Remove the CRYPTO_EX_new callback.

This callback is never used. The one caller I've ever seen is in Android
code which isn't built with BoringSSL and it was a no-op.

It also doesn't actually make much sense. A callback cannot reasonably
assume that it sees every, say, SSL_CTX created because the index may be
registered after the first SSL_CTX is created. Nor is there any point in
an EX_DATA consumer in one file knowing about an SSL_CTX created in
completely unrelated code.

Replace all the pointers with a typedef to int*. This will ensure code
which passes NULL or 0 continues to compile while breaking code which
passes an actual function.

This simplifies some object creation functions which now needn't worry
about CRYPTO_new_ex_data failing. (Also avoids bouncing on the lock, but
it's taking a read lock, so this doesn't really matter.)

BUG=391192

Change-Id: I02893883c6fa8693682075b7b130aa538a0a1437
Reviewed-on: https://boringssl-review.googlesource.com/6625
Reviewed-by: Adam Langley <agl@google.com>

ssl/ssl_lib.c

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 5e4d997..c65e607 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -274,7 +274,7 @@
     goto err;
   }
 
-  CRYPTO_new_ex_data(&g_ex_data_class_ssl_ctx, ret, &ret->ex_data);
+  CRYPTO_new_ex_data(&ret->ex_data);
 
   ret->max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH;
 
@@ -424,7 +424,7 @@
 
   s->rwstate = SSL_NOTHING;
 
-  CRYPTO_new_ex_data(&g_ex_data_class_ssl, s, &s->ex_data);
+  CRYPTO_new_ex_data(&s->ex_data);
 
   s->psk_identity_hint = NULL;
   if (ctx->psk_identity_hint) {
@@ -2060,11 +2060,11 @@
 
 long SSL_get_verify_result(const SSL *ssl) { return ssl->verify_result; }
 
-int SSL_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
+int SSL_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
                          CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func) {
   int index;
   if (!CRYPTO_get_ex_new_index(&g_ex_data_class_ssl, &index, argl, argp,
-                               new_func, dup_func, free_func)) {
+                               dup_func, free_func)) {
     return -1;
   }
   return index;
@@ -2078,12 +2078,12 @@
   return CRYPTO_get_ex_data(&ssl->ex_data, idx);
 }
 
-int SSL_CTX_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func,
+int SSL_CTX_get_ex_new_index(long argl, void *argp, CRYPTO_EX_unused *unused,
                              CRYPTO_EX_dup *dup_func,
                              CRYPTO_EX_free *free_func) {
   int index;
   if (!CRYPTO_get_ex_new_index(&g_ex_data_class_ssl_ctx, &index, argl, argp,
-                               new_func, dup_func, free_func)) {
+                               dup_func, free_func)) {
     return -1;
   }
   return index;