Re: [PATCH 1/5] X.509: Extract both parts of the AuthorityKeyIdentifier [ver #2]
From: Dmitry Kasatkin
Date: Thu Dec 04 2014 - 07:16:37 EST
On 26/11/14 16:17, David Howells wrote:
> Extract both parts of the AuthorityKeyIdentifier, not just the keyIdentifier,
> as the second part can be used to match X.509 certificates by issuer and
> serialNumber.
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> ---
>
> crypto/asymmetric_keys/Makefile | 8 +-
> crypto/asymmetric_keys/pkcs7_trust.c | 4 -
> crypto/asymmetric_keys/pkcs7_verify.c | 12 +-
> crypto/asymmetric_keys/x509_akid.asn1 | 35 +++++++
> crypto/asymmetric_keys/x509_cert_parser.c | 142 ++++++++++++++++++-----------
> crypto/asymmetric_keys/x509_parser.h | 5 +
> crypto/asymmetric_keys/x509_public_key.c | 8 +-
> 7 files changed, 145 insertions(+), 69 deletions(-)
> create mode 100644 crypto/asymmetric_keys/x509_akid.asn1
>
> diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
> index e47fcd9ac5e8..cd1406f9b14a 100644
> --- a/crypto/asymmetric_keys/Makefile
> +++ b/crypto/asymmetric_keys/Makefile
> @@ -15,15 +15,21 @@ obj-$(CONFIG_PUBLIC_KEY_ALGO_RSA) += rsa.o
> obj-$(CONFIG_X509_CERTIFICATE_PARSER) += x509_key_parser.o
> x509_key_parser-y := \
> x509-asn1.o \
> + x509_akid-asn1.o \
> x509_rsakey-asn1.o \
> x509_cert_parser.o \
> x509_public_key.o
>
> -$(obj)/x509_cert_parser.o: $(obj)/x509-asn1.h $(obj)/x509_rsakey-asn1.h
> +$(obj)/x509_cert_parser.o: \
> + $(obj)/x509-asn1.h \
> + $(obj)/x509_akid-asn1.h \
> + $(obj)/x509_rsakey-asn1.h
> $(obj)/x509-asn1.o: $(obj)/x509-asn1.c $(obj)/x509-asn1.h
> +$(obj)/x509_akid-asn1.o: $(obj)/x509_akid-asn1.c $(obj)/x509_akid-asn1.h
> $(obj)/x509_rsakey-asn1.o: $(obj)/x509_rsakey-asn1.c $(obj)/x509_rsakey-asn1.h
>
> clean-files += x509-asn1.c x509-asn1.h
> +clean-files += x509_akid-asn1.c x509_akid-asn1.h
> clean-files += x509_rsakey-asn1.c x509_rsakey-asn1.h
>
> #
> diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
> index 1d29376072da..f802cf118053 100644
> --- a/crypto/asymmetric_keys/pkcs7_trust.c
> +++ b/crypto/asymmetric_keys/pkcs7_trust.c
> @@ -85,8 +85,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
> /* No match - see if the root certificate has a signer amongst the
> * trusted keys.
> */
> - if (last && last->authority) {
> - key = x509_request_asymmetric_key(trust_keyring, last->authority,
> + if (last && last->auth_skid) {
> + key = x509_request_asymmetric_key(trust_keyring, last->auth_skid,
> false);
> if (!IS_ERR(key)) {
> x509 = last;
> diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
> index cd455450b069..5e956c5b9071 100644
> --- a/crypto/asymmetric_keys/pkcs7_verify.c
> +++ b/crypto/asymmetric_keys/pkcs7_verify.c
> @@ -187,11 +187,11 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
> goto maybe_missing_crypto_in_x509;
>
> pr_debug("- issuer %s\n", x509->issuer);
> - if (x509->authority)
> + if (x509->auth_skid)
> pr_debug("- authkeyid %*phN\n",
> - x509->authority->len, x509->authority->data);
> + x509->auth_skid->len, x509->auth_skid->data);
>
> - if (!x509->authority ||
> + if (!x509->auth_skid ||
> strcmp(x509->subject, x509->issuer) == 0) {
> /* If there's no authority certificate specified, then
> * the certificate must be self-signed and is the root
> @@ -216,13 +216,13 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
> * list to see if the next one is there.
