Re: [PATCHv3 1/6] integrity: define '.evm' as a builtin 'trusted' keyring

[Petko Manolov]

On 15-10-22 21:49:25, Dmitry Kasatkin wrote:
> Require all keys added to the EVM keyring be signed by an
> existing trusted key on the system trusted keyring.
> 
> This patch also switches IMA to use integrity_init_keyring().
> 
> Changes in v3:
> * Added 'init_keyring' config based variable to skip initializing
>   keyring instead of using  __integrity_init_keyring() wrapper.
> * Added dependency back to CONFIG_IMA_TRUSTED_KEYRING
> 
> Changes in v2:
> * Replace CONFIG_EVM_TRUSTED_KEYRING with IMA and EVM common
>   CONFIG_INTEGRITY_TRUSTED_KEYRING configuration option
> * Deprecate CONFIG_IMA_TRUSTED_KEYRING but keep it for config
>   file compatibility. (Mimi Zohar)
> 
> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@xxxxxxxxxx>
> ---
>  security/integrity/Kconfig        | 11 +++++++++++
>  security/integrity/digsig.c       | 14 ++++++++++++--
>  security/integrity/evm/evm_main.c |  8 +++++---
>  security/integrity/ima/Kconfig    |  5 ++++-
>  security/integrity/ima/ima.h      | 12 ------------
>  security/integrity/ima/ima_init.c |  2 +-
>  security/integrity/integrity.h    |  5 ++---
>  7 files changed, 35 insertions(+), 22 deletions(-)
> 
> diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
> index 73c457b..21d7568 100644
> --- a/security/integrity/Kconfig
> +++ b/security/integrity/Kconfig
> @@ -41,6 +41,17 @@ config INTEGRITY_ASYMMETRIC_KEYS
>  	  This option enables digital signature verification using
>  	  asymmetric keys.
>  
> +config INTEGRITY_TRUSTED_KEYRING
> +	bool "Require all keys on the integrity keyrings be signed"
> +	depends on SYSTEM_TRUSTED_KEYRING
> +	depends on INTEGRITY_ASYMMETRIC_KEYS
> +	select KEYS_DEBUG_PROC_KEYS
> +	default y
> +	help
> +	   This option requires that all keys added to the .ima and
> +	   .evm keyrings be signed by a key on the system trusted
> +	   keyring.
> +
>  config INTEGRITY_AUDIT
>  	bool "Enables integrity auditing support "
>  	depends on AUDIT
> diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
> index 5be9ffb..8ef1511 100644
> --- a/security/integrity/digsig.c
> +++ b/security/integrity/digsig.c
> @@ -24,15 +24,22 @@
>  static struct key *keyring[INTEGRITY_KEYRING_MAX];
>  
>  static const char *keyring_name[INTEGRITY_KEYRING_MAX] = {
> +#ifndef CONFIG_INTEGRITY_TRUSTED_KEYRING
>  	"_evm",
> -	"_module",
> -#ifndef CONFIG_IMA_TRUSTED_KEYRING
>  	"_ima",
>  #else
> +	".evm",
>  	".ima",
>  #endif
> +	"_module",
>  };
>  
> +#ifdef CONFIG_INTEGRITY_TRUSTED_KEYRING
> +static bool init_keyring __initdata = true;
> +#else
> +static bool init_keyring __initdata;
> +#endif
> +
>  int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
>  			    const char *digest, int digestlen)
>  {
> @@ -68,6 +75,9 @@ int __init integrity_init_keyring(const unsigned int id)
>  	const struct cred *cred = current_cred();
>  	int err = 0;
>  
> +	if (!init_keyring)
> +		return 0;
> +
>  	keyring[id] = keyring_alloc(keyring_name[id], KUIDT_INIT(0),
>  				    KGIDT_INIT(0), cred,
>  				    ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
> diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
> index 1334e02..75b7e30 100644
> --- a/security/integrity/evm/evm_main.c
> +++ b/security/integrity/evm/evm_main.c
> @@ -478,15 +478,17 @@ static int __init init_evm(void)
>  
>  	evm_init_config();
>  
> +	error = integrity_init_keyring(INTEGRITY_KEYRING_EVM);
> +	if (error)
> +		return error;
> +
>  	error = evm_init_secfs();
>  	if (error < 0) {
>  		pr_info("Error registering secfs\n");
> -		goto err;
> +		return error;
>  	}
>  
>  	return 0;
> -err:
> -	return error;
>  }
>  
>  /*
> diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> index df30334..a292b88 100644
> --- a/security/integrity/ima/Kconfig
> +++ b/security/integrity/ima/Kconfig
> @@ -123,14 +123,17 @@ config IMA_APPRAISE
>  	  If unsure, say N.
>  
>  config IMA_TRUSTED_KEYRING
> -	bool "Require all keys on the .ima keyring be signed"
> +	bool "Require all keys on the .ima keyring be signed (deprecated)"
>  	depends on IMA_APPRAISE && SYSTEM_TRUSTED_KEYRING
>  	depends on INTEGRITY_ASYMMETRIC_KEYS
> +	select INTEGRITY_TRUSTED_KEYRING
>  	default y
>  	help
>  	   This option requires that all keys added to the .ima
>  	   keyring be signed by a key on the system trusted keyring.
>  
> +	   This option is deprecated in favor of INTEGRITY_TRUSTED_KEYRING
> +
>  config IMA_LOAD_X509
>  	bool "Load X509 certificate onto the '.ima' trusted keyring"
>  	depends on IMA_TRUSTED_KEYRING


