[PATCH v2 2/8] crypto/sha256: Export a sha256_{init,update,final}_direct() API

From: Andy Lutomirski
Date: Tue Jan 10 2017 - 18:25:08 EST


This provides a very simple interface for kernel code to use to do
synchronous, unaccelerated, virtual-address-based SHA256 hashing
without needing to create a crypto context.

Subsequent patches will make this work without building the crypto
core and will use to avoid making BPF-based tracing depend on
crypto.

Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
crypto/sha256_generic.c | 31 ++++++++++++++++++++++++++-----
include/crypto/sha.h | 24 ++++++++++++++++++++++++
include/crypto/sha256_base.h | 13 -------------
3 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/crypto/sha256_generic.c b/crypto/sha256_generic.c
index 8f9c47e1a96e..573e114382f9 100644
--- a/crypto/sha256_generic.c
+++ b/crypto/sha256_generic.c
@@ -240,24 +240,45 @@ static void sha256_generic_block_fn(struct sha256_state *sst, u8 const *src,
}
}

+void sha256_update_direct(struct sha256_state *sctx, const u8 *data,
+ unsigned int len)
+{
+ __sha256_base_do_update(sctx, data, len, sha256_generic_block_fn);
+}
+EXPORT_SYMBOL(sha256_update_direct);
+
int crypto_sha256_update(struct shash_desc *desc, const u8 *data,
unsigned int len)
{
- return sha256_base_do_update(desc, data, len, sha256_generic_block_fn);
+ sha256_update_direct(shash_desc_ctx(desc), data, len);
+ return 0;
}
EXPORT_SYMBOL(crypto_sha256_update);

static int sha256_final(struct shash_desc *desc, u8 *out)
{
- sha256_base_do_finalize(desc, sha256_generic_block_fn);
- return sha256_base_finish(desc, out);
+ __sha256_final_direct(shash_desc_ctx(desc),
+ crypto_shash_digestsize(desc->tfm), out);
+ return 0;
}

+void __sha256_final_direct(struct sha256_state *sctx, unsigned int digest_size,
+ u8 *out)
+{
+ sha256_do_finalize_direct(sctx, sha256_generic_block_fn);
+ __sha256_base_finish(sctx, digest_size, out);
+}
+EXPORT_SYMBOL(sha256_final_direct);
+
int crypto_sha256_finup(struct shash_desc *desc, const u8 *data,
unsigned int len, u8 *hash)
{
- sha256_base_do_update(desc, data, len, sha256_generic_block_fn);
- return sha256_final(desc, hash);
+ struct sha256_state *sctx = shash_desc_ctx(desc);
+ unsigned int digest_size = crypto_shash_digestsize(desc->tfm);
+
+ sha256_update_direct(sctx, data, len);
+ __sha256_final_direct(sctx, digest_size, hash);
+ return 0;
}
EXPORT_SYMBOL(crypto_sha256_finup);

diff --git a/include/crypto/sha.h b/include/crypto/sha.h
index c94d3eb1cefd..0df1a0e42c95 100644
--- a/include/crypto/sha.h
+++ b/include/crypto/sha.h
@@ -88,6 +88,30 @@ struct sha512_state {
u8 buf[SHA512_BLOCK_SIZE];
};

+static inline void sha256_init_direct(struct sha256_state *sctx)
+{
+ sctx->state[0] = SHA256_H0;
+ sctx->state[1] = SHA256_H1;
+ sctx->state[2] = SHA256_H2;
+ sctx->state[3] = SHA256_H3;
+ sctx->state[4] = SHA256_H4;
+ sctx->state[5] = SHA256_H5;
+ sctx->state[6] = SHA256_H6;
+ sctx->state[7] = SHA256_H7;
+ sctx->count = 0;
+}
+
+extern void sha256_update_direct(struct sha256_state *sctx, const u8 *data,
+ unsigned int len);
+
+extern void __sha256_final_direct(struct sha256_state *sctx,
+ unsigned int digest_size, u8 *out);
+
+static inline void sha256_final_direct(struct sha256_state *sctx, u8 *out)
+{
+ __sha256_final_direct(sctx, SHA256_DIGEST_SIZE, out);
+}
+
struct shash_desc;

extern int crypto_sha1_update(struct shash_desc *desc, const u8 *data,
diff --git a/include/crypto/sha256_base.h b/include/crypto/sha256_base.h
index fc77b8e099a7..9bbe73ce458f 100644
--- a/include/crypto/sha256_base.h
+++ b/include/crypto/sha256_base.h
@@ -37,19 +37,6 @@ static inline int sha224_base_init(struct shash_desc *desc)
return 0;
}

-static inline void sha256_init_direct(struct sha256_state *sctx)
-{
- sctx->state[0] = SHA256_H0;
- sctx->state[1] = SHA256_H1;
- sctx->state[2] = SHA256_H2;
- sctx->state[3] = SHA256_H3;
- sctx->state[4] = SHA256_H4;
- sctx->state[5] = SHA256_H5;
- sctx->state[6] = SHA256_H6;
- sctx->state[7] = SHA256_H7;
- sctx->count = 0;
-}
-
static inline int sha256_base_init(struct shash_desc *desc)
{
sha256_init_direct(shash_desc_ctx(desc));
--
2.9.3