From 9672b125531f4d3eda3d8483cf1d63d71ebc9875 Mon Sep 17 00:00:00 2001
From: Tor Brede Vekterli <vekterli@yahooinc.com>
Date: Thu, 5 May 2022 10:54:35 +0000
Subject: Early return from asciistream file read if file is empty

Avoids a transitive vespalib::string append with nullptr buffer and
zero length, which in turn ends up passing nullptr to memmove, which
is undefined.
---
 vespalib/src/vespa/vespalib/stllike/asciistream.cpp | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'vespalib')

diff --git a/vespalib/src/vespa/vespalib/stllike/asciistream.cpp b/vespalib/src/vespa/vespalib/stllike/asciistream.cpp
index eb127c7051a..6b673363d2d 100644
--- a/vespalib/src/vespa/vespalib/stllike/asciistream.cpp
+++ b/vespalib/src/vespa/vespalib/stllike/asciistream.cpp
@@ -628,6 +628,9 @@ asciistream::createFromFile(stringref fileName)
         if (sz < 0) {
             throw IoException("Failed getting size of  file " + fileName + " : Error=" + file.getLastErrorString(), IoException::UNSPECIFIED, VESPA_STRLOC);
         }
+        if (sz == 0) {
+            return is;
+        }
         alloc::Alloc buf = alloc::Alloc::alloc(sz);
         ssize_t actual = file.Read(buf.get(), sz);
         if (actual != sz) {
-- 
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