Add ssl_crl_hash_dir module

This module is an implementation of the ssl_crl_cache_api behaviour.
It can be used when there is a directory containing CRLs for all
relevant CAs, in the form used by e.g. Apache.  The module assumes
that the directory is being updated through an external process.

2 files changed, 195 insertions, 12 deletions

diff --git a/lib/ssl/test/make_certs.erl b/lib/ssl/test/make_certs.erl
index 5eebf773a7..ed1a6523ed 100644
--- a/lib/ssl/test/make_certs.erl
+++ b/lib/ssl/test/make_certs.erl
@@ -172,11 +172,15 @@ revoke(Root, CA, User, C) ->
     gencrl(Root, CA, C).
 
 gencrl(Root, CA, C) ->
+    %% By default, the CRL is valid for 24 hours from now.
+    gencrl(Root, CA, C, 24).
+
+gencrl(Root, CA, C, CrlHours) ->
     CACnfFile = filename:join([Root, CA, "ca.cnf"]),
     CACRLFile = filename:join([Root, CA, "crl.pem"]),
     Cmd = [C#config.openssl_cmd, " ca"
 	   " -gencrl ",
-	   " -crlhours 24",
+	   " -crlhours ", integer_to_list(CrlHours),
 	   " -out ", CACRLFile,
 	   " -config ", CACnfFile],
     Env = [{"ROOTDIR", filename:absname(Root)}], 
diff --git a/lib/ssl/test/ssl_crl_SUITE.erl b/lib/ssl/test/ssl_crl_SUITE.erl
index 5b86027210..27005682e9 100644
--- a/lib/ssl/test/ssl_crl_SUITE.erl
+++ b/lib/ssl/test/ssl_crl_SUITE.erl
@@ -41,20 +41,26 @@ groups() ->
     [
      {check_true, [],  [{group, v2_crl},
 			{group, v1_crl},
-			{group, idp_crl}]},
+			{group, idp_crl},
+                        {group, crl_hash_dir}]},
      {check_peer, [],   [{group, v2_crl},
 			 {group, v1_crl},
-			 {group, idp_crl}]},
+			 {group, idp_crl},
+                         {group, crl_hash_dir}]},
      {check_best_effort, [], [{group, v2_crl},
 			       {group, v1_crl},
-			      {group, idp_crl}]},
+			      {group, idp_crl},
+			      {group, crl_hash_dir}]},
      {v2_crl,  [], basic_tests()},
      {v1_crl,  [], basic_tests()},
-     {idp_crl, [], basic_tests()}].
+     {idp_crl, [], basic_tests()},
+     {crl_hash_dir, [], basic_tests() ++ crl_hash_dir_tests()}].
 
 basic_tests() ->
     [crl_verify_valid, crl_verify_revoked, crl_verify_no_crl].
 
+crl_hash_dir_tests() ->
+    [crl_hash_dir_collision, crl_hash_dir_expired].
 
 init_per_suite(Config) ->
     case os:find_executable("openssl") of
@@ -101,7 +107,24 @@ init_per_group(Group, Config0) ->
 	    CertDir = filename:join(?config(priv_dir, Config0), Group),
 	    {CertOpts, Config} = init_certs(CertDir, Group, Config0),
 	    {ok, _} =  make_certs:all(DataDir, CertDir, CertOpts),
-	    [{cert_dir, CertDir}, {idp_crl, false} | Config]
+	    case Group of
+		crl_hash_dir ->
+		    CrlDir = filename:join(CertDir, "crls"),
+		    %% Copy CRLs to their hashed filenames.
+		    %% Find the hashes with 'openssl crl -noout -hash -in crl.pem'.
+		    populate_crl_hash_dir(CertDir, CrlDir,
+					  [{"erlangCA", "d6134ed3"},
+					   {"otpCA", "d4c8d7e5"}],
+					  replace),
+		    CrlCacheOpts = [{crl_cache,
+				     {ssl_crl_hash_dir,
+				      {internal, [{dir, CrlDir}]}}}];
+		_ ->
+		    CrlCacheOpts = []
+	    end,
+	    [{crl_cache_opts, CrlCacheOpts},
+	     {cert_dir, CertDir},
+	     {idp_crl, false} | Config]
     end.
 
