diff options
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/asymmetric_keys/asymmetric_type.c | 102 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/pkcs7_parser.h | 1 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/pkcs7_verify.c | 32 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/restrict.c | 161 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/x509_parser.h | 1 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/x509_public_key.c | 15 |
6 files changed, 293 insertions, 19 deletions
diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index 6600181..e4b0ed3 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -17,6 +17,7 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/ctype.h> +#include <keys/system_keyring.h> #include "asymmetric_keys.h" MODULE_LICENSE("GPL"); @@ -451,15 +452,100 @@ static void asymmetric_key_destroy(struct key *key) asymmetric_key_free_kids(kids); } +static struct key_restriction *asymmetric_restriction_alloc( + key_restrict_link_func_t check, + struct key *key) +{ + struct key_restriction *keyres = + kzalloc(sizeof(struct key_restriction), GFP_KERNEL); + + if (!keyres) + return ERR_PTR(-ENOMEM); + + keyres->check = check; + keyres->key = key; + keyres->keytype = &key_type_asymmetric; + + return keyres; +} + +/* + * look up keyring restrict functions for asymmetric keys + */ +static struct key_restriction *asymmetric_lookup_restriction( + const char *restriction) +{ + char *restrict_method; + char *parse_buf; + char *next; + struct key_restriction *ret = ERR_PTR(-EINVAL); + + if (strcmp("builtin_trusted", restriction) == 0) + return asymmetric_restriction_alloc( + restrict_link_by_builtin_trusted, NULL); + + if (strcmp("builtin_and_secondary_trusted", restriction) == 0) + return asymmetric_restriction_alloc( + restrict_link_by_builtin_and_secondary_trusted, NULL); + + parse_buf = kstrndup(restriction, PAGE_SIZE, GFP_KERNEL); + if (!parse_buf) + return ERR_PTR(-ENOMEM); + + next = parse_buf; + restrict_method = strsep(&next, ":"); + + if ((strcmp(restrict_method, "key_or_keyring") == 0) && next) { + char *key_text; + key_serial_t serial; + struct key *key; + key_restrict_link_func_t link_fn = + restrict_link_by_key_or_keyring; + bool allow_null_key = false; + + key_text = strsep(&next, ":"); + + if (next) { + if (strcmp(next, "chain") != 0) + goto out; + + link_fn = restrict_link_by_key_or_keyring_chain; + allow_null_key = true; + } + + if (kstrtos32(key_text, 0, &serial) < 0) + goto out; + + if ((serial == 0) && allow_null_key) { + key = NULL; + } else { + key = key_lookup(serial); + if (IS_ERR(key)) { + ret = ERR_CAST(key); + goto out; + } + } + + ret = asymmetric_restriction_alloc(link_fn, key); + if (IS_ERR(ret)) + key_put(key); + } + +out: + kfree(parse_buf); + return ret; +} + struct key_type key_type_asymmetric = { - .name = "asymmetric", - .preparse = asymmetric_key_preparse, - .free_preparse = asymmetric_key_free_preparse, - .instantiate = generic_key_instantiate, - .match_preparse = asymmetric_key_match_preparse, - .match_free = asymmetric_key_match_free, - .destroy = asymmetric_key_destroy, - .describe = asymmetric_key_describe, + .name = "asymmetric", + .preparse = asymmetric_key_preparse, + .free_preparse = asymmetric_key_free_preparse, + .instantiate = generic_key_instantiate, + .match_preparse = asymmetric_key_match_preparse, + .match_free = asymmetric_key_match_free, + .destroy = asymmetric_key_destroy, + .describe = asymmetric_key_describe, + .lookup_restriction = asymmetric_lookup_restriction, }; EXPORT_SYMBOL_GPL(key_type_asymmetric); diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h index f4e8107..ac341e1 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.h +++ b/crypto/asymmetric_keys/pkcs7_parser.h @@ -23,6 +23,7 @@ struct pkcs7_signed_info { struct x509_certificate *signer; /* Signing certificate (in msg->certs) */ unsigned index; bool unsupported_crypto; /* T if not usable due to missing crypto */ + bool blacklisted; /* Message digest - the digest of the Content Data (or NULL) */ const void *msgdigest; diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index 2ffd697..2d93d9e 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -190,6 +190,18 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, x509->subject, x509->raw_serial_size, x509->raw_serial); x509->seen = true; + + if (x509->blacklisted) { + /* If this cert is blacklisted, then mark everything + * that depends on this as blacklisted too. + */ + sinfo->blacklisted = true; + for (p = sinfo->signer; p != x509; p = p->signer) + p->blacklisted = true; + pr_debug("- blacklisted\n"); + return 0; + } + if (x509->unsupported_key) goto unsupported_crypto_in_x509; @@ -357,17 +369,19 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, * * (*) -EBADMSG if some part of the message was invalid, or: * - * (*) -ENOPKG if none of the signature chains are verifiable because suitable - * crypto modules couldn't be found, or: + * (*) 0 if no signature chains were found to be blacklisted or to contain + * unsupported crypto, or: * - * (*) 0 if all the signature chains that don't incur -ENOPKG can be verified - * (note that a signature chain may be of zero length), or: + * (*) -EKEYREJECTED if a blacklisted key was encountered, or: + * + * (*) -ENOPKG if none of the signature chains are verifiable because suitable + * crypto modules couldn't be found. */ int pkcs7_verify(struct pkcs7_message *pkcs7, enum key_being_used_for usage) { struct pkcs7_signed_info *sinfo; - int enopkg = -ENOPKG; + int actual_ret = -ENOPKG; int ret; kenter(""); @@ -412,6 +426,8 @@ int pkcs7_verify(struct pkcs7_message *pkcs7, for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { ret = pkcs7_verify_one(pkcs7, sinfo); + if (sinfo->blacklisted && actual_ret == -ENOPKG) + actual_ret = -EKEYREJECTED; if (ret < 0) { if (ret == -ENOPKG) { sinfo->unsupported_crypto = true; @@ -420,11 +436,11 @@ int pkcs7_verify(struct pkcs7_message *pkcs7, kleave(" = %d", ret); return ret; } - enopkg = 0; + actual_ret = 0; } - kleave(" = %d", enopkg); - return enopkg; + kleave(" = %d", actual_ret); + return actual_ret; } EXPORT_SYMBOL_GPL(pkcs7_verify); diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c index 19d1afb9..86fb685 100644 --- a/crypto/asymmetric_keys/restrict.c +++ b/crypto/asymmetric_keys/restrict.c @@ -56,9 +56,10 @@ __setup("ca_keys=", ca_keys_setup); /** * restrict_link_by_signature - Restrict additions to a ring of public keys - * @trust_keyring: A ring of keys that can be used to vouch for the new cert. + * @dest_keyring: Keyring being linked to. * @type: The type of key being added. * @payload: The payload of the new key. + * @trust_keyring: A ring of keys that can be used to vouch for the new cert. * * Check the new certificate against the ones in the trust keyring. If one of * those is the signing key and validates the new certificate, then mark the @@ -69,9 +70,10 @@ __setup("ca_keys=", ca_keys_setup); * signature check fails or the key is blacklisted and some other error if * there is a matching certificate but the signature check cannot be performed. */ -int restrict_link_by_signature(struct key *trust_keyring, +int restrict_link_by_signature(struct key *dest_keyring, const struct key_type *type, - const union key_payload *payload) + const union key_payload *payload, + struct key *trust_keyring) { const struct public_key_signature *sig; struct key *key; @@ -106,3 +108,156 @@ int restrict_link_by_signature(struct key *trust_keyring, key_put(key); return ret; } + +static bool match_either_id(const struct asymmetric_key_ids *pair, + const struct asymmetric_key_id *single) +{ + return (asymmetric_key_id_same(pair->id[0], single) || + asymmetric_key_id_same(pair->id[1], single)); +} + +static int key_or_keyring_common(struct key *dest_keyring, + const struct key_type *type, + const union key_payload *payload, + struct key *trusted, bool check_dest) +{ + const struct public_key_signature *sig; + struct key *key = NULL; + int ret; + + pr_devel("==>%s()\n", __func__); + + if (!dest_keyring) + return -ENOKEY; + else if (dest_keyring->type != &key_type_keyring) + return -EOPNOTSUPP; + + if (!trusted && !check_dest) + return -ENOKEY; + + if (type != &key_type_asymmetric) + return -EOPNOTSUPP; + + sig = payload->data[asym_auth]; + if (!sig->auth_ids[0] && !sig->auth_ids[1]) + return -ENOKEY; + + if (trusted) { + if (trusted->type == &key_type_keyring) { + /* See if we have a key that signed this one. */ + key = find_asymmetric_key(trusted, sig->auth_ids[0], + sig->auth_ids[1], false); + if (IS_ERR(key)) + key = NULL; + } else if (trusted->type == &key_type_asymmetric) { + const struct asymmetric_key_ids *signer_ids; + + signer_ids = asymmetric_key_ids(trusted); + + /* + * The auth_ids come from the candidate key (the + * one that is being considered for addition to + * dest_keyring) and identify the key that was + * used to sign. + * + * The signer_ids are identifiers for the + * signing key specified for dest_keyring. + * + * The first auth_id is the preferred id, and + * the second is the fallback. If only one + * auth_id is