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[v4,08/14] crypto: ecdh - comply with crypto_kpp_maxsize()

Message ID 1495696696-22580-9-git-send-email-tudor.ambarus@microchip.com (mailing list archive)
State Accepted
Delegated to: Herbert Xu
Headers show

Commit Message

Tudor Ambarus May 25, 2017, 7:18 a.m. UTC 
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>
---
 crypto/ecdh.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
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Patch

diff --git a/crypto/ecdh.c b/crypto/ecdh.c
index ed1464a..4aa0b0c 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)