[CRYPTO] aead: Make authsize a run-time parameter

As it is authsize is an algorithm paramter which cannot be changed at
run-time.  This is inconvenient because hardware that implements such
algorithms would have to register each authsize that they support
separately.

Since authsize is a property common to all AEAD algorithms, we can add
a function setauthsize that sets it at run-time, just like setkey.

This patch does exactly that and also changes authenc so that authsize
is no longer a parameter of its template.

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

4 files changed, 38 insertions, 32 deletions

diff --git a/crypto/aead.c b/crypto/aead.c
index 84a3501fb478..f23c2b0ee009 100644
--- a/crypto/aead.c
+++ b/crypto/aead.c
@@ -53,6 +53,24 @@ static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
         return aead->setkey(tfm, key, keylen);
 }
 
+int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
+{
+        int err;
+
+        if (authsize > crypto_aead_alg(tfm)->maxauthsize)
+                return -EINVAL;
+
+        if (crypto_aead_alg(tfm)->setauthsize) {
+                err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
+                if (err)
+                        return err;
+        }
+
+        crypto_aead_crt(tfm)->authsize = authsize;
+        return 0;
+}
+EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
+
 static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
                                         u32 mask)
 {
@@ -64,14 +82,14 @@ static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
         struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
         struct aead_tfm *crt = &tfm->crt_aead;
 
-        if (max(alg->authsize, alg->ivsize) > PAGE_SIZE / 8)
+        if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
                 return -EINVAL;
 
         crt->setkey = setkey;
         crt->encrypt = alg->encrypt;
         crt->decrypt = alg->decrypt;
         crt->ivsize = alg->ivsize;
-        crt->authsize = alg->authsize;
+        crt->authsize = alg->maxauthsize;
 
         return 0;
 }
@@ -85,7 +103,7 @@ static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
         seq_printf(m, "type         : aead\n");
         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
         seq_printf(m, "ivsize       : %u\n", aead->ivsize);
-        seq_printf(m, "authsize     : %u\n", aead->authsize);
+        seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
 }
 
 const struct crypto_type crypto_aead_type = {
diff --git a/crypto/authenc.c b/crypto/authenc.c
index 66fb2aa5c325..5df5fb169cbe 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -24,7 +24,6 @@ struct authenc_instance_ctx {
         struct crypto_spawn auth;
         struct crypto_spawn enc;
 
-        unsigned int authsize;
         unsigned int enckeylen;
 };
 
@@ -76,8 +75,6 @@ out:
 static int crypto_authenc_hash(struct aead_request *req)
 {
         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
-        struct authenc_instance_ctx *ictx =
-                crypto_instance_ctx(crypto_aead_alg_instance(authenc));
         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
         struct crypto_hash *auth = ctx->auth;
         struct hash_desc desc = {
@@ -111,7 +108,8 @@ auth_unlock:
         if (err)
                 return err;
 
-        scatterwalk_map_and_copy(hash, dst, cryptlen, ictx->authsize, 1);
+        scatterwalk_map_and_copy(hash, dst, cryptlen,
+                                 crypto_aead_authsize(authenc), 1);
         return 0;
 }
 
@@ -147,8 +145,6 @@ static int crypto_authenc_encrypt(struct aead_request *req)
 static int crypto_authenc_verify(struct aead_request *req)
 {
         struct crypto_aead *authenc = crypto_aead_reqtfm(req);
-        struct authenc_instance_ctx *ictx =
-                crypto_instance_ctx(crypto_aead_alg_instance(authenc));
         struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
         struct crypto_hash *auth = ctx->auth;
         struct hash_desc desc = {
@@ -186,7 +182,7 @@ auth_unlock:
         if (err)
                 return err;
 
-        authsize = ictx->authsize;
+        authsize = crypto_aead_authsize(authenc);
         scatterwalk_map_and_copy(ihash, src, cryptlen, authsize, 0);
         return memcmp(ihash, ohash, authsize) ? -EINVAL : 0;
 }
@@ -224,18 +220,12 @@ static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
         struct crypto_authenc_ctx *ctx = crypto_tfm_ctx(tfm);
         struct crypto_hash *auth;
         struct crypto_ablkcipher *enc;
-        unsigned int digestsize;
         int err;
 
         auth = crypto_spawn_hash(&ictx->auth);
         if (IS_ERR(auth))
                 return PTR_ERR(auth);
 
-        err = -EINVAL;
-        digestsize = crypto_hash_digestsize(auth);
-        if (ictx->authsize > digestsize)
-                goto err_free_hash;
-
         enc = crypto_spawn_ablkcipher(&ictx->enc);
         err = PTR_ERR(enc);
         if (IS_ERR(enc))
@@ -246,7 +236,7 @@ static int crypto_authenc_init_tfm(struct crypto_tfm *tfm)
         tfm->crt_aead.reqsize = max_t(unsigned int,
                                       (crypto_hash_alignmask(auth) &
                                        ~(crypto_tfm_ctx_alignment() - 1)) +
-                                      digestsize * 2,
+                                      crypto_hash_digestsize(auth) * 2,
                                       sizeof(struct ablkcipher_request) +
                                       crypto_ablkcipher_reqsize(enc));
 
