zpcprovider for sign/verify (ecdsa/eddsa) by holger-dengler · Pull Request #41 · opencryptoki/libzpc

holger-dengler · 2026-04-10T15:05:26Z

This PR requires PR #40.

This PR adds OpenSSL provider support for libzpc. This first version covers the main functionality for store, keymgmt, sign/verify and decoder support.

As the series add a lot of new code, it is split into many commits to make the review (hopefully) a bit easier.

ToDo:

public key support for store/decoder
alloc/free needs some debugging

Restriction:

the tests uses hard-coded public keys, so running tests on other machines require code changes in tprovider.c.
the provider only supports uv origins, so testing is limited to SEL environments.

ifranzki · 2026-04-13T06:49:57Z

Are you looking at the Travis build failures? You might need to build OpenSSL from source to have a 3.5.0 version to build against.

holger-dengler · 2026-04-13T07:03:06Z

Yes, a fix for the travis is in progress. It looks like travis only provides 3.0 out of the box. So I'll build my own. At least 3.5, better 4.0.

holger-dengler · 2026-05-02T16:09:50Z

The update contains:

re-order of the commits (move test to the end of the series)
rework of signature/eddsa
pick review comments
minor fixes

The new dependency to OpenSSL requires a custom built OpenSSL, as long it is available as distro package. This workaround can be removed, if OpenSSL v3.5 or later is available as distro package. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

holger-dengler · 2026-05-02T17:45:24Z

Another update (force push) to remove the merge conflicts and add a fix for travis.

ifranzki · 2026-05-04T07:13:38Z

I would suggest to also add tests that utilize the openssl application to use protected key origins. For example, creating/signing a certificate with a protected key origin specified via URI or PEM using openssl x509 -in cert.csr -out cert.pem -req -signkey <protected key origin> -days 1001.

holger-dengler · 2026-05-04T08:03:54Z

I would suggest to also add tests that utilize the openssl application to use protected key origins. For example, creating/signing a certificate with a protected key origin specified via URI or PEM using openssl x509 -in cert.csr -out cert.pem -req -signkey <protected key origin> -days 1001.

I plan to rework the test. tprovider will be renamed (t_provider) and changed to do only the lookup for the provider components. All key-related functional test will be moved to a new t_openssl test script, which uses openssl to create keys and call the functions. such a split is required to run the tests in a CI.

ifranzki · 2026-05-05T06:22:21Z

+
+	if (strcmp(obj->origin_type, "uv") == 0) {
+		/* uv only: import pubkey */
+		if ((rc = zpc_ec_key_import_clear(key, obj->origin_pubkey.p,


The pub key is optional. If I try to load a URI without a pub key I get:

OSSL_STORE_load() [uri=hbkzpc:origin-type=uv;origin-alg=prime256v1;origin-blob=19ac19eb0e630b2dd14a935ff3d5614b2e458efe25da35b06c52e1e23c347b22] 000003FFF7FA8720:error:41000036:zpcprovider:zpc_key_update:No EC key parts given:/root/libzpc/src/keymgmt.c:69:

I was unsure, if a private key without public key makes any sense. But anyhow, I will change it.

When the ypckey tool allows to create URIs without a pub key then you must be able to handle it :-)

IIRC zpckey requires the public key for UV ec-keys.

Aehm no:

# ./zpckey compose -t uv -a prime256v1 --uv-secret-id 19ac19eb0e630b2dd14a935ff3d5614b2e458efe25da35b06c52e1e23c347b22 p256.asr --outform URI hbkzpc:origin-type=uv;origin-alg=prime256v1;origin-blob=19ac19eb0e630b2dd14a935ff3d5614b2e458efe25da35b06c52e1e23c347b22

No error about the missing public key. I agree that for most use cases, the public key should be there, but there can be legit use cases for keys without a public key. So I think it is technically possible to handle keys with just the private key.

