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nexpie-grafana-theme
Commit 62485898 by Arve Knudsen Committed by GitHub
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grafana-cli: Fix security issue (#28888) 

* grafana-cli: Fix security issue

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

* grafana-cli: Add and improve tests

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
parent 2b155813
Showing with 69 additions and 66 deletions
pkg/cmd/grafana-cli/commands/install_command.go
......@@ -222,27 +222,33 @@ func removeGitBuildFromName(pluginName, filename string) string {
const permissionsDeniedMessage = "could not create %q, permission denied, make sure you have write access to plugin dir"
func extractFiles(archiveFile string, pluginName string, filePath string, allowSymlinks bool) error {
logger.Debugf("Extracting archive %v to %v...\n", archiveFile, filePath)
func extractFiles(archiveFile string, pluginName string, dstDir string, allowSymlinks bool) error {
var err error
dstDir, err = filepath.Abs(dstDir)
if err != nil {
return err
}
logger.Debugf("Extracting archive %q to %q...\n", archiveFile, dstDir)
r, err := zip.OpenReader(archiveFile)
if err != nil {
return err
}
for _, zf := range r.File {
newFileName := removeGitBuildFromName(pluginName, zf.Name)
if !isPathSafe(newFileName, filepath.Join(filePath, pluginName)) {
return fmt.Errorf("filepath: %q tries to write outside of plugin directory: %q, this can be a security risk",
zf.Name, filepath.Join(filePath, pluginName))
if filepath.IsAbs(zf.Name) || strings.HasPrefix(zf.Name, ".."+string(filepath.Separator)) {
return fmt.Errorf(
"archive member %q tries to write outside of plugin directory: %q, this can be a security risk",
zf.Name, dstDir)
}
newFile := filepath.Join(filePath, newFileName)
dstPath := filepath.Clean(filepath.Join(dstDir, removeGitBuildFromName(pluginName, zf.Name)))
if zf.FileInfo().IsDir() {
// We can ignore gosec G304 here since it makes sense to give all users read access
// nolint:gosec
if err := os.MkdirAll(newFile, 0755); err != nil {
if err := os.MkdirAll(dstPath, 0755); err != nil {
if os.IsPermission(err) {
return fmt.Errorf(permissionsDeniedMessage, newFile)
return fmt.Errorf(permissionsDeniedMessage, dstPath)
}
return err
......@@ -254,7 +260,7 @@ func extractFiles(archiveFile string, pluginName string, filePath string, allowS
// Create needed directories to extract file
// We can ignore gosec G304 here since it makes sense to give all users read access
// nolint:gosec
if err := os.MkdirAll(filepath.Dir(newFile), 0755); err != nil {
if err := os.MkdirAll(filepath.Dir(dstPath), 0755); err != nil {
return errutil.Wrap("failed to create directory to extract plugin files", err)
}
......@@ -263,14 +269,14 @@ func extractFiles(archiveFile string, pluginName string, filePath string, allowS
logger.Warnf("%v: plugin archive contains a symlink, which is not allowed. Skipping \n", zf.Name)
continue
}
if err := extractSymlink(zf, newFile); err != nil {
if err := extractSymlink(zf, dstPath); err != nil {
logger.Errorf("Failed to extract symlink: %v \n", err)
continue
}
continue
}
if err := extractFile(zf, newFile); err != nil {
if err := extractFile(zf, dstPath); err != nil {
return errutil.Wrap("failed to extract file", err)
}
}
......@@ -337,11 +343,3 @@ func extractFile(file *zip.File, filePath string) (err error) {
_, err = io.Copy(dst, src)
return err
}
