openssh unix dev - Feb 2019 - [PATCH] Cygwin: rel 3.0 drops requirement for privileged non-SYSTEM account

Seteuid now creates user token using S4U.  We don't create a token
from scratch anymore, so we don't need the "Create a process
token"
privilege.  The service can run under SYSTEM again.
---
 contrib/cygwin/ssh-host-config | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/contrib/cygwin/ssh-host-config b/contrib/cygwin/ssh-host-config
index cc36ea102f42..2e15d02fbbc1 100644
--- a/contrib/cygwin/ssh-host-config
+++ b/contrib/cygwin/ssh-host-config
@@ -394,14 +394,8 @@ install_service() {
     then
       csih_get_cygenv "${cygwin_value}"
 
-      if ( csih_is_nt2003 || [ "$csih_FORCE_PRIVILEGED_USER" =
"yes" ] )
+      if ( [ "$csih_FORCE_PRIVILEGED_USER" = "yes" ] )
       then
-	csih_inform "On Windows Server 2003, Windows Vista, and above, the"
-	csih_inform "SYSTEM account cannot setuid to other users -- a
capability"
-	csih_inform "sshd requires.  You need to have or to create a
privileged"
-	csih_inform "account.  This script will help you do so."
-	echo
-
 	[ "${opt_force}" = "yes" ] && opt_f=-f
 	[ -n "${user_account}" ] && opt_u="-u
""${user_account}"""
 	csih_select_privileged_username ${opt_f} ${opt_u} sshd
@@ -412,11 +406,12 @@ install_service() {
 	  csih_request "Do you want to proceed anyway?" || exit 1
 	  let ++ret
 	fi
+	# Never returns empty if NT or above
+	run_service_as=$(csih_service_should_run_as)
+      else
+	run_service_as="SYSTEM"
       fi
 
-      # Never returns empty if NT or above
-      run_service_as=$(csih_service_should_run_as)
-
       if [ "${run_service_as}" =
"${csih_PRIVILEGED_USERNAME}" ]
       then
 	password="${csih_PRIVILEGED_PASSWORD}"
-- 
2.20.1

On 16/2/19 11:51 pm, Corinna Vinschen wrote:
> Seteuid now creates user token using S4U.  We don't create a token
> from scratch anymore, so we don't need the "Create a process
token"
> privilege.  The service can run under SYSTEM again.
It seems like your patch breaks OpenSSH on Windows Vista, Server 2003, 
and possibly others.? I oppose changes that needlessly break systems.

On Feb 17 14:47, David Newall wrote:
> On 16/2/19 11:51 pm, Corinna Vinschen wrote:
> > Seteuid now creates user token using S4U.  We don't create a token
> > from scratch anymore, so we don't need the "Create a process
token"
> > privilege.  The service can run under SYSTEM again.
> 
> It seems like your patch breaks OpenSSH on Windows Vista, Server 2003, and
> possibly others.? I oppose changes that needlessly break systems.
- Windows 2003 isn't supported by Cygwin anymore

- S4U has been introduced with Windows 2003

- Vista is newer than Windows 2003


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat
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