crypto: rsa-pkcs1pad - simplify error handling in pkcs1pad_create()

Simplify the error handling in pkcs1pad_create() by taking advantage of
crypto_grab_akcipher() now handling an ERR_PTR() name and by taking
advantage of crypto_drop_akcipher() now accepting (as a no-op) a spawn
that hasn't been grabbed yet.

While we're at it, also simplify the way the hash_name optional argument
is handled.  We only need to check whether it's present in one place,
and we can just assign directly to ctx->digest_info.

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

diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index 176b63a..d31031d 100644 (file)
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -596,14 +596,11 @@ static void pkcs1pad_free(struct akcipher_instance *inst)
 
 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 {
-       const struct rsa_asn1_template *digest_info;
        struct crypto_attr_type *algt;
        u32 mask;
        struct akcipher_instance *inst;
        struct pkcs1pad_inst_ctx *ctx;
-       struct crypto_akcipher_spawn *spawn;
        struct akcipher_alg *rsa_alg;
-       const char *rsa_alg_name;
        const char *hash_name;
        int err;
 
@@ -616,60 +613,49 @@ static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
 
        mask = crypto_requires_sync(algt->type, algt->mask);
 
-       rsa_alg_name = crypto_attr_alg_name(tb[1]);
-       if (IS_ERR(rsa_alg_name))
-               return PTR_ERR(rsa_alg_name);
-
-       hash_name = crypto_attr_alg_name(tb[2]);
-       if (IS_ERR(hash_name))
-               hash_name = NULL;
-
-       if (hash_name) {
-               digest_info = rsa_lookup_asn1(hash_name);
-               if (!digest_info)
-                       return -EINVAL;
-       } else
-               digest_info = NULL;
-
        inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
        if (!inst)
                return -ENOMEM;
 
        ctx = akcipher_instance_ctx(inst);
-       spawn = &ctx->spawn;
-       ctx->digest_info = digest_info;
 
-       err = crypto_grab_akcipher(spawn, akcipher_crypto_instance(inst),
-                                  rsa_alg_name, 0, mask);
+       err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
+                                  crypto_attr_alg_name(tb[1]), 0, mask);
        if (err)
-               goto out_free_inst;
+               goto err_free_inst;
 
-       rsa_alg = crypto_spawn_akcipher_alg(spawn);
+       rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
 
        err = -ENAMETOOLONG;
-
-       if (!hash_name) {
+       hash_name = crypto_attr_alg_name(tb[2]);
+       if (IS_ERR(hash_name)) {
                if (snprintf(inst->alg.base.cra_name,
                             CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
                             rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
-                       goto out_drop_alg;
+                       goto err_free_inst;
 
                if (snprintf(inst->alg.base.cra_driver_name,
                             CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
                             rsa_alg->base.cra_driver_name) >=
                             CRYPTO_MAX_ALG_NAME)
-                       goto out_drop_alg;
+                       goto err_free_inst;
        } else {
+               ctx->digest_info = rsa_lookup_asn1(hash_name);
+               if (!ctx->digest_info) {
+                       err = -EINVAL;
+                       goto err_free_inst;
+               }
+
                if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
                             "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
                             hash_name) >= CRYPTO_MAX_ALG_NAME)
-                       goto out_drop_alg;
+                       goto err_free_inst;
 
                if (snprintf(inst->alg.base.cra_driver_name,
                             CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
                             rsa_alg->base.cra_driver_name,
                             hash_name) >= CRYPTO_MAX_ALG_NAME)
-                       goto out_drop_alg;
+                       goto err_free_inst;
        }
 
        inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
@@ -691,15 +677,10 @@ static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
        inst->free = pkcs1pad_free;
 
        err = akcipher_register_instance(tmpl, inst);
-       if (err)
-               goto out_drop_alg;
-
-       return 0;
-
-out_drop_alg:
-       crypto_drop_akcipher(spawn);
-out_free_inst:
-       kfree(inst);
+       if (err) {
+err_free_inst:
+               pkcs1pad_free(inst);
+       }
        return err;
 }