KEYRING
> v5: Rename to machine keyring
> v6: Change subject name (suggested by Mimi)
> Rename restrict_link_by_builtin_secondary_and_ca_trusted
> to restrict_link_by_builtin_secondary_and_machine (suggested by
> Mimi)
> v7: Unmodified from v6
> ---
> certs/system_keyring.c | 23 +++++++++++++++++++++++
> include/keys/system_keyring.h | 6 ++++++
> 2 files changed, 29 insertions(+)
>
> diff --git a/certs/system_keyring.c b/certs/system_keyring.c
> index bc7e44fc82c2..71a00add9805 100644
> --- a/certs/system_keyring.c
> +++ b/certs/system_keyring.c
> @@ -99,6 +99,29 @@ void __init set_machine_trusted_keys(struct key *keyring)
> {
> machine_trusted_keys = keyring;
> }
> +
> +/**

This begins the start of kernel doc.

> + * restrict_link_by_builtin_secondary_and_machine

Missing are the parameter defintions. Please refer to
Documentation/doc-guide/kernel-doc.rst for details.

Mimi

> + *
> + * Restrict the addition of keys into a keyring based on the key-to-be-added
> + * being vouched for by a key in either the built-in, the secondary, or
> + * the machine keyrings.
> + */
> +int restrict_link_by_builtin_secondary_and_machine(
> + struct key *dest_keyring,
> + const struct key_type *type,
> + const union key_payload *payload,
> + struct key *restrict_key)
> +{
> + if (machine_trusted_keys && type == &key_type_keyring &&
> + dest_keyring == secondary_trusted_keys &&
> + payload == &machine_trusted_keys->payload)
> + /* Allow the machine keyring to be added to the secondary */
> + return 0;
> +
> + return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
> + payload, restrict_key);
> +}
> #endif
>
> /*
> diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
> index 98c9b10cdc17..2419a735420f 100644
> --- a/include/keys/system_keyring.h
> +++ b/include/keys/system_keyring.h
> @@ -39,8 +39,14 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
> #endif
>
> #ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
> +extern int restrict_link_by_builtin_secondary_and_machine(
> + struct key *dest_keyring,
> + const struct key_type *type,
> + const union key_payload *payload,
> + struct key *restrict_key);
> extern void __init set_machine_trusted_keys(struct key *keyring);
> #else
> +#define restrict_link_by_builtin_secondary_and_machine restrict_link_by_builtin_trusted
> static inline void __init set_machine_trusted_keys(struct key *keyring)
> {
> }

2021-11-19 02:53:28

by Eric Snowberg

Subject: Re: [PATCH v7 11/17] KEYS: Introduce link restriction for machine keys

> On Nov 18, 2021, at 5:20 PM, Mimi Zohar <[email protected]> wrote:
>
> Hi Eric,
>
> On Mon, 2021-11-15 at 19:15 -0500, Eric Snowberg wrote:
>> Introduce a new link restriction that includes the trusted builtin,
>> secondary and machine keys. The restriction is based on the key to be
>> added being vouched for by a key in any of these three keyrings.
>>
>> Suggested-by: Mimi Zohar <[email protected]>
>> Signed-off-by: Eric Snowberg <[email protected]>
>> ---
>> v3: Initial version
>> v4: moved code under CONFIG_INTEGRITY_MOK_KEYRING
>> v5: Rename to machine keyring
>> v6: Change subject name (suggested by Mimi)
>> Rename restrict_link_by_builtin_secondary_and_ca_trusted
>> to restrict_link_by_builtin_secondary_and_machine (suggested by
>> Mimi)
>> v7: Unmodified from v6
>> ---
>> certs/system_keyring.c | 23 +++++++++++++++++++++++
>> include/keys/system_keyring.h | 6 ++++++
>> 2 files changed, 29 insertions(+)
>>
>> diff --git a/certs/system_keyring.c b/certs/system_keyring.c
>> index bc7e44fc82c2..71a00add9805 100644
>> --- a/certs/system_keyring.c
>> +++ b/certs/system_keyring.c
>> @@ -99,6 +99,29 @@ void __init set_machine_trusted_keys(struct key *keyring)
>> {
>> machine_trusted_keys = keyring;
>> }
>> +
>> +/**
>
> This begins the start of kernel doc.
>
>> + * restrict_link_by_builtin_secondary_and_machine
>
> Missing are the parameter defintions. Please refer to
> Documentation/doc-guide/kernel-doc.rst for details.

I’ll add this in the next round, thanks.