LibC: fflush() should not dereference stream if it is NULL

1 files changed, 10 insertions, 3 deletions

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;
 }