crypto: Make unloading of crypto safer

Facts:
crypto nif-lib registers callback functions that openssl uses
for memory management and thread synchronization. The callback
functions can only be set once, openssl does not allow changing the
callback functions.

Problem:
If openssl is dynamicly linked to crypto, you might get s scenario
where the crypto lib is unloaded while leaving openssl loaded
with its old pointers to the unloaded crypto code intact.
If crypto is then reloaded (by init:restart() for example), the crypto
nif-lib might get relocated at a different address. crypto calls
openssl which in turn calls the old invalid callback functions...kaboom.

Solution:
Break apart the callback functions into a separate dynamic lib that
crypto loads with dlopen. When crypto is unloaded the callback lib is
left in place to be reused if/when crypto is loaded again.

1 files changed, 3 insertions, 3 deletions

diff --git a/lib/crypto/src/crypto.erl b/lib/crypto/src/crypto.erl
index 0089e79a4f..21f507f153 100644
--- a/lib/crypto/src/crypto.erl
+++ b/lib/crypto/src/crypto.erl
@@ -114,7 +114,7 @@
 
 -on_load(on_load/0).
 
--define(CRYPTO_NIF_VSN,101).
+-define(CRYPTO_NIF_VSN,201).
 
 on_load() ->
     LibBaseName = "crypto",
@@ -140,7 +140,7 @@ on_load() ->
 		      end
 	      end,
     Lib = filename:join([PrivDir, "lib", LibName]),
-    Status = case erlang:load_nif(Lib, ?CRYPTO_NIF_VSN) of
+    Status = case erlang:load_nif(Lib, {?CRYPTO_NIF_VSN,Lib}) of
 		 ok -> ok;
 		 {error, {load_failed, _}}=Error1 ->
 		     ArchLibDir = 
@@ -152,7 +152,7 @@ on_load() ->
 			 [] -> Error1;
 			 _ ->
 			     ArchLib = filename:join([ArchLibDir, LibName]),
-			     erlang:load_nif(ArchLib, ?CRYPTO_NIF_VSN)
+			     erlang:load_nif(ArchLib, {?CRYPTO_NIF_VSN,ArchLib})
 		     end;
 		 Error1 -> Error1
 	     end,