Access denied error when building from source

[OdeToCode]

Following the instructions in the build from source WIki on a Win10 machine. Running restore completes with no errors. Running build generates the following 4 errors.

Build FAILED.

ALINK : error AL1078: Error signing assembly -- Access is denied. [C:\Users\scott\repos\AspNetCore\src\Middleware\Localization\sample\LocalizationSample.csproj]
ALINK : error AL1078: Error signing assembly -- Access is denied. [C:\Users\scott\repos\AspNetCore\src\Middleware\Localization\testassets\LocalizationWebsite\LocalizationWebsite.csproj]
ALINK : error AL1078: Error signing assembly -- Access is denied. [C:\Users\scott\repos\AspNetCore\src\Mvc\test\WebSites\RazorPagesWebSite\RazorPagesWebSite.csproj]
ALINK : error AL1078: Error signing assembly -- Access is denied. [C:\Users\scott\repos\AspNetCore\src\Components\test\testassets\BasicTestApp\BasicTestApp.csproj]
    0 Warning(s)
    4 Error(s)

Digging into the logs, I can see al.exe running with the following command line for the first error:

C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\al.exe 
  /culture:es-ES /delaysign- 
  /keyfile:C:\Users\scott\.nuget\packages\microsoft.dotnet.arcade.sdk\5.0.0-beta.19574.1\tools\snk/AspNetCore.snk
  /out:C:\Users\scott\repos\AspNetCore\artifacts\obj\LocalizationSample\Debug\netcoreapp5.0\es-ES\LocalizationSample.resources.dll 
 /template:C:\Users\scott\repos\AspNetCore\artifacts\obj\LocalizationSample\Debug\netcoreapp5.0\LocalizationSample.dll
 /embed:C:\Users\scott\repos\AspNetCore\artifacts\obj\LocalizationSample\Debug\netcoreapp5.0\LocalizationSample.My.Resources.Startup.es-ES.resources

With the sysinternals tools, I can see the ACCESS DENIED error popping up when al.exe tries to create a file: C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys\eecbfdd95d7ed9110d5942eb026463f1_7990d07d-81f1-4e2e-a733-048b6f7c81bc.

[pranavkm]

There's a workaround listed here: https://github.com/dotnet/corefx/issues/3784#issuecomment-404795417. Since this issue isn't specific to AspNetCore, we'll use the other issue to track addressing it.

[OdeToCode]

The proposed workaround is to give yourself Full Control over the MachineKeys folder. MachineKeys is the folder where private keys from all users and system processes appear, so the proposed work around is dangerously wrong and opens a vulnerability.

The MachineKeys folder requires special permissions as I have documented here: https://odetocode.com/blogs/scott/archive/2020/01/12/solving-access-denied-in-crypto-machine-keys.aspx