From 590b53fac9ebdb259b32e82805dec1cc96987930 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Tue, 3 May 2022 15:14:56 -0400 Subject: [release-branch.go1.17] os/exec: return clear error for missing cmd.Path Following up on CL 403694, there is a bit of confusion about when Path is and isn't set, along with now the exported Err field. Catch the case where Path and Err (and lookPathErr) are all unset and give a helpful error. Updates #52574 Followup after #43724. Fixes #53056 Fixes CVE-2022-30580 Change-Id: I03205172aef3801c3194f5098bdb93290c02b1b6 Reviewed-on: https://go-review.googlesource.com/c/go/+/403759 Reviewed-by: Bryan Mills Reviewed-by: Roland Shoemaker (cherry picked from commit 960ffa98ce73ef2c2060c84c7ac28d37a83f345e) Reviewed-on: https://go-review.googlesource.com/c/go/+/408578 Run-TryBot: Roland Shoemaker TryBot-Result: Gopher Robot --- src/os/exec/exec.go | 3 +++ src/os/exec/exec_test.go | 8 ++++++++ 2 files changed, 11 insertions(+) diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go index 0c495755116..505de58e84d 100644 --- a/src/os/exec/exec.go +++ b/src/os/exec/exec.go @@ -374,6 +374,9 @@ func lookExtensions(path, dir string) (string, error) { // The Wait method will return the exit code and release associated resources // once the command exits. func (c *Cmd) Start() error { + if c.Path == "" && c.lookPathErr == nil { + c.lookPathErr = errors.New("exec: no command") + } if c.lookPathErr != nil { c.closeDescriptors(c.closeAfterStart) c.closeDescriptors(c.closeAfterWait) diff --git a/src/os/exec/exec_test.go b/src/os/exec/exec_test.go index d854e0de843..a951be718d3 100644 --- a/src/os/exec/exec_test.go +++ b/src/os/exec/exec_test.go @@ -1156,3 +1156,11 @@ func TestChildCriticalEnv(t *testing.T) { t.Error("no SYSTEMROOT found") } } + +func TestNoPath(t *testing.T) { + err := new(exec.Cmd).Start() + want := "exec: no command" + if err == nil || err.Error() != want { + t.Errorf("new(Cmd).Start() = %v, want %q", err, want) + } +} -- cgit v1.2.3-54-g00ecf