@@ -273,7 +263,6 @@ static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
         struct crypto_alg *auth;
         struct crypto_alg *enc;
         struct authenc_instance_ctx *ctx;
-        unsigned int authsize;
         unsigned int enckeylen;
         int err;
 
@@ -286,18 +275,13 @@ static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
         if (IS_ERR(auth))
                 return ERR_PTR(PTR_ERR(auth));
 
-        err = crypto_attr_u32(tb[2], &authsize);
-        inst = ERR_PTR(err);
-        if (err)
-                goto out_put_auth;
-
-        enc = crypto_attr_alg(tb[3], CRYPTO_ALG_TYPE_BLKCIPHER,
+        enc = crypto_attr_alg(tb[2], CRYPTO_ALG_TYPE_BLKCIPHER,
                               CRYPTO_ALG_TYPE_BLKCIPHER_MASK);
         inst = ERR_PTR(PTR_ERR(enc));
         if (IS_ERR(enc))
                 goto out_put_auth;
 
-        err = crypto_attr_u32(tb[4], &enckeylen);
+        err = crypto_attr_u32(tb[3], &enckeylen);
         if (err)
                 goto out_put_enc;
 
@@ -308,18 +292,17 @@ static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
 
         err = -ENAMETOOLONG;
         if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
-                     "authenc(%s,%u,%s,%u)", auth->cra_name, authsize,
+                     "authenc(%s,%s,%u)", auth->cra_name,
                      enc->cra_name, enckeylen) >= CRYPTO_MAX_ALG_NAME)
                 goto err_free_inst;
 
         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
-                     "authenc(%s,%u,%s,%u)", auth->cra_driver_name,
-                     authsize, enc->cra_driver_name, enckeylen) >=
+                     "authenc(%s,%s,%u)", auth->cra_driver_name,
+                     enc->cra_driver_name, enckeylen) >=
             CRYPTO_MAX_ALG_NAME)
                 goto err_free_inst;
 
         ctx = crypto_instance_ctx(inst);
-        ctx->authsize = authsize;
         ctx->enckeylen = enckeylen;
 
         err = crypto_init_spawn(&ctx->auth, auth, inst, CRYPTO_ALG_TYPE_MASK);
@@ -337,7 +320,9 @@ static struct crypto_instance *crypto_authenc_alloc(struct rtattr **tb)
         inst->alg.cra_type = &crypto_aead_type;
 
         inst->alg.cra_aead.ivsize = enc->cra_blkcipher.ivsize;
-        inst->alg.cra_aead.authsize = authsize;
+        inst->alg.cra_aead.maxauthsize = auth->cra_type == &crypto_hash_type ?
+                                         auth->cra_hash.digestsize :
+                                         auth->cra_digest.dia_digestsize;
 
         inst->alg.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
 
diff --git a/crypto/gcm.c b/crypto/gcm.c
index ad8b8b9aeef2..5681c7957b88 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -414,7 +414,7 @@ static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
         inst->alg.cra_alignmask = __alignof__(u32) - 1;
         inst->alg.cra_type = &crypto_aead_type;
         inst->alg.cra_aead.ivsize = 12;
-        inst->alg.cra_aead.authsize = 16;
+        inst->alg.cra_aead.maxauthsize = 16;
         inst->alg.cra_ctxsize = sizeof(struct crypto_gcm_ctx);
         inst->alg.cra_init = crypto_gcm_init_tfm;
         inst->alg.cra_exit = crypto_gcm_exit_tfm;
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index f56ae8721bc9..48aa5959abbb 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -187,11 +187,12 @@ struct ablkcipher_alg {
 struct aead_alg {
         int (*setkey)(struct crypto_aead *tfm, const u8 *key,
                       unsigned int keylen);
+        int (*setauthsize)(struct crypto_aead *tfm, unsigned int authsize);
         int (*encrypt)(struct aead_request *req);
         int (*decrypt)(struct aead_request *req);
 
         unsigned int ivsize;
-        unsigned int authsize;
+        unsigned int maxauthsize;
 };
 
 struct blkcipher_alg {
@@ -754,6 +755,8 @@ static inline int crypto_aead_setkey(struct crypto_aead *tfm, const u8 *key,
         return crypto_aead_crt(tfm)->setkey(tfm, key, keylen);
 }
 
+int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize);
+
 static inline struct crypto_aead *crypto_aead_reqtfm(struct aead_request *req)
 {
         return __crypto_aead_cast(req->base.tfm);