Validate CorrelationContext size and skip everything after 1024 chars (#36)

Author: Liudmila Molkova

src/Microsoft.AspNet.TelemetryCorrelation/ActivityExtensions.cs

@@ -25,6 +25,11 @@ public static class ActivityExtensions
         /// </summary>
         internal const string CorrelationContextHeaderName = "Correlation-Context";
 
+        /// <summary>
+        /// Maximum length of Correlation-Context herader value.
+        /// </summary>
+        internal const int MaxCorrelationContextLength = 1024;
+
         /// <summary>
         /// Reads Request-Id and Correlation-Context headers and sets ParentId and Baggage on Activity.
         /// </summary>
@@ -61,11 +66,24 @@ public static bool Extract(this Activity activity, NameValueCollection requestHe
                 var baggages = requestHeaders.GetValues(CorrelationContextHeaderName);
                 if (baggages != null)
                 {
+                    int correlationContextLength = -1;
                     // there may be several Correlation-Context header
                     foreach (var item in baggages)
                     {
+                        if (correlationContextLength >= MaxCorrelationContextLength)
+                        {
+                            break;
+                        }
+
                         foreach (var pair in item.Split(','))
                         {
+                            correlationContextLength += pair.Length + 1; // pair and comma
+
+                            if (correlationContextLength >= MaxCorrelationContextLength)
+                            {
+                                break;
+                            }
+
                             if (NameValueHeaderValue.TryParse(pair, out NameValueHeaderValue baggageItem))
                             {
                                 activity.AddBaggage(baggageItem.Name, baggageItem.Value);

test/Microsoft.AspNet.TelemetryCorrelation.Tests/ActivityExtensionsTest.cs

@@ -130,5 +130,51 @@ public void Can_Restore_Baggages_When_Some_MalFormat_CorrelationContext_In_Heade
             var actualBaggage = activity.Baggage.OrderBy(kvp => kvp.Key);
             Assert.Equal(expectedBaggage, actualBaggage);
         }
+
+        [Theory]
+        [InlineData("key0=value0,key1=value1,key2=value2,key3=value3,key4=value4,key5=value5,key6=value6,key7=value7,key8=value8,key9=value9," +
+                    "key10=value10,key11=value11,key12=value12,key13=value13,key14=value14,key15=value15,key16=value16,key17=value17,key18=value18,key19=value19," +
+                    "key20=value20,key21=value21,key22=value22,key23=value23,key24=value24,key25=value25,key26=value26,key27=value27,key28=value28,key29=value29," +
+                    "key30=value30,key31=value31,key32=value32,key33=value33,key34=value34,key35=value35,key36=value36,key37=value37,key38=value38,key39=value39," +
+                    "key40=value40,key41=value41,key42=value42,key43=value43,key44=value44,key45=value45,key46=value46,key47=value47,key48=value48,key49=value49," +
+                    "key50=value50,key51=value51,key52=value52,key53=value53,key54=value54,key55=value55,key56=value56,key57=value57,key58=value58,key59=value59," +
+                    "key60=value60,key61=value61,key62=value62,key63=value63,key64=value64,key65=value65,key66=value66,key67=value67,key68=value68,key69=value69," +
+                    "key70=value70,key71=value71,key72=value72,key73=value73,k100=vx", 1023)] //1023 chars
+        [InlineData("key0=value0,key1=value1,key2=value2,key3=value3,key4=value4,key5=value5,key6=value6,key7=value7,key8=value8,key9=value9," +
+                    "key10=value10,key11=value11,key12=value12,key13=value13,key14=value14,key15=value15,key16=value16,key17=value17,key18=value18,key19=value19," +
+                    "key20=value20,key21=value21,key22=value22,key23=value23,key24=value24,key25=value25,key26=value26,key27=value27,key28=value28,key29=value29," +
+                    "key30=value30,key31=value31,key32=value32,key33=value33,key34=value34,key35=value35,key36=value36,key37=value37,key38=value38,key39=value39," +
+                    "key40=value40,key41=value41,key42=value42,key43=value43,key44=value44,key45=value45,key46=value46,key47=value47,key48=value48,key49=value49," +
+                    "key50=value50,key51=value51,key52=value52,key53=value53,key54=value54,key55=value55,key56=value56,key57=value57,key58=value58,key59=value59," +
+                    "key60=value60,key61=value61,key62=value62,key63=value63,key64=value64,key65=value65,key66=value66,key67=value67,key68=value68,key69=value69," +
+                    "key70=value70,key71=value71,key72=value72,key73=value73,k100=vx1", 1024)] //1024 chars
+        [InlineData("key0=value0,key1=value1,key2=value2,key3=value3,key4=value4,key5=value5,key6=value6,key7=value7,key8=value8,key9=value9," +
+                    "key10=value10,key11=value11,key12=value12,key13=value13,key14=value14,key15=value15,key16=value16,key17=value17,key18=value18,key19=value19," +
+                    "key20=value20,key21=value21,key22=value22,key23=value23,key24=value24,key25=value25,key26=value26,key27=value27,key28=value28,key29=value29," +
+                    "key30=value30,key31=value31,key32=value32,key33=value33,key34=value34,key35=value35,key36=value36,key37=value37,key38=value38,key39=value39," +
+                    "key40=value40,key41=value41,key42=value42,key43=value43,key44=value44,key45=value45,key46=value46,key47=value47,key48=value48,key49=value49," +
+                    "key50=value50,key51=value51,key52=value52,key53=value53,key54=value54,key55=value55,key56=value56,key57=value57,key58=value58,key59=value59," +
+                    "key60=value60,key61=value61,key62=value62,key63=value63,key64=value64,key65=value65,key66=value66,key67=value67,key68=value68,key69=value69," +
+                    "key70=value70,key71=value71,key72=value72,key73=value73,key74=value74", 1029)] //more than 1024 chars
+        public void Validates_Correlation_Context_Length(string correlationContext, int expectedLength)
+        {
+            var activity = new Activity(TestActivityName);
+            var requestHeaders = new NameValueCollection
+            {
+                { ActivityExtensions.RequestIDHeaderName, "|abc.1" },
+                { ActivityExtensions.CorrelationContextHeaderName, correlationContext }
+            };
+            Assert.True(activity.Extract(requestHeaders));
+
+            var baggageItems = Enumerable.Range(0, 74).Select(i => new KeyValuePair<string, string>("key" + i, "value" + i)).ToList();
+            if (expectedLength < 1024)
+            {
+                baggageItems.Add(new KeyValuePair<string, string>("k100", "vx"));
+            }
+
+            var expectedBaggage = baggageItems.OrderBy(kvp => kvp.Key);
+            var actualBaggage = activity.Baggage.OrderBy(kvp => kvp.Key);
+            Assert.Equal(expectedBaggage, actualBaggage);
+        }
     }
 }