consolidate aes ctr code

1 files changed, 14 insertions, 34 deletions

diff --git a/dl3.c b/dl3.c
index 68328a2..d5298cb 100644
--- a/dl3.c
+++ b/dl3.c
@@ -123,22 +123,21 @@ static int create_gcrypt_km(gcry_sexp_t *km,
 #define NULL_BYTES \
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 
-static void calculate_kd(struct hdcp_session_info *info)
+static void calc_kd_ctr(struct hdcp_session_info *info, uint8_t ctr,
+			uint8_t *buf)
 {
-	uint8_t *buf;
+	uint8_t tmp[100];
 	unsigned char input[] = {NULL_BYTES, NULL_BYTES};
 	uint8_t iv[16];
-	uint8_t tmp[100];
 	int outl;
 	int ret;
 
-	buf = info->kd;
-	memset(buf, 0, KD_SIZE);
-
 	memset(iv, 0, 16);
 
 	memcpy(iv, info->rtx, 8);
 
+	iv[sizeof(iv)-1] = ctr; /* iv is now r_tx|ctr */
+
 	ret = EVP_EncryptInit_ex(&info->aes_ctx, EVP_aes_128_ctr(), NULL, info->km, iv);
 	assert(ret == 1);
 
@@ -150,20 +149,16 @@ static void calculate_kd(struct hdcp_session_info *info)
 	assert(ret == 1);
 	assert(outl == 0);
 
-	iv[sizeof(iv)-1] = 0x01; /* iv is now r_tx|0...01 */
-
-	ret = EVP_EncryptInit_ex(&info->aes_ctx, EVP_aes_128_ctr(), NULL, info->km, iv);
-	assert(ret == 1);
+}
+static void calculate_kd(struct hdcp_session_info *info)
+{
+	uint8_t *buf;
+	buf = info->kd;
+	memset(buf, 0, KD_SIZE);
 
-	ret = EVP_EncryptUpdate(&info->aes_ctx, &buf[16], &outl, input, sizeof(input));
-	assert(ret == 1);
-	assert(outl == sizeof(input));
+	calc_kd_ctr(info, 0, buf);
 
-	ret = EVP_EncryptFinal_ex(&info->aes_ctx, tmp, &outl);
-	assert(ret == 1);
-	assert(outl == 0);
-
-	assert(ret == 1);
+	calc_kd_ctr(info, 1, &buf[16]);
 }
 
 static void calculate_edkey_ks(struct hdcp_session_info *info)
@@ -176,22 +171,7 @@ static void calculate_edkey_ks(struct hdcp_session_info *info)
 	uint8_t tmp[100];
 	int i;
 
-	memset(iv, 0, 16);
-
-	memcpy(iv, info->rtx, 8);
-
-	iv[sizeof(iv)-1] = 0x02; /* iv is now r_tx|0...02 */
-
-	ret = EVP_EncryptInit_ex(&info->aes_ctx, EVP_aes_128_ctr(), NULL, info->km, iv);
-	assert(ret == 1);
-
-	ret = EVP_EncryptUpdate(&info->aes_ctx, buf, &outl, input, sizeof(input));
-	assert(ret == 1);
-	assert(outl == sizeof(input));
-
-	ret = EVP_EncryptFinal_ex(&info->aes_ctx, tmp, &outl);
-	assert(ret == 1);
-	assert(outl == 0);
+	calc_kd_ctr(info, 2, buf);
 
 	/* we have dkey2 in buf now */
 	printf("dkey2:");