Stop decoding exceptions escaping from GetDecoderStream

2 files changed, 63 insertions, 35 deletions

diff --git a/crypto/src/openpgp/PgpUtilities.cs b/crypto/src/openpgp/PgpUtilities.cs
index 055f99636..7d96dee8d 100644
--- a/crypto/src/openpgp/PgpUtilities.cs
+++ b/crypto/src/openpgp/PgpUtilities.cs
@@ -417,7 +417,20 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
 
 				return inputStream;
             }
-            else
+
+            if (!IsPossiblyBase64(ch))
+            {
+                inputStream.Position = markedPos;
+
+				return new ArmoredInputStream(inputStream);
+            }
+
+			byte[]	buf = new byte[ReadAhead];
+            int		count = 1;
+            int		index = 1;
+
+			buf[0] = (byte)ch;
+            while (count != ReadAhead && (ch = inputStream.ReadByte()) >= 0)
             {
                 if (!IsPossiblyBase64(ch))
                 {
@@ -426,51 +439,49 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp
 					return new ArmoredInputStream(inputStream);
                 }
 
-				byte[]	buf = new byte[ReadAhead];
-                int		count = 1;
-                int		index = 1;
-
-				buf[0] = (byte)ch;
-                while (count != ReadAhead && (ch = inputStream.ReadByte()) >= 0)
+				if (ch != '\n' && ch != '\r')
                 {
-                    if (!IsPossiblyBase64(ch))
-                    {
-                        inputStream.Position = markedPos;
+                    buf[index++] = (byte)ch;
+                }
 
-						return new ArmoredInputStream(inputStream);
-                    }
+				count++;
+            }
 
-					if (ch != '\n' && ch != '\r')
-                    {
-                        buf[index++] = (byte)ch;
-                    }
+			inputStream.Position = markedPos;
 
-					count++;
-                }
+			//
+            // nothing but new lines, little else, assume regular armoring
+            //
+            if (count < 4)
+            {
+                return new ArmoredInputStream(inputStream);
+            }
 
-				inputStream.Position = markedPos;
+			//
+            // test our non-blank data
+            //
+            byte[] firstBlock = new byte[8];
 
-				//
-                // nothing but new lines, little else, assume regular armoring
-                //
-                if (count < 4)
-                {
-                    return new ArmoredInputStream(inputStream);
-                }
+			Array.Copy(buf, 0, firstBlock, 0, firstBlock.Length);
 
-				//
-                // test our non-blank data
-                //
-                byte[] firstBlock = new byte[8];
-				Array.Copy(buf, 0, firstBlock, 0, firstBlock.Length);
-				byte[] decoded = Base64.Decode(firstBlock);
+            try
+            {
+                byte[] decoded = Base64.Decode(firstBlock);
 
-				//
+                //
                 // it's a base64 PGP block.
                 //
-				bool hasHeaders = (decoded[0] & 0x80) == 0;
+                bool hasHeaders = (decoded[0] & 0x80) == 0;
 
-				return new ArmoredInputStream(inputStream, hasHeaders);
+                return new ArmoredInputStream(inputStream, hasHeaders);
+            }
+            catch (IOException e)
+            {
+                throw e;
+            }
+            catch (Exception e)
+            {
+                throw new IOException(e.Message);
             }
         }
 
diff --git a/crypto/test/src/openpgp/test/PGPArmoredTest.cs b/crypto/test/src/openpgp/test/PGPArmoredTest.cs
index aa13477ed..e48827a35 100644
--- a/crypto/test/src/openpgp/test/PGPArmoredTest.cs
+++ b/crypto/test/src/openpgp/test/PGPArmoredTest.cs
@@ -87,6 +87,22 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp.Tests
 			return matches;
 		}
 
+        private void pgpUtilTest()
+        {
+            // check decoder exception isn't escaping.
+            MemoryStream bIn = new MemoryStream(Strings.ToByteArray("abcde"), false);
+
+            try
+            {
+                PgpUtilities.GetDecoderStream(bIn);
+                Fail("no exception");
+            }
+            catch (IOException)
+            {
+                // expected: ignore.
+            }
+        }
+
 		private void blankLineTest()
 		{
 			byte[] blankLineBytes = Encoding.ASCII.GetBytes(blankLineData);
@@ -241,6 +257,7 @@ namespace Org.BouncyCastle.Bcpg.OpenPgp.Tests
 			}
 
 			blankLineTest();
+            pgpUtilTest();
 		}
 
 		public override string Name