Fixed potential stack overflow when calculating changes to DtStart, D…

…tEnd, etc.
rianjs · Nov 8, 2019 · 4543db4 · 4543db4
1 parent 4b86b46
commit 4543db4
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Showing 2 changed files with 28 additions and 15 deletions.
diff --git a/net-core/Ical.Net/CalendarComponents/CalendarEvent.cs b/net-core/Ical.Net/CalendarComponents/CalendarEvent.cs
@@ -43,7 +43,7 @@ public override IDateTime DtStart
  set
  {
  base.DtStart = value;
- ExtrapolateTimes();
+ ExtrapolateTimes(2);
  }
  }
 
@@ -66,7 +66,7 @@ public virtual IDateTime DtEnd
  if (!Equals(DtEnd, value))
  {
  Properties.Set("DTEND", value);
- ExtrapolateTimes();
+ ExtrapolateTimes(0);
  }
  }
  }
@@ -100,7 +100,7 @@ public virtual TimeSpan Duration
  if (!Equals(Duration, value))
  {
  Properties.Set("DURATION", value);
- ExtrapolateTimes();
+ ExtrapolateTimes(1);
  }
  }
  }
@@ -258,20 +258,27 @@ protected override void OnDeserialized(StreamingContext context)
  {
  base.OnDeserialized(context);
 
- ExtrapolateTimes();
+ ExtrapolateTimes(-1);
  }
 
- private void ExtrapolateTimes()
+ private void ExtrapolateTimes(int source)
  {
- if (DtEnd == null && DtStart != null && Duration != default(TimeSpan))
+ /*
+ * Source values, a fix introduced to prevent stack overflow exceptions from occuring.
+ * -1 = Anybody, stack overflow could maybe still occur in this case?
+ * 0 = End
+ * 1 = Duration
+ * 2 = DtStart
+ */
+ if (DtEnd == null && DtStart != null && Duration != default(TimeSpan) && source != 0)
  {
  DtEnd = DtStart.Add(Duration);
  }
- else if (Duration == default(TimeSpan) && DtStart != null && DtEnd != null)
+ else if (Duration == default(TimeSpan) && DtStart != null && DtEnd != null && source != 1)
  {
  Duration = DtEnd.Subtract(DtStart);
  }
- else if (DtStart == null && Duration != default(TimeSpan) && DtEnd != null)
+ else if (DtStart == null && Duration != default(TimeSpan) && DtEnd != null && source != 2)
  {
  DtStart = DtEnd.Subtract(Duration);
  }

diff --git a/net-core/Ical.Net/CalendarComponents/Todo.cs b/net-core/Ical.Net/CalendarComponents/Todo.cs
@@ -34,7 +34,7 @@ public override IDateTime DtStart
  set
  {
  base.DtStart = value;
- ExtrapolateTimes();
+ ExtrapolateTimes(2);
  }
  }
 
@@ -47,7 +47,7 @@ public virtual IDateTime Due
  set
  {
  Properties.Set("DUE", value);
- ExtrapolateTimes();
+ ExtrapolateTimes(0);
  }
  }
 
@@ -70,7 +70,7 @@ public virtual TimeSpan Duration
  set
  {
  Properties.Set("DURATION", value);
- ExtrapolateTimes();
+ ExtrapolateTimes(1);
  }
  }
 
@@ -186,17 +186,23 @@ protected override void OnDeserializing(StreamingContext context)
  base.OnDeserializing(context);
  }
 
- private void ExtrapolateTimes()
+ private void ExtrapolateTimes(int source)
  {
- if (Due == null && DtStart != null && Duration != default(TimeSpan))
+ /*
+ * Source values, a fix introduced to prevent StackOverflow exceptions from occuring.
+ * 0 = Due
+ * 1 = Duration
+ * 2 = DtStart
+ */
+ if (Due == null && DtStart != null && Duration != default(TimeSpan) && source != 0)
  {
  Due = DtStart.Add(Duration);
  }
- else if (Duration == default(TimeSpan) && DtStart != null && Due != null)
+ else if (Duration == default(TimeSpan) && DtStart != null && Due != null && source != 1)
  {
  Duration = Due.Subtract(DtStart);
  }
- else if (DtStart == null && Duration != default(TimeSpan) && Due != null)
+ else if (DtStart == null && Duration != default(TimeSpan) && Due != null && source != 2)
  {
  DtStart = Due.Subtract(Duration);
  }