How to include libsodium.net on ASP.NET

Question

I have an old webservice build on ASP.NET (using .asmx) files. I need to use sodium.net - unfortunately it fails while loading the dependent libsodium.dll file. Any ideas about what I make wrong?

• I have added libsodium.net through NuGet.

• I have renamed the 64 bit DLL to "libsodium.dll" (and other naming conventions too).

• I have tried to reference libsodium.dll directly but VS rejects it (not a valid DLL). So I have added it as "content" instead with "copy to output".

• After building I can see that the website/Bin folder contains both sodium.dll (the .NET assembly) and libsodium.net.

• When I try to use libsodium.net I get:

  ERROR 2015-02-02 11:14:27,118 13798ms [41] CabinetService doRequest - Caught: The type initializer for 'Sodium.SodiumCore' threw an exception. System.TypeInitializationException: The type initializer for 'Sodium.SodiumCore' threw an exception. ---> System.DllNotFoundException: Unable to load DLL 'libsodium.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E) at DynamicDllInvokeType.sodium_init() at Sodium.SodiumCore..cctor() --- End of inner exception stack trace --- at Sodium.SodiumCore.LibraryName() at Sodium.SecretBox.Create(Byte[] message, Byte[] nonce, Byte[] key) at Macaroons.SecretBoxCryptoAlgorithm.Encrypt(Byte[] key, Byte[] plainText) in c:\Projects\Macaroons.Net\Macaroons.Net\SecretBoxCryptoAlgorithm.cs:line 58

So it cannot find "libsodium.dll" even though it is in the Bin folder. I did also try to remove the dependency on "sodium.net" where after I got a runtime error saying "sodium.net" is missing - when I re-added it, that error disappeared and I got the one above instead (indicating the "sodium.net" loads correctly).

So I open up the website shadow folder in "C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\cabinetservice" and search for "sodium". The only result is "sodium.dll" in some subfolder. There is no "libsodium.dll".

So apparently ASP.NET ignores the "libsodium.dll" file when creating the shadow copy of the website.

I have also tried adding the libsodium.dll (32 bit) to C:\Windows\System32 and libsodium.dll (64 bit) to C:\Windows\SysWOW64. Same result.

And I have tried C:\Windows\Microsoft.NET\assembly\GAC_32\libsodium and C:\Windows\Microsoft.NET\assembly\GAC_64\libsodium. Same result.

How can I make ASP.NET aware of the dependency?

Answer 1

It turns out that ASP.NET doesn't make shadow copies of unmanaged DLLs such as libsodium.dll and libsodium-64.dll.

Sodium.dll (the managed code) tries to load the DLLs from either the same directory as the shadow copy of Sodium.dll (which is not going to work) - or some where in the PATH environment variable's directories.

My solution was to add the AppDomain \Bin directory to the path before calling any Sodium code:

// Make it possible to load unmanaged libsodium DLLs that .NET does not make shadow copies of.
// -> Simply point the "path" variable to the Bin directory.
string path = Environment.GetEnvironmentVariable("PATH");
string binDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Bin");
Environment.SetEnvironmentVariable("PATH", path + ";" + binDir);

Update January 2018 (from Jordan Rieger's answer):

Note that you may also need to install the Microsoft Visual C++ 2015 Redistributable on your server (either the x64 or x86 target, depending on your process.)

Don't forget to restart your app pool (I did an IIS reset) after installing the redistributable.

Answer 2

Note that you may also need to install the Microsoft Visual C++ 2015 Redistributable on your server (either the x64 or x86 target, depending on your process.)

Don't forget to restart your app pool (I did an IIS reset) after installing the redistributable.

See my comment on https://stackoverflow.com/a/45078280/284704.