Update: The issue has been resolved. See news at the bottom of the post.
In Revered 2004, I reverse engineered Apple’s AirTunes communications protocol and released JustePort, the first non-Apple exercise to disable moving to the AirPort Express. Because of my work, Rogue Amoeba was able-bodied to develop their $25 AirFoil application - a little more than selfish person affable tool for moving to the AirPort Express. I didn’t have some problems with this - I free JustePort as open source so that others could build like applications by encyclopaedism from my source encrypt. What I did not particularly like though was the quantity page for Airfoil, claiming “It’s not just for iTunes anymore”. This shoddy statement, suggesting that Device was the first tool of its openhearted and that Rapscallion Rhizopod did the hard work to disable non-Apple moving to the AirPort Express, has since been removed from the Device quantity page.
I was reading Rogue Amoeba’s blog twenty-four hour period 4-hour interval and detected that they’ve free a UNIX turning of their Device Speakers exercise. Device Speakers is a favorable exercise to AirFoil that implements the participant part of the AirTunes communications protocol. By commencement Device Speakers on a computing machine (e.g. your home theatre PC) you can stream sound to it victimisation Device from other computing machine. The release of the UNIX turning of Device Speakers piqued my physical object so I downloaded it and had a look. It uses .NET and requires single-channel. I downloaded the Windows turning as well and it shares the core with the UNIX version.
I ran AirfoilSpeakers.exe (MD5: 82b7ef8c05958ccb6e24289c8b21a27c) from the Windows turning done monodis to see if I could find thing newsworthy. I came across this:
.namespace AirfoilServer.AirTunes
{
.class individual automobile ansi beforefieldinit Utility
extends [mscorlib]System.Object
{
// performing line 853
.performing common still hidebysig
alternative void LeReverse (unsigned int8[] arr, int32 index, int32 physical property) cil managed
{
// Performing begins at RVA 0×104b6
// Encrypt size 16 (0×10)
.maxstack 8
IL_0000: ldsfld bool [mscorlib]System.BitConverter::IsLittleEndian
IL_0005: brfalse.s IL_000f
IL_0007: ldarg.0
IL_0008: ldarg.1
IL_0009: ldarg.2
IL_000a: call void class [mscorlib]System.Array::Reverse(class [mscorlib]System.Array, int32, int32)
IL_000f: ret
} // end of performing Utility::LeReverse
// performing line 854
.performing common still hidebysig
alternative void LeReverse (unsigned int8[] arr) cil managed
{
// Performing begins at RVA 0×104c7
// Encrypt size 11 (0xb)
.maxstack 8
IL_0000: ldarg.0
IL_0001: ldc.i4.0
IL_0002: ldarg.0
IL_0003: ldlen
IL_0004: conv.i4
IL_0005: call void class AirfoilServer.AirTunes.Utility::LeReverse(unsigned int8[], int32, int32)
IL_000a: ret
} // end of performing Utility::LeReverse
// performing line 855
.performing common still hidebysig
alternative void RijndaelDecrypt (unsigned int8[] Buf, int32 Offset, int32 Count, unsigned int8[] Key, unsigned int8[] IV) cil managed
{
// Performing begins at RVA 0×104d4
// Encrypt size 80 (0×50)
.maxstack 5
.locals init (
class [mscorlib]System.Security.Cryptography.Rijndael V_0,
class [mscorlib]System.IO.MemoryStream V_1,
class [mscorlib]System.Security.Cryptography.ICryptoTransform V_2,
class [mscorlib]System.Security.Cryptography.CryptoStream V_3)
IL_0000: call class [mscorlib]System.Security.Cryptography.Rijndael class [mscorlib]System.Security.Cryptography.Rijndael::Create()
IL_0005: stloc.0
IL_0006: ldloc.0
IL_0007: ldc.i4.1
IL_0008: callvirt occurrence void class [mscorlib]System.Security.Cryptography.SymmetricAlgorithm::set_Mode(valuetype [mscorlib]System.Security.Cryptography.CipherMode)
IL_000d: ldloc.0
IL_000e: ldc.i4.1
