linux-kernel - [PATCH] crypto: md5 - Implement export_core() and import

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Message-ID: <20250906215417.89584-1-ebiggers@kernel.org>
Date: Sat,  6 Sep 2025 14:54:17 -0700
From: Eric Biggers <ebiggers@...nel.org>
To: linux-crypto@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	Ard Biesheuvel <ardb@...nel.org>,
	"Jason A . Donenfeld" <Jason@...c4.com>,
	Eric Biggers <ebiggers@...nel.org>
Subject: [PATCH] crypto: md5 - Implement export_core() and import_core()

Since commit 9d7a0ab1c753 ("crypto: ahash - Handle partial blocks in
API"), the recently-added export_core() and import_core() methods in
struct shash_alg have effectively become mandatory (even though it is
not tested or enforced), since legacy drivers that need a fallback
depend on them.  Make crypto/md5.c compatible with these legacy drivers
by adding export_core() and import_core() methods to it.

Fixes: ba8ee22a7f92 ("crypto: md5 - Wrap library and add HMAC support")
Signed-off-by: Eric Biggers <ebiggers@...nel.org>
---

This patch is targeting libcrypto-next

 crypto/md5.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/crypto/md5.c b/crypto/md5.c
index d05c53e6f3c2c..c167d203c710a 100644
--- a/crypto/md5.c
+++ b/crypto/md5.c
@@ -44,10 +44,22 @@ static int __crypto_md5_import(struct md5_ctx *ctx, const void *in)
 	p += sizeof(*ctx);
 	ctx->bytecount += *p;
 	return 0;
 }
 
+static int __crypto_md5_export_core(const struct md5_ctx *ctx, void *out)
+{
+	memcpy(out, ctx, offsetof(struct md5_ctx, buf));
+	return 0;
+}
+
+static int __crypto_md5_import_core(struct md5_ctx *ctx, const void *in)
+{
+	memcpy(ctx, in, offsetof(struct md5_ctx, buf));
+	return 0;
+}
+
 const u8 md5_zero_message_hash[MD5_DIGEST_SIZE] = {
 	0xd4, 0x1d, 0x8c, 0xd9, 0x8f, 0x00, 0xb2, 0x04,
 	0xe9, 0x80, 0x09, 0x98, 0xec, 0xf8, 0x42, 0x7e,
 };
 EXPORT_SYMBOL_GPL(md5_zero_message_hash);
@@ -88,10 +100,20 @@ static int crypto_md5_export(struct shash_desc *desc, void *out)
 static int crypto_md5_import(struct shash_desc *desc, const void *in)
 {
 	return __crypto_md5_import(MD5_CTX(desc), in);
 }
 
+static int crypto_md5_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_md5_export_core(MD5_CTX(desc), out);
+}
+
+static int crypto_md5_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_md5_import_core(MD5_CTX(desc), in);
+}
+
 #define HMAC_MD5_KEY(tfm) ((struct hmac_md5_key *)crypto_shash_ctx(tfm))
 #define HMAC_MD5_CTX(desc) ((struct hmac_md5_ctx *)shash_desc_ctx(desc))
 
 static int crypto_hmac_md5_setkey(struct crypto_shash *tfm,
 				  const u8 *raw_key, unsigned int keylen)
@@ -137,10 +159,23 @@ static int crypto_hmac_md5_import(struct shash_desc *desc, const void *in)
 
 	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;
 	return __crypto_md5_import(&ctx->hash_ctx, in);
 }
 
+static int crypto_hmac_md5_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_md5_export_core(&HMAC_MD5_CTX(desc)->hash_ctx, out);
+}
+
+static int crypto_hmac_md5_import_core(struct shash_desc *desc, const void *in)
+{
+	struct hmac_md5_ctx *ctx = HMAC_MD5_CTX(desc);
+
+	ctx->ostate = HMAC_MD5_KEY(desc->tfm)->ostate;
+	return __crypto_md5_import_core(&ctx->hash_ctx, in);
+}
+
 static struct shash_alg algs[] = {
 	{
 		.base.cra_name		= "md5",
 		.base.cra_driver_name	= "md5-lib",
 		.base.cra_priority	= 300,
@@ -151,10 +186,12 @@ static struct shash_alg algs[] = {
 		.update			= crypto_md5_update,
 		.final			= crypto_md5_final,
 		.digest			= crypto_md5_digest,
 		.export			= crypto_md5_export,
 		.import			= crypto_md5_import,
+		.export_core		= crypto_md5_export_core,
+		.import_core		= crypto_md5_import_core,
 		.descsize		= sizeof(struct md5_ctx),
 		.statesize		= MD5_SHASH_STATE_SIZE,
 	},
 	{
 		.base.cra_name		= "hmac(md5)",
@@ -169,10 +206,12 @@ static struct shash_alg algs[] = {
 		.update			= crypto_hmac_md5_update,
 		.final			= crypto_hmac_md5_final,
 		.digest			= crypto_hmac_md5_digest,
 		.export			= crypto_hmac_md5_export,
 		.import			= crypto_hmac_md5_import,
+		.export_core		= crypto_hmac_md5_export_core,
+		.import_core		= crypto_hmac_md5_import_core,
 		.descsize		= sizeof(struct hmac_md5_ctx),
 		.statesize		= MD5_SHASH_STATE_SIZE,
 	},
 };
 

base-commit: 8d2702c5dc96bc441879b83becbccedeb2bd4476
-- 
2.50.1