From c99d6608825c02783a58cddd930794cd0d35ab03 Mon Sep 17 00:00:00 2001
From: Anton Kling <anton@kling.gg>
Date: Sun, 5 May 2024 16:20:26 +0200
Subject: LibC: fflush() should not dereference stream if it is NULL

---
 userland/libc/stdio/fflush.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'userland')

diff --git a/userland/libc/stdio/fflush.c b/userland/libc/stdio/fflush.c
index 3042efa..1cadc72 100644
--- a/userland/libc/stdio/fflush.c
+++ b/userland/libc/stdio/fflush.c
@@ -1,8 +1,15 @@
 #include <stdio.h>
+#include <syscall.h>
+#include <errno.h>
 
 // https://pubs.opengroup.org/onlinepubs/9699919799/functions/fflush.html
 int fflush(FILE *stream) {
-  if (stream->fflush)
-    stream->fflush(stream);
-  return 0;
+  if (stream) {
+    if (stream->fflush) {
+      stream->fflush(stream);
+      return 0;
+    }
+  }
+  errno = ENXIO;
+  return -1;
 }
-- 
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