From a07c8a556c6446e63ada2f6af129d91adf0d9f63 Mon Sep 17 00:00:00 2001
From: Ondrej Kozina <okozina@redhat.com>
Date: Tue, 2 Dec 2025 11:07:04 +0100
Subject: [PATCH] Fix C std23 related warnings with new glibc.

C standard library functions now preserves qualifiers passed
to some functions. In case of strchr() if the passed argument is
const qualified also the returned value is const qualified. Similarly
if the passed argument is not const qualified neither is the return
value.

This patch makes libcryptsetup compliant with the change and should
be backward compatible with older std libraries.

Thanks Vojta Trefny for heads-up.
---
 lib/crypto_backend/crypto_storage.c | 2 +-
 lib/libdevmapper.c                  | 4 ++--
 lib/luks1/keyencryption.c           | 3 ++-
 lib/tcrypt/tcrypt.c                 | 8 +++++---
 lib/utils_keyring.c                 | 3 ++-
 5 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/lib/crypto_backend/crypto_storage.c b/lib/crypto_backend/crypto_storage.c
index 9f8fa839..edd4db7d 100644
--- a/lib/crypto_backend/crypto_storage.c
+++ b/lib/crypto_backend/crypto_storage.c
@@ -77,7 +77,7 @@ static int crypt_sector_iv_init(struct crypt_sector_iv *ctx,
 		ctx->type = IV_PLAIN;
 	} else if (!strncasecmp(iv_name, "essiv:", 6)) {
 		struct crypt_hash *h = NULL;
-		char *hash_name = strchr(iv_name, ':');
+		const char *hash_name = strchr(iv_name, ':');
 		int hash_size;
 		char tmp[256];
 
diff --git a/lib/libdevmapper.c b/lib/libdevmapper.c
index 69a677fe..13ec0317 100644
--- a/lib/libdevmapper.c
+++ b/lib/libdevmapper.c
@@ -3287,7 +3287,7 @@ int dm_is_dm_kernel_name(const char *name)
 int dm_uuid_cmp(const char *dm_uuid, const char *hdr_uuid)
 {
 	int i, j;
-	char *str;
+	const char *str;
 
 	if (!dm_uuid || !hdr_uuid)
 		return -EINVAL;
@@ -3322,7 +3322,7 @@ int dm_uuid_cmp(const char *dm_uuid, const char *hdr_uuid)
 int dm_uuid_integrity_cmp(const char *dm_uuid, const char *dmi_uuid)
 {
 	int i;
-	char *str, *stri;
+	const char *str, *stri;
 
 	if (!dm_uuid || !dmi_uuid)
 		return -EINVAL;
diff --git a/lib/luks1/keyencryption.c b/lib/luks1/keyencryption.c
index 5698318c..de8aa30e 100644
--- a/lib/luks1/keyencryption.c
+++ b/lib/luks1/keyencryption.c
@@ -18,7 +18,8 @@
 static void _error_hint(struct crypt_device *ctx, const char *device,
 			const char *cipher, const char *mode, size_t keyLength)
 {
-	char *c, cipher_spec[MAX_CIPHER_LEN * 3];
+	const char *c;
+	char cipher_spec[MAX_CIPHER_LEN * 3];
 
 	if (snprintf(cipher_spec, sizeof(cipher_spec), "%s-%s", cipher, mode) < 0)
 		return;
diff --git a/lib/tcrypt/tcrypt.c b/lib/tcrypt/tcrypt.c
index 2fd95399..8fbe6514 100644
--- a/lib/tcrypt/tcrypt.c
+++ b/lib/tcrypt/tcrypt.c
@@ -1002,8 +1002,10 @@ static int TCRYPT_status_one(struct crypt_device *cd, const char *name,
 {
 	struct crypt_dm_active_device dmd;
 	struct dm_target *tgt = &dmd.segment;
-	char dm_name[PATH_MAX], *c;
+	const char *c;
+	char dm_name[PATH_MAX];
 	int r;
+	size_t cipher_len = MAX_CIPHER_LEN;
 
 	if (snprintf(dm_name, sizeof(dm_name), "%s_%d", name, index) < 0)
 		return -ENOMEM;
@@ -1027,9 +1029,9 @@ static int TCRYPT_status_one(struct crypt_device *cd, const char *name,
 
 	if (is_tcrypt_subdev(dmd.uuid, base_uuid)) {
 		if ((c = strchr(tgt->u.crypt.cipher, '-')))
-			*c = '\0';
+			cipher_len = c - tgt->u.crypt.cipher;
 		strcat(cipher, "-");
-		strncat(cipher, tgt->u.crypt.cipher, MAX_CIPHER_LEN);
+		strncat(cipher, tgt->u.crypt.cipher, cipher_len);
 		*key_size += crypt_volume_key_length(tgt->u.crypt.vk);
 		tcrypt_hdr->d.mk_offset = tgt->u.crypt.offset * SECTOR_SIZE;
 		device_free(cd, *device);
diff --git a/lib/utils_keyring.c b/lib/utils_keyring.c
index 3106a606..73df3461 100644
--- a/lib/utils_keyring.c
+++ b/lib/utils_keyring.c
@@ -299,7 +299,8 @@ const char *key_type_name(key_type_t type)
 
 key_type_t keyring_type_and_name(const char *key_name, const char **name)
 {
-	char type[16], *name_tmp;
+	const char *name_tmp;
+	char type[16];
 	size_t type_len;
 
 	if (!key_name || key_name[0] != '%')