From 2fa1aa9e9e816d97428307fdf5a50aa5c51501e5 Mon Sep 17 00:00:00 2001
From: fduncanh <fduncanh@gmail.com>
Date: Wed, 12 Jan 2022 17:17:22 -0500
Subject: [PATCH] fix crypto.c:aes_cbc_reset, use it to avoid continuous
 malloc/free of aes_ctx_audio

---
 lib/crypto.c      |  2 +-
 lib/raop_buffer.c | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/crypto.c b/lib/crypto.c
index 30e9f14..a14fb99 100644
--- a/lib/crypto.c
+++ b/lib/crypto.c
@@ -165,7 +165,7 @@ void aes_cbc_decrypt(aes_ctx_t *ctx, const uint8_t *in, uint8_t *out, int len) {
 }
 
 void aes_cbc_reset(aes_ctx_t *ctx) {
-    aes_reset(ctx, EVP_aes_128_ctr(), ctx->direction);
+    aes_reset(ctx, EVP_aes_128_cbc(), ctx->direction);
 }
 
 void aes_cbc_destroy(aes_ctx_t *ctx) {
diff --git a/lib/raop_buffer.c b/lib/raop_buffer.c
index 4b4062b..c3b2812 100755
--- a/lib/raop_buffer.c
+++ b/lib/raop_buffer.c
@@ -49,7 +49,7 @@ struct raop_buffer_s {
     /* Key and IV used for decryption */
     unsigned char aeskey[RAOP_AESKEY_LEN];
     unsigned char aesiv[RAOP_AESIV_LEN];
-
+    aes_ctx_t *aes_ctx_audio;
     /* First and last seqnum */
     int is_empty;
     unsigned short first_seqnum;
@@ -74,6 +74,7 @@ raop_buffer_init(logger_t *logger,
     raop_buffer->logger = logger;
     memcpy(raop_buffer->aeskey, aeskey, RAOP_AESKEY_LEN);
     memcpy(raop_buffer->aesiv, aesiv, RAOP_AESIV_LEN);
+    raop_buffer->aes_ctx_audio = NULL;
 
 #ifdef DUMP_AUDIO
     if (file_keyiv != NULL) {
@@ -104,6 +105,8 @@ raop_buffer_destroy(raop_buffer_t *raop_buffer)
         }
     }
 
+    aes_cbc_destroy(raop_buffer->aes_ctx_audio);
+
     if (raop_buffer) {
         free(raop_buffer);
     }
@@ -158,9 +161,12 @@ raop_buffer_decrypt(raop_buffer_t *raop_buffer, unsigned char *data, unsigned ch
     encryptedlen = payload_size / 16*16;
     memset(output, 0, payload_size);
     // Need to be initialized internally
-    aes_ctx_t *aes_ctx_audio = aes_cbc_init(raop_buffer->aeskey, raop_buffer->aesiv, AES_DECRYPT);
-    aes_cbc_decrypt(aes_ctx_audio, &data[12], output, encryptedlen);
-    aes_cbc_destroy(aes_ctx_audio);
+    if (!raop_buffer->aes_ctx_audio) {
+        raop_buffer->aes_ctx_audio = aes_cbc_init(raop_buffer->aeskey, raop_buffer->aesiv, AES_DECRYPT);
+    } else {
+        aes_cbc_reset(raop_buffer->aes_ctx_audio);
+    }
+    aes_cbc_decrypt(raop_buffer->aes_ctx_audio, &data[12], output, encryptedlen);
 
     memcpy(output + encryptedlen, &data[12 + encryptedlen], payload_size - encryptedlen);
     *outputlen = payload_size;