Permission denied error on NuGetFallbackFolder after update to SDK 2.1.500

Steps to reproduce

Running Ubuntu 18.04:

1. update to dotnet core sdk 2.1.500 (via apt update/upgrade)
2. try doing “dotnet run” or “dotnet restore”

Actual behavior

Produces a message stating an error on permissions to the NuGetFallbackFolder.

Permission denied to modify the '/usr/share/dotnet/sdk/NuGetFallbackFolder' folder.

Here are some options to fix this error:
----------------------------------------
1. Re-run this command with elevated access.
2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
3. Copy the .NET Core SDK to a non-protected location and use it from there.

Expected behavior

Worked properly before the update

Environment data

NET Core SDK (reflecting any global.json):
 Version:   2.1.500
 Commit:    b68b931422

Runtime Environment:
 OS Name:     ubuntu
 OS Version:  18.04
 OS Platform: Linux
 RID:         ubuntu.18.04-x64
 Base Path:   /usr/share/dotnet/sdk/2.1.500/

Host (useful for support):
  Version: 2.1.6
  Commit:  3f4f8eebd8

.NET Core SDKs installed:
  2.1.500 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.6 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.6 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.6 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

[thothothotho]

Everytime Ubuntu updates the dotnet package, I have this warning again and need to use one of the available workaround (usually doing a sudo dotnet new console in a dummy directory)

[thothothotho]

Why don’t you add a post install script in the ubuntu package that does exactly that ? (sudo dotnet new console)