From 9282a0fd29ab1d5363daf68bee361eadf936363d Mon Sep 17 00:00:00 2001
From: Damien Stuart <dstart@dstuart.org>
Date: Sun, 14 Mar 2010 03:45:03 +0000
Subject: [PATCH] Changed to fix possible double-free bug under some
 circumstances.

git-svn-id: file:///home/mbr/svn/fwknop/trunk@210 510a4753-2344-4c79-9c09-4d669213fbeb
---
 lib/fko_funcs.c       |  1 +
 lib/fko_state.h       |  2 +-
 server/incoming_spa.c | 10 ++++++++--
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/fko_funcs.c b/lib/fko_funcs.c
index 6e12c5c3..8c75d67b 100644
--- a/lib/fko_funcs.c
+++ b/lib/fko_funcs.c
@@ -184,6 +184,7 @@ fko_new_with_data(fko_ctx_t *r_ctx, char *enc_msg, char *dec_key)
         if(res != FKO_SUCCESS)
         {
             fko_destroy(ctx);
+            *r_ctx = NULL; /* Make sure the caller ctx is null just in case */
             return(res);
         }
     }
diff --git a/lib/fko_state.h b/lib/fko_state.h
index ea22eacc..dacc0e0e 100644
--- a/lib/fko_state.h
+++ b/lib/fko_state.h
@@ -80,7 +80,7 @@ typedef enum {
 
 /* Macros used for determining ctx initialization state.
 */
-#define CTX_INITIALIZED(ctx) (ctx->initval == FKO_CTX_INITIALIZED)
+#define CTX_INITIALIZED(ctx) (ctx != NULL && ctx->initval == FKO_CTX_INITIALIZED)
 
 #endif /* FKO_STATE_H */
 
diff --git a/server/incoming_spa.c b/server/incoming_spa.c
index ea45324c..5bdbf72a 100644
--- a/server/incoming_spa.c
+++ b/server/incoming_spa.c
@@ -33,7 +33,11 @@
 int
 incoming_spa(fko_srv_options_t *opts)
 {
-    fko_ctx_t       ctx;
+    /* Always a good idea to initialize ctx to null if it will be used
+     * repeatedly (especially when using fko_new_with_data().
+    */
+    fko_ctx_t       ctx = NULL;
+
     char            *spa_ip_demark;
     char            spa_msg_src_ip[16];
     char            spa_msg_remain[1024]; /* --DSS should not have arbitrary limit */
@@ -372,7 +376,9 @@ display_ctx(ctx);
 
 
 clean_and_bail:
-    fko_destroy(ctx);
+    if(ctx != NULL)
+        fko_destroy(ctx);
+
     return(res);
 }