[v4 PATCH 7/8] crypto: rsa-pkcs1pad - Move key size check to setkey

[Herbert Xu <herbert@gondor.apana.org.au>]

Rather than repeatedly checking the key size on each operation,
we should be checking it once when the key is set.

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

 crypto/rsa-pkcs1pad.c |   56 +++++++++++++++++++++++---------------------------
 1 file changed, 26 insertions(+), 30 deletions(-)

diff --git a/crypto/rsa-pkcs1pad.c b/crypto/rsa-pkcs1pad.c
index db19284..ebd8514 100644
--- a/crypto/rsa-pkcs1pad.c
+++ b/crypto/rsa-pkcs1pad.c
@@ -111,40 +111,48 @@ static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
 		unsigned int keylen)
 {
 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
-	int err, size;
+	int err;
+
+	ctx->key_size = 0;
 
 	err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
+	if (err)
+		return err;
 
-	if (!err) {
-		/* Find out new modulus size from rsa implementation */
-		size = crypto_akcipher_maxsize(ctx->child);
+	/* Find out new modulus size from rsa implementation */
+	err = crypto_akcipher_maxsize(ctx->child);
+	if (err < 0)
+		return err;
 
-		ctx->key_size = size > 0 ? size : 0;
-		if (size <= 0)
-			err = size;
-	}
+	if (err > PAGE_SIZE)
+		return -ENOTSUPP;
 
-	return err;
+	ctx->key_size = err;
+	return 0;
 }
 
 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
 		unsigned int keylen)
 {
 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
-	int err, size;
+	int err;
+
+	ctx->key_size = 0;
 
 	err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
+	if (err)
+		return err;
 
-	if (!err) {
-		/* Find out new modulus size from rsa implementation */
-		size = crypto_akcipher_maxsize(ctx->child);
+	/* Find out new modulus size from rsa implementation */
+	err = crypto_akcipher_maxsize(ctx->child);
+	if (err < 0)
+		return err;
 
-		ctx->key_size = size > 0 ? size : 0;
-		if (size <= 0)
-			err = size;
-	}
+	if (err > PAGE_SIZE)
+		return -ENOTSUPP;
 
-	return err;
+	ctx->key_size = err;
+	return 0;
 }
 
 static int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
@@ -247,9 +255,6 @@ static int pkcs1pad_encrypt(struct akcipher_request *req)
 		return -EOVERFLOW;
 	}
 
-	if (ctx->key_size > PAGE_SIZE)
-		return -ENOTSUPP;
-
 	/*
 	 * Replace both input and output to add the padding in the input and
 	 * the potential missing leading zeros in the output.
@@ -367,9 +372,6 @@ static int pkcs1pad_decrypt(struct akcipher_request *req)
 	if (!ctx->key_size || req->src_len != ctx->key_size)
 		return -EINVAL;
 
-	if (ctx->key_size > PAGE_SIZE)
-		return -ENOTSUPP;
-
 	/* Reuse input buffer, output to a new buffer */
 	req_ctx->child_req.src = req->src;
 	req_ctx->child_req.src_len = req->src_len;
@@ -420,9 +422,6 @@ static int pkcs1pad_sign(struct akcipher_request *req)
 		return -EOVERFLOW;
 	}
 
-	if (ctx->key_size > PAGE_SIZE)
-		return -ENOTSUPP;
-
 	/*
 	 * Replace both input and output to add the padding in the input and
 	 * the potential missing leading zeros in the output.
@@ -560,9 +559,6 @@ static int pkcs1pad_verify(struct akcipher_request *req)
 	if (!ctx->key_size || req->src_len < ctx->key_size)
 		return -EINVAL;
 
-	if (ctx->key_size > PAGE_SIZE)
-		return -ENOTSUPP;
-
 	/* Reuse input buffer, output to a new buffer */
 	req_ctx->child_req.src = req->src;
 	req_ctx->child_req.src_len = req->src_len;