[RFC PATCH v4 05/14] X.509: Make certificate parser public

Aneesh Kumar K.V (Arm)
2026-04-27T06:52:03Z

From: Lukas Wunner <lukas@wunner.de>

The upcoming support for PCI device authentication with CMA-SPDM
(PCIe r6.1 sec 6.31) requires validating the Subject Alternative Name
in X.509 certificates.

High-level functions for X.509 parsing such as key_create_or_update()
throw away the internal, low-level struct x509_certificate after
extracting the struct public_key and public_key_signature from it.
The Subject Alternative Name is thus inaccessible when using those
functions.

Afford CMA-SPDM access to the Subject Alternative Name by making struct
x509_certificate public, together with the functions for parsing an
X.509 certificate into such a struct and freeing such a struct.

The private header file x509_parser.h previously included <linux/time.h>
for the definition of time64_t. That definition was since moved to
<linux/time64.h> by commit 361a3bf00582 ("time64: Add time64.h header
and define struct timespec64"), so adjust the #include directive as part
of the move to the new public header file <keys/x509-parser.h>.

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
crypto/asymmetric_keys/x509_parser.h | 42 +--------------------
include/keys/x509-parser.h | 55 ++++++++++++++++++++++++++++
2 files changed, 56 insertions(+), 41 deletions(-)
create mode 100644 include/keys/x509-parser.h

diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
index b7aeebdddb36..39f1521b773d 100644
--- a/crypto/asymmetric_keys/x509_parser.h
+++ b/crypto/asymmetric_keys/x509_parser.h
@@ -5,51 +5,11 @@
* Written by David Howells (dhowells@redhat.com)
*/

-#include <linux/cleanup.h>
-#include <linux/time.h>
-#include <crypto/public_key.h>
-#include <keys/asymmetric-type.h>
-#include <crypto/sha2.h>
-
-struct x509_certificate {
- struct x509_certificate *next;
- struct x509_certificate *signer; /* Certificate that signed this one */
- struct public_key *pub; /* Public key details */
- struct public_key_signature *sig; /* Signature parameters */
- u8 sha256[SHA256_DIGEST_SIZE]; /* Hash for blacklist purposes */
- char *issuer; /* Name of certificate issuer */
- char *subject; /* Name of certificate subject */
- struct asymmetric_key_id *id; /* Issuer + Serial number */
- struct asymmetric_key_id *skid; /* Subject + subjectKeyId (optional) */
- time64_t valid_from;
- time64_t valid_to;
- const void *tbs; /* Signed data */
- unsigned tbs_size; /* Size of signed data */
- unsigned raw_sig_size; /* Size of signature */
- const void *raw_sig; /* Signature data */
- const void *raw_serial; /* Raw serial number in ASN.1 */
- unsigned raw_serial_size;
- unsigned raw_issuer_size;
- const void *raw_issuer; /* Raw issuer name in ASN.1 */
- const void *raw_subject; /* Raw subject name in ASN.1 */
- unsigned raw_subject_size;
- unsigned raw_skid_size;
- const void *raw_skid; /* Raw subjectKeyId in ASN.1 */
- unsigned index;
- bool seen; /* Infinite recursion prevention */
- bool verified;
- bool self_signed; /* T if self-signed (check unsupported_sig too) */
- bool unsupported_sig; /* T if signature uses unsupported crypto */
- bool blacklisted;
-};
+#include <keys/x509-parser.h>

/*
* x509_cert_parser.c
*/
-extern void x509_free_certificate(struct x509_certificate *cert);
-DEFINE_FREE(x509_free_certificate, struct x509_certificate *,
- if (!IS_ERR(_T)) x509_free_certificate(_T))
-extern struct x509_certificate *x509_cert_parse(const void *data, size_t datalen);
extern int x509_decode_time(time64_t *_t, size_t hdrlen,
unsigned char tag,
const unsigned char *value, size_t vlen);
diff --git a/include/keys/x509-parser.h b/include/keys/x509-parser.h
new file mode 100644
index 000000000000..8b68e720693a
--- /dev/null
+++ b/include/keys/x509-parser.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* X.509 certificate parser
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#ifndef _KEYS_X509_PARSER_H
+#define _KEYS_X509_PARSER_H
+
+#include <linux/cleanup.h>
+#include <linux/time.h>
+#include <crypto/public_key.h>
+#include <keys/asymmetric-type.h>
+#include <crypto/sha2.h>
+
+struct x509_certificate {
+ struct x509_certificate *next;
+ struct x509_certificate *signer; /* Certificate that signed this one */
+ struct public_key *pub; /* Public key details */
+ struct public_key_signature *sig; /* Signature parameters */
+ u8 sha256[SHA256_DIGEST_SIZE]; /* Hash for blacklist purposes */
+ char *issuer; /* Name of certificate issuer */
+ char *subject; /* Name of certificate subject */
+ struct asymmetric_key_id *id; /* Issuer + Serial number */
+ struct asymmetric_key_id *skid; /* Subject + subjectKeyId (optional) */
+ time64_t valid_from;
+ time64_t valid_to;
+ const void *tbs; /* Signed data */
+ unsigned tbs_size; /* Size of signed data */
+ unsigned raw_sig_size; /* Size of signature */
+ const void *raw_sig; /* Signature data */
+ const void *raw_serial; /* Raw serial number in ASN.1 */
+ unsigned raw_serial_size;
+ unsigned raw_issuer_size;
+ const void *raw_issuer; /* Raw issuer name in ASN.1 */
+ const void *raw_subject; /* Raw subject name in ASN.1 */
+ unsigned raw_subject_size;
+ unsigned raw_skid_size;
+ const void *raw_skid; /* Raw subjectKeyId in ASN.1 */
+ unsigned index;
+ bool seen; /* Infinite recursion prevention */
+ bool verified;
+ bool self_signed; /* T if self-signed (check unsupported_sig too) */
+ bool unsupported_sig; /* T if signature uses unsupported crypto */
+ bool blacklisted;
+};
+
+struct x509_certificate *x509_cert_parse(const void *data, size_t datalen);
+void x509_free_certificate(struct x509_certificate *cert);
+
+DEFINE_FREE(x509_free_certificate, struct x509_certificate *,
+ if (!IS_ERR(_T)) x509_free_certificate(_T))
+
+#endif /* _KEYS_X509_PARSER_H */
--
2.43.0