[PATCH 09/18] lib/crypto: sha256: Add sha224() and sha224_update()

[Eric Biggers]

Add a one-shot SHA-224 computation function sha224(), for consistency
with sha256(), sha384(), and sha512() which all already exist.

Similarly, add sha224_update().  While for now it's identical to
sha256_update(), omitting it makes the API harder to use since users
have to "know" which functions are the same between SHA-224 and SHA-256.
Also, this is a prerequisite for using different context types for each.

Signed-off-by: Eric Biggers <ebiggers at kernel.org>
---
 include/crypto/sha2.h           | 10 ++++++++--
 lib/crypto/sha256.c             | 10 ++++++++++
 lib/crypto/tests/sha224_kunit.c | 13 +------------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/include/crypto/sha2.h b/include/crypto/sha2.h
index bb181b7996cdc..e31da0743a522 100644
--- a/include/crypto/sha2.h
+++ b/include/crypto/sha2.h
@@ -112,22 +112,28 @@ struct sha512_state {
 	u64 state[SHA512_DIGEST_SIZE / 8];
 	u64 count[2];
 	u8 buf[SHA512_BLOCK_SIZE];
 };
 
+void sha256_update(struct sha256_state *sctx, const u8 *data, size_t len);
+
 static inline void sha224_init(struct sha256_state *sctx)
 {
 	sha224_block_init(&sctx->ctx);
 }
-/* Simply use sha256_update as it is equivalent to sha224_update. */
+static inline void sha224_update(struct sha256_state *sctx,
+				 const u8 *data, size_t len)
+{
+	sha256_update(sctx, data, len);
+}
 void sha224_final(struct sha256_state *sctx, u8 out[SHA224_DIGEST_SIZE]);
+void sha224(const u8 *data, size_t len, u8 out[SHA224_DIGEST_SIZE]);
 
 static inline void sha256_init(struct sha256_state *sctx)
 {
 	sha256_block_init(&sctx->ctx);
 }
-void sha256_update(struct sha256_state *sctx, const u8 *data, size_t len);
 void sha256_final(struct sha256_state *sctx, u8 out[SHA256_DIGEST_SIZE]);
 void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE]);
 
 /* State for the SHA-512 (and SHA-384) compression function */
 struct sha512_block_state {
diff --git a/lib/crypto/sha256.c b/lib/crypto/sha256.c
index 573ccecbf48bf..ccaae70880166 100644
--- a/lib/crypto/sha256.c
+++ b/lib/crypto/sha256.c
@@ -68,10 +68,20 @@ void sha256_final(struct sha256_state *sctx, u8 out[SHA256_DIGEST_SIZE])
 {
 	__sha256_final(sctx, out, SHA256_DIGEST_SIZE);
 }
 EXPORT_SYMBOL(sha256_final);
 
+void sha224(const u8 *data, size_t len, u8 out[SHA224_DIGEST_SIZE])
+{
+	struct sha256_state sctx;
+
+	sha224_init(&sctx);
+	sha224_update(&sctx, data, len);
+	sha224_final(&sctx, out);
+}
+EXPORT_SYMBOL(sha224);
+
 void sha256(const u8 *data, size_t len, u8 out[SHA256_DIGEST_SIZE])
 {
 	struct sha256_state sctx;
 
 	sha256_init(&sctx);
diff --git a/lib/crypto/tests/sha224_kunit.c b/lib/crypto/tests/sha224_kunit.c
index 5015861a55112..c484c1d4a2a5e 100644
--- a/lib/crypto/tests/sha224_kunit.c
+++ b/lib/crypto/tests/sha224_kunit.c
@@ -3,26 +3,15 @@
  * Copyright 2025 Google LLC
  */
 #include <crypto/sha2.h>
 #include "sha224-testvecs.h"
 
-/* TODO: add sha224() to the library itself */
-static inline void sha224(const u8 *data, size_t len,
-			  u8 out[SHA224_DIGEST_SIZE])
-{
-	struct sha256_state state;
-
-	sha224_init(&state);
-	sha256_update(&state, data, len);
-	sha224_final(&state, out);
-}
-
 #define HASH sha224
 #define HASH_CTX sha256_state
 #define HASH_SIZE SHA224_DIGEST_SIZE
 #define HASH_INIT sha224_init
-#define HASH_UPDATE sha256_update
+#define HASH_UPDATE sha224_update
 #define HASH_FINAL sha224_final
 #define HASH_TESTVECS sha224_testvecs
 /* TODO: add HMAC-SHA224 support to the library, then enable the tests for it */
 #include "hash-test-template.h"
 
-- 
2.50.0