cli/command/image: build: remove permissions warning on Windows

This warning was added in [moby@4a8b3ca] to print a warning when building
Linux images from a Windows client. Window's filesystem does not have an
"executable" bit, which mean that, for example, copying a shell script
to an image during build would lose the executable bit. So for Windows
clients, the executable bit would be set on all files, unconditionally.

Originally this was detected in the client, which had direct access to
the API response headers, but when refactoring the client to use a common
library in [moby@535c4c9], this was refactored into a `ImageBuildResponse`
wrapper, deconstructing the API response into an `io.Reader` and a string
field containing only the `OSType` header.

This was the only use and only purpose of the `OSType` field, and now that
BuildKit is the default builder for Linux images, this warning didn't get
printed unless BuildKit was explicitly disabled.

This patch removes the warning, so that we can potentially remove the
field, or the `ImageBuildResponse` type altogether.

[moby@4a8b3ca]: moby/moby@4a8b3ca
[moby@535c4c9]: moby/moby@535c4c9

Signed-off-by: Sebastiaan van Stijn <[email protected]>
(cherry picked from commit af65ee4)
Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

cli/command/image/build.go

@@ -10,7 +10,6 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"runtime"
 	"strings"
 
 	"github.com/distribution/reference"
@@ -385,16 +384,6 @@ func runBuild(ctx context.Context, dockerCli command.Cli, options buildOptions)
 		return err
 	}
 
-	// Windows: show error message about modified file permissions if the
-	// daemon isn't running Windows.
-	if response.OSType != "windows" && runtime.GOOS == "windows" && !options.quiet {
-		_, _ = fmt.Fprintln(dockerCli.Out(), "SECURITY WARNING: You are building a Docker "+
-			"image from Windows against a non-Windows Docker host. All files and "+
-			"directories added to build context will have '-rwxr-xr-x' permissions. "+
-			"It is recommended to double check and reset permissions for sensitive "+
-			"files and directories.")
-	}
-
 	// Everything worked so if -q was provided the output from the daemon
 	// should be just the image ID and we'll print that to stdout.
 	if options.quiet {