Fix context locking

[openssl.git] / crypto / threads_win.c

diff --git a/crypto/threads_win.c b/crypto/threads_win.c
index ad4f5e151b522eff7d4f20ff8139d527c6b53d67..73203834c184cbbc522a7bce29a5f453420141d4 100644 (file)
--- a/crypto/threads_win.c
+++ b/crypto/threads_win.c
@@ -1,7 +1,7 @@
 /*
- * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
  *
- * Licensed under the OpenSSL license (the "License").  You may not use
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
  * in the file LICENSE in the source distribution or at
  * https://www.openssl.org/source/license.html
@@ -24,11 +24,15 @@ CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void)
         return NULL;
     }
 
+#if !defined(_WIN32_WCE)
     /* 0x400 is the spin count value suggested in the documentation */
     if (!InitializeCriticalSectionAndSpinCount(lock, 0x400)) {
         OPENSSL_free(lock);
         return NULL;
     }
+#else
+    InitializeCriticalSection(lock);
+#endif
 
     return lock;
 }
@@ -101,7 +105,26 @@ int CRYPTO_THREAD_init_local(CRYPTO_THREAD_LOCAL *key, void (*cleanup)(void *))
 
 void *CRYPTO_THREAD_get_local(CRYPTO_THREAD_LOCAL *key)
 {
-    return TlsGetValue(*key);
+    DWORD last_error;
+    void *ret;
+
+    /*
+     * TlsGetValue clears the last error even on success, so that callers may
+     * distinguish it successfully returning NULL or failing. It is documented
+     * to never fail if the argument is a valid index from TlsAlloc, so we do
+     * not need to handle this.
+     *
+     * However, this error-mangling behavior interferes with the caller's use of
+     * GetLastError. In particular SSL_get_error queries the error queue to
+     * determine whether the caller should look at the OS's errors. To avoid
+     * destroying state, save and restore the Windows error.
+     *
+     * https://msdn.microsoft.com/en-us/library/windows/desktop/ms686812(v=vs.85).aspx
+     */
+    last_error = GetLastError();
+    ret = TlsGetValue(*key);
+    SetLastError(last_error);
+    return ret;
 }
 
 int CRYPTO_THREAD_set_local(CRYPTO_THREAD_LOCAL *key, void *val)
@@ -136,18 +159,6 @@ int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock)
     return 1;
 }
 
-int CRYPTO_atomic_read(int *val, int *ret, CRYPTO_RWLOCK *lock)
-{
-    *ret = InterlockedCompareExchange(val, 0, 0);
-    return 1;
-}
-
-int CRYPTO_atomic_write(int *val, int n, CRYPTO_RWLOCK *lock)
-{
-    InterlockedExchange(val, n);
-    return 1;
-}
-
 int openssl_init_fork_handlers(void)
 {
     return 0;