From: Daniel Stenberg <daniel@haxx.se>
Date: Wed, 11 Sep 2024 12:12:41 +0000 (+0200)
Subject: multi: check that the multi handle is valid in curl_multi_assign
X-Git-Tag: curl-8_10_1~46
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=48f61e781a01e6a8dbc4a347e280644b1c68ab6a;p=thirdparty%2Fcurl.git

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
---

diff --git a/lib/multi.c b/lib/multi.c
index 062d09cc0b..78e5c0a1e5 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);