[PATCH] NULL ctx pointer in ssh_cipher_clear()

[Valerio De Benedetto <valerio@xxxxxxxxxxxxx>]

If ssh_handle_key_exchange() fails, when ssh_free() is called
cipher->ctx is NULL

From 70d711443d47310fa1094943ca3a5046e7a5787b Mon Sep 17 00:00:00 2001
From: debevv <valerio@xxxxxxxxxxxxx>
Date: Tue, 6 Jun 2017 09:28:58 +0200
Subject: [PATCH] If ssh_handle_key_exchange() fails, when ssh_free() is called
 cipher->ctx is NULL

Signed-off-by: debevv <valerio@xxxxxxxxxxxxx>
---
 src/wrapper.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/wrapper.c b/src/wrapper.c
index af166da..db33446 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -120,11 +120,13 @@ void ssh_cipher_clear(struct ssh_cipher_struct *cipher){
     SAFE_FREE(cipher->key);
   }
 #endif
-  if (cipher->cleanup != NULL){
-    cipher->cleanup(cipher);
-  }
+  if(cipher->ctx) {
+    if (cipher->cleanup != NULL){
+      cipher->cleanup(cipher);
+    }
 #ifdef HAVE_LIBCRYPTO
-  EVP_CIPHER_CTX_free(cipher->ctx);
+    EVP_CIPHER_CTX_free(cipher->ctx);
+  }
 #endif
 }
 
-- 
2.7.4