From 3e9b3a3798885b31fe316cafa57425f44bcd1a2c Mon Sep 17 00:00:00 2001
From: Tobias Blomberg <sm0svx@users.noreply.github.com>
Date: Thu, 26 Jul 2018 23:22:49 +0200
Subject: [PATCH] curl: Fix segfault when -H @headerfile is empty

The curl binary would crash if the -H command line option was given a
filename to read using the @filename syntax but that file was empty.

Closes #2797
---
 src/tool_getparam.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/tool_getparam.c b/src/tool_getparam.c
index cc3fcf3a5..e42a894cb 100644
--- a/src/tool_getparam.c
+++ b/src/tool_getparam.c
@@ -1706,7 +1706,7 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
           warnf(global, "Failed to open %s!\n", &nextarg[1]);
         else {
           err = file2memory(&string, &len, file);
-          if(!err) {
+          if(!err && string) {
             /* Allow strtok() here since this isn't used threaded */
             /* !checksrc! disable BANNEDFUNC 2 */
             char *h = strtok(string, "\r\n");