10c3bad652
Fixes #2522 Skip embedding client.alloc_dir when building chroot. If a user configures a Nomad client agent so that the chroot_env will embed the client.alloc_dir, Nomad will happily infinitely recurse while building the chroot until something horrible happens. The best case scenario is the filesystem's path length limit is hit. The worst case scenario is disk space is exhausted. A bad agent configuration will look something like this: ```hcl data_dir = "/tmp/nomad-badagent" client { enabled = true chroot_env { # Note that the source matches the data_dir "/tmp/nomad-badagent" = "/ohno" # ... } } ``` Note that `/ohno/client` (the state_dir) will still be created but not `/ohno/alloc` (the alloc_dir). While I cannot think of a good reason why someone would want to embed Nomad's client (and possibly server) directories in chroots, there should be no cause for harm. chroots are only built when Nomad runs as root, and Nomad disables running exec jobs as root by default. Therefore even if client state is copied into chroots, it will be inaccessible to tasks. Skipping the `data_dir` and `{client,server}.state_dir` is possible, but this PR attempts to implement the minimum viable solution to reduce risk of unintended side effects or bugs. When running tests as root in a vm without the fix, the following error occurs: ``` === RUN TestAllocDir_SkipAllocDir alloc_dir_test.go:520: Error Trace: alloc_dir_test.go:520 Error: Received unexpected error: Couldn't create destination file /tmp/TestAllocDir_SkipAllocDir1457747331/001/nomad/test/testtask/nomad/test/testtask/.../nomad/test/testtask/secrets/.nomad-mount: open /tmp/TestAllocDir_SkipAllocDir1457747331/001/nomad/test/.../testtask/secrets/.nomad-mount: file name too long Test: TestAllocDir_SkipAllocDir --- FAIL: TestAllocDir_SkipAllocDir (22.76s) ``` Also removed unused Copy methods on AllocDir and TaskDir structs. Thanks to @eveld for not letting me forget about this!
139 lines
3.7 KiB
Go
139 lines
3.7 KiB
Go
package allocdir
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import (
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"io/ioutil"
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"os"
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"path/filepath"
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"testing"
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"github.com/hashicorp/nomad/helper/testlog"
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)
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// Test that building a chroot will skip nonexistent directories.
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func TestTaskDir_EmbedNonexistent(t *testing.T) {
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tmp, err := ioutil.TempDir("", "AllocDir")
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if err != nil {
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t.Fatalf("Couldn't create temp dir: %v", err)
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}
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defer os.RemoveAll(tmp)
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d := NewAllocDir(testlog.HCLogger(t), tmp, "test")
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defer d.Destroy()
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td := d.NewTaskDir(t1.Name)
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if err := d.Build(); err != nil {
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t.Fatalf("Build() failed: %v", err)
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}
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fakeDir := "/foobarbaz"
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mapping := map[string]string{fakeDir: fakeDir}
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if err := td.embedDirs(mapping); err != nil {
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t.Fatalf("embedDirs(%v) should should skip %v since it does not exist", mapping, fakeDir)
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}
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}
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// Test that building a chroot copies files from the host into the task dir.
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func TestTaskDir_EmbedDirs(t *testing.T) {
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tmp, err := ioutil.TempDir("", "AllocDir")
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if err != nil {
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t.Fatalf("Couldn't create temp dir: %v", err)
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}
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defer os.RemoveAll(tmp)
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d := NewAllocDir(testlog.HCLogger(t), tmp, "test")
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defer d.Destroy()
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td := d.NewTaskDir(t1.Name)
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if err := d.Build(); err != nil {
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t.Fatalf("Build() failed: %v", err)
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}
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// Create a fake host directory, with a file, and a subfolder that contains
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// a file.
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host, err := ioutil.TempDir("", "AllocDirHost")
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if err != nil {
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t.Fatalf("Couldn't create temp dir: %v", err)
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}
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defer os.RemoveAll(host)
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subDirName := "subdir"
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subDir := filepath.Join(host, subDirName)
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if err := os.MkdirAll(subDir, 0777); err != nil {
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t.Fatalf("Failed to make subdir %v: %v", subDir, err)
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}
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file := "foo"
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subFile := "bar"
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if err := ioutil.WriteFile(filepath.Join(host, file), []byte{'a'}, 0777); err != nil {
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t.Fatalf("Couldn't create file in host dir %v: %v", host, err)
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}
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if err := ioutil.WriteFile(filepath.Join(subDir, subFile), []byte{'a'}, 0777); err != nil {
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t.Fatalf("Couldn't create file in host subdir %v: %v", subDir, err)
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}
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// Create mapping from host dir to task dir.
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taskDest := "bin/test/"
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mapping := map[string]string{host: taskDest}
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if err := td.embedDirs(mapping); err != nil {
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t.Fatalf("embedDirs(%v) failed: %v", mapping, err)
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}
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exp := []string{filepath.Join(td.Dir, taskDest, file), filepath.Join(td.Dir, taskDest, subDirName, subFile)}
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for _, f := range exp {
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if _, err := os.Stat(f); os.IsNotExist(err) {
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t.Fatalf("File %v not embedded: %v", f, err)
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}
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}
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}
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// Test that task dirs for image based isolation don't require root.
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func TestTaskDir_NonRoot_Image(t *testing.T) {
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if os.Geteuid() == 0 {
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t.Skip("test should be run as non-root user")
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}
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tmp, err := ioutil.TempDir("", "AllocDir")
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if err != nil {
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t.Fatalf("Couldn't create temp dir: %v", err)
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}
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defer os.RemoveAll(tmp)
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d := NewAllocDir(testlog.HCLogger(t), tmp, "test")
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defer d.Destroy()
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td := d.NewTaskDir(t1.Name)
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if err := d.Build(); err != nil {
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t.Fatalf("Build() failed: %v", err)
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}
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if err := td.Build(false, nil); err != nil {
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t.Fatalf("TaskDir.Build failed: %v", err)
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}
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}
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// Test that task dirs with no isolation don't require root.
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func TestTaskDir_NonRoot(t *testing.T) {
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if os.Geteuid() == 0 {
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t.Skip("test should be run as non-root user")
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}
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tmp, err := ioutil.TempDir("", "AllocDir")
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if err != nil {
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t.Fatalf("Couldn't create temp dir: %v", err)
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}
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defer os.RemoveAll(tmp)
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d := NewAllocDir(testlog.HCLogger(t), tmp, "test")
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defer d.Destroy()
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td := d.NewTaskDir(t1.Name)
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if err := d.Build(); err != nil {
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t.Fatalf("Build() failed: %v", err)
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}
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if err := td.Build(false, nil); err != nil {
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t.Fatalf("TaskDir.Build failed: %v", err)
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}
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// ${TASK_DIR}/alloc should not exist!
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if _, err = os.Stat(td.SharedTaskDir); !os.IsNotExist(err) {
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t.Fatalf("Expected a NotExist error for shared alloc dir in task dir: %q", td.SharedTaskDir)
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}
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}
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