This change works for me:

--- "a/src/keymgmt.c" +++ "b/src/keymgmt.c" @@ -53,7 +53,8 @@ static int zpc_key_update(struct obj *obj) if (strcmp(obj->origin_type, "uv") == 0) { /* uv only: import pubkey */ - if ((rc = zpc_ec_key_import_clear(key, obj->origin_pubkey.p, + if (obj->origin_pubkey.p != NULL && + (rc = zpc_ec_key_import_clear(key, obj->origin_pubkey.p, obj->origin_pubkey.plen, NULL, 0))) goto err;

The gtest release 1.11.0 produce build problems because of outdated versions. Updating to version v1.12.1 fixes the problems. While at it, migrate from archive-download to git checkout. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

The libzpc API is no longer exposed as static or shared library. The object module is only available for internal purpose. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

ifranzki · 2026-05-05T08:19:49Z

I would move the provider sources into a subdirectory, e.g. src/provider/. Maybe even move the library sources into a subdirectory e.g. src/lib/.

Add signature algorithms for sign/verify with ECDSA and EDDSA keys. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add the supported TLS properties of the hbkzpc provider. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

The ASN.1 module provides DER en-/decoding for hbkzpc-URIs. These functions are required for the decoder/encoder support. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add internal object build target for ASN.1 module. The internal object can be shared between targets. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add decoders for PEM and DER to support hbkzpc-URI files. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

To use the zpc functionality via the OpenSSL API, the zpc provider has to be defined in the OpenSSL configuration. The build configures the template and creates a `openssl.cnf` file, which can be used for test purposes. The configuration file will be created in the build output folder. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add provider test framework with a base retrieval of the hbkzpc provider. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Integrate new provider testcases for builds with test enabled. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add tests for the sore-loader. It covers mainly the open()/load()/eof() sequence. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add test for loading a EVP PKEY object from a hbkzpc-URI via store and keymgmt. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add sign/verify tests for full and pre-hashed messages. The verification is checked across both variants. Note: The test covers only ECDSA and uses a hard-coded key origin. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add tests for the DER encoding. It takes the hard-coded ECDSA key and stores it as a file. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add simple decoder fetch test. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Add tests to use hbkzpc-URI file for sign/verify (instead of loading the URI via store). Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

holger-dengler · 2026-05-11T07:29:54Z

ed-curves still need additional testing.

ifranzki · 2026-05-12T06:29:21Z

+}
+
+static const OSSL_DISPATCH kmgmt_ecdsa_functions[] = {
+	DISPATCH_DEFN(KEYMGMT, NEW, kmgmt_new),


You should also implement the KEYMGMT_dup function. If this is missing, then an EVP_PKEY_dup() will not work.

Internally EVP_PKEY_dup() tries to be smart: if the dup function is not implemented, then it attempts to duplicate the key by exporting the old key and importing it into the new key.
BUT: You only export the public key, you can't export the private key, so it fails already here. Furthermore, you don't implement the import function either, so it won't work anyway.

Solution: Implement the dup function to properly duplicate the key internals.

ifranzki · 2026-05-12T06:30:51Z

+}
+
+static const OSSL_DISPATCH ecdsa_functions[] = {
+	DISPATCH_DEFN(SIGNATURE, NEWCTX,               ecdsa_newctx),


You should also implement the SIGNATURE_dupctx function. Without that functions like EVP_PKEY_CTX_dup() and EVP_MD_CTX_dup() won't work.

ifranzki · 2026-05-12T12:07:01Z

+static const OSSL_DISPATCH kmgmt_ecdsa_functions[] = {
+	DISPATCH_DEFN(KEYMGMT, NEW, kmgmt_new),
+	DISPATCH_DEFN(KEYMGMT, FREE, kmgmt_free),
+	DISPATCH_DEFN(KEYMGMT, LOAD, kmgmt_load),


You might consider to also implement the KEYMGMT_match function. This is used with EVP_PKEY_eq() / EVP_PKEY_cmp().

