syscall: disable Setuid/Setgid on linux

Update #1435

This proposal disables Setuid and Setgid on all linux platforms.

Issue 1435 has been open for a long time, and it is unlikely to be addressed soon so an argument was made by a commenter

https://code.google.com/p/go/issues/detail?id=1435#c45

That these functions should made to fail rather than succeed in their broken state.

LGTM=ruiu, iant
R=iant, ruiu
CC=golang-codereviews
https://golang.org/cl/106170043

1 files changed, 14 insertions, 1 deletions

diff --git a/src/pkg/syscall/syscall_linux.go b/src/pkg/syscall/syscall_linux.go
index cdba97d2e7..138a695fd3 100644
--- a/src/pkg/syscall/syscall_linux.go
+++ b/src/pkg/syscall/syscall_linux.go
@@ -807,7 +807,20 @@ func Mount(source string, target string, fstype string, flags uintptr, data stri
 //sysnb	Setpgid(pid int, pgid int) (err error)
 //sysnb	Setsid() (pid int, err error)
 //sysnb	Settimeofday(tv *Timeval) (err error)
-//sysnb	Setuid(uid int) (err error)
+
+// issue 1435.
+// On linux Setuid and Setgid only affects the current thread, not the process.
+// This does not match what most callers expect so we must return an error
+// here rather than letting the caller think that the call succeeded.
+
+func Setuid(uid int) (err error) {
+	return EOPNOTSUPP
+}
+
+func Setgid(uid int) (err error) {
+	return EOPNOTSUPP
+}
+
 //sys	Setpriority(which int, who int, prio int) (err error)
 //sys	Setxattr(path string, attr string, data []byte, flags int) (err error)
 //sys	Symlink(oldpath string, newpath string) (err error)