From ffb70f61bab1482a3bd0f85fd8f1e9c9909df2ca Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Tue, 17 Jun 2014 11:56:58 +0300 Subject: [PATCH] KEYS: validate certificate trust only with selected key 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 'ca_keys' to identify the specific key which must be used for trust validation of certificates. Simplified Mimi's "KEYS: define an owner trusted keyring" patch. Changelog: - support for builtin x509 public keys only - export "asymmetric_keyid_match" - remove ifndefs MODULE - rename kernel boot parameter from keys_ownerid to ca_keys Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar --- Documentation/kernel-parameters.txt | 5 +++++ crypto/asymmetric_keys/asymmetric_type.c | 1 + crypto/asymmetric_keys/x509_public_key.c | 19 +++++++++++++++++++ 3 files changed, 25 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8b2ab54..bdb193a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -566,6 +566,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. possible to determine what the correct size should be. This option provides an override for these situations. + ca_keys= [KEYS] This parameter identifies a specific key(s) on + the system trusted keyring to be used for certificate + trust validation. + format: id: + ccw_timeout_log [S390] See Documentation/s390/CommonIO for details. diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index 1fd1d30..c948df5 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -49,6 +49,7 @@ int asymmetric_keyid_match(const char *kid, const char *id) return 1; } +EXPORT_SYMBOL_GPL(asymmetric_keyid_match); /* * Match asymmetric keys on (part of) their name diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 436fbd8..d376195 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -24,6 +24,22 @@ #include "public_key.h" #include "x509_parser.h" +static char *ca_keyid; + +#ifndef MODULE +static int __init ca_keys_setup(char *str) +{ + if (!str) /* default system keyring */ + return 1; + + if (strncmp(str, "id:", 3) == 0) + ca_keyid = str; /* owner key 'id:xxxxxx' */ + + return 1; +} +__setup("ca_keys=", ca_keys_setup); +#endif + /* * Find a key in the given keyring by issuer and authority. */ @@ -171,6 +187,9 @@ static int x509_validate_trust(struct x509_certificate *cert, if (!trust_keyring) return -EOPNOTSUPP; + if (ca_keyid && !asymmetric_keyid_match(cert->authority, ca_keyid)) + return -EPERM; + key = x509_request_asymmetric_key(trust_keyring, cert->issuer, strlen(cert->issuer), cert->authority, -- 2.7.4