diff options
| -rw-r--r-- | crypto/asymmetric_keys/pkcs7_verify.c | 38 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/x509_cert_parser.c | 10 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/x509_parser.h | 7 | ||||
| -rw-r--r-- | crypto/asymmetric_keys/x509_public_key.c | 126 |
4 files changed, 110 insertions, 71 deletions
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index 1426f03e630b..44b746e9df1b 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -190,9 +190,8 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, x509->subject, x509->raw_serial_size, x509->raw_serial); x509->seen = true; - ret = x509_get_sig_params(x509); - if (ret < 0) - goto maybe_missing_crypto_in_x509; + if (x509->unsupported_key) + goto unsupported_crypto_in_x509; pr_debug("- issuer %s\n", x509->issuer); sig = x509->sig; @@ -203,22 +202,14 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, pr_debug("- authkeyid.skid %*phN\n", sig->auth_ids[1]->len, sig->auth_ids[1]->data); - if ((!x509->sig->auth_ids[0] && !x509->sig->auth_ids[1]) || - strcmp(x509->subject, x509->issuer) == 0) { + if (x509->self_signed) { /* If there's no authority certificate specified, then * the certificate must be self-signed and is the root * of the chain. Likewise if the cert is its own * authority. */ - pr_debug("- no auth?\n"); - if (x509->raw_subject_size != x509->raw_issuer_size || - memcmp(x509->raw_subject, x509->raw_issuer, - x509->raw_issuer_size) != 0) - return 0; - - ret = x509_check_signature(x509->pub, x509); - if (ret < 0) - goto maybe_missing_crypto_in_x509; + if (x509->unsupported_sig) + goto unsupported_crypto_in_x509; x509->signer = x509; pr_debug("- self-signed\n"); return 0; @@ -270,7 +261,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, sinfo->index); return 0; } - ret = x509_check_signature(p->pub, x509); + ret = public_key_verify_signature(p->pub, p->sig); if (ret < 0) return ret; x509->signer = p; @@ -282,16 +273,14 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, might_sleep(); } -maybe_missing_crypto_in_x509: +unsupported_crypto_in_x509: /* Just prune the certificate chain at this point if we lack some * crypto module to go further. Note, however, we don't want to set - * sinfo->missing_crypto as the signed info block may still be + * sinfo->unsupported_crypto as the signed info block may still be * validatable against an X.509 cert lower in the chain that we have a * trusted copy of. */ - if (ret == -ENOPKG) - return 0; - return ret; + return 0; } /* @@ -378,9 +367,8 @@ int pkcs7_verify(struct pkcs7_message *pkcs7, enum key_being_used_for usage) { struct pkcs7_signed_info *sinfo; - struct x509_certificate *x509; int enopkg = -ENOPKG; - int ret, n; + int ret; kenter(""); @@ -422,12 +410,6 @@ int pkcs7_verify(struct pkcs7_message *pkcs7, return -EINVAL; } - for (n = 0, x509 = pkcs7->certs; x509; x509 = x509->next, n++) { - ret = x509_get_sig_params(x509); - if (ret < 0) - return ret; - } - for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) { ret = pkcs7_verify_one(pkcs7, sinfo); if (ret < 0) { diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c index a2fefa713614..865f46ea724f 100644 --- a/crypto/asymmetric_keys/x509_cert_parser.c +++ b/crypto/asymmetric_keys/x509_cert_parser.c @@ -108,6 +108,11 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen) cert->pub->keylen = ctx->key_size; + /* Grab the signature bits */ + ret = x509_get_sig_params(cert); + if (ret < 0) + goto error_decode; + /* Generate cert issuer + serial number key ID */ kid = asymmetric_key_generate_id(cert->raw_serial, cert->raw_serial_size, @@ -119,6 +124,11 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen) } cert->id = kid; + /* Detect self-signed certificates */ + ret = x509_check_for_self_signed(cert); + if (ret < 0) + goto error_decode; + kfree(ctx); return cert; diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h index 26a4d83e4e6d..f24f4d808e7f 100644 --- a/crypto/asymmetric_keys/x509_parser.h +++ b/crypto/asymmetric_keys/x509_parser.h @@ -40,7 +40,9 @@ struct x509_certificate { bool seen; /* Infinite recursion prevention */ bool verified; bool trusted; - bool unsupported_crypto; /* T if can't be verified due to missing crypto */ + 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 */ }; /* @@ -56,5 +58,4 @@ extern int x509_decode_time(time64_t *_t, size_t hdrlen, * x509_public_key.c */ extern int x509_get_sig_params(struct x509_certificate *cert); -extern int x509_check_signature(const struct public_key *pub, - struct x509_certificate *cert); +extern int x509_check_for_self_signed(struct x509_certificate *cert); diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 4cd102de174c..752d8d5b48fa 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -161,10 +161,17 @@ int x509_get_sig_params(struct x509_certificate *cert) pr_devel("==>%s()\n", __func__); - if (cert->unsupported_crypto) - return -ENOPKG; - if (sig->s) + if (!cert->pub->pkey_algo) + cert->unsupported_key = true; + + if (!sig->pkey_algo) + cert->unsupported_sig = true; + + /* We