Move the _hidden_* static variables in dasync to be constructed in bind

The _hidden_* variables were being created on-the-fly. It is better to
create them once up front during bind to avoid any potential race
conditions.
Reviewed-by: NTim Hudson <tjh@openssl.org>

engines/e_dasync.c

@@ -101,26 +101,13 @@ static int dasync_sha1_update(EVP_MD_CTX *ctx, const void *data,
                              size_t count);
 static int dasync_sha1_final(EVP_MD_CTX *ctx, unsigned char *md);
 
+/*
+ * Holds the EVP_MD object for sha1 in this engine. Set up once only during
+ * engine bind and can then be reused many times.
+ */
 static EVP_MD *_hidden_sha1_md = NULL;
 static const EVP_MD *dasync_sha1(void)
 {
-    if (_hidden_sha1_md == NULL) {
-        EVP_MD *md;
-
-        if ((md = EVP_MD_meth_new(NID_sha1, NID_sha1WithRSAEncryption)) == NULL
-            || !EVP_MD_meth_set_result_size(md, SHA_DIGEST_LENGTH)
-            || !EVP_MD_meth_set_input_blocksize(md, SHA_CBLOCK)
-            || !EVP_MD_meth_set_app_datasize(md,
-                                             sizeof(EVP_MD *) + sizeof(SHA_CTX))
-            || !EVP_MD_meth_set_flags(md, EVP_MD_FLAG_DIGALGID_ABSENT)
-            || !EVP_MD_meth_set_init(md, dasync_sha1_init)
-            || !EVP_MD_meth_set_update(md, dasync_sha1_update)
-            || !EVP_MD_meth_set_final(md, dasync_sha1_final)) {
-            EVP_MD_meth_free(md);
-            md = NULL;
-        }
-        _hidden_sha1_md = md;
-    }
     return _hidden_sha1_md;
 }
 static void destroy_digests(void)
@@ -128,6 +115,7 @@ static void destroy_digests(void)
     EVP_MD_meth_free(_hidden_sha1_md);
     _hidden_sha1_md = NULL;
 }
+
 static int dasync_digest_nids(const int **nids)
 {
     static int digest_nids[2] = { 0, 0 };
@@ -203,7 +191,6 @@ static int dasync_aes128_cbc_hmac_sha1_cleanup(EVP_CIPHER_CTX *ctx);
 
 struct aes_128_cbc_pipeline_ctx {
     void *inner_cipher_data;
-    unsigned char dummy[256];
     unsigned int numpipes;
     unsigned char **inbufs;
     unsigned char **outbufs;
@@ -213,13 +200,81 @@ struct aes_128_cbc_pipeline_ctx {
     unsigned int aadctr;
 };
 
+/*
+ * Holds the EVP_CIPHER object for aes_128_cbc in this engine. Set up once only
+ * during engine bind and can then be reused many times.
+ */
 static EVP_CIPHER *_hidden_aes_128_cbc = NULL;
 static const EVP_CIPHER *dasync_aes_128_cbc(void)
 {
-    if (_hidden_aes_128_cbc == NULL)
-        _hidden_aes_128_cbc = EVP_CIPHER_meth_new(NID_aes_128_cbc,
-                                                  16 /* block size */,
-                                                  16 /* key len */);
+    return _hidden_aes_128_cbc;
+}
+
+/*
+ * Holds the EVP_CIPHER object for aes_128_cbc_hmac_sha1 in this engine. Set up
+ * once only during engine bind and can then be reused many times.
+ */
+static EVP_CIPHER *_hidden_aes_128_cbc_hmac_sha1 = NULL;
+static const EVP_CIPHER *dasync_aes_128_cbc_hmac_sha1(void)
+{
+    return _hidden_aes_128_cbc_hmac_sha1;
+}
+
+static void destroy_ciphers(void)
+{
+    EVP_CIPHER_meth_free(_hidden_aes_128_cbc);
+    EVP_CIPHER_meth_free(_hidden_aes_128_cbc_hmac_sha1);
+    _hidden_aes_128_cbc = NULL;
+    _hidden_aes_128_cbc_hmac_sha1 = NULL;
+}
+
+static int dasync_ciphers(ENGINE *e, const EVP_CIPHER **cipher,
+                                   const int **nids, int nid);
+
+static int dasync_cipher_nids[] = {
+    NID_aes_128_cbc,
+    NID_aes_128_cbc_hmac_sha1,
+    0
+};
+
+static int bind_dasync(ENGINE *e)
+{
+    /* Ensure the dasync error handling is set up */
+    ERR_load_DASYNC_strings();
+
+    if (!ENGINE_set_id(e, engine_dasync_id)
+        || !ENGINE_set_name(e, engine_dasync_name)
+        || !ENGINE_set_RSA(e, &dasync_rsa_method)
+        || !ENGINE_set_digests(e, dasync_digests)
+        || !ENGINE_set_ciphers(e, dasync_ciphers)
+        || !ENGINE_set_destroy_function(e, dasync_destroy)
+        || !ENGINE_set_init_function(e, dasync_init)
+        || !ENGINE_set_finish_function(e, dasync_finish)) {
+        DASYNCerr(DASYNC_F_BIND_DASYNC, DASYNC_R_INIT_FAILED);
+        return 0;
+    }
+
+    /*
+     * Set up the EVP_CIPHER and EVP_MD objects for the ciphers/digests
+     * supplied by this engine
+     */
+    _hidden_sha1_md = EVP_MD_meth_new(NID_sha1, NID_sha1WithRSAEncryption);
+    if (_hidden_sha1_md == NULL
+        || !EVP_MD_meth_set_result_size(_hidden_sha1_md, SHA_DIGEST_LENGTH)
+        || !EVP_MD_meth_set_input_blocksize(_hidden_sha1_md, SHA_CBLOCK)
+        || !EVP_MD_meth_set_app_datasize(_hidden_sha1_md,
+                                         sizeof(EVP_MD *) + sizeof(SHA_CTX))
+        || !EVP_MD_meth_set_flags(_hidden_sha1_md, EVP_MD_FLAG_DIGALGID_ABSENT)
+        || !EVP_MD_meth_set_init(_hidden_sha1_md, dasync_sha1_init)
+        || !EVP_MD_meth_set_update(_hidden_sha1_md, dasync_sha1_update)
+        || !EVP_MD_meth_set_final(_hidden_sha1_md, dasync_sha1_final)) {
+        EVP_MD_meth_free(_hidden_sha1_md);
+        _hidden_sha1_md = NULL;
+    }
+
+    _hidden_aes_128_cbc = EVP_CIPHER_meth_new(NID_aes_128_cbc,
+                                              16 /* block size */,
+                                              16 /* key len */);
     if (_hidden_aes_128_cbc == NULL
             || !EVP_CIPHER_meth_set_iv_length(_hidden_aes_128_cbc,16)
             || !EVP_CIPHER_meth_set_flags(_hidden_aes_128_cbc,
@@ -239,17 +294,11 @@ static const EVP_CIPHER *dasync_aes_128_cbc(void)
         EVP_CIPHER_meth_free(_hidden_aes_128_cbc);
         _hidden_aes_128_cbc = NULL;
     }
-    return _hidden_aes_128_cbc;
-}
 