As long as one of the two PKEYs are from a provider that supports the match function, it works by exporting the (public) key data from the one pkey who's provider does not have a match function and import it into the other provider and then call match of that provider. So this works, e.g. compare a PKEY from your provider with a PKEY from the default provider.

What not works is to compare two PKEYs which are both from a provider that does not support the match function. I.e. comparing two PKEYs from your provider. Here the comparison always returns 0 (different) because evp_keymgmt_match() return 0 if no match function is available.

Not sure how important that case is though, so feel free to move this to a later stage.

ifranzki · 2026-05-12T12:41:35Z

+			return OSSL_RV_ERR;
+	}
+
+	return rv;


This should return OSSL_RV_OK, here, but rv is initialized with OSSL_RV_ERR.

ifranzki · 2026-05-12T12:42:38Z

+	TLS_GROUP_ENTRY("P-384", "secp384r1", "EC", 1),
+	TLS_GROUP_ENTRY("secp521r1", "secp521r1", "EC", 2),
+	TLS_GROUP_ENTRY("P-521", "secp521r1", "EC", 2),
+	TLS_GROUP_ENTRY("x25519", "X25519", "X25519", 3),


I wonder if you should really supply the x25519 and x448 entries. Your provider does not support Montgomery keys of those types, and also no ECDH with Montgomery keys.

ifranzki · 2026-05-12T12:55:54Z

+	if (p) {
+		const char *mdname = NULL;
+
+		if (OSSL_PARAM_get_utf8_ptr(p, &mdname) != OSSL_RV_OK ||


OSSL_PARAM_get_utf8_ptr() does not work here. OSSL_SIGNATURE_PARAM_DIGEST is of data type utf8_string, but not utf8_ptr.

So you must use OSSL_PARAM_get_utf8_string_ptr() instead.

ifranzki · 2026-05-12T12:56:13Z

+	if (p) {
+		const char *edi = NULL;
+
+		if (OSSL_PARAM_get_utf8_ptr(p, &edi) != OSSL_RV_OK ||


Use OSSL_PARAM_get_utf8_string_ptr() instead.

ifranzki · 2026-05-12T14:35:28Z

+	if (bits)
+		*bits = alg_param_map[i].bits;
+	if (secbits)
+		*bits = alg_param_map[i].secbits;


should be *secbits = alg_param_map[i].secbits;

ifranzki · 2026-05-12T14:35:51Z

+	if (secbits)
+		*bits = alg_param_map[i].secbits;
+	if (sigsz)
+		*bits = alg_param_map[i].sigsz;


should be *sigsz = alg_param_map[i].sigsz;

holger-dengler requested review from fcallies and ifranzki April 10, 2026 15:05

holger-dengler commented Apr 13, 2026

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Comment thread src/uri.c Outdated

ifranzki reviewed Apr 13, 2026

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Comment thread src/provider.c Outdated

ifranzki reviewed Apr 13, 2026

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Comment thread src/object.h Outdated

ifranzki reviewed Apr 13, 2026

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Comment thread src/signature.c Outdated

ifranzki reviewed Apr 14, 2026

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Comment thread src/signature.c

holger-dengler force-pushed the provider-sign branch 2 times, most recently from 7c72889 to 1659e06 Compare May 2, 2026 15:53

holger-dengler requested a review from ifranzki May 2, 2026 16:10

travis: Add OpenSSL custom build

b30816d

The new dependency to OpenSSL requires a custom built OpenSSL, as long it is available as distro package. This workaround can be removed, if OpenSSL v3.5 or later is available as distro package. Signed-off-by: Holger Dengler <dengler@linux.ibm.com>

holger-dengler force-pushed the provider-sign branch from 9258c6f to 6d1b3d8 Compare May 2, 2026 17:44

holger-dengler mentioned this pull request May 2, 2026

new tool zpckey for UV key origins #43

Open