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-rw-r--r--crypto/asymmetric_keys/pkcs7_verify.c38
-rw-r--r--crypto/asymmetric_keys/x509_cert_parser.c10
-rw-r--r--crypto/asymmetric_keys/x509_parser.h7
-rw-r--r--crypto/asymmetric_keys/x509_public_key.c126
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 */
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-04 15:00:32 +0300