Fix permissions when packaging artifacts

The file permissions in our cross platform packages were all over the
place. Problems included:

- Executable text files
- Executable MSIL files
- Files not readable by world or group

In addition to just looking bad, it could cause problems in cases where
someone takes the tarballs and copies them to a global location (as
root) because now the deps file was not readable by non root users.

Add an additional step when setting everything up to put sensible
permissions on everything before building os specific packages and
tarballs.

Fixes #2004

scripts/dotnet-cli-build/PackageTargets.cs

@@ -61,6 +61,8 @@ namespace Microsoft.DotNet.Cli.Build
 
             Directory.CreateDirectory(cliSdkRoot);
             Utils.CopyDirectoryRecursively(Path.Combine(Dirs.Stage2, "sdk"), cliSdkRoot, true);
+            FixPermissions(cliSdkRoot);
+
             c.BuildContext["CLISDKRoot"] = cliSdkRoot;
             return c.Success();
         }
@@ -81,6 +83,7 @@ namespace Microsoft.DotNet.Cli.Build
                 var destFile = file.Replace(Dirs.Stage2, sharedHostRoot);
                 File.Copy(file, destFile, true);
             }
+            FixPermissions(sharedHostRoot);
 
             c.BuildContext["SharedHostPublishRoot"] = sharedHostRoot;
             return c.Success();
@@ -97,6 +100,8 @@ namespace Microsoft.DotNet.Cli.Build
 
             Directory.CreateDirectory(sharedFxRoot);
             Utils.CopyDirectoryRecursively(Path.Combine(Dirs.Stage2, "shared"), sharedFxRoot, true);
+            FixPermissions(sharedFxRoot);
+
             c.BuildContext["SharedFrameworkPublishRoot"] = sharedFxRoot;
             return c.Success();
         }
@@ -242,5 +247,17 @@ namespace Microsoft.DotNet.Cli.Build
                 .Execute()
                 .EnsureSuccessful();
         }
+
+        private static void FixPermissions(string directory)
+        {
+            if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                // Reset everything to user readable/writeable and group and world readable.
+                FS.ChmodAll(directory, "*", "644");
+
+                // Now make things that should be executable, executable.
+                FS.FixModeFlags(directory);
+            }
+        }
     }
 }