lib/crypto: sha256: Make library API use strongly-typed contexts

Currently the SHA-224 and SHA-256 library functions can be mixed
arbitrarily, even in ways that are incorrect, for example using
sha224_init() and sha256_final().  This is because they operate on the
same structure, sha256_state.

Introduce stronger typing, as I did for SHA-384 and SHA-512.

Also as I did for SHA-384 and SHA-512, use the names *_ctx instead of
*_state.  The *_ctx names have the following small benefits:

- They're shorter.
- They avoid an ambiguity with the compression function state.
- They're consistent with the well-known OpenSSL API.
- Users usually name the variable 'sctx' anyway, which suggests that
  *_ctx would be the more natural name for the actual struct.

Therefore: update the SHA-224 and SHA-256 APIs, implementation, and
calling code accordingly.

In the new structs, also strongly-type the compression function state.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250630160645.3198-7-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

1 files changed, 6 insertions, 6 deletions

diff --git a/drivers/char/tpm/tpm2-sessions.c b/drivers/char/tpm/tpm2-sessions.c
index 7b5049b3d476..bdb119453dfb 100644
--- a/drivers/char/tpm/tpm2-sessions.c
+++ b/drivers/char/tpm/tpm2-sessions.c
@@ -390,7 +390,7 @@ static int tpm2_create_primary(struct tpm_chip *chip, u32 hierarchy,
  * on every operation, so we weld the hmac init and final functions in
  * here to give it the same usage characteristics as a regular hash
  */
-static void tpm2_hmac_init(struct sha256_state *sctx, u8 *key, u32 key_len)
+static void tpm2_hmac_init(struct sha256_ctx *sctx, u8 *key, u32 key_len)
 {
 	u8 pad[SHA256_BLOCK_SIZE];
 	int i;
@@ -406,7 +406,7 @@ static void tpm2_hmac_init(struct sha256_state *sctx, u8 *key, u32 key_len)
 	sha256_update(sctx, pad, sizeof(pad));
 }
 
-static void tpm2_hmac_final(struct sha256_state *sctx, u8 *key, u32 key_len,
+static void tpm2_hmac_final(struct sha256_ctx *sctx, u8 *key, u32 key_len,
 			    u8 *out)
 {
 	u8 pad[SHA256_BLOCK_SIZE];
@@ -440,7 +440,7 @@ static void tpm2_KDFa(u8 *key, u32 key_len, const char *label, u8 *u,
 	const __be32 bits = cpu_to_be32(bytes * 8);
 
 	while (bytes > 0) {
-		struct sha256_state sctx;
+		struct sha256_ctx sctx;
 		__be32 c = cpu_to_be32(counter);
 
 		tpm2_hmac_init(&sctx, key, key_len);
@@ -467,7 +467,7 @@ static void tpm2_KDFa(u8 *key, u32 key_len, const char *label, u8 *u,
 static void tpm2_KDFe(u8 z[EC_PT_SZ], const char *str, u8 *pt_u, u8 *pt_v,
 		      u8 *out)
 {
-	struct sha256_state sctx;
+	struct sha256_ctx sctx;
 	/*
 	 * this should be an iterative counter, but because we know
 	 *  we're only taking 32 bytes for the point using a sha256
@@ -592,7 +592,7 @@ void tpm_buf_fill_hmac_session(struct tpm_chip *chip, struct tpm_buf *buf)
 	u8 *hmac = NULL;
 	u32 attrs;
 	u8 cphash[SHA256_DIGEST_SIZE];
-	struct sha256_state sctx;
+	struct sha256_ctx sctx;
 
 	if (!auth)
 		return;
@@ -750,7 +750,7 @@ int tpm_buf_check_hmac_response(struct tpm_chip *chip, struct tpm_buf *buf,
 	off_t offset_s, offset_p;
 	u8 rphash[SHA256_DIGEST_SIZE];
 	u32 attrs, cc;
-	struct sha256_state sctx;
+	struct sha256_ctx sctx;
 	u16 tag = be16_to_cpu(head->tag);
 	int parm_len, len, i, handles;