From b4973069342bdeae5a4b76fa3bb4119179d8a816 Mon Sep 17 00:00:00 2001
From: Ondrej Kozina <okozina@redhat.com>
Date: Wed, 7 May 2025 14:15:09 +0200
Subject: [PATCH] Add method in keyslot_context to get stored key size.

Only applicable for CRYPT_KC_TYPE_KEY and
CRYPT_KC_TYPE_VK_KEYRING.
---
 lib/keyslot_context.c | 30 ++++++++++++++++++++++++++++++
 lib/keyslot_context.h |  9 ++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/lib/keyslot_context.c b/lib/keyslot_context.c
index a4d58c31..183c250a 100644
--- a/lib/keyslot_context.c
+++ b/lib/keyslot_context.c
@@ -555,6 +555,23 @@ static void keyring_context_free(struct crypt_keyslot_context *kc)
 	free(kc->u.kr.i_key_description);
 }
 
+static int keyring_get_key_size(struct crypt_device *cd, struct crypt_keyslot_context *kc, size_t *r_key_size)
+{
+	int r;
+
+	assert(kc && kc->type == CRYPT_KC_TYPE_VK_KEYRING);
+	assert(r_key_size);
+
+	if (!kc->u.vk_kr.i_key_size) {
+		r = crypt_keyring_get_keysize_by_name(cd, kc->u.vk_kr.key_description, &kc->u.vk_kr.i_key_size);
+		if (r < 0)
+			return r;
+	}
+
+	*r_key_size = kc->u.vk_kr.i_key_size;
+	return 0;
+}
+
 void crypt_keyslot_context_init_by_keyring_internal(struct crypt_keyslot_context *kc,
 	const char *key_description)
 {
@@ -578,6 +595,17 @@ static void key_context_free(struct crypt_keyslot_context *kc)
 	crypt_free_volume_key(kc->u.k.i_vk);
 }
 
+static int key_get_key_size(struct crypt_device *cd __attribute__((unused)),
+			       struct crypt_keyslot_context *kc,
+			       size_t *r_key_size)
+{
+	assert(kc && kc->type == CRYPT_KC_TYPE_KEY);
+	assert(r_key_size);
+
+	*r_key_size = kc->u.k.volume_key_size;
+	return 0;
+}
+
 void crypt_keyslot_context_init_by_key_internal(struct crypt_keyslot_context *kc,
 	const char *volume_key,
 	size_t volume_key_size)
@@ -596,6 +624,7 @@ void crypt_keyslot_context_init_by_key_internal(struct crypt_keyslot_context *kc
 	kc->get_fvault2_volume_key = get_fvault2_volume_key_by_key;
 	kc->get_verity_volume_key = get_generic_signed_key_by_key;
 	kc->get_integrity_volume_key = get_generic_volume_key_by_key;
+	kc->get_key_size = key_get_key_size;
 	kc->context_free = key_context_free;
 	crypt_keyslot_context_init_common(kc);
 }
@@ -1135,6 +1164,7 @@ static int _crypt_keyslot_context_init_by_vk_in_keyring(const char *key_descript
 
 	tmp->get_luks2_key = get_key_by_vk_in_keyring;
 	tmp->get_luks2_volume_key = get_volume_key_by_vk_in_keyring;
+	tmp->get_key_size = keyring_get_key_size;
 	tmp->context_free = vk_in_keyring_context_free;
 	crypt_keyslot_context_init_common(tmp);
 
diff --git a/lib/keyslot_context.h b/lib/keyslot_context.h
index 45d28170..a2e42b20 100644
--- a/lib/keyslot_context.h
+++ b/lib/keyslot_context.h
@@ -61,7 +61,12 @@ typedef int (*keyslot_context_get_passphrase) (
 	size_t *r_passphrase_size);
 
 typedef void (*keyslot_context_free) (
-		struct crypt_keyslot_context *kc);
+	struct crypt_keyslot_context *kc);
+
+typedef int (*keyslot_context_get_key_size) (
+	struct crypt_device *cd,
+	struct crypt_keyslot_context *kc,
+	size_t *r_key_size);
 
 #define KC_VERSION_BASIC          UINT8_C(1)
 #define KC_VERSION_SELF_CONTAINED UINT8_C(2)
@@ -117,6 +122,7 @@ struct crypt_keyslot_context {
 	struct {
 		const char *key_description;
 		char *i_key_description;
+		size_t i_key_size;
 	} vk_kr;
 	} u;
 
@@ -134,6 +140,7 @@ struct crypt_keyslot_context {
 	keyslot_context_get_generic_signed_key	get_verity_volume_key;
 	keyslot_context_get_generic_volume_key	get_integrity_volume_key;
 	keyslot_context_get_passphrase		get_passphrase;
+	keyslot_context_get_key_size		get_key_size;
 	keyslot_context_free			context_free;
 };