Avoid potential NRE is the UserCAStore could not be created. ref: desk #33432

1 files changed, 9 insertions, 5 deletions

diff --git a/mcs/class/System/System.Security.Cryptography.X509Certificates/X509Chain.cs b/mcs/class/System/System.Security.Cryptography.X509Certificates/X509Chain.cs
index 99f40f4d0c1..7dfd434c85a 100644
--- a/mcs/class/System/System.Security.Cryptography.X509Certificates/X509Chain.cs
+++ b/mcs/class/System/System.Security.Cryptography.X509Certificates/X509Chain.cs
@@ -878,8 +878,12 @@ namespace System.Security.Cryptography.X509Certificates {
 			return X509ChainStatusFlags.NoError;
 		}
 
-		static MX.X509Crl CheckCrls (string subject, string ski, ArrayList crls)
+		static MX.X509Crl CheckCrls (string subject, string ski, MX.X509Store store)
 		{
+			if (store == null)
+				return null;
+
+			var crls = store.Crls;
 			foreach (MX.X509Crl crl in crls) {
 				if (crl.IssuerName == subject && (ski.Length == 0 || ski == GetAuthorityKeyIdentifier (crl)))
 					return crl;
@@ -893,21 +897,21 @@ namespace System.Security.Cryptography.X509Certificates {
 			string ski = GetSubjectKeyIdentifier (caCertificate);
 
 			// consider that the LocalMachine directories could not exists... and cannot be created by the user
-			var result = (LMCAStore.Store == null) ? null : CheckCrls (subject, ski, LMCAStore.Store.Crls);
+			MX.X509Crl result = CheckCrls (subject, ski, LMCAStore.Store);
 			if (result != null)
 				return result;
 			if (location == StoreLocation.CurrentUser) {
-				result = CheckCrls (subject, ski, UserCAStore.Store.Crls);
+				result = CheckCrls (subject, ski, UserCAStore.Store);
 				if (result != null)
 					return result;
 			}
 
 			// consider that the LocalMachine directories could not exists... and cannot be created by the user
-			result = (LMRootStore.Store == null) ? null : CheckCrls (subject, ski, LMRootStore.Store.Crls);
+			result = CheckCrls (subject, ski, LMRootStore.Store);
 			if (result != null)
 				return result;
 			if (location == StoreLocation.CurrentUser) {
-				result = CheckCrls (subject, ski, UserRootStore.Store.Crls);
+				result = CheckCrls (subject, ski, UserRootStore.Store);
 				if (result != null)
 					return result;
 			}