WIP: Feature/pkcs11 token by MPeisl · Pull Request #461 · gyroidos/cml

MPeisl · 2024-04-18T13:09:16Z

Support for generic PKCS#11 tokens:

scd/pkcs11-lib/*: contains headers and helper libraries
scd/pkcs11-test/*: unit-tests for p11token module
scd/p11token: actual scd_token implementation for PKCS#11-API

~~TODO: integration in daemon~~
TODO: integration testing
TODO before merging: squash commits

MPeisl · 2026-04-29T16:30:00Z

Refactored module loading, addressed change request. This PR currently depends on #586

quitschbo · 2026-07-10T07:14:57Z

+	// An open session handle is the ground truth for "already unlocked".
+	// Do not rely on the generic token->locked flag here: p11token_unlock may
+	// be invoked directly (e.g. from p11token_change_pin) without going through
+	// the token_unlock() wrapper that maintains that flag.


multi-line comments pleas use following style:

/* * line1 * line2 */

quitschbo · 2026-07-10T07:15:18Z

+	// flag: when called directly (e.g. from p11token_change_pin) that flag is
+	// not maintained, and keying off it would skip C_Logout/C_CloseSession/
+	// C_Finalize/dlclose, leaking the session and leaving the module
+	// C_Initialize'd (breaking the next unlock with CKR_CRYPTOKI_ALREADY_INITIALIZED).


multi-line comment

quitschbo · 2026-07-10T07:19:50Z

+} p11_cipher_params_t;
+
+int
+int_pkcs11_wrap_to_pkcs7(const unsigned char *ciphertext, size_t ct_len,


declare static, isn't exposed by header

quitschbo · 2026-07-10T07:20:04Z

+}
+
+int
+int_pkcs7_unwrap_to_pkcs11(const unsigned char *der, int der_len, p11_cipher_params_t *params,


declare static, isn't exposed by header

quitschbo · 2026-07-10T07:25:26Z

+
+// TODO: use pairing secret?
+token_err_t
+p11token_unlock(void *int_token, const char *passwd, UNUSED const unsigned char *pairing_secret,


quitschbo · 2026-07-10T07:26:31Z

+ * lock token and cleanup data structure
+*/
+void
+p11token_free(void *int_token)


quitschbo · 2026-07-10T08:03:22Z

+error:
+	if (pt) {
+		mem_free0(pt);
+	}


if (ct) mem_free0(ct); evtl. mem_memset0 beforehand (is encrypted anyway but wrapped key)

quitschbo · 2026-07-10T08:03:35Z

+	IF_TRUE_GOTO_ERROR(pt_len > INT_MAX, error);
+	*plain_key = pt;
+	*plain_key_len = (int)pt_len;
+


if (ct) mem_free0(ct); evtl. mem_memset0 beforehand (is encrypted anyway but wrapped key)

quitschbo · 2026-07-10T08:18:31Z

+	P11_CHECK_RV_GOTO(ctx->C_CloseSession(sh), error);
+
+	// free slot id ptr
+	mem_free(slot);


possible double free if next check failes and goes to error_init.
move mem_free(slot) after the Unload Module block? Double safe with mem_free0

quitschbo · 2026-07-10T08:20:00Z

+	token->ctx = NULL;
+	token->sh = NULL;
+	token->module = NULL;
+	token->initialized = true;


mem_free0(slot)

This commit unifies the usage of the 'const' qualifier in the token API. Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

Add a new PKCS11-backed token (TOKEN_TYPE_PKCS11) implementation to scd. Support is enabled at compile time using the PKCS11 build flag. PKCS#11-modules are loaded dynamically at runtime based on a configurable module path. Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

Add support for new tokentype offered by scd. Add new 'pkcs11_module' configuration option. Similar to usbtoken or softtoken one can now configure a container to use a specific PKCS#11 module. Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

Pass scd-specific environment variables defined in 'device.conf' to scd-unit. Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

This commit contains several enhancements and security hardening improvements to the PKCS#11 token type. Parts are based on severall rounds of AI-based security audits with corresponding code suggestions. All proposed changes have been manually reviewed and applied on a per case basis. Assisted-by: Claude:claude-fable-5 Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

Guard PKCS#11 related changes to the protobuf files such that they are excluded in CC_MODE builds. Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

Add key derivation function which implements PBKDF2-HMAC-SHA256. Assisted-by: Claude:claude-fable-5 Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

Bind user-pin to pairing device secret using a KDF. Assisted-by: Claude:claude-fable-5 Signed-off-by: Maximilian Peisl <maximilian.peisl@aisec.fraunhofer.de>

MPeisl force-pushed the feature/pkcs11-token branch from b99a779 to cb36751 Compare April 18, 2024 15:02