1 files changed, 456 insertions, 174 deletions

diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index facbf26bc6bb..b37cae914987 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -1,39 +1,41 @@
+// 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)
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
  */
 
 #define pr_fmt(fmt) "X.509: "fmt
 #include <linux/kernel.h>
+#include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/oid_registry.h>
-#include "public_key.h"
+#include <crypto/public_key.h>
 #include "x509_parser.h"
-#include "x509-asn1.h"
-#include "x509_rsakey-asn1.h"
+#include "x509.asn1.h"
+#include "x509_akid.asn1.h"
 
 struct x509_parse_context {
 	struct x509_certificate	*cert;		/* Certificate being constructed */
 	unsigned long	data;			/* Start of data */
-	const void	*cert_start;		/* Start of cert content */
 	const void	*key;			/* Key data */
 	size_t		key_size;		/* Size of key data */
+	const void	*params;		/* Key parameters */
+	size_t		params_size;		/* Size of key parameters */
+	enum OID	key_algo;		/* Algorithm used by the cert's key */
 	enum OID	last_oid;		/* Last OID encountered */
-	enum OID	algo_oid;		/* Algorithm OID */
-	unsigned char	nr_mpi;			/* Number of MPIs stored */
+	enum OID	sig_algo;		/* Algorithm used to sign the cert */
 	u8		o_size;			/* Size of organizationName (O) */
 	u8		cn_size;		/* Size of commonName (CN) */
 	u8		email_size;		/* Size of emailAddress */
 	u16		o_offset;		/* Offset of organizationName (O) */
 	u16		cn_offset;		/* Offset of commonName (CN) */
 	u16		email_offset;		/* Offset of emailAddress */
+	unsigned	raw_akid_size;
+	const void	*raw_akid;		/* Raw authorityKeyId in ASN.1 */
+	const void	*akid_raw_issuer;	/* Raw directoryName in authorityKeyId */
+	unsigned	akid_raw_issuer_size;
 };
 
 /*
@@ -42,34 +44,39 @@ struct x509_parse_context {
 void x509_free_certificate(struct x509_certificate *cert)
 {
 	if (cert) {
-		public_key_destroy(cert->pub);
+		public_key_free(cert->pub);
+		public_key_signature_free(cert->sig);
 		kfree(cert->issuer);
 		kfree(cert->subject);
-		kfree(cert->fingerprint);
-		kfree(cert->authority);
+		kfree(cert->id);
+		kfree(cert->skid);
 		kfree(cert);
 	}
 }
+EXPORT_SYMBOL_GPL(x509_free_certificate);
 
 /*
  * Parse an X.509 certificate
  */
 struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 {
-	struct x509_certificate *cert;
-	struct x509_parse_context *ctx;
+	struct x509_certificate *cert __free(x509_free_certificate) = NULL;
+	struct x509_parse_context *ctx __free(kfree) = NULL;
+	struct asymmetric_key_id *kid;
 	long ret;
 
-	ret = -ENOMEM;
 	cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
 	if (!cert)
-		goto error_no_cert;
+		return ERR_PTR(-ENOMEM);
 	cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
 	if (!cert->pub)
-		goto error_no_ctx;
+		return ERR_PTR(-ENOMEM);
+	cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL);
+	if (!cert->sig)
+		return ERR_PTR(-ENOMEM);
 	ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
 	if (!ctx)
-		goto error_no_ctx;
+		return ERR_PTR(-ENOMEM);
 
 	ctx->cert = cert;
 	ctx->data = (unsigned long)data;
@@ -77,24 +84,55 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 	/* Attempt to decode the certificate */
 	ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
 	if (ret < 0)
-		goto error_decode;
+		return ERR_PTR(ret);
+
+	/* Decode the AuthorityKeyIdentifier */
+	if (ctx->raw_akid) {
+		pr_devel("AKID: %u %*phN\n",
+			 ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid);
+		ret = asn1_ber_decoder(&x509_akid_decoder, ctx,
+				       ctx->raw_akid, ctx->raw_akid_size);
+		if (ret < 0) {
+			pr_warn("Couldn't decode AuthKeyIdentifier\n");
+			return ERR_PTR(ret);
+		}
+	}
 
