crypt32: Fix race condition in loading default provider.

5c8aa891 · Juan Lang · Alexandre Julliard · 027236b0 · 5c8aa891
Commit 5c8aa891 authored Jan 14, 2008 by Juan Lang Committed by Alexandre Julliard Jan 15, 2008
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Showing with 10 additions and 2 deletions

main.c dlls/crypt32/main.c +10 -2

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--- a/dlls/crypt32/main.c
+++ b/dlls/crypt32/main.c
@@ -59,8 +59,16 @@ BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD fdwReason, PVOID pvReserved)
 HCRYPTPROV CRYPT_GetDefaultProvider(void)
 {
    if (!hDefProv)
-        CryptAcquireContextW(&hDefProv, NULL, MS_ENHANCED_PROV_W,
-         PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
+    {
+        HCRYPTPROV prov;
+
+        CryptAcquireContextW(&prov, NULL, MS_ENHANCED_PROV_W, PROV_RSA_FULL,
+         CRYPT_VERIFYCONTEXT);
+        InterlockedCompareExchangePointer((PVOID *)&hDefProv, (PVOID)prov,
+         NULL);
+        if (hDefProv != prov)
+            CryptReleaseContext(prov, 0);
+    }
    return hDefProv;
 }