check the hash if we can - even if we can't then verify it */ + if (!sig->hash_algo) { + cert->unsupported_sig = true; return 0; + } sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL); if (!sig->s) @@ -178,8 +185,8 @@ int x509_get_sig_params(struct x509_certificate *cert) tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); if (IS_ERR(tfm)) { if (PTR_ERR(tfm) == -ENOENT) { - cert->unsupported_crypto = true; - return -ENOPKG; + cert->unsupported_sig = true; + return 0; } return PTR_ERR(tfm); } @@ -212,29 +219,53 @@ error: pr_devel("<==%s() = %d\n", __func__, ret); return ret; } -EXPORT_SYMBOL_GPL(x509_get_sig_params); /* - * Check the signature on a certificate using the provided public key + * Check for self-signedness in an X.509 cert and if found, check the signature + * immediately if we can. */ -int x509_check_signature(const struct public_key *pub, - struct x509_certificate *cert) +int x509_check_for_self_signed(struct x509_certificate *cert) { - int ret; + int ret = 0; pr_devel("==>%s()\n", __func__); - ret = x509_get_sig_params(cert); - if (ret < 0) - return ret; + if (cert->sig->auth_ids[0] || cert->sig->auth_ids[1]) { + /* If the AKID is present it may have one or two parts. If + * both are supplied, both must match. + */ + bool a = asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]); + bool b = asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0]); + + if (!a && !b) + goto not_self_signed; + + ret = -EKEYREJECTED; + if (((a && !b) || (b && !a)) && + cert->sig->auth_ids[0] && cert->sig->auth_ids[1]) + goto out; + } + + ret = public_key_verify_signature(cert->pub, cert->sig); + if (ret < 0) { + if (ret == -ENOPKG) { + cert->unsupported_sig = true; + ret = 0; + } + goto out; + } + + pr_devel("Cert Self-signature verified"); + cert->self_signed = true; - ret = public_key_verify_signature(pub, cert->sig); - if (ret == -ENOPKG) - cert->unsupported_crypto = true; - pr_debug("Cert Verification: %d\n", ret); +out: + pr_devel("<==%s() = %d\n", __func__, ret); return ret; + +not_self_signed: + pr_devel("<==%s() = 0 [not]\n", __func__); + return 0; } -EXPORT_SYMBOL_GPL(x509_check_signature); /* * Check the new certificate against the ones in the trust keyring. If one of @@ -252,22 +283,30 @@ static int x509_validate_trust(struct x509_certificate *cert, struct key *key; int ret = 1; + if (!sig->auth_ids[0] && !sig->auth_ids[1]) + return 1; + if (!trust_keyring) return -EOPNOTSUPP; - if (ca_keyid && !asymmetric_key_id_partial(sig->auth_ids[1], ca_keyid)) return -EPERM; + if (cert->unsupported_sig) + return -ENOPKG; key = x509_request_asymmetric_key(trust_keyring, sig->auth_ids[0], sig->auth_ids[1], false); - if (!IS_ERR(key)) { - if (!use_builtin_keys - || test_bit(KEY_FLAG_BUILTIN, &key->flags)) - ret = x509_check_signature(key->payload.data[asym_crypto], - cert); - key_put(key); + if (IS_ERR(key)) + return PTR_ERR(key); + + if (!use_builtin_keys || + test_bit(KEY_FLAG_BUILTIN, &key->flags)) { + ret = public_key_verify_signature( + key->payload.data[asym_crypto], cert->sig); + if (ret == -ENOPKG) + cert->unsupported_sig = true; } + key_put(key); return ret; } @@ -290,34 +329,41 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) pr_devel("Cert Issuer: %s\n", cert->issuer); pr_devel("Cert Subject: %s\n", cert->subject); - if (!cert->pub->pkey_algo || - !cert->sig->pkey_algo || - !cert->sig->hash_algo) { + if (cert->unsupported_key) { ret = -ENOPKG; goto error_free_cert; } pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo); pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to); - pr_devel("Cert Signature: %s + %s\n", - cert->sig->pkey_algo, - cert->sig->hash_algo); cert->pub->id_type = "X509"; - /* Check the signature on the key if it appears to be self-signed */ - if ((!cert->sig->auth_ids[0] && !cert->sig->auth_ids[1]) || - asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]) || - asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0])) { - ret = x509_check_signature(cert->pub, cert); /* self-signed */ - if (ret < 0) - goto error_free_cert; - } else if (!prep->trusted) { + /* See if we can derive the trustability of this certificate. + * + * When it comes to self-signed certificates, we cannot evaluate + * trustedness except by the fact that we obtained it from a trusted + * location. So we just rely on x509_validate_trust() failing in this + * case. + * + * Note that there's a possibility of a self-signed cert matching a + * cert that we have (most likely a duplicate that we already trust) - + * in which case it will be marked trusted. + */ + if (cert->unsupported_sig || cert->self_signed) { + public_key_signature_free(cert->sig); + cert->sig = NULL; + } else { + pr_devel("Cert Signature: %s + %s\n", + cert->sig->pkey_algo, cert->sig->hash_algo); + ret = x509_validate_trust(cert, get_system_trusted_keyring()); if (ret) ret = x509_validate_trust(cert, get_ima_mok_keyring()); + if (ret == -EKEYREJECTED) + goto error_free_cert; if (!ret) - prep->trusted = 1; + prep->trusted = true; } /* Propose a description */ |