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| author | Eric Snowberg <eric.snowberg@oracle.com> | 2022-01-26 05:58:28 +0300 |
|---|---|---|
| committer | Jarkko Sakkinen <jarkko@kernel.org> | 2022-03-08 14:55:52 +0300 |
| commit | d19967764ba876f5c82dabaa28f983b21eb642a2 (patch) | |
| tree | ebfe7a4f013e4bc28177ad7dc247071a05615def /security/integrity/digsig.c | |
| parent | e561752c317023c1f68df3950641747475fdcb29 (diff) | |
| download | linux-d19967764ba876f5c82dabaa28f983b21eb642a2.tar.xz | |
integrity: Introduce a Linux keyring called machine
Many UEFI Linux distributions boot using shim. The UEFI shim provides
what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure
Boot DB and MOK keys to validate the next step in the boot chain. The
MOK facility can be used to import user generated keys. These keys can
be used to sign an end-users development kernel build. When Linux
boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux
.platform keyring.
Define a new Linux keyring called machine. This keyring shall contain just
MOK keys and not the remaining keys in the platform keyring. This new
machine keyring will be used in follow on patches. Unlike keys in the
platform keyring, keys contained in the machine keyring will be trusted
within the kernel if the end-user has chosen to do so.
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Diffstat (limited to 'security/integrity/digsig.c')
| -rw-r--r-- | security/integrity/digsig.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c index 3b06a01bd0fd..2b7fa85613c0 100644 --- a/security/integrity/digsig.c +++ b/security/integrity/digsig.c @@ -30,6 +30,7 @@ static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = { ".ima", #endif ".platform", + ".machine", }; #ifdef CONFIG_IMA_KEYRINGS_PERMIT_SIGNED_BY_BUILTIN_OR_SECONDARY @@ -126,7 +127,8 @@ int __init integrity_init_keyring(const unsigned int id) perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH; - if (id == INTEGRITY_KEYRING_PLATFORM) { + if (id == INTEGRITY_KEYRING_PLATFORM || + id == INTEGRITY_KEYRING_MACHINE) { restriction = NULL; goto out; } @@ -139,7 +141,14 @@ int __init integrity_init_keyring(const unsigned int id) return -ENOMEM; restriction->check = restrict_link_to_ima; - perm |= KEY_USR_WRITE; + + /* + * MOK keys can only be added through a read-only runtime services + * UEFI variable during boot. No additional keys shall be allowed to + * load into the machine keyring following init from userspace. + */ + if (id != INTEGRITY_KEYRING_MACHINE) + perm |= KEY_USR_WRITE; out: return __integrity_init_keyring(id, perm, restriction); |