> */
> pr_debug("- want %*phN\n",
> - x509->authority->len, x509->authority->data);
> + x509->auth_skid->len, x509->auth_skid->data);
> for (p = pkcs7->certs; p; p = p->next) {
> if (!p->skid)
> continue;
> pr_debug("- cmp [%u] %*phN\n",
> p->index, p->skid->len, p->skid->data);
> - if (asymmetric_key_id_same(p->skid, x509->authority))
> + if (asymmetric_key_id_same(p->skid, x509->auth_skid))
> goto found_issuer;
> }
>
> @@ -338,8 +338,6 @@ int pkcs7_verify(struct pkcs7_message *pkcs7)
> ret = x509_get_sig_params(x509);
> if (ret < 0)
> return ret;
> - pr_debug("X.509[%u] %*phN\n",
> - n, x509->authority->len, x509->authority->data);
> }
>
> for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
> diff --git a/crypto/asymmetric_keys/x509_akid.asn1 b/crypto/asymmetric_keys/x509_akid.asn1
> new file mode 100644
> index 000000000000..1a33231a75a8
> --- /dev/null
> +++ b/crypto/asymmetric_keys/x509_akid.asn1
> @@ -0,0 +1,35 @@
> +-- X.509 AuthorityKeyIdentifier
> +-- rfc5280 section 4.2.1.1
> +
> +AuthorityKeyIdentifier ::= SEQUENCE {
> + keyIdentifier [0] IMPLICIT KeyIdentifier OPTIONAL,
> + authorityCertIssuer [1] IMPLICIT GeneralNames OPTIONAL,
> + authorityCertSerialNumber [2] IMPLICIT CertificateSerialNumber OPTIONAL
> + }
> +
> +KeyIdentifier ::= OCTET STRING ({ x509_akid_note_kid })
> +
> +CertificateSerialNumber ::= INTEGER ({ x509_akid_note_serial })
> +
> +GeneralNames ::= SEQUENCE OF GeneralName
> +
> +GeneralName ::= CHOICE {
> + otherName [0] ANY,
> + rfc822Name [1] IA5String,
> + dNSName [2] IA5String,
> + x400Address [3] ANY,
> + directoryName [4] Name ({ x509_akid_note_name }),
> + ediPartyName [5] ANY,
> + uniformResourceIdentifier [6] IA5String,
> + iPAddress [7] OCTET STRING,
> + registeredID [8] OBJECT IDENTIFIER
> + }
> +
> +Name ::= SEQUENCE OF RelativeDistinguishedName
> +
> +RelativeDistinguishedName ::= SET OF AttributeValueAssertion
> +
> +AttributeValueAssertion ::= SEQUENCE {
> + attributeType OBJECT IDENTIFIER ({ x509_note_OID }),
> + attributeValue ANY ({ x509_extract_name_segment })
> + }
> diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
> index a668d90302d3..e9d6586fdf89 100644
> --- a/crypto/asymmetric_keys/x509_cert_parser.c
> +++ b/crypto/asymmetric_keys/x509_cert_parser.c
> @@ -18,6 +18,7 @@
> #include "public_key.h"
> #include "x509_parser.h"
> #include "x509-asn1.h"
> +#include "x509_akid-asn1.h"
> #include "x509_rsakey-asn1.h"
>
> struct x509_parse_context {
> @@ -35,6 +36,10 @@ struct x509_parse_context {
> 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;
> };
>
> /*
> @@ -48,7 +53,8 @@ void x509_free_certificate(struct x509_certificate *cert)
> kfree(cert->subject);
> kfree(cert->id);
> kfree(cert->skid);
> - kfree(cert->authority);
> + kfree(cert->auth_id);
> + kfree(cert->auth_skid);
> kfree(cert->sig.digest);
> mpi_free(cert->sig.rsa.s);
> kfree(cert);
> @@ -85,6 +91,18 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
> if (ret < 0)
> goto error_decode;
>
> + /* 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");
> + goto error_decode;
> + }
> + }
> +
> /* Decode the public key */
> ret = asn1_ber_decoder(&x509_rsakey_decoder, ctx,
> ctx->key, ctx->key_size);
> @@ -422,7 +440,6 @@ int x509_process_extension(void *context, size_t hdrlen,
> struct x509_parse_context *ctx = context;
> struct asymmetric_key_id *kid;
> const unsigned char *v = value;
> - int i;
>
> pr_debug("Extension: %u\n", ctx->last_oid);
>
> @@ -449,57 +466,8 @@ int x509_process_extension(void *context, size_t hdrlen,
>
> if (ctx->last_oid == OID_authorityKeyIdentifier) {
> /* Get hold of the CA key fingerprint */
> - if (ctx->cert->authority || vlen < 5)
> - return -EBADMSG;
> -
> - /* Authority Key Identifier must be a Constructed SEQUENCE */
