libressl/0036-magma-fix-IV-handling-for-CTR-mode.patch

From 0f87b92f702c83c1cc18798d1b05b9aacd8ce186 Mon Sep 17 00:00:00 2001
From: Dmitry Baryshkov <dbaryshkov@gmail.com>
Date: Fri, 17 Apr 2020 23:07:07 +0300
Subject: [PATCH 36/87] magma: fix IV handling for CTR mode

magma-ctr uses half length IV per the specification, which is
handled correctly.  However we still have to zero the second half of IV.
Do so in ctr_init_key() callback.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
---
 src/lib/libcrypto/evp/e_magma.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/lib/libcrypto/evp/e_magma.c b/src/lib/libcrypto/evp/e_magma.c
index 712f79278..c88b25827 100644
--- a/src/lib/libcrypto/evp/e_magma.c
+++ b/src/lib/libcrypto/evp/e_magma.c
@@ -96,6 +96,19 @@ Magma_ofb64_encrypt(const unsigned char *in, unsigned char *out, size_t length,
 			(block64_f)Magma_encrypt);
 }
 
+static int
+magma_ctr_init_key(EVP_CIPHER_CTX *ctx, const unsigned char *key,
+    const unsigned char *iv, int enc)
+{
+	if (iv)
+		memset(ctx->iv + 4, 0, 4);
+
+	if (!key)
+		return 1;
+
+	return magma_init_key(ctx, key, iv, enc);
+}
+
 static int
 magma_ctr_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, const unsigned char *in,
 		size_t len)
@@ -114,8 +127,8 @@ IMPLEMENT_BLOCK_CIPHER(magma, ks, Magma, EVP_MAGMA_CTX,
 		magma_ctl)
 
 BLOCK_CIPHER_def1(magma, ctr, ctr, CTR, EVP_MAGMA_CTX,
-		NID_magma, 1, 32, 4, 0,
-		magma_init_key, NULL,
+		NID_magma, 1, 32, 4, EVP_CIPH_ALWAYS_CALL_INIT,
+		magma_ctr_init_key, NULL,
 		EVP_CIPHER_set_asn1_iv,
 		EVP_CIPHER_get_asn1_iv,
 		magma_ctl)
-- 
2.17.1