From cff82a1384a7c3837e7fecbf740e0897e53a0894 Mon Sep 17 00:00:00 2001
From: Florian Forster <octo@collectd.org>
Date: Fri, 22 Dec 2023 15:44:56 +0100
Subject: [PATCH] utf8: Handle `NULL` inputs gracefully.

---
 src/utils/utf8/utf8.c      | 4 ++++
 src/utils/utf8/utf8_test.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/src/utils/utf8/utf8.c b/src/utils/utf8/utf8.c
index e00770cc0..9530ad5b9 100644
--- a/src/utils/utf8/utf8.c
+++ b/src/utils/utf8/utf8.c
@@ -52,6 +52,10 @@ static uint32_t decode(uint32_t state, uint32_t byte) {
 }
 
 bool utf8_valid(char const *s) {
+  if (s == NULL) {
+    return false;
+  }
+
   uint32_t state = 0;
   for (size_t i = 0; s[i] != 0; i++) {
     state = decode(state, (uint8_t)s[i]);
diff --git a/src/utils/utf8/utf8_test.c b/src/utils/utf8/utf8_test.c
index dc9197ddd..c90705c0f 100644
--- a/src/utils/utf8/utf8_test.c
+++ b/src/utils/utf8/utf8_test.c
@@ -41,6 +41,11 @@ DEF_TEST(utf8_valid) {
           .input = "",
           .want = true,
       },
+      {
+          .name = "null string",
+          .input = NULL,
+          .want = false,
+      },
       {
           .name = "The greek work \"kosme\"",
           .input = (char[]){0xce, 0xba, 0xe1, 0xbd, 0xb9, 0xcf, 0x83, 0xce,
-- 
2.47.3