Cherry-pick #19793 to 7.x: [Elastic Agent] Fix saving of agent configuration on Windows to have proper ACLs

NOTICE.txt

@@ -10641,6 +10641,25 @@ Exhibit B - “Incompatible With Secondary Licenses” Notice
       the Mozilla Public License, v. 2.0.
 
 
+--------------------------------------------------------------------------------
+Dependency : github.com/hectane/go-acl
+Version: v0.0.0-20190604041725-da78bae5fc95
+Licence type (autodetected): MIT
+--------------------------------------------------------------------------------
+
+Contents of probable licence file $GOMODCACHE/github.com/hectane/[email protected]/LICENSE.txt:
+
+The MIT License (MIT)
+
+Copyright (c) 2015 Nathan Osman
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
 --------------------------------------------------------------------------------
 Dependency : github.com/elastic/dhcp
 Version: v0.0.0-20200227161230-57ec251c7eb3

go.mod

@@ -99,6 +99,7 @@ require (
 	github.com/h2non/filetype v1.0.12
 	github.com/hashicorp/go-multierror v1.1.0
 	github.com/hashicorp/golang-lru v0.5.2-0.20190520140433-59383c442f7d // indirect
+	github.com/hectane/go-acl v0.0.0-20190604041725-da78bae5fc95
 	github.com/insomniacslk/dhcp v0.0.0-20180716145214-633285ba52b2
 	github.com/jmoiron/sqlx v1.2.1-0.20190826204134-d7d95172beb5
 	github.com/joeshaw/multierror v0.0.0-20140124173710-69b34d4ec901

go.sum

@@ -422,6 +422,8 @@ github.com/haya14busa/go-actions-toolkit v0.0.0-20200105081403-ca0307860f01 h1:H
 github.com/haya14busa/go-actions-toolkit v0.0.0-20200105081403-ca0307860f01/go.mod h1:1DWDZmeYf0LX30zscWb7K9rUMeirNeBMd5Dum+seUhc=
 github.com/haya14busa/go-checkstyle v0.0.0-20170303121022-5e9d09f51fa1/go.mod h1:RsN5RGgVYeXpcXNtWyztD5VIe7VNSEqpJvF2iEH7QvI=
 github.com/haya14busa/secretbox v0.0.0-20180525171038-07c7ecf409f5/go.mod h1:FGO/dXIFZnan7KvvUSFk1hYMnoVNzB6NTMPrmke8SSI=
+github.com/hectane/go-acl v0.0.0-20190604041725-da78bae5fc95 h1:S4qyfL2sEm5Budr4KVMyEniCy+PbS55651I/a+Kn/NQ=
+github.com/hectane/go-acl v0.0.0-20190604041725-da78bae5fc95/go.mod h1:QiyDdbZLaJ/mZP4Zwc9g2QsfaEA4o7XvvgZegSci5/E=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
@@ -811,6 +813,7 @@ golang.org/x/sys v0.0.0-20190422165155-953cdadca894/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190507160741-ecd444e8653b/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190514135907-3a4b5fb9f71f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20190529164535-6a60838ec259/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190606165138-5da285871e9c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190624142023-c5567b49c5d0/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190801041406-cbf593c0f2f3/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

x-pack/elastic-agent/pkg/agent/storage/storage.go

@@ -12,6 +12,8 @@ import (
 	"os"
 	"time"
 
+	"github.com/hectane/go-acl"
+
 	"github.com/elastic/beats/v7/libbeat/common/file"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/errors"
 )
@@ -129,6 +131,13 @@ func (r *ReplaceOnSuccessStore) Save(in io.Reader) error {
 		}
 	}
 
+	if err := acl.Chmod(r.target, perms); err != nil {
+		return errors.New(err,
+			fmt.Sprintf("could not set permissions target file %s", r.target),
+			errors.TypeFilesystem,
+			errors.M(errors.MetaKeyPath, r.target))
+	}
+
 	return nil
 }
 
@@ -178,6 +187,13 @@ func (d *DiskStore) Save(in io.Reader) error {
 			errors.M(errors.MetaKeyPath, d.target))
 	}
 
+	if err := acl.Chmod(d.target, perms); err != nil {
+		return errors.New(err,
+			fmt.Sprintf("could not set permissions target file %s", d.target),
+			errors.TypeFilesystem,
+			errors.M(errors.MetaKeyPath, d.target))
+	}
+
 	return nil
 }
 

x-pack/elastic-agent/pkg/agent/storage/storage_test.go

@@ -11,6 +11,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -49,11 +50,7 @@ func TestReplaceOrRollbackStore(t *testing.T) {
 
 		require.True(t, bytes.Equal(writtenContent, replaceWith))
 		requireFilesCount(t, dir, 2)
-
-		info, err := os.Stat(target)
-		require.NoError(t, err)
-
-		require.Equal(t, perms, info.Mode())
+		checkPerms(t, target, perms)
 	})
 
 	t.Run("when save is not successful", func(t *testing.T) {
@@ -103,10 +100,6 @@ func TestReplaceOrRollbackStore(t *testing.T) {
 		require.True(t, bytes.Equal(writtenContent, replaceWith))
 		requireFilesCount(t, dir, 1)
 
-		info, err := os.Stat(target)
-		require.NoError(t, err)
-
-		require.Equal(t, perms, info.Mode())
 	})
 
 	t.Run("when target file do not exist", func(t *testing.T) {
@@ -135,11 +128,7 @@ func TestDiskStore(t *testing.T) {
 		require.NoError(t, err)
 
 		require.Equal(t, msg, content)
-
-		info, err := os.Stat(target)
-		require.NoError(t, err)
-
-		require.Equal(t, perms, info.Mode())
+		checkPerms(t, target, perms)
 	})
 
 	t.Run("when the target do no exist", func(t *testing.T) {
@@ -158,11 +147,7 @@ func TestDiskStore(t *testing.T) {
 		require.NoError(t, err)
 
 		require.Equal(t, msg, content)
-
-		info, err := os.Stat(target)
-		require.NoError(t, err)
-
-		require.Equal(t, perms, info.Mode())
+		checkPerms(t, target, perms)
 	})
 
 	t.Run("return an io.ReadCloser to the target file", func(t *testing.T) {
@@ -178,11 +163,7 @@ func TestDiskStore(t *testing.T) {
 		content, err := ioutil.ReadAll(r)
 		require.NoError(t, err)
 		require.Equal(t, msg, content)
-
-		info, err := os.Stat(target)
-		require.NoError(t, err)
-
-		require.Equal(t, perms, info.Mode())
+		checkPerms(t, target, perms)
 	})
 }
 
@@ -210,3 +191,14 @@ func requireFilesCount(t *testing.T, dir string, l int) {
 	require.NoError(t, err)
 	require.Equal(t, l, len(files))
 }
+
+func checkPerms(t *testing.T, target string, expected os.FileMode) {
+	t.Helper()
+	if runtime.GOOS == "windows" {
+		// Windows API validation of ACL is skipped, as its very complicated.
+		return
+	}
+	info, err := os.Stat(target)
+	require.NoError(t, err)
+	require.Equal(t, expected, info.Mode())
+}