unix: avoid index out of range in *setxattr on BSD
Passing an empty data []byte to Fsetxattr/Setxattr/Lsetxattr leads
to an index out of range panic. Fix this by passing an nil
unsafe.Pointer to the underlying syscall in this case.
Change-Id: I5ef3983c6304c5317ed5b49afc4ed19791864dbb
Reviewed-on: https://go-review.googlesource.com/c/146198
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/unix/xattr_bsd.go b/unix/xattr_bsd.go
index 9304993..30c1d71 100644
--- a/unix/xattr_bsd.go
+++ b/unix/xattr_bsd.go
@@ -81,7 +81,10 @@
// flags are unused on FreeBSD
func Fsetxattr(fd int, attr string, data []byte, flags int) (err error) {
- d := unsafe.Pointer(&data[0])
+ var d unsafe.Pointer
+ if len(data) > 0 {
+ d = unsafe.Pointer(&data[0])
+ }
datasiz := len(data)
nsid, a, err := xattrnamespace(attr)
@@ -94,7 +97,10 @@
}
func Setxattr(file string, attr string, data []byte, flags int) (err error) {
- d := unsafe.Pointer(&data[0])
+ var d unsafe.Pointer
+ if len(data) > 0 {
+ d = unsafe.Pointer(&data[0])
+ }
datasiz := len(data)
nsid, a, err := xattrnamespace(attr)
@@ -107,7 +113,10 @@
}
func Lsetxattr(link string, attr string, data []byte, flags int) (err error) {
- d := unsafe.Pointer(&data[0])
+ var d unsafe.Pointer
+ if len(data) > 0 {
+ d = unsafe.Pointer(&data[0])
+ }
datasiz := len(data)
nsid, a, err := xattrnamespace(attr)
diff --git a/unix/xattr_test.go b/unix/xattr_test.go
index 11a76ce..57fc84f 100644
--- a/unix/xattr_test.go
+++ b/unix/xattr_test.go
@@ -24,13 +24,19 @@
xattrName := "user.test"
xattrDataSet := "gopher"
- err := unix.Setxattr(f, xattrName, []byte(xattrDataSet), 0)
+
+ err := unix.Setxattr(f, xattrName, []byte{}, 0)
if err == unix.ENOTSUP || err == unix.EOPNOTSUPP {
t.Skip("filesystem does not support extended attributes, skipping test")
} else if err != nil {
t.Fatalf("Setxattr: %v", err)
}
+ err = unix.Setxattr(f, xattrName, []byte(xattrDataSet), 0)
+ if err != nil {
+ t.Fatalf("Setxattr: %v", err)
+ }
+
// find size
size, err := unix.Listxattr(f, nil)
if err != nil {