 end_per_group(_GroupName, Config) ->
@@ -164,9 +187,10 @@ crl_verify_valid(Config) when is_list(Config) ->
 			   {crl_cache, {ssl_crl_cache, {internal, [{http, 5000}]}}},
 			   {verify, verify_peer}];
 		      false ->
-			  [{cacertfile, filename:join([PrivDir, "server", "cacerts.pem"])},
-			   {crl_check, Check},
-			   {verify, verify_peer}]
+			  ?config(crl_cache_opts, Config) ++
+			      [{cacertfile, filename:join([PrivDir, "server", "cacerts.pem"])},
+			       {crl_check, Check},
+			       {verify, verify_peer}]
 		  end,			  
     {ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
 
@@ -196,9 +220,10 @@ crl_verify_revoked(Config)  when is_list(Config) ->
 			   {crl_check, Check},
 			   {verify, verify_peer}];
 		      false ->
-			  [{cacertfile, filename:join([PrivDir, "revoked", "cacerts.pem"])},
-			   {crl_check, Check},
-			   {verify, verify_peer}]
+			  ?config(crl_cache_opts, Config) ++
+			      [{cacertfile, filename:join([PrivDir, "revoked", "cacerts.pem"])},
+			       {crl_check, Check},
+			       {verify, verify_peer}]
 		  end,	
     
     crl_verify_error(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts,
@@ -251,6 +276,132 @@ crl_verify_no_crl(Config) when is_list(Config) ->
             crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts)
     end.
 
+crl_hash_dir_collision() ->
+    [{doc,"Verify ssl_crl_hash_dir behaviour with hash collisions"}].
+crl_hash_dir_collision(Config) when is_list(Config) ->
+    PrivDir = ?config(cert_dir, Config),
+    Check = ?config(crl_check, Config),
+
+    %% Create two CAs whose names hash to the same value
+    CA1 = "hash-collision-0000000000",
+    CA2 = "hash-collision-0258497583",
+    CertsConfig = make_certs:make_config([]),
+    make_certs:intermediateCA(PrivDir, CA1, "erlangCA", CertsConfig),
+    make_certs:intermediateCA(PrivDir, CA2, "erlangCA", CertsConfig),
+
+    make_certs:enduser(PrivDir, CA1, "collision-client-1", CertsConfig),
+    make_certs:enduser(PrivDir, CA2, "collision-client-2", CertsConfig),
+
+    [ServerOpts1, ServerOpts2] =
+	[
+	 [{keyfile, filename:join([PrivDir, EndUser, "key.pem"])},
+	  {certfile, filename:join([PrivDir, EndUser, "cert.pem"])},
+	  {cacertfile, filename:join([PrivDir, EndUser, "cacerts.pem"])}]
+	 || EndUser <- ["collision-client-1", "collision-client-2"]],
+
+    %% Add CRLs for our new CAs into the CRL hash directory.
+    %% Find the hashes with 'openssl crl -noout -hash -in crl.pem'.
+    CrlDir = filename:join(PrivDir, "crls"),
+    populate_crl_hash_dir(PrivDir, CrlDir,
+			  [{CA1, "b68fc624"},
+			   {CA2, "b68fc624"}],
+			 replace),
+
+    ClientOpts = ?config(crl_cache_opts, Config) ++
+	[{cacertfile, filename:join([PrivDir, "erlangCA", "cacerts.pem"])},
+	 {crl_check, Check},
+	 {verify, verify_peer}],
+
+    {ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
+
+    %% Neither certificate revoked; both succeed.
+    crl_verify_valid(Hostname, ServerNode, ServerOpts1, ClientNode, ClientOpts),
+    crl_verify_valid(Hostname, ServerNode, ServerOpts2, ClientNode, ClientOpts),
+
+    make_certs:revoke(PrivDir, CA1, "collision-client-1", CertsConfig),
+    populate_crl_hash_dir(PrivDir, CrlDir,
+			  [{CA1, "b68fc624"},
+			   {CA2, "b68fc624"}],
+			 replace),
+
+    %% First certificate revoked; first fails, second succeeds.
+    crl_verify_error(Hostname, ServerNode, ServerOpts1, ClientNode, ClientOpts,
+                     "certificate revoked"),
+    crl_verify_valid(Hostname, ServerNode, ServerOpts2, ClientNode, ClientOpts),
+
+    make_certs:revoke(PrivDir, CA2, "collision-client-2", CertsConfig),
+    populate_crl_hash_dir(PrivDir, CrlDir,
+			  [{CA1, "b68fc624"},
+			   {CA2, "b68fc624"}],
+			 replace),
+
+    %% Second certificate revoked; both fail.
+    crl_verify_error(Hostname, ServerNode, ServerOpts1, ClientNode, ClientOpts,
