From ddcd14922465ca3775f1cb2f4b8cb24d2e03ea02 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar@beutner.name>
Date: Mon, 19 Apr 2021 22:10:11 +0200
Subject: [PATCH] LibC: Avoid division by zero in fread()/fwrite()

---
 Userland/Libraries/LibC/stdio.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Userland/Libraries/LibC/stdio.cpp b/Userland/Libraries/LibC/stdio.cpp
index f847e10b4b..5a58bb89bb 100644
--- a/Userland/Libraries/LibC/stdio.cpp
+++ b/Userland/Libraries/LibC/stdio.cpp
@@ -777,6 +777,8 @@ size_t fread(void* ptr, size_t size, size_t nmemb, FILE* stream)
     VERIFY(!Checked<size_t>::multiplication_would_overflow(size, nmemb));
 
     size_t nread = stream->read(reinterpret_cast<u8*>(ptr), size * nmemb);
+    if (!nread)
+        return 0;
     return nread / size;
 }
 
@@ -786,6 +788,8 @@ size_t fwrite(const void* ptr, size_t size, size_t nmemb, FILE* stream)
     VERIFY(!Checked<size_t>::multiplication_would_overflow(size, nmemb));
 
     size_t nwritten = stream->write(reinterpret_cast<const u8*>(ptr), size * nmemb);
+    if (!nwritten)
+        return 0;
     return nwritten / size;
 }