Remove path walk from localFile.Mknod

Replace mknod call with mknodat equivalent to protect
against symlink attacks. Also added Mknod tests.

Remove goferfs reliance on gofer to check for file
existence before creating a synthetic entry.

Updates #2923

PiperOrigin-RevId: 327544516

1 files changed, 9 insertions, 9 deletions

diff --git a/runsc/fsgofer/fsgofer_unsafe.go b/runsc/fsgofer/fsgofer_unsafe.go
index 542b54365..f11fea40d 100644
--- a/runsc/fsgofer/fsgofer_unsafe.go
+++ b/runsc/fsgofer/fsgofer_unsafe.go
@@ -15,18 +15,18 @@
 package fsgofer
 
 import (
-	"syscall"
 	"unsafe"
 
+	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/syserr"
 )
 
-func utimensat(dirFd int, name string, times [2]syscall.Timespec, flags int) error {
+func utimensat(dirFd int, name string, times [2]unix.Timespec, flags int) error {
 	// utimensat(2) doesn't accept empty name, instead name must be nil to make it
 	// operate directly on 'dirFd' unlike other *at syscalls.
 	var namePtr unsafe.Pointer
 	if name != "" {
-		nameBytes, err := syscall.BytePtrFromString(name)
+		nameBytes, err := unix.BytePtrFromString(name)
 		if err != nil {
 			return err
 		}
@@ -35,8 +35,8 @@ func utimensat(dirFd int, name string, times [2]syscall.Timespec, flags int) err
 
 	timesPtr := unsafe.Pointer(&times[0])
 
-	if _, _, errno := syscall.Syscall6(
-		syscall.SYS_UTIMENSAT,
+	if _, _, errno := unix.Syscall6(
+		unix.SYS_UTIMENSAT,
 		uintptr(dirFd),
 		uintptr(namePtr),
 		uintptr(timesPtr),
@@ -52,7 +52,7 @@ func utimensat(dirFd int, name string, times [2]syscall.Timespec, flags int) err
 func renameat(oldDirFD int, oldName string, newDirFD int, newName string) error {
 	var oldNamePtr unsafe.Pointer
 	if oldName != "" {
-		nameBytes, err := syscall.BytePtrFromString(oldName)
+		nameBytes, err := unix.BytePtrFromString(oldName)
 		if err != nil {
 			return err
 		}
@@ -60,15 +60,15 @@ func renameat(oldDirFD int, oldName string, newDirFD int, newName string) error
 	}
 	var newNamePtr unsafe.Pointer
 	if newName != "" {
-		nameBytes, err := syscall.BytePtrFromString(newName)
+		nameBytes, err := unix.BytePtrFromString(newName)
 		if err != nil {
 			return err
 		}
 		newNamePtr = unsafe.Pointer(nameBytes)
 	}
 
-	if _, _, errno := syscall.Syscall6(
-		syscall.SYS_RENAMEAT,
+	if _, _, errno := unix.Syscall6(
+		unix.SYS_RENAMEAT,
 		uintptr(oldDirFD),
 		uintptr(oldNamePtr),
 		uintptr(newDirFD),