From d84a95de116d5547baa8f816e0e6a1050eaa7ac5 Mon Sep 17 00:00:00 2001
From: Daniel Gustafsson <daniel@yesql.se>
Date: Tue, 14 May 2024 10:19:41 +0200
Subject: [PATCH] hsts: explicitly skip blank lines

Keep blank lines or lines containing only whitespace to make it all
the way to the more expensive sscanf call in hsts_add.

Closes: #13603
Reviewed-by: Daniel Stenberg <daniel@haxx.se>
---
 lib/hsts.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/hsts.c b/lib/hsts.c
index 72b80a46ca..a5e7676138 100644
--- a/lib/hsts.c
+++ b/lib/hsts.c
@@ -523,8 +523,11 @@ static CURLcode hsts_load(struct hsts *h, const char *file)
       char *lineptr = Curl_dyn_ptr(&buf);
       while(*lineptr && ISBLANK(*lineptr))
         lineptr++;
-      if(*lineptr == '#')
-        /* skip commented lines */
+      /*
+       * Skip empty or commented lines, since we know the line will have a
+       * trailing newline from Curl_get_line we can treat length 1 as empty.
+       */
+      if((*lineptr == '#') || strlen(lineptr) <= 1)
         continue;
 
       hsts_add(h, lineptr);