From 48f61e781a01e6a8dbc4a347e280644b1c68ab6a Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 11 Sep 2024 14:12:41 +0200
Subject: [PATCH] multi: check that the multi handle is valid in
 curl_multi_assign

By requiring that the multi handle is fine, it can detect bad usage
better and by that avoid crashes. Like in the #14860 case, which is an
application calling curl_multi_assign() with a NULL pointer multi
handle.

Reported-by: Carlo Cabrera
Fixes #14860
Closes #14862

Conflict:NA
Reference:https://github.com/curl/curl/commit/48f61e781a01e6a8dbc4a347e280644b1c68ab6a
---
 lib/multi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/multi.c b/lib/multi.c
index 062d09cc0..78e5c0a1e 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -3688,6 +3688,8 @@ CURLMcode curl_multi_assign(struct Curl_multi *multi, curl_socket_t s,
                             void *hashp)
 {
   struct Curl_sh_entry *there = NULL;
+  if(!GOOD_MULTI_HANDLE(multi))
+    return CURLM_BAD_HANDLE;
 
   there = sh_getentry(&multi->sockhash, s);
 
-- 
2.33.0