From 706eff9f1f144e6c9a1ed9c9646007760921cf67 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Sat, 16 Sep 2023 22:37:28 +0200
Subject: [PATCH] rand: fix 'alnum': array is too small to include a
 terminating null character

It was that small on purpose, but this change now adds the null byte to
avoid the error.

Follow-up to 3aa3cc9b052353b1

Reported-by: Dan Fandrich
Ref: #11838
Closes #11870
---
 lib/rand.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/rand.c b/lib/rand.c
index 8cac9383ac..d7935b397e 100644
--- a/lib/rand.c
+++ b/lib/rand.c
@@ -275,14 +275,14 @@ CURLcode Curl_rand_hex(struct Curl_easy *data, unsigned char *rnd,
  * alphanumerical chars PLUS a null-terminating byte.
  */
 
-static const char alnum[26 + 26 + 10] =
+static const char alnum[] =
   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
 
 CURLcode Curl_rand_alnum(struct Curl_easy *data, unsigned char *rnd,
                          size_t num)
 {
   CURLcode result = CURLE_OK;
-  const int alnumspace = sizeof(alnum);
+  const int alnumspace = sizeof(alnum) - 1;
   unsigned int r;
   DEBUGASSERT(num > 1);