-	/* Decode the public key */
-	ret = asn1_ber_decoder(&x509_rsakey_decoder, ctx,
-			       ctx->key, ctx->key_size);
-	if (ret < 0)
-		goto error_decode;
+	cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL);
+	if (!cert->pub->key)
+		return ERR_PTR(-ENOMEM);
+
+	cert->pub->keylen = ctx->key_size;
 
-	kfree(ctx);
-	return cert;
+	cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL);
+	if (!cert->pub->params)
+		return ERR_PTR(-ENOMEM);
 
-error_decode:
-	kfree(ctx);
-error_no_ctx:
-	x509_free_certificate(cert);
-error_no_cert:
-	return ERR_PTR(ret);
+	cert->pub->paramlen = ctx->params_size;
+	cert->pub->algo = ctx->key_algo;
+
+	/* Grab the signature bits */
+	ret = x509_get_sig_params(cert);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	/* Generate cert issuer + serial number key ID */
+	kid = asymmetric_key_generate_id(cert->raw_serial,
+					 cert->raw_serial_size,
+					 cert->raw_issuer,
+					 cert->raw_issuer_size);
+	if (IS_ERR(kid))
+		return ERR_CAST(kid);
+	cert->id = kid;
+
+	/* Detect self-signed certificates */
+	ret = x509_check_for_self_signed(cert);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	return_ptr(cert);
 }
+EXPORT_SYMBOL_GPL(x509_cert_parse);
 
 /*
  * Note an OID when we find one for later processing when we know how
@@ -135,54 +173,106 @@ int x509_note_tbs_certificate(void *context, size_t hdrlen,
 }
 
 /*
- * Record the public key algorithm
+ * Record the algorithm that was used to sign this certificate.
  */
-int x509_note_pkey_algo(void *context, size_t hdrlen,
-			unsigned char tag,
-			const void *value, size_t vlen)
+int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag,
+		       const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
 
 	pr_debug("PubKey Algo: %u\n", ctx->last_oid);
 
 	switch (ctx->last_oid) {
-	case OID_md2WithRSAEncryption:
-	case OID_md3WithRSAEncryption:
 	default:
 		return -ENOPKG; /* Unsupported combination */
 
-	case OID_md4WithRSAEncryption:
-		ctx->cert->sig_hash_algo = PKEY_HASH_MD5;
-		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
-		break;
-
 	case OID_sha1WithRSAEncryption:
-		ctx->cert->sig_hash_algo = PKEY_HASH_SHA1;
-		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
-		break;
+		ctx->cert->sig->hash_algo = "sha1";
+		goto rsa_pkcs1;
 
 	case OID_sha256WithRSAEncryption:
-		ctx->cert->sig_hash_algo = PKEY_HASH_SHA256;
-		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
-		break;
+		ctx->cert->sig->hash_algo = "sha256";
+		goto rsa_pkcs1;
 
 	case OID_sha384WithRSAEncryption:
-		ctx->cert->sig_hash_algo = PKEY_HASH_SHA384;
-		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
-		break;
+		ctx->cert->sig->hash_algo = "sha384";
+		goto rsa_pkcs1;
 
 	case OID_sha512WithRSAEncryption:
-		ctx->cert->sig_hash_algo = PKEY_HASH_SHA512;
-		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
-		break;
+		ctx->cert->sig->hash_algo = "sha512";
+		goto rsa_pkcs1;
 
