[PATCH v2 0/1] MR8179: crypt32: Fix invalid access of list head.

[Yuxuan Shui (＠yshui)]

At the end of LIST_FOR_EACH_ENTRY, assuming no matches are found, `provider` will point to the list
head, not NULL, as a result we call IsEqualGUID on invalid memory.

--
  v2: crypt32: Fix invalid access of list head.

https://gitlab.winehq.org/wine/wine/-/merge_requests/8179

[PATCH v2 1/1] crypt32: Fix invalid access of list head.

[Yuxuan Shui]

From: Yuxuan Shui

At the end of LIST_FOR_EACH_ENTRY, assuming no matches were found, `provider` will point to the list
head, instead of being NULL. As a result we call IsEqualGUID on invalid memory.
---
 dlls/crypt32/sip.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dlls/crypt32/sip.c b/dlls/crypt32/sip.c
index 132f491b2f1..d9da19b6272 100644
--- a/dlls/crypt32/sip.c
+++ b/dlls/crypt32/sip.c
@@ -562,10 +562,11 @@ static WINE_SIP_PROVIDER *CRYPT_GetCachedSIP(const GUID *pgSubject)
     LIST_FOR_EACH_ENTRY(provider, &providers, WINE_SIP_PROVIDER, entry)
     {
         if (IsEqualGUID(pgSubject, &provider->subject))
+        {
+            ret = provider;
             break;
+        }
     }
-    if (provider && IsEqualGUID(pgSubject, &provider->subject))
-        ret = provider;
     LeaveCriticalSection(&providers_cs);
     return ret;
 }