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SubjectRe: [PATCH v1a 1/2] KEYS: validate certificate trust only with selected owner key
On 16/06/14 14:43, Mimi Zohar wrote:
> On Thu, 2014-06-12 at 23:17 +0300, Dmitry Kasatkin wrote:
>> 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 by a
>> particular key on the system keyring.
>>
>> This patch defines a new kernel parameter 'keys_ownerid' to specify
>> owner's key id which must be used for trust validation of certificates.
>>
>> Idea belongs to Mimi Zohar.
>>
>> Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
>> ---
>> Documentation/kernel-parameters.txt | 5 +++++
>> crypto/asymmetric_keys/x509_public_key.c | 23 +++++++++++++++++++++++
>> 2 files changed, 28 insertions(+)
>>
>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
>> index 7116fda..7a810d3 100644
>> --- a/Documentation/kernel-parameters.txt
>> +++ b/Documentation/kernel-parameters.txt
>> @@ -1434,6 +1434,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
>> use the HighMem zone if it exists, and the Normal
>> zone if it does not.
>>
>> + keys_ownerid=[KEYS] This parameter identifies a specific key(s) on
>> + the system trusted keyring to be used for certificate
>> + trust validation.
>> + format: id:<keyid>
>> +
>> kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
>> Format: <Controller#>[,poll interval]
>> The controller # is the number of the ehci usb debug
>> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
>> index 7a9b386..d46b790 100644
>> --- a/crypto/asymmetric_keys/x509_public_key.c
>> +++ b/crypto/asymmetric_keys/x509_public_key.c
>> @@ -24,6 +24,19 @@
>> #include "public_key.h"
>> #include "x509_parser.h"
>>
>> +static char *owner_keyid;
>> +static int __init default_owner_keyid_set(char *str)
>> +{
>> + if (!str) /* default system keyring */
>> + return 1;
>> +
>> + if (strncmp(str, "id:", 3) == 0)
>> + owner_keyid = str; /* owner local key 'id:xxxxxx' */
>> +
>> + return 1;
>> +}
>> +__setup("keys_ownerid=", default_owner_keyid_set);
>> +
>> /*
>> * Find a key in the given keyring by issuer and authority.
>> */
>> @@ -169,6 +182,16 @@ static int x509_validate_trust(struct x509_certificate *cert,
>> if (!trust_keyring)
>> return -EOPNOTSUPP;
>>
>> + if (owner_keyid) {
>> + /* validate trust only with the owner_keyid if specified */
>> + /* partial match of keyid according to the asymmetric_type.c */
>> + int idlen = strlen(owner_keyid) - 3; /* - id: */
>> + int authlen = strlen(cert->authority);
>> + char *auth = cert->authority + authlen - idlen;
>> + if (idlen > authlen || strcasecmp(owner_keyid + 3, auth))
>> + return -EPERM;
>> + }
>> +
> We shouldn't hard code the test here, but use the key type's match
> function. For example, the "KEYS: define an owner trusted keyring" (v4)
> patch defined a key_match() function.
>
> thanks,

Right.

I addressed this in the following patchset.

Thanks.


>
> Mimi
>
>> key = x509_request_asymmetric_key(trust_keyring,
>> cert->issuer, strlen(cert->issuer),
>> cert->authority,
>
>
>
> --
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