Handle inconsistent \0 in Pkcs9Document{Name|Description}

dotnet · Nov 24, 2020 · 2e8c4c7 · 2e8c4c7
1 parent 664b962
commit 2e8c4c7
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Showing 2 changed files with 62 additions and 1 deletion.
diff --git a/src/libraries/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/PkcsHelpers.cs b/src/libraries/System.Security.Cryptography.Pkcs/src/Internal/Cryptography/PkcsHelpers.cs
@@ -227,7 +227,20 @@ public static string OctetStringToUnicode(this byte[] octets)
             if (octets.Length < 2)
                 return string.Empty;   // .NET Framework compat: 0-length byte array maps to string.empty. 1-length byte array gets passed to Marshal.PtrToStringUni() with who knows what outcome.
 
-            string s = Encoding.Unicode.GetString(octets, 0, octets.Length - 2);
+            int end = octets.Length;
+            int endMinusOne = end - 1;
+
+            // Truncate the string to before the first embedded \0 (probably the last two bytes).
+            for (int i = 0; i < endMinusOne; i += 2)
+            {
+                if (octets[i] == 0 && octets[i + 1] == 0)
+                {
+                    end = i;
+                    break;
+                }
+            }
+
+            string s = Encoding.Unicode.GetString(octets, 0, end);
             return s;
         }
 

diff --git a/src/libraries/System.Security.Cryptography.Pkcs/tests/Pkcs9AttributeTests.cs b/src/libraries/System.Security.Cryptography.Pkcs/tests/Pkcs9AttributeTests.cs
@@ -177,6 +177,30 @@ public static void DocumentDescriptionFromRawData()
             Assert.Equal(s_OidDocumentDescription, oid);
         }
 
+        [Fact]
+        public static void DocumentDescriptionMissingTerminator()
+        {
+            byte[] rawData = "041e4d00790020004400650073006300720069007000740069006f006e002100".HexToByteArray();
+            Pkcs9DocumentDescription p = new Pkcs9DocumentDescription(rawData);
+            Assert.Equal(rawData, p.RawData);
+            string cookedData = p.DocumentDescription;
+            Assert.Equal("My Description!", cookedData);
+            string oid = p.Oid.Value;
+            Assert.Equal(s_OidDocumentDescription, oid);
+        }
+
+        [Fact]
+        public static void DocumentDescriptionEmbeddedTerminator()
+        {
+            byte[] rawData = "041e4d00790020004400650073006300720000007000740069006f006e000000".HexToByteArray();
+            Pkcs9DocumentDescription p = new Pkcs9DocumentDescription(rawData);
+            Assert.Equal(rawData, p.RawData);
+            string cookedData = p.DocumentDescription;
+            Assert.Equal("My Descr", cookedData);
+            string oid = p.Oid.Value;
+            Assert.Equal(s_OidDocumentDescription, oid);
+        }
+
         [Fact]
         public static void DocumentDescriptionFromCookedData()
         {
@@ -226,6 +250,30 @@ public static void DocumentNameFromRawData()
             Assert.Equal(s_OidDocumentName, oid);
         }
 
+        [Fact]
+        public static void DocumentNameMissingTerminator()
+        {
+            byte[] rawData = "04104d00790020004e0061006d0065002100".HexToByteArray();
+            Pkcs9DocumentName p = new Pkcs9DocumentName(rawData);
+            Assert.Equal(rawData, p.RawData);
+            string cookedData = p.DocumentName;
+            Assert.Equal("My Name!", cookedData);
+            string oid = p.Oid.Value;
+            Assert.Equal(s_OidDocumentName, oid);
+        }
+
+        [Fact]
+        public static void DocumentNameEmbeddedTerminator()
+        {
+            byte[] rawData = "04104d00790020004e006100000065000000".HexToByteArray();
+            Pkcs9DocumentName p = new Pkcs9DocumentName(rawData);
+            Assert.Equal(rawData, p.RawData);
+            string cookedData = p.DocumentName;
+            Assert.Equal("My Na", cookedData);
+            string oid = p.Oid.Value;
+            Assert.Equal(s_OidDocumentName, oid);
+        }
+
         [Fact]
         public static void DocumentNameFromCookedData()
         {