[PATCH 2/3] crypto: sha256 - Implement export_core() and import_core()

[Eric Biggers <ebiggers@kernel.org>]

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/sha256.c compatible with these legacy
drivers by adding export_core() and import_core() methods to it.

Reported-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reported-by: Ovidiu Panait <ovidiu.panait.oss@gmail.com>
Closes: https://lore.kernel.org/r/aLSnCc9Ws5L9y+8X@gcabiddu-mobl.ger.corp.intel.com
Fixes: 07f090959bba ("crypto: sha256 - Use same state format as legacy drivers")
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 crypto/sha256.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

diff --git a/crypto/sha256.c b/crypto/sha256.c
index 052806559f06c..fb81defe084c6 100644
--- a/crypto/sha256.c
+++ b/crypto/sha256.c
@@ -48,10 +48,23 @@ static int __crypto_sha256_import(struct __sha256_ctx *ctx, const void *in)
 	p += sizeof(*ctx);
 	ctx->bytecount += *p;
 	return 0;
 }
 
+static int __crypto_sha256_export_core(const struct __sha256_ctx *ctx,
+				       void *out)
+{
+	memcpy(out, ctx, offsetof(struct __sha256_ctx, buf));
+	return 0;
+}
+
+static int __crypto_sha256_import_core(struct __sha256_ctx *ctx, const void *in)
+{
+	memcpy(ctx, in, offsetof(struct __sha256_ctx, buf));
+	return 0;
+}
+
 /* SHA-224 */
 
 const u8 sha224_zero_message_hash[SHA224_DIGEST_SIZE] = {
 	0xd1, 0x4a, 0x02, 0x8c, 0x2a, 0x3a, 0x2b, 0xc9, 0x47,
 	0x61, 0x02, 0xbb, 0x28, 0x82, 0x34, 0xc4, 0x15, 0xa2,
@@ -96,10 +109,20 @@ static int crypto_sha224_export(struct shash_desc *desc, void *out)
 static int crypto_sha224_import(struct shash_desc *desc, const void *in)
 {
 	return __crypto_sha256_import(&SHA224_CTX(desc)->ctx, in);
 }
 
+static int crypto_sha224_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&SHA224_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha224_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha256_import_core(&SHA224_CTX(desc)->ctx, in);
+}
+
 /* SHA-256 */
 
 const u8 sha256_zero_message_hash[SHA256_DIGEST_SIZE] = {
 	0xe3, 0xb0, 0xc4, 0x42, 0x98, 0xfc, 0x1c, 0x14,
 	0x9a, 0xfb, 0xf4, 0xc8, 0x99, 0x6f, 0xb9, 0x24,
@@ -144,10 +167,20 @@ static int crypto_sha256_export(struct shash_desc *desc, void *out)
 static int crypto_sha256_import(struct shash_desc *desc, const void *in)
 {
 	return __crypto_sha256_import(&SHA256_CTX(desc)->ctx, in);
 }
 
+static int crypto_sha256_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&SHA256_CTX(desc)->ctx, out);
+}
+
+static int crypto_sha256_import_core(struct shash_desc *desc, const void *in)
+{
+	return __crypto_sha256_import_core(&SHA256_CTX(desc)->ctx, in);
+}
+
 /* HMAC-SHA224 */
 
 #define HMAC_SHA224_KEY(tfm) ((struct hmac_sha224_key *)crypto_shash_ctx(tfm))
 #define HMAC_SHA224_CTX(desc) ((struct hmac_sha224_ctx *)shash_desc_ctx(desc))
 
@@ -196,10 +229,25 @@ static int crypto_hmac_sha224_import(struct shash_desc *desc, const void *in)
 
 	ctx->ctx.ostate = HMAC_SHA224_KEY(desc->tfm)->key.ostate;
 	return __crypto_sha256_import(&ctx->ctx.sha_ctx, in);
 }
 
+static int crypto_hmac_sha224_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&HMAC_SHA224_CTX(desc)->ctx.sha_ctx,
+					   out);
+}
+
+static int crypto_hmac_sha224_import_core(struct shash_desc *desc,
+					  const void *in)
+{
+	struct hmac_sha224_ctx *ctx = HMAC_SHA224_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA224_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha256_import_core(&ctx->ctx.sha_ctx, in);
+}
+
 /* HMAC-SHA256 */
 
