unix: avoid nil pointer dereference in Utime

tklauser · gopherbot · commit 68a4a8e945b2 · 2026-04-10T02:58:23.000-07:00
Passing a nil buf *Utimbuf to Utime on linux/{arm,arm64,loong64,riscv64} will cause a nil pointer dereference. Check buf explicitly to avoid this case. Change-Id: Ifb719f83029002f043919daa066af6b1fb4ebe03 Reviewed-on: https://go-review.googlesource.com/c/sys/+/764562 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com> Reviewed-by: David Chase <drchase@google.com>
diff --git a/unix/syscall_linux_arm.go b/unix/syscall_linux_arm.go
@@ -82,6 +82,9 @@ func Time(t *Time_t) (Time_t, error) {
 }
 
 func Utime(path string, buf *Utimbuf) error {
+	if buf == nil {
+		return Utimes(path, nil)
+	}
 	tv := []Timeval{
 		{Sec: buf.Actime},
 		{Sec: buf.Modtime},
diff --git a/unix/syscall_linux_arm64.go b/unix/syscall_linux_arm64.go
@@ -113,6 +113,9 @@ func Time(t *Time_t) (Time_t, error) {
 }
 
 func Utime(path string, buf *Utimbuf) error {
+	if buf == nil {
+		return Utimes(path, nil)
+	}
 	tv := []Timeval{
 		{Sec: buf.Actime},
 		{Sec: buf.Modtime},
diff --git a/unix/syscall_linux_loong64.go b/unix/syscall_linux_loong64.go
@@ -150,6 +150,9 @@ func Time(t *Time_t) (Time_t, error) {
 }
 
 func Utime(path string, buf *Utimbuf) error {
+	if buf == nil {
+		return Utimes(path, nil)
+	}
 	tv := []Timeval{
 		{Sec: buf.Actime},
 		{Sec: buf.Modtime},
diff --git a/unix/syscall_linux_riscv64.go b/unix/syscall_linux_riscv64.go
@@ -112,6 +112,9 @@ func Time(t *Time_t) (Time_t, error) {
 }
 
 func Utime(path string, buf *Utimbuf) error {
+	if buf == nil {
+		return Utimes(path, nil)
+	}
 	tv := []Timeval{
 		{Sec: buf.Actime},
 		{Sec: buf.Modtime},

Original file line number	Diff line number	Diff line change
`@@ -82,6 +82,9 @@ func Time(t *Time_t) (Time_t, error) {`
`82`	`82`	`}`
`83`	`83`
`84`	`84`	`func Utime(path string, buf *Utimbuf) error {`
	`85`	`+ if buf == nil {`
	`86`	`+ return Utimes(path, nil)`
	`87`	`+ }`
`85`	`88`	`tv := []Timeval{`
`86`	`89`	`{Sec: buf.Actime},`
`87`	`90`	`{Sec: buf.Modtime},`
Original file line number	Diff line number	Diff line change
`@@ -113,6 +113,9 @@ func Time(t *Time_t) (Time_t, error) {`
`113`	`113`	`}`
`114`	`114`
`115`	`115`	`func Utime(path string, buf *Utimbuf) error {`
	`116`	`+ if buf == nil {`
	`117`	`+ return Utimes(path, nil)`
	`118`	`+ }`
`116`	`119`	`tv := []Timeval{`
`117`	`120`	`{Sec: buf.Actime},`
`118`	`121`	`{Sec: buf.Modtime},`
Original file line number	Diff line number	Diff line change
`@@ -150,6 +150,9 @@ func Time(t *Time_t) (Time_t, error) {`
`150`	`150`	`}`
`151`	`151`
`152`	`152`	`func Utime(path string, buf *Utimbuf) error {`
	`153`	`+ if buf == nil {`
	`154`	`+ return Utimes(path, nil)`
	`155`	`+ }`
`153`	`156`	`tv := []Timeval{`
`154`	`157`	`{Sec: buf.Actime},`
`155`	`158`	`{Sec: buf.Modtime},`
Original file line number	Diff line number	Diff line change
`@@ -112,6 +112,9 @@ func Time(t *Time_t) (Time_t, error) {`
`112`	`112`	`}`
`113`	`113`
`114`	`114`	`func Utime(path string, buf *Utimbuf) error {`
	`115`	`+ if buf == nil {`
	`116`	`+ return Utimes(path, nil)`
	`117`	`+ }`
`115`	`118`	`tv := []Timeval{`
`116`	`119`	`{Sec: buf.Actime},`
`117`	`120`	`{Sec: buf.Modtime},`