-static EVP_CIPHER *_hidden_aes_128_cbc_hmac_sha1 = NULL;
-static const EVP_CIPHER *dasync_aes_128_cbc_hmac_sha1(void)
-{
-    if (_hidden_aes_128_cbc_hmac_sha1 == NULL)
-        _hidden_aes_128_cbc_hmac_sha1 = EVP_CIPHER_meth_new(
-                                                  NID_aes_128_cbc_hmac_sha1,
-                                                  16 /* block size */,
-                                                  16 /* key len */);
+    _hidden_aes_128_cbc_hmac_sha1 = EVP_CIPHER_meth_new(
+                                                NID_aes_128_cbc_hmac_sha1,
+                                                16 /* block size */,
+                                                16 /* key len */);
     if (_hidden_aes_128_cbc_hmac_sha1 == NULL
             || !EVP_CIPHER_meth_set_iv_length(_hidden_aes_128_cbc_hmac_sha1,16)
             || !EVP_CIPHER_meth_set_flags(_hidden_aes_128_cbc_hmac_sha1,
@@ -270,34 +319,6 @@ static const EVP_CIPHER *dasync_aes_128_cbc_hmac_sha1(void)
         EVP_CIPHER_meth_free(_hidden_aes_128_cbc_hmac_sha1);
         _hidden_aes_128_cbc_hmac_sha1 = NULL;
     }
-    return _hidden_aes_128_cbc_hmac_sha1;
-}
-
-static int dasync_ciphers(ENGINE *e, const EVP_CIPHER **cipher,
-                                   const int **nids, int nid);
-
-static int dasync_cipher_nids[] = {
-    NID_aes_128_cbc,
-    NID_aes_128_cbc_hmac_sha1,
-    0
-};
-
-static int bind_dasync(ENGINE *e)
-{
-    /* Ensure the dasync error handling is set up */
-    ERR_load_DASYNC_strings();
-
-    if (!ENGINE_set_id(e, engine_dasync_id)
-        || !ENGINE_set_name(e, engine_dasync_name)
-        || !ENGINE_set_RSA(e, &dasync_rsa_method)
-        || !ENGINE_set_digests(e, dasync_digests)
-        || !ENGINE_set_ciphers(e, dasync_ciphers)
-        || !ENGINE_set_destroy_function(e, dasync_destroy)
-        || !ENGINE_set_init_function(e, dasync_init)
-        || !ENGINE_set_finish_function(e, dasync_finish)) {
-        DASYNCerr(DASYNC_F_BIND_DASYNC, DASYNC_R_INIT_FAILED);
-        return 0;
-    }
 
     return 1;
 }
@@ -353,6 +374,7 @@ static int dasync_finish(ENGINE *e)
 static int dasync_destroy(ENGINE *e)
 {
     destroy_digests();
+    destroy_ciphers();
     ERR_unload_DASYNC_strings();
     return 1;
 }
@@ -382,7 +404,7 @@ static int dasync_ciphers(ENGINE *e, const EVP_CIPHER **cipher,
                                    const int **nids, int nid)
 {
     int ok = 1;
-    if (!cipher) {
+    if (cipher == NULL) {
         /* We are returning a list of supported nids */
         *nids = dasync_cipher_nids;
         return (sizeof(dasync_cipher_nids) -