 #define HMAC_SHA256_KEY(tfm) ((struct hmac_sha256_key *)crypto_shash_ctx(tfm))
 #define HMAC_SHA256_CTX(desc) ((struct hmac_sha256_ctx *)shash_desc_ctx(desc))
 
@@ -248,10 +296,25 @@ static int crypto_hmac_sha256_import(struct shash_desc *desc, const void *in)
 
 	ctx->ctx.ostate = HMAC_SHA256_KEY(desc->tfm)->key.ostate;
 	return __crypto_sha256_import(&ctx->ctx.sha_ctx, in);
 }
 
+static int crypto_hmac_sha256_export_core(struct shash_desc *desc, void *out)
+{
+	return __crypto_sha256_export_core(&HMAC_SHA256_CTX(desc)->ctx.sha_ctx,
+					   out);
+}
+
+static int crypto_hmac_sha256_import_core(struct shash_desc *desc,
+					  const void *in)
+{
+	struct hmac_sha256_ctx *ctx = HMAC_SHA256_CTX(desc);
+
+	ctx->ctx.ostate = HMAC_SHA256_KEY(desc->tfm)->key.ostate;
+	return __crypto_sha256_import_core(&ctx->ctx.sha_ctx, in);
+}
+
 /* Algorithm definitions */
 
 static struct shash_alg algs[] = {
 	{
 		.base.cra_name		= "sha224",
@@ -264,10 +327,12 @@ static struct shash_alg algs[] = {
 		.update			= crypto_sha224_update,
 		.final			= crypto_sha224_final,
 		.digest			= crypto_sha224_digest,
 		.export			= crypto_sha224_export,
 		.import			= crypto_sha224_import,
+		.export_core		= crypto_sha224_export_core,
+		.import_core		= crypto_sha224_import_core,
 		.descsize		= sizeof(struct sha224_ctx),
 		.statesize		= SHA256_SHASH_STATE_SIZE,
 	},
 	{
 		.base.cra_name		= "sha256",
@@ -280,10 +345,12 @@ static struct shash_alg algs[] = {
 		.update			= crypto_sha256_update,
 		.final			= crypto_sha256_final,
 		.digest			= crypto_sha256_digest,
 		.export			= crypto_sha256_export,
 		.import			= crypto_sha256_import,
+		.export_core		= crypto_sha256_export_core,
+		.import_core		= crypto_sha256_import_core,
 		.descsize		= sizeof(struct sha256_ctx),
 		.statesize		= SHA256_SHASH_STATE_SIZE,
 	},
 	{
 		.base.cra_name		= "hmac(sha224)",
@@ -298,10 +365,12 @@ static struct shash_alg algs[] = {
 		.update			= crypto_hmac_sha224_update,
 		.final			= crypto_hmac_sha224_final,
 		.digest			= crypto_hmac_sha224_digest,
 		.export			= crypto_hmac_sha224_export,
 		.import			= crypto_hmac_sha224_import,
+		.export_core		= crypto_hmac_sha224_export_core,
+		.import_core		= crypto_hmac_sha224_import_core,
 		.descsize		= sizeof(struct hmac_sha224_ctx),
 		.statesize		= SHA256_SHASH_STATE_SIZE,
 	},
 	{
 		.base.cra_name		= "hmac(sha256)",
@@ -316,10 +385,12 @@ static struct shash_alg algs[] = {
 		.update			= crypto_hmac_sha256_update,
 		.final			= crypto_hmac_sha256_final,
 		.digest			= crypto_hmac_sha256_digest,
 		.export			= crypto_hmac_sha256_export,
 		.import			= crypto_hmac_sha256_import,
+		.export_core		= crypto_hmac_sha256_export_core,
+		.import_core		= crypto_hmac_sha256_import_core,
 		.descsize		= sizeof(struct hmac_sha256_ctx),
 		.statesize		= SHA256_SHASH_STATE_SIZE,
 	},
 };
 
-- 
2.50.1