 	case OID_sha224WithRSAEncryption:
-		ctx->cert->sig_hash_algo = PKEY_HASH_SHA224;
-		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
-		break;
+		ctx->cert->sig->hash_algo = "sha224";
+		goto rsa_pkcs1;
+
+	case OID_id_ecdsa_with_sha1:
+		ctx->cert->sig->hash_algo = "sha1";
+		goto ecdsa;
+
+	case OID_id_rsassa_pkcs1_v1_5_with_sha3_256:
+		ctx->cert->sig->hash_algo = "sha3-256";
+		goto rsa_pkcs1;
+
+	case OID_id_rsassa_pkcs1_v1_5_with_sha3_384:
+		ctx->cert->sig->hash_algo = "sha3-384";
+		goto rsa_pkcs1;
+
+	case OID_id_rsassa_pkcs1_v1_5_with_sha3_512:
+		ctx->cert->sig->hash_algo = "sha3-512";
+		goto rsa_pkcs1;
+
+	case OID_id_ecdsa_with_sha224:
+		ctx->cert->sig->hash_algo = "sha224";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha256:
+		ctx->cert->sig->hash_algo = "sha256";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha384:
+		ctx->cert->sig->hash_algo = "sha384";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha512:
+		ctx->cert->sig->hash_algo = "sha512";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha3_256:
+		ctx->cert->sig->hash_algo = "sha3-256";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha3_384:
+		ctx->cert->sig->hash_algo = "sha3-384";
+		goto ecdsa;
+
+	case OID_id_ecdsa_with_sha3_512:
+		ctx->cert->sig->hash_algo = "sha3-512";
+		goto ecdsa;
+
+	case OID_gost2012Signature256:
+		ctx->cert->sig->hash_algo = "streebog256";
+		goto ecrdsa;
+
+	case OID_gost2012Signature512:
+		ctx->cert->sig->hash_algo = "streebog512";
+		goto ecrdsa;
 	}
 
-	ctx->algo_oid = ctx->last_oid;
+rsa_pkcs1:
+	ctx->cert->sig->pkey_algo = "rsa";
+	ctx->cert->sig->encoding = "pkcs1";
+	ctx->sig_algo = ctx->last_oid;
+	return 0;
+ecrdsa:
+	ctx->cert->sig->pkey_algo = "ecrdsa";
+	ctx->cert->sig->encoding = "raw";
+	ctx->sig_algo = ctx->last_oid;
+	return 0;
+ecdsa:
+	ctx->cert->sig->pkey_algo = "ecdsa";
+	ctx->cert->sig->encoding = "x962";
+	ctx->sig_algo = ctx->last_oid;
 	return 0;
 }
 
@@ -195,16 +285,45 @@ int x509_note_signature(void *context, size_t hdrlen,
 {
 	struct x509_parse_context *ctx = context;
 
-	pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen);
+	pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen);
 
-	if (ctx->last_oid != ctx->algo_oid) {
-		pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n",
-			ctx->algo_oid, ctx->last_oid);
+	/*
+	 * In X.509 certificates, the signature's algorithm is stored in two
+	 * places: inside the TBSCertificate (the data that is signed), and
+	 * alongside the signature.  These *must* match.
+	 */
+	if (ctx->last_oid != ctx->sig_algo) {
+		pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n",
+			ctx->last_oid, ctx->sig_algo);
 		return -EINVAL;
 	}
 
-	ctx->cert->sig = value;
-	ctx->cert->sig_size = vlen;
+	if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 ||
+	    strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 ||
+	    strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0) {
+		/* Discard the BIT STRING metadata */
+		if (vlen < 1 || *(const u8 *)value != 0)
+			return -EBADMSG;
+
+		value++;
+		vlen--;
+	}
+
+	ctx->cert->raw_sig = value;
+	ctx->cert->raw_sig_size = vlen;
+	return 0;
+}
+
+/*
+ * Note the certificate serial number
+ */
+int x509_note_serial(void *context, size_t hdrlen,
+		     unsigned char tag,
+		     const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	ctx->cert->raw_serial = value;
+	ctx->cert->raw_serial_size = vlen;
 	return 0;
 }
 
@@ -253,10 +372,9 @@ static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
 
 	/* Empty name string if no material */
 	if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
-		buffer = kmalloc(1, GFP_KERNEL);
+		buffer = kzalloc(1, GFP_KERNEL);
 		if (!buffer)
 			return -ENOMEM;
-		buffer[0] = 0;
 		goto done;
 	}
 