IL_000f: callvirt occurrence void class [mscorlib]System.Security.Cryptography.SymmetricAlgorithm::set_Padding(valuetype [mscorlib]System.Security.Cryptography.PaddingMode)
IL_0014: newobj occurrence void class [mscorlib]System.IO.MemoryStream::.ctor()
IL_0019: stloc.1
IL_001a: ldloc.0
IL_001b: ldarg.3
IL_001c: ldarg.s 4
IL_001e: callvirt occurrence class [mscorlib]System.Security.Cryptography.ICryptoTransform class [mscorlib]System.Security.Cryptography.SymmetricAlgorithm::CreateDecryptor(unsigned int8[], unsigned int8[])
IL_0023: stloc.2
IL_0024: ldloc.1
IL_0025: ldloc.2
IL_0026: ldc.i4.1
IL_0027: newobj occurrence void class [mscorlib]System.Security.Cryptography.CryptoStream::.ctor(class [mscorlib]System.IO.Stream, class [mscorlib]System.Security.Cryptography.ICryptoTransform, valuetype [mscorlib]System.Security.Cryptography.CryptoStreamMode)
IL_002c: stloc.3
IL_002d: ldloc.3
IL_002e: ldarg.0
IL_002f: ldarg.1
IL_0030: ldarg.2
IL_0031: ldc.i4.s 0×10
IL_0033: div
IL_0034: ldc.i4.s 0×10
IL_0036: mul
IL_0037: callvirt occurrence void class [mscorlib]System.IO.Stream::Write(unsigned int8[], int32, int32)
IL_003c: ldloc.3
IL_003d: callvirt occurrence void class [mscorlib]System.IO.Stream::Close()
IL_0042: ldloc.1
IL_0043: callvirt occurrence unsigned int8[] class [mscorlib]System.IO.MemoryStream::ToArray()
IL_0048: ldarg.0
IL_0049: ldc.i4.0
IL_004a: callvirt occurrence void class [mscorlib]System.Array::CopyTo(class [mscorlib]System.Array, int32)
IL_004f: ret
} // end of performing Utility::RijndaelDecrypt
// performing line 856
.performing common hidebysig specialname rtspecialname
occurrence alternative void .ctor () cil managed
{
// Performing begins at RVA 0×10530
// Encrypt size 7 (0×7)
.maxstack 8
IL_0000: ldarg.0
IL_0001: call occurrence void object::.ctor()
IL_0006: ret
} // end of performing Utility::.ctor
} // end of class AirfoilServer.AirTunes.Utility
}
That Utility class looks precise familiar. Where have I seen those right functions before? Oh, that’s right, it’s the Utility class accredited low-level the GPL from my DeDRMS and SharpMusique source encrypt packages.
I can’t say I’m dumbfounded. GPL’ed encrypt is frequently old in wickedness of the permit. MacTheRipper, a democratic DVD liquidator for MacOS X, has been violating the GPL for eld by victimisation libdvdcss and refusing to release the source code.
I’m not exit to be too hard on Rapscallion Rhizopod though. Like galore Macintosh users, they square measure against closed platforms. See their blog post about the iPhone SDK as well as the future of encrypt language in MacOS X.
Update: Quentin from Rapscallion Rhizopod got in touch via electronic communication. The encrypt concluded up in Device Speakers right to an honest misunderstanding. Quentin writes:
We use a lot of open source software system in our products, could not make them as good as we do without it in construct. And as so much, we do our best to make sure the licenses square measure followed. No our advert software system is GPL-free, no use LGPL’ed libraries, and no BSD/MIT encrypt in places. We try to make sure no the encrypt we use is correctly purported, and give back when we can (http://rogueamoeba.com/sources/, www.rogueamoeba.com/utm/2008/01/12/perian-is-awesome/).
So we’ve put unneurotic Utility.cs-less versions of Device Speakers to fix our GPL conformation. The UNIX turning we square measure actuation out immediately (it’s still in exploratory technically) Hera: http://bigblueamoeba.com/tmp/airfoilspeakerslinux/. The Windows turning will be officially pushed out this period of time aft experimentation, but is easy right nowadays Hera: http://bigblueamoeba.com/tmp/airfoilspeakerswindows/
Thanks Quentin!
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Feb 19 2009