present, it may match against + * either signer_id. If two auth_ids are + * present, the first auth_id must match one + * signer_id and the second auth_id must match + * the second signer_id. + */ + if (!sig->auth_ids[0] || !sig->auth_ids[1]) { + const struct asymmetric_key_id *auth_id; + + auth_id = sig->auth_ids[0] ?: sig->auth_ids[1]; + if (match_either_id(signer_ids, auth_id)) + key = __key_get(trusted); + + } else if (asymmetric_key_id_same(signer_ids->id[1], + sig->auth_ids[1]) && + match_either_id(signer_ids, + sig->auth_ids[0])) { + key = __key_get(trusted); + } + } else { + return -EOPNOTSUPP; + } + } + + if (check_dest && !key) { + /* See if the destination has a key that signed this one. */ + key = find_asymmetric_key(dest_keyring, sig->auth_ids[0], + sig->auth_ids[1], false); + if (IS_ERR(key)) + key = NULL; + } + + if (!key) + return -ENOKEY; + + ret = key_validate(key); + if (ret == 0) + ret = verify_signature(key, sig); + + key_put(key); + return ret; +} + +/** + * restrict_link_by_key_or_keyring - Restrict additions to a ring of public + * keys using the restrict_key information stored in the ring. + * @dest_keyring: Keyring being linked to. + * @type: The type of key being added. + * @payload: The payload of the new key. + * @trusted: A key or ring of keys that can be used to vouch for the new cert. + * + * Check the new certificate only against the key or keys passed in the data + * parameter. If one of those is the signing key and validates the new + * certificate, then mark the new certificate as being ok to link. + * + * Returns 0 if the new certificate was accepted, -ENOKEY if we + * couldn't find a matching parent certificate in the trusted list, + * -EKEYREJECTED if the signature check fails, and some other error if + * there is a matching certificate but the signature check cannot be + * performed. + */ +int restrict_link_by_key_or_keyring(struct key *dest_keyring, + const struct key_type *type, + const union key_payload *payload, + struct key *trusted) +{ + return key_or_keyring_common(dest_keyring, type, payload, trusted, + false); +} + +/** + * restrict_link_by_key_or_keyring_chain - Restrict additions to a ring of + * public keys using the restrict_key information stored in the ring. + * @dest_keyring: Keyring being linked to. + * @type: The type of key being added. + * @payload: The payload of the new key. + * @trusted: A key or ring of keys that can be used to vouch for the new cert. + * + * Check the new certificate only against the key or keys passed in the data + * parameter. If one of those is the signing key and validates the new + * certificate, then mark the new certificate as being ok to link. + * + * Returns 0 if the new certificate was accepted, -ENOKEY if we + * couldn't find a matching parent certificate in the trusted list, + * -EKEYREJECTED if the signature check fails, and some other error if + * there is a matching certificate but the signature check cannot be + * performed. + */ +int restrict_link_by_key_or_keyring_chain(struct key *dest_keyring, + const struct key_type *type, + const union key_payload *payload, + struct key *trusted) +{ + return key_or_keyring_common(dest_keyring, type, payload, trusted, + true); +} diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h index 05eef1c..e373e74 100644 --- a/crypto/asymmetric_keys/x509_parser.h +++ b/crypto/asymmetric_keys/x509_parser.h @@ -42,6 +42,7 @@ struct x509_certificate { bool self_signed; /* T if self-signed (check unsupported_sig too) */ bool unsupported_key; /* T if key uses unsupported crypto */ bool unsupported_sig; /* T if signature uses unsupported crypto */ + bool blacklisted; }; /* diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index fb73229..eea71dc 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -84,6 +84,16 @@ int x509_get_sig_params(struct x509_certificate *cert) goto error_2; might_sleep(); ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, sig->digest); + if (ret < 0) + goto error_2; + + ret = is_hash_blacklisted(sig->digest, sig->digest_size, "tbs"); + if (ret == -EKEYREJECTED) { + pr_err("Cert %*phN is blacklisted\n", + sig->digest_size, sig->digest); + cert->blacklisted = true; + ret = 0; + } error_2: kfree(desc); @@ -186,6 +196,11 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) cert->sig->pkey_algo, cert->sig->hash_algo); } + /* Don't permit addition of blacklisted keys */ + ret = -EKEYREJECTED; + if (cert->blacklisted) + goto error_free_cert; + /* Propose a description */ sulen = strlen(cert->subject); if (cert->raw_skid) { |
