diff options
Diffstat (limited to 'crypto/asymmetric_keys/x509_public_key.c')
| -rw-r--r-- | crypto/asymmetric_keys/x509_public_key.c | 109 |
1 files changed, 108 insertions, 1 deletions
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 3fc8a0634ed7..a0f7cd196c9b 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -18,11 +18,80 @@ #include <linux/asn1_decoder.h> #include <keys/asymmetric-subtype.h> #include <keys/asymmetric-parser.h> +#include <keys/system_keyring.h> #include <crypto/hash.h> #include "asymmetric_keys.h" #include "public_key.h" #include "x509_parser.h" +static bool use_builtin_keys; +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' */ + else if (strcmp(str, "builtin") == 0) + use_builtin_keys = true; + + return 1; +} +__setup("ca_keys=", ca_keys_setup); +#endif + +/* + * Find a key in the given keyring by issuer and authority. + */ +static struct key *x509_request_asymmetric_key(struct key *keyring, + const char *signer, + size_t signer_len, + const char *authority, + size_t auth_len) +{ + key_ref_t key; + char *id; + + /* Construct an identifier. */ + id = kmalloc(signer_len + 2 + auth_len + 1, GFP_KERNEL); + if (!id) + return ERR_PTR(-ENOMEM); + + memcpy(id, signer, signer_len); + id[signer_len + 0] = ':'; + id[signer_len + 1] = ' '; + memcpy(id + signer_len + 2, authority, auth_len); + id[signer_len + 2 + auth_len] = 0; + + pr_debug("Look up: \"%s\"\n", id); + + key = keyring_search(make_key_ref(keyring, 1), + &key_type_asymmetric, id); + if (IS_ERR(key)) + pr_debug("Request for module key '%s' err %ld\n", + id, PTR_ERR(key)); + kfree(id); + + if (IS_ERR(key)) { + switch (PTR_ERR(key)) { + /* Hide some search errors */ + case -EACCES: + case -ENOTDIR: + case -EAGAIN: + return ERR_PTR(-ENOKEY); + default: + return ERR_CAST(key); + } + } + + pr_devel("<==%s() = 0 [%x]\n", __func__, + key_serial(key_ref_to_ptr(key))); + return key_ref_to_ptr(key); +} + /* * Set up the signature parameters in an X.509 certificate. This involves * digesting the signed data and extracting the signature. @@ -103,6 +172,40 @@ int x509_check_signature(const struct public_key *pub, EXPORT_SYMBOL_GPL(x509_check_signature); /* + * 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 + * new certificate as being trusted. + * + * Return 0 if the new certificate was successfully validated, 1 if we couldn't + * find a matching parent certificate in the trusted list and an error if there + * is a matching certificate but the signature check fails. + */ +static int x509_validate_trust(struct x509_certificate *cert, + struct key *trust_keyring) +{ + struct key *key; + int ret = 1; + + 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, + strlen(cert->authority)); + if (!IS_ERR(key)) { + if (!use_builtin_keys + || test_bit(KEY_FLAG_BUILTIN, &key->flags)) + ret = x509_check_signature(key->payload.data, cert); + key_put(key); + } + return ret; +} + +/* * Attempt to parse a data blob for a key as an X509 certificate. */ static int x509_key_preparse(struct key_preparsed_payload *prep) @@ -155,9 +258,13 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) /* Check the signature on the key if it appears to be self-signed */ if (!cert->authority || strcmp(cert->fingerprint, cert->authority) == 0) { - ret = x509_check_signature(cert->pub, cert); + ret = x509_check_signature(cert->pub, cert); /* self-signed */ if (ret < 0) goto error_free_cert; + } else if (!prep->trusted) { + ret = x509_validate_trust(cert, get_system_trusted_keyring()); + if (!ret) + prep->trusted = 1; } /* Propose a description */ |