@@ -320,6 +438,18 @@ int x509_note_issuer(void *context, size_t hdrlen,
 		     const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
+	struct asymmetric_key_id *kid;
+
+	ctx->cert->raw_issuer = value;
+	ctx->cert->raw_issuer_size = vlen;
+
+	if (!ctx->cert->sig->auth_ids[2]) {
+		kid = asymmetric_key_generate_id(value, vlen, "", 0);
+		if (IS_ERR(kid))
+			return PTR_ERR(kid);
+		ctx->cert->sig->auth_ids[2] = kid;
+	}
+
 	return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
 }
 
@@ -328,48 +458,81 @@ int x509_note_subject(void *context, size_t hdrlen,
 		      const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
+	ctx->cert->raw_subject = value;
+	ctx->cert->raw_subject_size = vlen;
 	return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
 }
 
 /*
- * Extract the data for the public key algorithm
+ * Extract the parameters for the public key
  */
-int x509_extract_key_data(void *context, size_t hdrlen,
-			  unsigned char tag,
-			  const void *value, size_t vlen)
+int x509_note_params(void *context, size_t hdrlen,
+		     unsigned char tag,
+		     const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
 
-	if (ctx->last_oid != OID_rsaEncryption)
-		return -ENOPKG;
-
-	/* There seems to be an extraneous 0 byte on the front of the data */
-	ctx->cert->pkey_algo = PKEY_ALGO_RSA;
-	ctx->key = value + 1;
-	ctx->key_size = vlen - 1;
+	/*
+	 * AlgorithmIdentifier is used three times in the x509, we should skip
+	 * first and ignore third, using second one which is after subject and
+	 * before subjectPublicKey.
+	 */
+	if (!ctx->cert->raw_subject || ctx->key)
+		return 0;
+	ctx->params = value - hdrlen;
+	ctx->params_size = vlen + hdrlen;
 	return 0;
 }
 
 /*
- * Extract a RSA public key value
+ * Extract the data for the public key algorithm
  */
-int rsa_extract_mpi(void *context, size_t hdrlen,
-		    unsigned char tag,
-		    const void *value, size_t vlen)
+int x509_extract_key_data(void *context, size_t hdrlen,
+			  unsigned char tag,
+			  const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
-	MPI mpi;
+	enum OID oid;
 
-	if (ctx->nr_mpi >= ARRAY_SIZE(ctx->cert->pub->mpi)) {
-		pr_err("Too many public key MPIs in certificate\n");
-		return -EBADMSG;
-	}
+	ctx->key_algo = ctx->last_oid;
+	switch (ctx->last_oid) {
+	case OID_rsaEncryption:
+		ctx->cert->pub->pkey_algo = "rsa";
+		break;
+	case OID_gost2012PKey256:
+	case OID_gost2012PKey512:
+		ctx->cert->pub->pkey_algo = "ecrdsa";
+		break;
+	case OID_id_ecPublicKey:
+		if (parse_OID(ctx->params, ctx->params_size, &oid) != 0)
+			return -EBADMSG;
 
-	mpi = mpi_read_raw_data(value, vlen);
-	if (!mpi)
-		return -ENOMEM;
+		switch (oid) {
+		case OID_id_prime192v1:
+			ctx->cert->pub->pkey_algo = "ecdsa-nist-p192";
+			break;
+		case OID_id_prime256v1:
+			ctx->cert->pub->pkey_algo = "ecdsa-nist-p256";
+			break;
+		case OID_id_ansip384r1:
+			ctx->cert->pub->pkey_algo = "ecdsa-nist-p384";
+			break;
+		case OID_id_ansip521r1:
+			ctx->cert->pub->pkey_algo = "ecdsa-nist-p521";
+			break;
+		default:
+			return -ENOPKG;
+		}
+		break;
+	default:
+		return -ENOPKG;
+	}
 
-	ctx->cert->pub->mpi[ctx->nr_mpi++] = mpi;
+	/* Discard the BIT STRING metadata */
+	if (vlen < 1 || *(const u8 *)value != 0)
+		return -EBADMSG;
+	ctx->key = value + 1;
+	ctx->key_size = vlen - 1;
 	return 0;
 }
 
