crypto: chacha20poly1305 - use crypto_grab_ahash() and simplify error paths

Make the rfc7539 and rfc7539esp templates use the new function
crypto_grab_ahash() to initialize their ahash spawn.

This is needed to make all spawns be initialized in a consistent way.

Also simplify the error handling by taking advantage of crypto_drop_*()
now accepting (as a no-op) spawns that haven't been initialized yet, and
by taking advantage of crypto_grab_*() now handling ERR_PTR() names.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/chacha20poly1305.c b/crypto/chacha20poly1305.c
index 09d5a34..ccaea5c 100644 (file)
--- a/crypto/chacha20poly1305.c
+++ b/crypto/chacha20poly1305.c
@@ -16,8 +16,6 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 
-#include "internal.h"
-
 struct chachapoly_instance_ctx {
        struct crypto_skcipher_spawn chacha;
        struct crypto_ahash_spawn poly;
@@ -560,11 +558,9 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
        struct crypto_attr_type *algt;
        u32 mask;
        struct aead_instance *inst;
-       struct skcipher_alg *chacha;
-       struct crypto_alg *poly;
-       struct hash_alg_common *poly_hash;
        struct chachapoly_instance_ctx *ctx;
-       const char *chacha_name, *poly_name;
+       struct skcipher_alg *chacha;
+       struct hash_alg_common *poly;
        int err;
 
        if (ivsize > CHACHAPOLY_IV_SIZE)
@@ -579,68 +575,51 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
 
        mask = crypto_requires_sync(algt->type, algt->mask);
 
-       chacha_name = crypto_attr_alg_name(tb[1]);
-       if (IS_ERR(chacha_name))
-               return PTR_ERR(chacha_name);
-       poly_name = crypto_attr_alg_name(tb[2]);
-       if (IS_ERR(poly_name))
-               return PTR_ERR(poly_name);
-
-       poly = crypto_find_alg(poly_name, &crypto_ahash_type,
-                              CRYPTO_ALG_TYPE_HASH,
-                              CRYPTO_ALG_TYPE_AHASH_MASK | mask);
-       if (IS_ERR(poly))
-               return PTR_ERR(poly);
-       poly_hash = __crypto_hash_alg_common(poly);
-
-       err = -EINVAL;
-       if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
-               goto out_put_poly;
-
-       err = -ENOMEM;
        inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
        if (!inst)
-               goto out_put_poly;
-
+               return -ENOMEM;
        ctx = aead_instance_ctx(inst);
        ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
-       err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
-                                     aead_crypto_instance(inst));
-       if (err)
-               goto err_free_inst;
 
        err = crypto_grab_skcipher(&ctx->chacha, aead_crypto_instance(inst),
-                                  chacha_name, 0, mask);
+                                  crypto_attr_alg_name(tb[1]), 0, mask);
        if (err)
-               goto err_drop_poly;
-
+               goto err_free_inst;
        chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
 
+       err = crypto_grab_ahash(&ctx->poly, aead_crypto_instance(inst),
+                               crypto_attr_alg_name(tb[2]), 0, mask);
+       if (err)
+               goto err_free_inst;
+       poly = crypto_spawn_ahash_alg(&ctx->poly);
+
        err = -EINVAL;
+       if (poly->digestsize != POLY1305_DIGEST_SIZE)
+               goto err_free_inst;
        /* Need 16-byte IV size, including Initial Block Counter value */
        if (crypto_skcipher_alg_ivsize(chacha) != CHACHA_IV_SIZE)
-               goto out_drop_chacha;
+               goto err_free_inst;
        /* Not a stream cipher? */
        if (chacha->base.cra_blocksize != 1)
-               goto out_drop_chacha;
+               goto err_free_inst;
 
        err = -ENAMETOOLONG;
        if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
                     "%s(%s,%s)", name, chacha->base.cra_name,
-                    poly->cra_name) >= CRYPTO_MAX_ALG_NAME)
-               goto out_drop_chacha;
+                    poly->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
+               goto err_free_inst;
        if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
                     "%s(%s,%s)", name, chacha->base.cra_driver_name,
-                    poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
-               goto out_drop_chacha;
+                    poly->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
+               goto err_free_inst;
 
-       inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
-                                  CRYPTO_ALG_ASYNC;
+       inst->alg.base.cra_flags = (chacha->base.cra_flags |
+                                   poly->base.cra_flags) & CRYPTO_ALG_ASYNC;
        inst->alg.base.cra_priority = (chacha->base.cra_priority +
-                                      poly->cra_priority) / 2;
+                                      poly->base.cra_priority) / 2;
        inst->alg.base.cra_blocksize = 1;
        inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
-                                      poly->cra_alignmask;
+                                      poly->base.cra_alignmask;
        inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
                                     ctx->saltlen;
        inst->alg.ivsize = ivsize;
@@ -656,20 +635,11 @@ static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
        inst->free = chachapoly_free;
 
        err = aead_register_instance(tmpl, inst);
-       if (err)
-               goto out_drop_chacha;
-
-out_put_poly:
-       crypto_mod_put(poly);
-       return err;
-
-out_drop_chacha:
-       crypto_drop_skcipher(&ctx->chacha);
-err_drop_poly:
-       crypto_drop_ahash(&ctx->poly);
+       if (err) {
 err_free_inst:
-       kfree(inst);
-       goto out_put_poly;
+               chachapoly_free(inst);
+       }
+       return err;
 }
 
 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)