// isPathSafe checks if the filePath does not resolve outside of destination. This is used to prevent
// https://snyk.io/research/zip-slip-vulnerability
// Based on https://github.com/mholt/archiver/pull/65/files#diff-635e4219ee55ef011b2b32bba065606bR109
func isPathSafe(filePath string, destination string) bool {
destpath := filepath.Join(destination, filePath)
return strings.HasPrefix(destpath, destination)
}
pkg/cmd/grafana-cli/commands/install_command_test.go
......@@ -33,65 +33,82 @@ func TestRemoveGitBuildFromName(t *testing.T) {
func TestExtractFiles(t *testing.T) {
t.Run("Should preserve file permissions for plugin backend binaries for linux and darwin", func(t *testing.T) {
skipWindows(t)
pluginDir, del := setupFakePluginsDir(t)
defer del()
pluginsDir := setupFakePluginsDir(t)
archive := filepath.Join("testdata", "grafana-simple-json-datasource-ec18fa4da8096a952608a7e4c7782b4260b41bcf.zip")
err := extractFiles(archive, "grafana-simple-json-datasource", pluginDir, false)
err := extractFiles(archive, "grafana-simple-json-datasource", pluginsDir, false)
require.NoError(t, err)
// File in zip has permissions 755
fileInfo, err := os.Stat(filepath.Join(pluginDir, "grafana-simple-json-datasource",
fileInfo, err := os.Stat(filepath.Join(pluginsDir, "grafana-simple-json-datasource",
"simple-plugin_darwin_amd64"))
require.NoError(t, err)
assert.Equal(t, "-rwxr-xr-x", fileInfo.Mode().String())
// File in zip has permission 755
fileInfo, err = os.Stat(pluginDir + "/grafana-simple-json-datasource/simple-plugin_linux_amd64")
fileInfo, err = os.Stat(pluginsDir + "/grafana-simple-json-datasource/simple-plugin_linux_amd64")
require.NoError(t, err)
assert.Equal(t, "-rwxr-xr-x", fileInfo.Mode().String())
// File in zip has permission 644
fileInfo, err = os.Stat(pluginDir + "/grafana-simple-json-datasource/simple-plugin_windows_amd64.exe")
fileInfo, err = os.Stat(pluginsDir + "/grafana-simple-json-datasource/simple-plugin_windows_amd64.exe")
require.NoError(t, err)
assert.Equal(t, "-rw-r--r--", fileInfo.Mode().String())
// File in zip has permission 755
fileInfo, err = os.Stat(pluginDir + "/grafana-simple-json-datasource/non-plugin-binary")
fileInfo, err = os.Stat(pluginsDir + "/grafana-simple-json-datasource/non-plugin-binary")
require.NoError(t, err)
assert.Equal(t, "-rwxr-xr-x", fileInfo.Mode().String())
})
t.Run("Should ignore symlinks if not allowed", func(t *testing.T) {
pluginDir, del := setupFakePluginsDir(t)
defer del()
pluginsDir := setupFakePluginsDir(t)
err := extractFiles("testdata/plugin-with-symlink.zip", "plugin-with-symlink", pluginDir, false)
err := extractFiles("testdata/plugin-with-symlink.zip", "plugin-with-symlink", pluginsDir, false)
require.NoError(t, err)
_, err = os.Stat(pluginDir + "/plugin-with-symlink/text.txt")
_, err = os.Stat(pluginsDir + "/plugin-with-symlink/text.txt")
require.NoError(t, err)
_, err = os.Stat(pluginDir + "/plugin-with-symlink/symlink_to_txt")
assert.NotNil(t, err)
_, err = os.Stat(pluginsDir + "/plugin-with-symlink/symlink_to_txt")
assert.Error(t, err)
})
t.Run("Should extract symlinks if allowed", func(t *testing.T) {
skipWindows(t)
pluginDir, del := setupFakePluginsDir(t)
defer del()
pluginsDir := setupFakePluginsDir(t)
err := extractFiles("testdata/plugin-with-symlink.zip", "plugin-with-symlink", pluginDir, true)
err := extractFiles("testdata/plugin-with-symlink.zip", "plugin-with-symlink", pluginsDir, true)
require.NoError(t, err)