I guess we may as well remove this switch.  Otherwise somebody have to remember 
to post a patch that does so a few kernel releases after this one goes mainline.


> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index e2a60c3..9e82367 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -251,16 +251,4 @@ static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
>  	return -EINVAL;
>  }
>  #endif /* CONFIG_IMA_LSM_RULES */
> -
> -#ifdef CONFIG_IMA_TRUSTED_KEYRING
> -static inline int ima_init_keyring(const unsigned int id)
> -{
> -	return integrity_init_keyring(id);
> -}
> -#else
> -static inline int ima_init_keyring(const unsigned int id)
> -{
> -	return 0;
> -}
> -#endif /* CONFIG_IMA_TRUSTED_KEYRING */
>  #endif
> diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
> index e600cad..bd79f25 100644
> --- a/security/integrity/ima/ima_init.c
> +++ b/security/integrity/ima/ima_init.c
> @@ -116,7 +116,7 @@ int __init ima_init(void)
>  	if (!ima_used_chip)
>  		pr_info("No TPM chip found, activating TPM-bypass!\n");
>  
> -	rc = ima_init_keyring(INTEGRITY_KEYRING_IMA);
> +	rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);
>  	if (rc)
>  		return rc;
>  
> diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
> index 9c61687..07726a7 100644
> --- a/security/integrity/integrity.h
> +++ b/security/integrity/integrity.h
> @@ -125,8 +125,8 @@ int integrity_kernel_read(struct file *file, loff_t offset,
>  int __init integrity_read_file(const char *path, char **data);
>  
>  #define INTEGRITY_KEYRING_EVM		0
> -#define INTEGRITY_KEYRING_MODULE	1
> -#define INTEGRITY_KEYRING_IMA		2
> +#define INTEGRITY_KEYRING_IMA		1
> +#define INTEGRITY_KEYRING_MODULE	2
>  #define INTEGRITY_KEYRING_MAX		3
>  
>  #ifdef CONFIG_INTEGRITY_SIGNATURE
> @@ -149,7 +149,6 @@ static inline int integrity_init_keyring(const unsigned int id)
>  {
>  	return 0;
>  }
> -
>  #endif /* CONFIG_INTEGRITY_SIGNATURE */
>  
>  #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS
> -- 
> 2.1.4

ACK to the rest of the code.



		Petko
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