Fix panic in NewSystemd on nil values

sparrc · sparrc · commit 65478b8fddda · 2022-02-16T16:59:16.000-08:00
NewSystemd previously panicked if it was given a nil resource value for
resources.Memory.Max or resources.CPU.Weight (if resources.CPU or
resources.Memory is non-nil)

This also checks the value of Max and Weight before dereferencing them.

Signed-off-by: Cameron Sparr &lt;sparrc@users.noreply.github.com&gt;
diff --git a/v2/cpuv2_test.go b/v2/cpuv2_test.go
@@ -68,6 +68,25 @@ func TestSystemdCgroupCpuController(t *testing.T) {
 	checkFileContent(t, c.path, "cpu.weight", strconv.FormatUint(weight, 10))
 }
 
+func TestSystemdCgroupCpuController_NilWeight(t *testing.T) {
+	checkCgroupMode(t)
+	group := "testingCpuNilWeight.slice"
+	// nil weight defaults to 100
+	var quota int64 = 10000
+	var period uint64 = 8000
+	cpuMax := NewCPUMax(&quota, &period)
+	res := Resources{
+		CPU: &CPU{
+			Weight: nil,
+			Max:    cpuMax,
+		},
+	}
+	_, err := NewSystemd("/", group, -1, &res)
+	if err != nil {
+		t.Fatal("failed to init new cgroup systemd manager: ", err)
+	}
+}
+
 func TestExtractQuotaAndPeriod(t *testing.T) {
 	var (
 		period uint64
diff --git a/v2/manager.go b/v2/manager.go
@@ -734,12 +734,12 @@ func NewSystemd(slice, group string, pid int, resources *Resources) (*Manager, e
 		properties = append(properties, newSystemdProperty("PIDs", []uint32{uint32(pid)}))
 	}
 
-	if resources.Memory != nil && *resources.Memory.Max != 0 {
+	if resources.Memory != nil && resources.Memory.Max != nil && *resources.Memory.Max != 0 {
 		properties = append(properties,
 			newSystemdProperty("MemoryMax", uint64(*resources.Memory.Max)))
 	}
 
-	if resources.CPU != nil && *resources.CPU.Weight != 0 {
+	if resources.CPU != nil && resources.CPU.Weight != nil && *resources.CPU.Weight != 0 {
 		properties = append(properties,
 			newSystemdProperty("CPUWeight", *resources.CPU.Weight))
 	}

Original file line number	Diff line number	Diff line change
`@@ -734,12 +734,12 @@ func NewSystemd(slice, group string, pid int, resources Resources) (Manager, e`
`734`	`734`	`properties = append(properties, newSystemdProperty("PIDs", []uint32{uint32(pid)}))`
`735`	`735`	`}`
`736`	`736`
`737`		`- if resources.Memory != nil && *resources.Memory.Max != 0 {`
	`737`	`+ if resources.Memory != nil && resources.Memory.Max != nil && *resources.Memory.Max != 0 {`
`738`	`738`	`properties = append(properties,`
`739`	`739`	`newSystemdProperty("MemoryMax", uint64(*resources.Memory.Max)))`
`740`	`740`	`}`
`741`	`741`
`742`		`- if resources.CPU != nil && *resources.CPU.Weight != 0 {`
	`742`	`+ if resources.CPU != nil && resources.CPU.Weight != nil && *resources.CPU.Weight != 0 {`
`743`	`743`	`properties = append(properties,`
`744`	`744`	`newSystemdProperty("CPUWeight", *resources.CPU.Weight))`
`745`	`745`	`}`