From e9f49527e912eb81e9e3c0a1b32c703f858cecda Mon Sep 17 00:00:00 2001
From: Alexandre DOYEN <alexandre.doyen@cea.fr>
Date: Mon, 5 May 2025 09:49:56 +0200
Subject: [PATCH] We check before if the AFL_PRELOAD env variable is set

---
 instrumentation/afl-compiler-rt.o.c | 6 +++++-
 src/afl-forkserver.c                | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c
index 46d76624..2a563afc 100644
--- a/instrumentation/afl-compiler-rt.o.c
+++ b/instrumentation/afl-compiler-rt.o.c
@@ -1046,7 +1046,11 @@ static void __afl_start_forkserver(void) {
       /* In child process: close fds, resume execution. */
 
       if (unlikely(!child_pid)) {  // just to signal afl-fuzz faster
-        unsetenv("AFL_FORKSERVER_PARENT");
+        if (unlikely(getenv("AFL_PRELOAD") != NULL)) {
+
+          unsetenv("AFL_FORKSERVER_PARENT");
+
+        }
 
         //(void)nice(-20);
 
diff --git a/src/afl-forkserver.c b/src/afl-forkserver.c
index 0a1bd75f..d289ce8e 100644
--- a/src/afl-forkserver.c
+++ b/src/afl-forkserver.c
@@ -878,7 +878,11 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv,
 
     /* CHILD PROCESS */
 
-    setenv("AFL_FORKSERVER_PARENT", "1", 0);
+    if (unlikely(getenv("AFL_PRELOAD") != NULL)) {
+
+      setenv("AFL_FORKSERVER_PARENT", "1", 0);
+
+    }
 
     // enable terminating on sigpipe in the children
     struct sigaction sa;