_, err = os.Stat(pluginDir + "/plugin-with-symlink/symlink_to_txt")
_, err = os.Stat(pluginsDir + "/plugin-with-symlink/symlink_to_txt")
require.NoError(t, err)
fmt.Println(err)
})
t.Run("Should detect if archive members point outside of the destination directory", func(t *testing.T) {
pluginsDir := setupFakePluginsDir(t)
err := extractFiles("testdata/plugin-with-parent-member.zip", "plugin-with-parent-member",
pluginsDir, true)
require.EqualError(t, err, fmt.Sprintf(
`archive member "../member.txt" tries to write outside of plugin directory: %q, this can be a security risk`,
pluginsDir,
))
})
t.Run("Should detect if archive members are absolute", func(t *testing.T) {
pluginsDir := setupFakePluginsDir(t)
err := extractFiles("testdata/plugin-with-absolute-member.zip", "plugin-with-absolute-member",
pluginsDir, true)
require.EqualError(t, err, fmt.Sprintf(
`archive member "/member.txt" tries to write outside of plugin directory: %q, this can be a security risk`,
pluginsDir,
))
})
}
func TestInstallPluginCommand(t *testing.T) {
pluginsDir, cleanUp := setupFakePluginsDir(t)
defer cleanUp()
pluginsDir := setupFakePluginsDir(t)
c, err := commandstest.NewCliContext(map[string]string{"pluginsDir": pluginsDir})
require.NoError(t, err)
......@@ -132,29 +149,13 @@ func TestInstallPluginCommand(t *testing.T) {
assert.NoError(t, err)
}
func TestIsPathSafe(t *testing.T) {
dest := fmt.Sprintf("%stest%spath", string(os.PathSeparator), string(os.PathSeparator))
t.Run("Should be true on nested destinations", func(t *testing.T) {
assert.True(t, isPathSafe("dest", dest))
assert.True(t, isPathSafe("dest/one", dest))
assert.True(t, isPathSafe("../path/dest/one", dest))
})
t.Run("Should be false on destinations outside of path", func(t *testing.T) {
assert.False(t, isPathSafe("../dest", dest))
assert.False(t, isPathSafe("../../", dest))
assert.False(t, isPathSafe("../../test", dest))
})
}
func TestSelectVersion(t *testing.T) {
t.Run("Should return error when requested version does not exist", func(t *testing.T) {
_, err := SelectVersion(
makePluginWithVersions(versionArg{Version: "version"}),
"1.1.1",
)
assert.NotNil(t, err)
assert.Error(t, err)
})
t.Run("Should return error when no version supports current arch", func(t *testing.T) {
......@@ -162,7 +163,7 @@ func TestSelectVersion(t *testing.T) {
makePluginWithVersions(versionArg{Version: "version", Arch: []string{"non-existent"}}),
"",
)
assert.NotNil(t, err)
assert.Error(t, err)
})
t.Run("Should return error when requested version does not support current arch", func(t *testing.T) {
......@@ -173,7 +174,7 @@ func TestSelectVersion(t *testing.T) {
),
"1.1.1",
)
assert.NotNil(t, err)
assert.Error(t, err)
})
t.Run("Should return latest available for arch when no version specified", func(t *testing.T) {
......@@ -210,18 +211,22 @@ func TestSelectVersion(t *testing.T) {
})
}
func setupFakePluginsDir(t *testing.T) (string, func()) {
func setupFakePluginsDir(t *testing.T) string {
dirname := "testdata/fake-plugins-dir"
err := os.RemoveAll(dirname)
require.Nil(t, err)
require.NoError(t, err)
err = os.MkdirAll(dirname, 0750)
require.Nil(t, err)
return dirname, func() {
require.NoError(t, err)
t.Cleanup(func() {
err := os.RemoveAll(dirname)
require.NoError(t, err)
}
assert.NoError(t, err)
})
dirname, err = filepath.Abs(dirname)
require.NoError(t, err)
return dirname
}
func skipWindows(t *testing.T) {
......
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