From 79f6a5c7bd684f2e6007ee505b522440beb86bf0 Mon Sep 17 00:00:00 2001 From: Wander Lairson Costa Date: Fri, 10 Feb 2017 04:10:48 -0200 Subject: syscall: only call setgroups if we need to If the caller set ups a Credential in os/exec.Command, os/exec.Command.Start will end up calling setgroups(2), even if no supplementary groups were given. Only root can call setgroups(2) on BSD kernels, which causes Start to fail for non-root users when they try to set uid and gid for the new process. We fix by introducing a new field to syscall.Credential named NoSetGroups, and setgroups(2) is only called if it is false. We make this field with inverted logic to preserve backward compatibility. RELNOTES=yes Change-Id: I3cff1f21c117a1430834f640ef21fd4e87e06804 Reviewed-on: https://go-review.googlesource.com/36697 Reviewed-by: Ian Lance Taylor --- src/syscall/exec_bsd.go | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'src/syscall/exec_bsd.go') diff --git a/src/syscall/exec_bsd.go b/src/syscall/exec_bsd.go index 317645fae5..31a4099559 100644 --- a/src/syscall/exec_bsd.go +++ b/src/syscall/exec_bsd.go @@ -146,9 +146,11 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr if ngroups > 0 { groups = uintptr(unsafe.Pointer(&cred.Groups[0])) } - _, _, err1 = RawSyscall(SYS_SETGROUPS, ngroups, groups, 0) - if err1 != 0 { - goto childerror + if !cred.NoSetGroups { + _, _, err1 = RawSyscall(SYS_SETGROUPS, ngroups, groups, 0) + if err1 != 0 { + goto childerror + } } _, _, err1 = RawSyscall(SYS_SETGID, uintptr(cred.Gid), 0, 0) if err1 != 0 { -- cgit v1.3-5-g9baa