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Fix crash when trying to read empty replay files

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It was crashing because it tried to seek 8 bytes before the end
of a file that was empty (zero length).

I also added a few more checks and another try/catch to prevent
any more crashes related to damaged files.
This commit is contained in:
Pavlos Touboulidis
2014-05-13 22:29:56 +03:00
parent f4c52eefae
commit 38a5e326f6
1 changed files with 34 additions and 20 deletions
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24
OpenRA.Game/FileFormats/ReplayMetadata.cs
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@@ -46,8 +46,8 @@ namespace OpenRA.FileFormats
if (version != MetaVersion) if (version != MetaVersion)
throw new NotSupportedException("Metadata version {0} is not supported".F(version)); throw new NotSupportedException("Metadata version {0} is not supported".F(version));
// Read game info // Read game info (max 100K limit as a safeguard against corrupted files)
string data = ReadUtf8String(reader); string data = ReadUtf8String(reader, 1024 * 100);
GameInfo = GameInformation.Deserialize(data); GameInfo = GameInformation.Deserialize(data);
} }
@@ -87,13 +87,18 @@ namespace OpenRA.FileFormats
if (!fs.CanSeek) if (!fs.CanSeek)
return null; return null;
if (fs.Length < 20)
return null;
try
{
fs.Seek(-(4 + 4), SeekOrigin.End); fs.Seek(-(4 + 4), SeekOrigin.End);
using (var reader = new BinaryReader(fs)) using (var reader = new BinaryReader(fs))
{ {
var dataLength = reader.ReadInt32(); var dataLength = reader.ReadInt32();
if (reader.ReadInt32() == MetaEndMarker) if (reader.ReadInt32() == MetaEndMarker)
{ {
// go back end marker + length storage + data + version + start marker // go back by (end marker + length storage + data + version + start marker) bytes
fs.Seek(-(4 + 4 + dataLength + 4 + 4), SeekOrigin.Current); fs.Seek(-(4 + 4 + dataLength + 4 + 4), SeekOrigin.Current);
try try
{ {
@@ -109,6 +114,11 @@ namespace OpenRA.FileFormats
} }
} }
} }
}
catch (IOException ex)
{
Log.Write("debug", ex.ToString());
}
return null; return null;
} }
@@ -128,9 +138,13 @@ namespace OpenRA.FileFormats
return 4 + bytes.Length; return 4 + bytes.Length;
} }
static string ReadUtf8String(BinaryReader reader) static string ReadUtf8String(BinaryReader reader, int maxLength)
{ {
return Encoding.UTF8.GetString(reader.ReadBytes(reader.ReadInt32())); var length = reader.ReadInt32();
if (length > maxLength)
throw new InvalidOperationException("The length of the string ({0}) is longer than the maximum allowed ({1}).".F(length, maxLength));
return Encoding.UTF8.GetString(reader.ReadBytes(length));
} }
} }
} }