1 files changed, 27 insertions, 21 deletions

diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go
index 97d9a65ea..816352218 100755
--- a/pkg/sentry/syscalls/linux/sys_xattr.go
+++ b/pkg/sentry/syscalls/linux/sys_xattr.go
@@ -25,12 +25,12 @@ import (
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
-// Getxattr implements linux syscall getxattr(2).
-func Getxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+// GetXattr implements linux syscall getxattr(2).
+func GetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	pathAddr := args[0].Pointer()
 	nameAddr := args[1].Pointer()
 	valueAddr := args[2].Pointer()
-	size := args[3].SizeT()
+	size := uint64(args[3].SizeT())
 
 	path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
 	if err != nil {
@@ -39,22 +39,28 @@ func Getxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 
 	valueLen := 0
 	err = fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
-		value, err := getxattr(t, d, dirPath, nameAddr)
+		// If getxattr(2) is called with size 0, the size of the value will be
+		// returned successfully even if it is nonzero. In that case, we need to
+		// retrieve the entire attribute value so we can return the correct size.
+		requestedSize := size
+		if size == 0 || size > linux.XATTR_SIZE_MAX {
+			requestedSize = linux.XATTR_SIZE_MAX
+		}
+
+		value, err := getXattr(t, d, dirPath, nameAddr, uint64(requestedSize))
 		if err != nil {
 			return err
 		}
 
 		valueLen = len(value)
-		if size == 0 {
-			return nil
-		}
-		if size > linux.XATTR_SIZE_MAX {
-			size = linux.XATTR_SIZE_MAX
-		}
-		if valueLen > int(size) {
+		if uint64(valueLen) > requestedSize {
 			return syserror.ERANGE
 		}
 
+		// Skip copying out the attribute value if size is 0.
+		if size == 0 {
+			return nil
+		}
 		_, err = t.CopyOutBytes(valueAddr, []byte(value))
 		return err
 	})
@@ -64,8 +70,8 @@ func Getxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 	return uintptr(valueLen), nil, nil
 }
 
-// getxattr implements getxattr from the given *fs.Dirent.
-func getxattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr usermem.Addr) (string, error) {
+// getXattr implements getxattr(2) from the given *fs.Dirent.
+func getXattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr usermem.Addr, size uint64) (string, error) {
 	if dirPath && !fs.IsDir(d.Inode.StableAttr) {
 		return "", syserror.ENOTDIR
 	}
@@ -83,15 +89,15 @@ func getxattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr usermem.Addr)
 		return "", syserror.EOPNOTSUPP
 	}
 
-	return d.Inode.Getxattr(name)
+	return d.Inode.GetXattr(t, name, size)
 }
 
-// Setxattr implements linux syscall setxattr(2).
-func Setxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+// SetXattr implements linux syscall setxattr(2).
+func SetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
 	pathAddr := args[0].Pointer()
 	nameAddr := args[1].Pointer()
 	valueAddr := args[2].Pointer()
-	size := args[3].SizeT()
+	size := uint64(args[3].SizeT())
 	flags := args[4].Uint()
 
 	path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
@@ -104,12 +110,12 @@ func Setxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 	}
 
 	return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
-		return setxattr(t, d, dirPath, nameAddr, valueAddr, size, flags)
+		return setXattr(t, d, dirPath, nameAddr, valueAddr, uint64(size), flags)
 	})
 }
 
-// setxattr implements setxattr from the given *fs.Dirent.
-func setxattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr, valueAddr usermem.Addr, size uint, flags uint32) error {
+// setXattr implements setxattr(2) from the given *fs.Dirent.
+func setXattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr, valueAddr usermem.Addr, size uint64, flags uint32) error {
 	if dirPath && !fs.IsDir(d.Inode.StableAttr) {
 		return syserror.ENOTDIR
 	}
@@ -136,7 +142,7 @@ func setxattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr, valueAddr us
 		return syserror.EOPNOTSUPP
 	}
 
-	return d.Inode.Setxattr(name, value)
+	return d.Inode.SetXattr(t, name, value, flags)
 }
 
 func copyInXattrName(t *kernel.Task, nameAddr usermem.Addr) (string, error) {