From: Andrew Bartlett <abartlet@samba.org>
Date: Thu, 30 Sep 2021 22:09:48 +0000 (+1300)
Subject: CVE-2020-25718 s4-rpc_server: Obtain the user tokenGroups earlier
X-Git-Tag: samba-4.13.14~53
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0a3ebd1d1b92a865b632c44d211facd1a3bf58a9;p=thirdparty%2Fsamba.git

CVE-2020-25718 s4-rpc_server: Obtain the user tokenGroups earlier

This will allow the creation of a common helper routine that
takes the token SID list (from tokenGroups or struct auth_user_info_dc)
and returns the allowed/denied result.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14558

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>
---

diff --git a/source4/rpc_server/drsuapi/getncchanges.c b/source4/rpc_server/drsuapi/getncchanges.c
index c7d2addd104..bc30e73e06b 100644
--- a/source4/rpc_server/drsuapi/getncchanges.c
+++ b/source4/rpc_server/drsuapi/getncchanges.c
@@ -1282,6 +1282,20 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
 		goto allowed;
 	}
 
+	/*
+	 * The SID list needs to include itself as well as the tokenGroups.
+	 *
+	 * TODO determine if sIDHistory is required for this check
+	 */
+	werr = samdb_result_sid_array_ndr(b_state->sam_ctx_system, obj_res->msgs[0],
+					  mem_ctx, "tokenGroups",
+					  &num_token_sids,
+					  &token_sids,
+					  object_sid, 1);
+	if (!W_ERROR_IS_OK(werr) || token_sids==NULL) {
+		goto denied;
+	}
+
 	/* but it isn't allowed to get anyone elses krbtgt secrets */
 	if (samdb_result_dn(b_state->sam_ctx_system, mem_ctx,
 			    obj_res->msgs[0], "msDS-KrbTgtLinkBL", NULL)) {
@@ -1310,20 +1324,6 @@ static WERROR getncchanges_repl_secret(struct drsuapi_bind_state *b_state,
 		goto denied;
 	}
 
-	/*
-	 * The SID list needs to include itself as well as the tokenGroups.
-	 *
-	 * TODO determine if sIDHistory is required for this check
-	 */
-	werr = samdb_result_sid_array_ndr(b_state->sam_ctx_system, obj_res->msgs[0],
-					  mem_ctx, "tokenGroups",
-					  &num_token_sids,
-					  &token_sids,
-					  object_sid, 1);
-	if (!W_ERROR_IS_OK(werr) || token_sids==NULL) {
-		goto denied;
-	}
-
 	if (never_reveal_sids &&
 	    sid_list_match(num_token_sids,
 			   token_sids,
diff --git a/source4/rpc_server/netlogon/dcerpc_netlogon.c b/source4/rpc_server/netlogon/dcerpc_netlogon.c
index c8dd0ceeb77..51c6666a164 100644
--- a/source4/rpc_server/netlogon/dcerpc_netlogon.c
+++ b/source4/rpc_server/netlogon/dcerpc_netlogon.c
@@ -2872,6 +2872,20 @@ static bool sam_rodc_access_check(struct ldb_context *sam_ctx,
 		goto denied;
 	}
 
+	/*
+	 * The SID list needs to include itself as well as the tokenGroups.
+	 *
+	 * TODO determine if sIDHistory is required for this check
+	 */
+	werr = samdb_result_sid_array_ndr(sam_ctx, obj_res->msgs[0],
+					  mem_ctx, "tokenGroups",
+					  &num_token_sids,
+					  &token_sids,
+					  object_sid, 1);
+	if (!W_ERROR_IS_OK(werr) || token_sids==NULL) {
+		goto denied;
+	}
+
 	werr = samdb_result_sid_array_dn(sam_ctx, rodc_res->msgs[0],
 					 mem_ctx, "msDS-NeverRevealGroup",
 					 &num_never_reveal_sids,
@@ -2888,20 +2902,6 @@ static bool sam_rodc_access_check(struct ldb_context *sam_ctx,
 		goto denied;
 	}
 
-	/*
-	 * The SID list needs to include itself as well as the tokenGroups.
-	 *
-	 * TODO determine if sIDHistory is required for this check
-	 */
-	werr = samdb_result_sid_array_ndr(sam_ctx, obj_res->msgs[0],
-					  mem_ctx, "tokenGroups",
-					  &num_token_sids,
-					  &token_sids,
-					  object_sid, 1);
-	if (!W_ERROR_IS_OK(werr) || token_sids==NULL) {
-		goto denied;
-	}
-
 	if (never_reveal_sids &&
 	    sid_list_match(num_token_sids,
 			   token_sids,