+                     "certificate revoked"),
+    crl_verify_error(Hostname, ServerNode, ServerOpts2, ClientNode, ClientOpts,
+                     "certificate revoked"),
+
+    ok.
+
+crl_hash_dir_expired() ->
+    [{doc,"Verify ssl_crl_hash_dir behaviour with expired CRLs"}].
+crl_hash_dir_expired(Config) when is_list(Config) ->
+    PrivDir = ?config(cert_dir, Config),
+    Check = ?config(crl_check, Config),
+
+    CA = "CRL-maybe-expired-CA",
+    %% Add "issuing distribution point", to ensure that verification
+    %% fails if there is no valid CRL.
+    CertsConfig = make_certs:make_config([{issuing_distribution_point, true}]),
+    make_certs:intermediateCA(PrivDir, CA, "erlangCA", CertsConfig),
+    EndUser = "CRL-maybe-expired",
+    make_certs:enduser(PrivDir, CA, EndUser, CertsConfig),
+
+    ServerOpts =  [{keyfile, filename:join([PrivDir, EndUser, "key.pem"])},
+		   {certfile, filename:join([PrivDir, EndUser, "cert.pem"])},
+		   {cacertfile, filename:join([PrivDir, EndUser, "cacerts.pem"])}],
+    ClientOpts = ?config(crl_cache_opts, Config) ++
+	[{cacertfile, filename:join([PrivDir, CA, "cacerts.pem"])},
+	 {crl_check, Check},
+	 {verify, verify_peer}],
+    {ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
+
+    %% First make a CRL that expired yesterday.
+    make_certs:gencrl(PrivDir, CA, CertsConfig, -24),
+    CrlDir = filename:join(PrivDir, "crls"),
+    populate_crl_hash_dir(PrivDir, CrlDir,
+			  [{CA, "1627b4b0"}],
+			  replace),
+
+    %% Since the CRL has expired, it's treated as missing, and the
+    %% outcome depends on the crl_check setting.
+    case Check of
+        true ->
+            %% The error "revocation status undetermined" gets turned
+            %% into "bad certificate".
+            crl_verify_error(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts,
+                             "bad certificate");
+        peer ->
+            crl_verify_error(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts,
+                             "bad certificate");
+        best_effort ->
+            %% In "best effort" mode, we consider the certificate not
+            %% to be revoked if we can't find the appropriate CRL.
+            crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts)
+    end,
+
+    %% Now make a CRL that expires tomorrow.
+    make_certs:gencrl(PrivDir, CA, CertsConfig, 24),
+    CrlDir = filename:join(PrivDir, "crls"),
+    populate_crl_hash_dir(PrivDir, CrlDir,
+			  [{CA, "1627b4b0"}],
+			  add),
+
+    %% With a valid CRL, verification should always pass.
+    crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts),
+
+    ok.
+
 crl_verify_valid(Hostname, ServerNode, ServerOpts, ClientNode, ClientOpts) ->
     Server = ssl_test_lib:start_server([{node, ServerNode}, {port, 0}, 
 					{from, self()}, 
@@ -311,3 +462,31 @@ make_dir_path(PathComponents) ->
 
 rename_crl(Filename) ->
     file:rename(Filename, Filename ++ ".notfound").
+
+populate_crl_hash_dir(CertDir, CrlDir, CAsHashes, AddOrReplace) ->
+    ok = filelib:ensure_dir(filename:join(CrlDir, "crls")),
+    case AddOrReplace of
+	replace ->
+	    %% Delete existing files, so we can override them.
+	    [ok = file:delete(FileToDelete) ||
+		{_CA, Hash} <- CAsHashes,
+		FileToDelete <- filelib:wildcard(
+				  filename:join(CrlDir, Hash ++ ".r*"))];
+	add ->
+	    ok
+    end,
+    %% Create new files, incrementing suffix if needed to find unique names.
+    [{ok, _} =
+	 file:copy(filename:join([CertDir, CA, "crl.pem"]),
+		   find_free_name(CrlDir, Hash, 0))
+     || {CA, Hash} <- CAsHashes],
+    ok.
+
+find_free_name(CrlDir, Hash, N) ->
+    Name = filename:join(CrlDir, Hash ++ ".r" ++ integer_to_list(N)),
+    case filelib:is_file(Name) of
+	true ->
+	    find_free_name(CrlDir, Hash, N + 1);
+	false ->
+	    Name
+    end.