archive/tar, archive/zip: revert documentation of ErrInsecurePath

CL 452616 disables path security checks by default, enabling them
only when GODEBUG=tarinsecurepath=0 or GODEBUG=zipinsecurepath=0
is set. Remove now-obsolete documenation of the path checks.

For #55356

Change-Id: I4ae57534efe9e27368d5e67773a502dd0e56eff4
Reviewed-on: https://go-review.googlesource.com/c/go/+/458875
Reviewed-by: Russ Cox <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Run-TryBot: Damien Neil <[email protected]>

src/archive/tar/reader.go

@@ -45,15 +45,6 @@ func NewReader(r io.Reader) *Reader {
 // Any remaining data in the current file is automatically discarded.
 //
 // io.EOF is returned at the end of the input.
-//
-// ErrInsecurePath and a valid *Header are returned if the next file's name is:
-//
-//   - absolute;
-//   - a relative path escaping the current directory, such as "../a"; or
-//   - on Windows, a reserved file name such as "NUL".
-//
-// The caller may ignore the ErrInsecurePath error,
-// but is then responsible for sanitizing paths as appropriate.
 func (tr *Reader) Next() (*Header, error) {
 	if tr.err != nil {
 		return nil, tr.err

src/archive/zip/reader.go

@@ -87,17 +87,6 @@ func OpenReader(name string) (*ReadCloser, error) {
 
 // NewReader returns a new Reader reading from r, which is assumed to
 // have the given size in bytes.
-//
-// ErrInsecurePath and a valid *Reader are returned if the names of any
-// files in the archive:
-//
-//   - are absolute;
-//   - are a relative path escaping the current directory, such as "../a";
-//   - contain a backslash (\) character; or
-//   - on Windows, are a reserved file name such as "NUL".
-//
-// The caller may ignore the ErrInsecurePath error,
-// but is then responsible for sanitizing paths as appropriate.
 func NewReader(r io.ReaderAt, size int64) (*Reader, error) {
 	if size < 0 {
 		return nil, errors.New("zip: size cannot be negative")