From 6df34886540699e165dc367a7f44bcc2332a38fd Mon Sep 17 00:00:00 2001
From: Ondrej Kozina <okozina@redhat.com>
Date: Tue, 26 Jan 2021 12:37:31 +0100
Subject: [PATCH] Add token handler version function prototype.

Dynamicaly loaded token handlers should provide
version string for debug purposes.
---
 lib/libcryptsetup.h        | 11 +++++++++++
 lib/luks2/luks2_internal.h |  1 +
 lib/luks2/luks2_token.c    | 27 ++++++++++++++++++++++++++-
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/lib/libcryptsetup.h b/lib/libcryptsetup.h
index d2e12cd3..08f70b0d 100644
--- a/lib/libcryptsetup.h
+++ b/lib/libcryptsetup.h
@@ -2205,6 +2205,16 @@ typedef int (*crypt_token_validate_func) (struct crypt_device *cd, const char *j
  */
 typedef void (*crypt_token_dump_func) (struct crypt_device *cd, const char *json);
 
+/**
+ * Token handler version function prototype.
+ * This function is supposed to return pointer to version string information.
+ *
+ * @note The returned string is advised to contain only version.
+ *	 For example '1.0.0' or 'v1.2.3.4'.
+ *
+ */
+typedef const char * (*crypt_token_version_func) (void);
+
 /**
  * Token handler
  */
@@ -2234,6 +2244,7 @@ int crypt_token_register(const crypt_token_handler *handler);
 #define CRYPT_TOKEN_ABI_BUFFER_FREE "cryptsetup_token_buffer_free"
 #define CRYPT_TOKEN_ABI_VALIDATE    "cryptsetup_token_validate"
 #define CRYPT_TOKEN_ABI_DUMP        "cryptsetup_token_dump"
+#define CRYPT_TOKEN_ABI_VERSION     "cryptsetup_token_version"
 
 /**
  * Activate device or check key using a token.
diff --git a/lib/luks2/luks2_internal.h b/lib/luks2/luks2_internal.h
index 6a84a475..0095e1c2 100644
--- a/lib/luks2/luks2_internal.h
+++ b/lib/luks2/luks2_internal.h
@@ -184,6 +184,7 @@ struct crypt_token_handler_v2 {
 	/* here ends v1. Do not touch anything above */
 
 	crypt_token_open_pin_func open_pin;
+	crypt_token_version_func version;
 
 	void *dlhandle;
 };
diff --git a/lib/luks2/luks2_token.c b/lib/luks2/luks2_token.c
index 191444f2..5d6a10ca 100644
--- a/lib/luks2/luks2_token.c
+++ b/lib/luks2/luks2_token.c
@@ -77,6 +77,24 @@ static bool token_validate_v1(struct crypt_device *cd, const crypt_token_handler
 	return true;
 }
 
+#if USE_EXTERNAL_TOKENS
+static bool token_validate_v2(struct crypt_device *cd, const struct crypt_token_handler_internal *h)
+{
+	if (!h)
+		return false;
+
+	if (!token_validate_v1(cd, &h->u.v1))
+		return false;
+
+	if (!h->u.v2.version) {
+		log_dbg(cd, "Token handler does not provide " CRYPT_TOKEN_ABI_VERSION " function.");
+		return false;
+	}
+
+	return true;
+}
+#endif
+
 static int
 crypt_token_load_external(struct crypt_device *cd, const char *name, struct crypt_token_handler_internal *ret)
 {
@@ -114,12 +132,19 @@ crypt_token_load_external(struct crypt_device *cd, const char *name, struct cryp
 	token->validate = token_dlvsym(cd, h, CRYPT_TOKEN_ABI_VALIDATE, CRYPT_TOKEN_ABI_VERSION1);
 	token->dump = token_dlvsym(cd, h, CRYPT_TOKEN_ABI_DUMP, CRYPT_TOKEN_ABI_VERSION1);
 	token->open_pin = token_dlvsym(cd, h, CRYPT_TOKEN_ABI_OPEN_PIN, CRYPT_TOKEN_ABI_VERSION1);
+	token->version = token_dlvsym(cd, h, CRYPT_TOKEN_ABI_VERSION, CRYPT_TOKEN_ABI_VERSION1);
 
-	if (!token_validate_v1(cd, &ret->u.v1)) {
+	if (!token_validate_v2(cd, ret)) {
 		r = -EINVAL;
 		goto err;
 	}
 
+	r = snprintf(buf, sizeof(buf), "%s", token->version() ?: "");
+	if (r < 0 || (size_t)r >= sizeof(buf))
+		*buf = '\0';
+
+	log_dbg(cd, "Token handler %s-%s loaded sucessfuly.", token->name, buf);
+
 	token->dlhandle = h;
 	ret->version = 2;