@@ -384,146 +547,199 @@ int x509_process_extension(void *context, size_t hdrlen,
 			   const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
+	struct asymmetric_key_id *kid;
 	const unsigned char *v = value;
-	char *f;
-	int i;
 
 	pr_debug("Extension: %u\n", ctx->last_oid);
 
 	if (ctx->last_oid == OID_subjectKeyIdentifier) {
 		/* Get hold of the key fingerprint */
-		if (vlen < 3)
+		if (ctx->cert->skid || vlen < 3)
 			return -EBADMSG;
 		if (v[0] != ASN1_OTS || v[1] != vlen - 2)
 			return -EBADMSG;
 		v += 2;
 		vlen -= 2;
 
-		f = kmalloc(vlen * 2 + 1, GFP_KERNEL);
-		if (!f)
-			return -ENOMEM;
-		for (i = 0; i < vlen; i++)
-			sprintf(f + i * 2, "%02x", v[i]);
-		pr_debug("fingerprint %s\n", f);
-		ctx->cert->fingerprint = f;
+		ctx->cert->raw_skid_size = vlen;
+		ctx->cert->raw_skid = v;
+		kid = asymmetric_key_generate_id(v, vlen, "", 0);
+		if (IS_ERR(kid))
+			return PTR_ERR(kid);
+		ctx->cert->skid = kid;
+		pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
 		return 0;
 	}
 
-	if (ctx->last_oid == OID_authorityKeyIdentifier) {
-		size_t key_len;
-
-		/* Get hold of the CA key fingerprint */
-		if (vlen < 5)
+	if (ctx->last_oid == OID_keyUsage) {
+		/*
+		 * Get hold of the keyUsage bit string
+		 * v[1] is the encoding size
+		 *       (Expect either 0x02 or 0x03, making it 1 or 2 bytes)
+		 * v[2] is the number of unused bits in the bit string
+		 *       (If >= 3 keyCertSign is missing when v[1] = 0x02)
+		 * v[3] and possibly v[4] contain the bit string
+		 *
+		 * From RFC 5280 4.2.1.3:
+		 *   0x04 is where keyCertSign lands in this bit string
+		 *   0x80 is where digitalSignature lands in this bit string
+		 */
+		if (v[0] != ASN1_BTS)
 			return -EBADMSG;
-
-		/* Authority Key Identifier must be a Constructed SEQUENCE */
-		if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5)))
+		if (vlen < 4)
 			return -EBADMSG;
-
-		/* Authority Key Identifier is not indefinite length */
-		if (unlikely(vlen == ASN1_INDEFINITE_LENGTH))
+		if (v[2] >= 8)
 			return -EBADMSG;
+		if (v[3] & 0x80)
+			ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_DIGITALSIG;
+		if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04))
+			ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
+		else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04))
+			ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN;
+		return 0;
+	}
 
-		if (vlen < ASN1_INDEFINITE_LENGTH) {
-			/* Short Form length */
-			if (v[1] != vlen - 2 ||
-			    v[2] != SEQ_TAG_KEYID ||
-			    v[3] > vlen - 4)
-				return -EBADMSG;
-
-			key_len = v[3];
-			v += 4;
-		} else {
-			/* Long Form length */
-			size_t seq_len = 0;
-			size_t sub = v[1] - ASN1_INDEFINITE_LENGTH;
-
-			if (sub > 2)
-				return -EBADMSG;
-
-			/* calculate the length from subsequent octets */
-			v += 2;
-			for (i = 0; i < sub; i++) {
-				seq_len <<= 8;
-				seq_len |= v[i];
-			}
-
-			if (seq_len != vlen - 2 - sub ||
-			    v[sub] != SEQ_TAG_KEYID ||
-			    v[sub + 1] > vlen - 4 - sub)
-				return -EBADMSG;
-
-			key_len = v[sub + 1];
-			v += (sub + 2);
-		}
+	if (ctx->last_oid == OID_authorityKeyIdentifier) {
+		/* Get hold of the CA key fingerprint */
+		ctx->raw_akid = v;
+		ctx->raw_akid_size = vlen;
+		return 0;
+	}
 
