crypto: hash - Export shash through ahash

This patch allows shash algorithms to be used through the ahash
interface.  This is required before we can convert digest algorithms
over to shash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 144 insertions, 1 deletions

diff --git a/crypto/shash.c b/crypto/shash.c
index 82ec4bd8d2f5..3f4c713a21ea 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -10,6 +10,7 @@
  *
  */
 
+#include <crypto/scatterwalk.h>
 #include <crypto/internal/hash.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
@@ -17,11 +18,15 @@
 #include <linux/slab.h>
 #include <linux/seq_file.h>
 
+static const struct crypto_type crypto_shash_type;
+
 static inline struct crypto_shash *__crypto_shash_cast(struct crypto_tfm *tfm)
 {
         return container_of(tfm, struct crypto_shash, base);
 }
 
+#include "internal.h"
+
 static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
                                   unsigned int keylen)
 {
@@ -167,6 +172,142 @@ int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
 }
 EXPORT_SYMBOL_GPL(crypto_shash_digest);
 
+static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
+                              unsigned int keylen)
+{
+        struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
+
+        return crypto_shash_setkey(*ctx, key, keylen);
+}
+
+static int shash_async_init(struct ahash_request *req)
+{
+        struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+        struct shash_desc *desc = ahash_request_ctx(req);
+
+        desc->tfm = *ctx;
+        desc->flags = req->base.flags;
+
+        return crypto_shash_init(desc);
+}
+
+static int shash_async_update(struct ahash_request *req)
+{
+        struct shash_desc *desc = ahash_request_ctx(req);
+        struct crypto_hash_walk walk;
+        int nbytes;
+
+        for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
+             nbytes = crypto_hash_walk_done(&walk, nbytes))
+                nbytes = crypto_shash_update(desc, walk.data, nbytes);
+
+        return nbytes;
+}
+
+static int shash_async_final(struct ahash_request *req)
+{
+        return crypto_shash_final(ahash_request_ctx(req), req->result);
+}
+
+static int shash_async_digest(struct ahash_request *req)
+{
+        struct scatterlist *sg = req->src;
+        unsigned int offset = sg->offset;
+        unsigned int nbytes = req->nbytes;
+        int err;
+
+        if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
+                struct crypto_shash **ctx =
+                        crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+                struct shash_desc *desc = ahash_request_ctx(req);
+                void *data;
+
+                desc->tfm = *ctx;
+                desc->flags = req->base.flags;
+
+                data = crypto_kmap(sg_page(sg), 0);
+                err = crypto_shash_digest(desc, data + offset, nbytes,
+                                          req->result);
+                crypto_kunmap(data, 0);
+                crypto_yield(desc->flags);
+                goto out;
+        }
+
+        err = shash_async_init(req);
+        if (err)
+                goto out;
+
+        err = shash_async_update(req);
+        if (err)
+                goto out;
+
+        err = shash_async_final(req);
+
+out:
+        return err;
+}
+
+static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
+{
+        struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
+
+        crypto_free_shash(*ctx);
+}
+
+static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
+{
+        struct crypto_alg *calg = tfm->__crt_alg;
+        struct shash_alg *alg = __crypto_shash_alg(calg);
+        struct ahash_tfm *crt = &tfm->crt_ahash;
+        struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
+        struct crypto_shash *shash;
+
+        if (!crypto_mod_get(calg))
+                return -EAGAIN;
+
+        shash = __crypto_shash_cast(crypto_create_tfm(
+                calg, &crypto_shash_type));
+        if (IS_ERR(shash)) {
+                crypto_mod_put(calg);
+                return PTR_ERR(shash);
+        }
+
+        *ctx = shash;
+        tfm->exit = crypto_exit_shash_ops_async;
+
+        crt->init = shash_async_init;
+        crt->update = shash_async_update;
+        crt->final  = shash_async_final;
+        crt->digest = shash_async_digest;
+        crt->setkey = shash_async_setkey;
+
+        crt->digestsize = alg->digestsize;
+        crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
+
+        return 0;
+}
+
+static int crypto_init_shash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
+{
+        switch (mask & CRYPTO_ALG_TYPE_MASK) {
+        case CRYPTO_ALG_TYPE_AHASH_MASK:
+                return crypto_init_shash_ops_async(tfm);
+        }
+
+        return -EINVAL;
+}
+
+static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
+                                         u32 mask)
+{
+        switch (mask & CRYPTO_ALG_TYPE_MASK) {
+        case CRYPTO_ALG_TYPE_AHASH_MASK:
+                return sizeof(struct crypto_shash *);
+        }
+
+        return 0;
+}
+
 static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
                                  const struct crypto_type *frontend)
 {
@@ -194,7 +335,9 @@ static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
 }
 
 static const struct crypto_type crypto_shash_type = {
+        .ctxsize = crypto_shash_ctxsize,
         .extsize = crypto_shash_extsize,
+        .init = crypto_init_shash_ops,
         .init_tfm = crypto_shash_init_tfm,
 #ifdef CONFIG_PROC_FS
         .show = crypto_shash_show,
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index ee95c748695c..44c72f0f9b05 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -38,8 +38,8 @@
 #define CRYPTO_ALG_TYPE_DIGEST          0x00000008
 #define CRYPTO_ALG_TYPE_HASH            0x00000009
 #define CRYPTO_ALG_TYPE_AHASH           0x0000000a
+#define CRYPTO_ALG_TYPE_SHASH           0x0000000b
 #define CRYPTO_ALG_TYPE_RNG             0x0000000c
-#define CRYPTO_ALG_TYPE_SHASH           0x0000000d
 
 #define CRYPTO_ALG_TYPE_HASH_MASK       0x0000000e
 #define CRYPTO_ALG_TYPE_AHASH_MASK      0x0000000c