> - if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5)))
> - return -EBADMSG;
> -
> - /* Authority Key Identifier is not indefinite length */
> - if (unlikely(vlen == ASN1_INDEFINITE_LENGTH))
> - return -EBADMSG;
> -
> - if (vlen < ASN1_INDEFINITE_LENGTH) {
> - /* Short Form length */
> - if (v[1] != vlen - 2 ||
> - v[2] != SEQ_TAG_KEYID ||
> - v[3] > vlen - 4)
> - return -EBADMSG;
> -
> - vlen = 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;
> -
> - vlen = v[sub + 1];
> - v += (sub + 2);
> - }
> -
> - kid = asymmetric_key_generate_id(ctx->cert->raw_issuer,
> - ctx->cert->raw_issuer_size,
> - v, vlen);
> - if (IS_ERR(kid))
> - return PTR_ERR(kid);
> - pr_debug("authkeyid %*phN\n", kid->len, kid->data);
> - ctx->cert->authority = kid;
> + ctx->raw_akid = v;
> + ctx->raw_akid_size = vlen;
> return 0;
> }
>
> @@ -569,3 +537,71 @@ int x509_note_not_after(void *context, size_t hdrlen,
> struct x509_parse_context *ctx = context;
> return x509_note_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->auth_skid)
> + return 0;
> +
> + kid = asymmetric_key_generate_id(ctx->cert->raw_issuer,
> + ctx->cert->raw_issuer_size,
> + value, vlen);
> + if (IS_ERR(kid))
> + return PTR_ERR(kid);
> + pr_debug("authkeyid %*phN\n", kid->len, kid->data);
> + ctx->cert->auth_skid = 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->auth_id)
> + 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->auth_id = kid;
> + return 0;
> +}
> diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h
> index 3dfe6b5d6f0b..c4d16ddbc2cb 100644
> --- a/crypto/asymmetric_keys/x509_parser.h
> +++ b/crypto/asymmetric_keys/x509_parser.h
> @@ -19,9 +19,10 @@ struct x509_certificate {
> struct public_key_signature sig; /* Signature parameters */
> char *issuer; /* Name of certificate issuer */
> char *subject; /* Name of certificate subject */
> - struct asymmetric_key_id *id; /* Serial number + issuer */
> + struct asymmetric_key_id *id; /* Issuer + Serial number */
> struct asymmetric_key_id *skid; /* Subject + subjectKeyId (optional) */
> - struct asymmetric_key_id *authority; /* Authority key identifier (optional) */
> + struct asymmetric_key_id *auth_id; /* CA AuthKeyId matching ->id (optional) */
> + struct asymmetric_key_id *auth_skid; /* CA AuthKeyId matching ->skid (optional) */
Hi David,
Why do you call it "auth_skid", not just akid in similar way as 'skid'?
Why it is "auth & skid"?
- Dmitry
> struct tm valid_from;
> struct tm valid_to;
> const void *tbs; /* Signed data */
> diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
> index a6c42031628e..a3d9ba999da5 100644
> --- a/crypto/asymmetric_keys/x509_public_key.c
> +++ b/crypto/asymmetric_keys/x509_public_key.c
> @@ -214,10 +214,10 @@ static int x509_validate_trust(struct x509_certificate *cert,
> if (!trust_keyring)
> return -EOPNOTSUPP;
>
> - if (ca_keyid && !asymmetric_key_id_partial(cert->authority, ca_keyid))
> + if (ca_keyid && !asymmetric_key_id_partial(cert->auth_skid, ca_keyid))
> return -EPERM;
>
> - key = x509_request_asymmetric_key(trust_keyring, cert->authority,
> + key = x509_request_asymmetric_key(trust_keyring, cert->auth_skid,
> false);
> if (!IS_ERR(key)) {
> if (!use_builtin_keys
> @@ -274,8 +274,8 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
> cert->pub->id_type = PKEY_ID_X509;
>
> /* Check the signature on the key if it appears to be self-signed */
> - if (!cert->authority ||
> - asymmetric_key_id_same(cert->skid, cert->authority)) {
> + if (!cert->auth_skid ||
> + asymmetric_key_id_same(cert->skid, cert->auth_skid)) {
> ret = x509_check_signature(cert->pub, cert); /* self-signed */
> if (ret < 0)
> goto error_free_cert;
>
>
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