updated job validate to refute job/group/task IDs containing null characters

updated CHANGELOG and upgrade guide

CHANGELOG.md

@@ -11,6 +11,7 @@ IMPROVEMENTS:
  * jobspec: Lowered minimum CPU allowed from 10 to 1. [[GH-8996](https://github.com/hashicorp/nomad/issues/8996)]
 
 __BACKWARDS INCOMPATIBILITIES:__
+ * core: job IDs, task group names, and task names are not allowed to contain null characters [[GH-9020](https://github.com/hashicorp/nomad/issues/9020)]
  * driver/docker: Tasks are now issued SIGTERM instead of SIGINT when stopping [[GH-8932](https://github.com/hashicorp/nomad/issues/8932)]
 
 BUG FIXES:

nomad/structs/structs.go

@@ -3943,6 +3943,8 @@ func (j *Job) Validate() error {
 		mErr.Errors = append(mErr.Errors, errors.New("Missing job ID"))
 	} else if strings.Contains(j.ID, " ") {
 		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a space"))
+	} else if strings.Contains(j.ID, "\000") {
+		mErr.Errors = append(mErr.Errors, errors.New("Job ID contains a null chararacter"))
 	}
 	if j.Name == "" {
 		mErr.Errors = append(mErr.Errors, errors.New("Missing job name"))
@@ -5740,6 +5742,8 @@ func (tg *TaskGroup) Validate(j *Job) error {
 	var mErr multierror.Error
 	if tg.Name == "" {
 		mErr.Errors = append(mErr.Errors, errors.New("Missing task group name"))
+	} else if strings.Contains(tg.Name, "\000") {
+		mErr.Errors = append(mErr.Errors, errors.New("Task group name contains null character"))
 	}
 	if tg.Count < 0 {
 		mErr.Errors = append(mErr.Errors, errors.New("Task group count can't be negative"))
@@ -6462,6 +6466,8 @@ func (t *Task) Validate(ephemeralDisk *EphemeralDisk, jobType string, tgServices
 		// We enforce this so that when creating the directory on disk it will
 		// not have any slashes.
 		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include slashes"))
+	} else if strings.Contains(t.Name, "\000") {
+		mErr.Errors = append(mErr.Errors, errors.New("Task name cannot include null characters"))
 	}
 	if t.Driver == "" {
 		mErr.Errors = append(mErr.Errors, errors.New("Missing task driver"))

nomad/structs/structs_test.go

@@ -185,7 +185,7 @@ func TestJob_ValidateNullChar(t *testing.T) {
 
 	// task name should not allow null characters
 	job.TaskGroups[0].Name = "so_much_better"
-	job.TaskGroups[0].Tasks[0].Name = "what_is_with_these_\000_chars"
+	job.TaskGroups[0].Tasks[0].Name = "ive_had_it_with_these_\000_chars_in_these_names"
 	assert.Error(job.Validate(), "null character in task name should not validate")
 }
 

website/pages/docs/upgrade/upgrade-specific.mdx

@@ -24,6 +24,12 @@ When stopping tasks running with the Docker task driver, Nomad documents that a
 versions of Nomad would issue `SIGINT` instead. Starting again with Nomad v0.13.0
 `SIGTERM` will be sent by default when stopping Docker tasks.
 
+### Null characters in job, task group, and task IDs
+
+Starting with Nomad v0.13.0, job will fail validation if any of the following
+contain null character: the job ID, the task group name, or the task name. Any
+jobs meeting this requirement should be modified before an update to v0.13.0.
+
 ## Nomad 0.12.0
 
 ### `mbits` and Task Network Resource deprecation