From d0efb48b8615292e05373caa27854e36e732668b Mon Sep 17 00:00:00 2001
From: Tudor-Dan Ambarus <tudor.ambarus@microchip.com>
Date: Thu, 25 May 2017 10:18:10 +0300
Subject: [PATCH] crypto: ecdh - comply with crypto_kpp_maxsize()
Git-commit: d0efb48b8615292e05373caa27854e36e732668b
References: FATE#326323
Patch-mainline: v4.13
crypto_kpp_maxsize() asks for the output buffer size without
caring for errors. It allways assume that will be called after
a valid setkey. Comply with it and return what he wants.
nbytes has no sense now, remove it and directly return the maxsize.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
crypto/ecdh.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/crypto/ecdh.c b/crypto/ecdh.c
index ed1464a5ce1b..4aa0b0cb4627 100644
--- a/crypto/ecdh.c
+++ b/crypto/ecdh.c
@@ -104,13 +104,12 @@ static int ecdh_compute_value(struct kpp_request *req)
return ret;
}
-static int ecdh_max_size(struct crypto_kpp *tfm)
+static unsigned int ecdh_max_size(struct crypto_kpp *tfm)
{
struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
- int nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT;
- /* Public key is made of two coordinates */
- return 2 * nbytes;
+ /* Public key is made of two coordinates, add one to the left shift */
+ return ctx->ndigits << (ECC_DIGITS_TO_BYTES_SHIFT + 1);
}
static void no_exit_tfm(struct crypto_kpp *tfm)
--
2.16.4