Add falg to --whitelist-var-run set to true to preserver default kaniko behaviour of /var/run ignored. Set it to false to add /var/run in destination directory

README.md

@@ -67,6 +67,7 @@ _If you are interested in contributing to kaniko, see [DEVELOPMENT.md](DEVELOPME
     - [--target](#--target)
     - [--tarPath](#--tarpath)
     - [--verbosity](#--verbosity)
+    - [--whitelist-var-run](#--whitelist-var-run)
   - [Debug Image](#debug-image)
 - [Security](#security)
 - [Comparison with Other Tools](#comparison-with-other-tools)
@@ -512,6 +513,10 @@ You need to set `--destination` as well (for example `--destination=image`).
 
 Set this flag as `--verbosity=<panic|fatal|error|warn|info|debug>` to set the logging level. Defaults to `info`.
 
+#### --whitelist-var-run
+
+Ignore /var/run when taking image snapshot. Set it to false to preserve /var/run/* in destination image. (Default true).
+
 ### Debug Image
 
 The kaniko executor image is based on scratch and doesn't contain a shell.

cmd/executor/cmd/root.go

@@ -73,6 +73,8 @@ var RootCmd = &cobra.Command{
 			if len(opts.Destinations) == 0 && opts.ImageNameDigestFile != "" {
 				return errors.New("You must provide --destination if setting ImageNameDigestFile")
 			}
+			// Update whitelisted paths
+			util.UpdateWhitelist(opts.WhitelistVarRun)
 		}
 		return nil
 	},
@@ -144,6 +146,7 @@ func addKanikoOptionsFlags() {
 	RootCmd.PersistentFlags().DurationVarP(&opts.CacheTTL, "cache-ttl", "", time.Hour*336, "Cache timeout in hours. Defaults to two weeks.")
 	RootCmd.PersistentFlags().VarP(&opts.InsecureRegistries, "insecure-registry", "", "Insecure registry using plain HTTP to push and pull. Set it repeatedly for multiple registries.")
 	RootCmd.PersistentFlags().VarP(&opts.SkipTLSVerifyRegistries, "skip-tls-verify-registry", "", "Insecure registry ignoring TLS verify to push and pull. Set it repeatedly for multiple registries.")
+	RootCmd.PersistentFlags().BoolVarP(&opts.WhitelistVarRun, "whitelist-var-run", "", true, "Ignore /var/run directory when taking image snapshot. Set it to false to preserve /var/run/ in destination image. (Default true).")
 }
 
 // addHiddenFlags marks certain flags as hidden from the executor help text

pkg/config/options.go

@@ -41,6 +41,8 @@ type KanikoOptions struct {
 	OCILayoutPath           string
 	Destinations            multiArg
 	BuildArgs               multiArg
+	InsecureRegistries      multiArg
+	SkipTLSVerifyRegistries multiArg
 	Insecure                bool
 	SkipTLSVerify           bool
 	InsecurePull            bool
@@ -50,8 +52,7 @@ type KanikoOptions struct {
 	NoPush                  bool
 	Cache                   bool
 	Cleanup                 bool
-	InsecureRegistries      multiArg
-	SkipTLSVerifyRegistries multiArg
+	WhitelistVarRun         bool
 }
 
 // WarmerOptions are options that are set by command line arguments to the cache warmer.

pkg/util/fs_util.go

@@ -50,13 +50,6 @@ var initialWhitelist = []WhitelistEntry{
 		Path:            "/kaniko",
 		PrefixMatchOnly: false,
 	},
-	{
-		// /var/run is a special case. It's common to mount in /var/run/docker.sock or something similar
-		// which leads to a special mount on the /var/run/docker.sock file itself, but the directory to exist
-		// in the image with no way to tell if it came from the base image or not.
-		Path:            "/var/run",
-		PrefixMatchOnly: false,
-	},
 	{
 		// similarly, we whitelist /etc/mtab, since there is no way to know if the file was mounted or came
 		// from the base image
@@ -792,3 +785,17 @@ func createParentDirectory(path string) error {
 	}
 	return nil
 }
+
+// UpdateInitialWhitelist will add /var/run to whitelisted paths if
+func UpdateWhitelist(whitelistVarRun bool) {
+	if !whitelistVarRun {
+		return
+	}
+	whitelist = append(initialWhitelist, WhitelistEntry{
+		// /var/run is a special case. It's common to mount in /var/run/docker.sock or something similar
+		// which leads to a special mount on the /var/run/docker.sock file itself, but the directory to exist
+		// in the image with no way to tell if it came from the base image or not.
+		Path:            "/var/run",
+		PrefixMatchOnly: false,
+	})
+}

pkg/util/fs_util_test.go

@@ -64,7 +64,6 @@ func Test_DetectFilesystemWhitelist(t *testing.T) {
 		{"/dev", false},
 		{"/dev/pts", false},
 		{"/sys", false},
-		{"/var/run", false},
 		{"/etc/mtab", false},
 	}
 	actualWhitelist := whitelist
@@ -1248,3 +1247,51 @@ func assertGetFSFromLayers(
 		}
 	}
 }
+
+func TestUpdateWhitelist(t *testing.T) {
+	tests := []struct {
+		name            string
+		whitelistVarRun bool
+		expected        []WhitelistEntry
+	}{
+		{
+			name:            "var/run whitelisted",
+			whitelistVarRun: true,
+			expected: []WhitelistEntry{
+				{
+					Path:            "/kaniko",
+					PrefixMatchOnly: false,
+				},
+				{
+					Path:            "/etc/mtab",
+					PrefixMatchOnly: false,
+				},
+				{
+					Path:            "/var/run",
+					PrefixMatchOnly: false,
+				},
+			},
+		},
+		{
+			name: "var/run not whitelisted",
+			expected: []WhitelistEntry{
+				{
+					Path:            "/kaniko",
+					PrefixMatchOnly: false,
+				},
+				{
+					Path:            "/etc/mtab",
+					PrefixMatchOnly: false,
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			whitelist = initialWhitelist
+			defer func() { whitelist = initialWhitelist }()
+			UpdateWhitelist(tt.whitelistVarRun)
+			testutil.CheckDeepEqual(t, tt.expected, whitelist)
+		})
+	}
+}