On Sat, Apr 07, 2018 at 09:29:30PM -0600, Theo de Raadt wrote:
> Philip Guenther <pguent...@proofpoint.com> wrote:
>
> > On Sat, 7 Apr 2018, Sebastien Marie wrote:
> > > While running testsuite on third-party program, I found some weird
> > > behaviour on us side regarding socketpair(2) and getpeereid(3).
> > >
> > > I ported the unit test to C (it was Rust) to check more easily.
> > >
> > > It just creates an UNIX domain socket using socketpair(2), and next
> > > check the euid/egid of the peer connected socket. The expected result is
> > > that euid of the peer is the euid of the process.
> > ...
> > > Could I have confirmation if it is a bug or not ? I am unsure if
> > > socketpair(2) should set the peer information or not. But at least,
> > > ENOTCONN is wrong: socketpair(2) returns connected sockets.
> >
> > That's a bug, IMO: socketpair(2) should support use of getpeereid(3).
>
> Yes, support should be added.
Here a diff to add getpeerid(3) support inside socketpair(2).
It fills unp_connid on the two sockets (there are connected each other).
I think it is the more simple way to achieve it. Moving the related code
from unp_connect() to unp_connect2() should be possible (only few direct
callers of {so,unp_}connect2() ), but unp_connid will not be copied on
the two sockets.
--
Sebastien Marie
Index: kern/uipc_syscalls.c
===================================================================
RCS file: /cvs/src/sys/kern/uipc_syscalls.c,v
retrieving revision 1.168
diff -u -p -r1.168 uipc_syscalls.c
--- kern/uipc_syscalls.c 28 Mar 2018 09:54:00 -0000 1.168
+++ kern/uipc_syscalls.c 8 Apr 2018 04:57:14 -0000
@@ -448,6 +448,7 @@ sys_socketpair(struct proc *p, void *v,
struct filedesc *fdp = p->p_fd;
struct file *fp1, *fp2;
struct socket *so1, *so2;
+ struct unpcb *unp1, *unp2;
int type, cloexec, nonblock, fflag, error, sv[2];
type = SCARG(uap, type) & ~(SOCK_CLOEXEC | SOCK_NONBLOCK);
@@ -461,6 +462,14 @@ sys_socketpair(struct proc *p, void *v,
error = socreate(SCARG(uap, domain), &so2, type, SCARG(uap, protocol));
if (error)
goto free1;
+
+ unp1 = sotounpcb(so1);
+ unp2 = sotounpcb(so2);
+ unp1->unp_connid.uid = unp2->unp_connid.uid = p->p_ucred->cr_uid;
+ unp1->unp_connid.gid = unp2->unp_connid.gid = p->p_ucred->cr_gid;
+ unp1->unp_connid.pid = unp2->unp_connid.pid = p->p_p->ps_pid;
+ unp1->unp_flags |= UNP_FEIDS;
+ unp2->unp_flags |= UNP_FEIDS;
error = soconnect2(so1, so2);
if (error != 0)