-		f = kmalloc(key_len * 2 + 1, GFP_KERNEL);
-		if (!f)
-			return -ENOMEM;
-		for (i = 0; i < key_len; i++)
-			sprintf(f + i * 2, "%02x", v[i]);
-		pr_debug("authority   %s\n", f);
-		ctx->cert->authority = f;
+	if (ctx->last_oid == OID_basicConstraints) {
+		/*
+		 * Get hold of the basicConstraints
+		 * v[1] is the encoding size
+		 *	(Expect 0x00 for empty SEQUENCE with CA:FALSE, or
+		 *	0x03 or greater for non-empty SEQUENCE)
+		 * v[2] is the encoding type
+		 *	(Expect an ASN1_BOOL for the CA)
+		 * v[3] is the length of the ASN1_BOOL
+		 *	(Expect 1 for a single byte boolean)
+		 * v[4] is the contents of the ASN1_BOOL
+		 *	(Expect 0xFF if the CA is TRUE)
+		 * vlen should match the entire extension size
+		 */
+		if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ))
+			return -EBADMSG;
+		if (vlen < 2)
+			return -EBADMSG;
+		if (v[1] != vlen - 2)
+			return -EBADMSG;
+		/* Empty SEQUENCE means CA:FALSE (default value omitted per DER) */
+		if (v[1] == 0)
+			return 0;
+		if (vlen >= 5 && v[2] == ASN1_BOOL && v[3] == 1 && v[4] == 0xFF)
+			ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA;
+		else
+			return -EBADMSG;
 		return 0;
 	}
 
 	return 0;
 }
 
-/*
- * Record a certificate time.
+/**
+ * x509_decode_time - Decode an X.509 time ASN.1 object
+ * @_t: The time to fill in
+ * @hdrlen: The length of the object header
+ * @tag: The object tag
+ * @value: The object value
+ * @vlen: The size of the object value
+ *
+ * Decode an ASN.1 universal time or generalised time field into a struct the
+ * kernel can handle and check it for validity.  The time is decoded thus:
+ *
+ *	[RFC5280 §4.1.2.5]
+ *	CAs conforming to this profile MUST always encode certificate validity
+ *	dates through the year 2049 as UTCTime; certificate validity dates in
+ *	2050 or later MUST be encoded as GeneralizedTime.  Conforming
+ *	applications MUST be able to process validity dates that are encoded in
+ *	either UTCTime or GeneralizedTime.
  */
-static int x509_note_time(struct tm *tm,  size_t hdrlen,
-			  unsigned char tag,
-			  const unsigned char *value, size_t vlen)
+int x509_decode_time(time64_t *_t,  size_t hdrlen,
+		     unsigned char tag,
+		     const unsigned char *value, size_t vlen)
 {
+	static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30,
+						       31, 31, 30, 31, 30, 31 };
 	const unsigned char *p = value;
+	unsigned year, mon, day, hour, min, sec, mon_len;
 
-#define dec2bin(X) ((X) - '0')
+#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; })
 #define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
 
 	if (tag == ASN1_UNITIM) {
 		/* UTCTime: YYMMDDHHMMSSZ */
 		if (vlen != 13)
 			goto unsupported_time;
-		tm->tm_year = DD2bin(p);
-		if (tm->tm_year >= 50)
-			tm->tm_year += 1900;
+		year = DD2bin(p);
+		if (year >= 50)
+			year += 1900;
 		else
-			tm->tm_year += 2000;
+			year += 2000;
 	} else if (tag == ASN1_GENTIM) {
 		/* GenTime: YYYYMMDDHHMMSSZ */
 		if (vlen != 15)
 			goto unsupported_time;
-		tm->tm_year = DD2bin(p) * 100 + DD2bin(p);
+		year = DD2bin(p) * 100 + DD2bin(p);
+		if (year >= 1950 && year <= 2049)
+			goto invalid_time;
 	} else {
 		goto unsupported_time;
 	}
 
