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Commit 32c4741c authored by Dmitry Kasatkin's avatar Dmitry Kasatkin Committed by Mimi Zohar
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KEYS: validate certificate trust only with builtin keys 



Instead of allowing public keys, with certificates signed by any
key on the system trusted keyring, to be added to a trusted keyring,
this patch further restricts the certificates to those signed only by
builtin keys on the system keyring.

This patch defines a new option 'builtin' for the kernel parameter
'keys_ownerid' to allow trust validation using builtin keys.

Simplified Mimi's "KEYS: define an owner trusted keyring" patch

Changelog v7:
- rename builtin_keys to use_builtin_keys

Signed-off-by: default avatarDmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
parent ffb70f61

Documentation/kernel-parameters.txt

+1 −1
Original line number Diff line number Diff line
@@ -569,7 +569,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
	ca_keys=	[KEYS] This parameter identifies a specific key(s) on

			the system trusted keyring to be used for certificate

			trust validation.

			format: id:<keyid>

			format: { id:<keyid> | builtin }



	ccw_timeout_log [S390]

			See Documentation/s390/CommonIO for details.

crypto/asymmetric_keys/x509_public_key.c

+6 −3
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include "public_key.h"

#include "x509_parser.h"



static bool use_builtin_keys;

static char *ca_keyid;



#ifndef MODULE
@@ -34,6 +35,8 @@ static int __init ca_keys_setup(char *str) 


	if (strncmp(str, "id:", 3) == 0)

		ca_keyid = str;	/* owner key 'id:xxxxxx' */

	else if (strcmp(str, "builtin") == 0)

		use_builtin_keys = true;



	return 1;

}
@@ -180,7 +183,6 @@ EXPORT_SYMBOL_GPL(x509_check_signature); 
static int x509_validate_trust(struct x509_certificate *cert,

			       struct key *trust_keyring)

{

	const struct public_key *pk;

	struct key *key;

	int ret = 1;
@@ -195,8 +197,9 @@ static int x509_validate_trust(struct x509_certificate *cert, 
					  cert->authority,

					  strlen(cert->authority));

	if (!IS_ERR(key))  {

		pk = key->payload.data;

		ret = x509_check_signature(pk, cert);

		if (!use_builtin_keys

		    || test_bit(KEY_FLAG_BUILTIN, &key->flags))

			ret = x509_check_signature(key->payload.data, cert);

		key_put(key);

	}

	return ret;

include/linux/key.h

+1 −0
Original line number Diff line number Diff line
@@ -170,6 +170,7 @@ struct key { 
#define KEY_FLAG_INVALIDATED	7	/* set if key has been invalidated */

#define KEY_FLAG_TRUSTED	8	/* set if key is trusted */

#define KEY_FLAG_TRUSTED_ONLY	9	/* set if keyring only accepts links to trusted keys */

#define KEY_FLAG_BUILTIN	10	/* set if key is builtin */



	/* the key type and key description string

	 * - the desc is used to match a key against search criteria

kernel/system_keyring.c

+1 −0
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ static __init int load_system_certificate_list(void) 
			pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",

			       PTR_ERR(key));

		} else {

			set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);

			pr_notice("Loaded X.509 cert '%s'\n",

				  key_ref_to_ptr(key)->description);

			key_ref_put(key);