crypto/cryptlib.c: resolve possible race in OPENSSL_isservice.

Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/6752)

diff --git a/crypto/cryptlib.c b/crypto/cryptlib.c
index ad727edf6a1d0e13f3e6d9a0f5a714ed81c5643b..a7894ddac3fcb3e831d03ed10d2d2ca4a6bf51b6 100644 (file)
--- a/crypto/cryptlib.c
+++ b/crypto/cryptlib.c
@@ -205,10 +205,14 @@ int OPENSSL_isservice(void)
 
     if (_OPENSSL_isservice.p == NULL) {
         HANDLE mod = GetModuleHandle(NULL);
+        FARPROC f;
+
         if (mod != NULL)
-            _OPENSSL_isservice.f = GetProcAddress(mod, "_OPENSSL_isservice");
-        if (_OPENSSL_isservice.p == NULL)
+            f = GetProcAddress(mod, "_OPENSSL_isservice");
+        if (f == NULL)
             _OPENSSL_isservice.p = (void *)-1;
+        else
+            _OPENSSL_isservice.f = f;
     }
 
     if (_OPENSSL_isservice.p != (void *)-1)