-	tm->tm_year -= 1900;
-	tm->tm_mon  = DD2bin(p) - 1;
-	tm->tm_mday = DD2bin(p);
-	tm->tm_hour = DD2bin(p);
-	tm->tm_min  = DD2bin(p);
-	tm->tm_sec  = DD2bin(p);
+	mon  = DD2bin(p);
+	day = DD2bin(p);
+	hour = DD2bin(p);
+	min  = DD2bin(p);
+	sec  = DD2bin(p);
 
 	if (*p != 'Z')
 		goto unsupported_time;
 
+	if (year < 1970 ||
+	    mon < 1 || mon > 12)
+		goto invalid_time;
+
+	mon_len = month_lengths[mon - 1];
+	if (mon == 2) {
+		if (year % 4 == 0) {
+			mon_len = 29;
+			if (year % 100 == 0) {
+				mon_len = 28;
+				if (year % 400 == 0)
+					mon_len = 29;
+			}
+		}
+	}
+
+	if (day < 1 || day > mon_len ||
+	    hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
+	    min > 59 ||
+	    sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
+		goto invalid_time;
+
+	*_t = mktime64(year, mon, day, hour, min, sec);
 	return 0;
 
 unsupported_time:
-	pr_debug("Got unsupported time [tag %02x]: '%*.*s'\n",
-		 tag, (int)vlen, (int)vlen, value);
+	pr_debug("Got unsupported time [tag %02x]: '%*phN'\n",
+		 tag, (int)vlen, value);
+	return -EBADMSG;
+invalid_time:
+	pr_debug("Got invalid time [tag %02x]: '%*phN'\n",
+		 tag, (int)vlen, value);
 	return -EBADMSG;
 }
+EXPORT_SYMBOL_GPL(x509_decode_time);
 
 int x509_note_not_before(void *context, size_t hdrlen,
 			 unsigned char tag,
 			 const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
-	return x509_note_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
+	return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
 }
 
 int x509_note_not_after(void *context, size_t hdrlen,
@@ -531,5 +747,71 @@ int x509_note_not_after(void *context, size_t hdrlen,
 			const void *value, size_t vlen)
 {
 	struct x509_parse_context *ctx = context;
-	return x509_note_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
+	return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
+}
+
+/*
+ * Note a key identifier-based AuthorityKeyIdentifier
+ */
+int x509_akid_note_kid(void *context, size_t hdrlen,
+		       unsigned char tag,
+		       const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	struct asymmetric_key_id *kid;
+
+	pr_debug("AKID: keyid: %*phN\n", (int)vlen, value);
+
+	if (ctx->cert->sig->auth_ids[1])
+		return 0;
+
+	kid = asymmetric_key_generate_id(value, vlen, "", 0);
+	if (IS_ERR(kid))
+		return PTR_ERR(kid);
+	pr_debug("authkeyid %*phN\n", kid->len, kid->data);
+	ctx->cert->sig->auth_ids[1] = kid;
+	return 0;
+}
+
+/*
+ * Note a directoryName in an AuthorityKeyIdentifier
+ */
+int x509_akid_note_name(void *context, size_t hdrlen,
+			unsigned char tag,
+			const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	pr_debug("AKID: name: %*phN\n", (int)vlen, value);
+
+	ctx->akid_raw_issuer = value;
+	ctx->akid_raw_issuer_size = vlen;
+	return 0;
+}
+
+/*
+ * Note a serial number in an AuthorityKeyIdentifier
+ */
+int x509_akid_note_serial(void *context, size_t hdrlen,
+			  unsigned char tag,
+			  const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	struct asymmetric_key_id *kid;
+
+	pr_debug("AKID: serial: %*phN\n", (int)vlen, value);
+
+	if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0])
+		return 0;
+
+	kid = asymmetric_key_generate_id(value,
+					 vlen,
+					 ctx->akid_raw_issuer,
+					 ctx->akid_raw_issuer_size);
+	if (IS_ERR(kid))
+		return PTR_ERR(kid);
+
+	pr_debug("authkeyid %*phN\n", kid->len, kid->data);
+	ctx->cert->sig->auth_ids[0] = kid;
+	return 0;
 }