Implement passing credentials as ancillary data on Unix domain sockets,
enabled with the LOCAL_CREDS socket option on the listener. Semantics are similar to BSD/OS's: - Creds are available with first data on SOCK_STREAM, and with every datagram on SOCK_DGRAM. - It is not possible to forge credentials. Different in that: - Different credential data structure (ours does not rely on the format of internal kernel data structures, and does not pass the login name). - We can pass creds and file descriptors at the same time (this does not work in BSD/OS). Luke Mewburn <lukem@netbsd.org> gets credit for inspiring me to implement this. :-)
This commit is contained in:
thorpej
parent
11cfadcaa1
commit
cc22126721
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@ -1,4 +1,41 @@
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/* $NetBSD: uipc_usrreq.c,v 1.29 1998/01/07 04:03:38 thorpej Exp $ */
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/* $NetBSD: uipc_usrreq.c,v 1.30 1998/01/07 22:57:09 thorpej Exp $ */
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/*-
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* Copyright (c) 1998 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
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* NASA Ames Research Center.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1997 Christopher G. Demetriou. All rights reserved.
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@ -63,10 +100,13 @@
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struct sockaddr_un sun_noname = { sizeof(sun_noname), AF_UNIX };
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ino_t unp_ino; /* prototype for fake inode numbers */
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struct mbuf *unp_addsockcred __P((struct proc *, struct mbuf *));
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int
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unp_output(m, control, unp)
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unp_output(m, control, unp, p)
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struct mbuf *m, *control;
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struct unpcb *unp;
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struct proc *p;
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{
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struct socket *so2;
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struct sockaddr_un *sun;
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@ -76,6 +116,8 @@ unp_output(m, control, unp)
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sun = unp->unp_addr;
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else
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sun = &sun_noname;
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if (unp->unp_conn->unp_flags & UNP_WANTCRED)
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control = unp_addsockcred(p, control);
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if (sbappendaddr(&so2->so_rcv, (struct sockaddr *)sun, m,
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control) == 0) {
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m_freem(control);
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@ -221,6 +263,12 @@ uipc_usrreq(so, req, m, nam, control, p)
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break;
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case PRU_SEND:
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/*
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* Note: unp_internalize() rejects any control message
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* other than SCM_RIGHTS, and only allows one. This
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* has the side-effect of preventing a caller from
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* forging SCM_CREDS.
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*/
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if (control && (error = unp_internalize(control, p)))
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break;
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switch (so->so_type) {
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@ -244,7 +292,7 @@ uipc_usrreq(so, req, m, nam, control, p)
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goto die;
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}
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}
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error = unp_output(m, control, unp);
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error = unp_output(m, control, unp, p);
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if (nam)
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unp_disconnect(unp);
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break;
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@ -256,6 +304,14 @@ uipc_usrreq(so, req, m, nam, control, p)
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if (unp->unp_conn == 0)
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panic("uipc 3");
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so2 = unp->unp_conn->unp_socket;
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if (unp->unp_conn->unp_flags & UNP_WANTCRED) {
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/*
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* Credentials are passed only once on
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* SOCK_STREAM.
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*/
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unp->unp_conn->unp_flags &= ~UNP_WANTCRED;
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control = unp_addsockcred(p, control);
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}
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/*
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* Send to paired receive port, and then reduce
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* send buffer hiwater marks to maintain backpressure.
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@ -326,6 +382,82 @@ release:
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return (error);
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}
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/*
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* Unix domain socket option processing.
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*/
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int
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uipc_ctloutput(op, so, level, optname, mp)
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int op;
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struct socket *so;
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int level, optname;
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struct mbuf **mp;
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{
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struct unpcb *unp = sotounpcb(so);
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struct mbuf *m = *mp;
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int optval = 0, error = 0;
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if (level != 0) {
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error = EINVAL;
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if (op == PRCO_SETOPT && m)
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(void) m_free(m);
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} else switch (op) {
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case PRCO_SETOPT:
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switch (optname) {
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case LOCAL_CREDS:
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if (m == NULL || m->m_len != sizeof(int))
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error = EINVAL;
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else {
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optval = *mtod(m, int *);
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switch (optname) {
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#define OPTSET(bit) \
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if (optval) \
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unp->unp_flags |= (bit); \
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else \
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unp->unp_flags &= ~(bit);
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case LOCAL_CREDS:
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OPTSET(UNP_WANTCRED);
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break;
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}
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}
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break;
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#undef OPTSET
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default:
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error = ENOPROTOOPT;
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break;
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}
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if (m)
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(void) m_free(m);
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break;
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case PRCO_GETOPT:
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switch (optname) {
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case LOCAL_CREDS:
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*mp = m = m_get(M_WAIT, MT_SOOPTS);
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m->m_len = sizeof(int);
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switch (optname) {
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#define OPTBIT(bit) (unp->unp_flags & (bit) ? 1 : 0)
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case LOCAL_CREDS:
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optval = OPTBIT(UNP_WANTCRED);
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break;
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}
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*mtod(m, int *) = optval;
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break;
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#undef OPTBIT
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default:
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error = ENOPROTOOPT;
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break;
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}
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break;
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}
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return (error);
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}
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/*
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* Both send and receive buffers are allocated PIPSIZ bytes of buffering
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* for stream sockets, although the total for sender and receiver is
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unp2->unp_addrlen);
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unp3->unp_addrlen = unp2->unp_addrlen;
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}
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unp3->unp_flags = unp2->unp_flags;
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so2 = so3;
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}
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error = unp_connect2(so, so2);
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return (0);
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}
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struct mbuf *
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unp_addsockcred(p, control)
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struct proc *p;
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struct mbuf *control;
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{
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struct cmsghdr *cmp;
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struct sockcred *sc;
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struct mbuf *m, *n;
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int len, i;
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len = sizeof(struct cmsghdr) + SOCKCREDSIZE(p->p_ucred->cr_ngroups);
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m = m_get(M_WAIT, MT_CONTROL);
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if (len > MLEN) {
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if (len > MCLBYTES)
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MEXTMALLOC(m, len, M_WAITOK);
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else
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MCLGET(m, M_WAIT);
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if ((m->m_flags & M_EXT) == 0) {
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m_free(m);
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return (control);
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}
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}
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m->m_len = len;
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m->m_next = NULL;
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cmp = mtod(m, struct cmsghdr *);
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sc = (struct sockcred *)CMSG_DATA(cmp);
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cmp->cmsg_len = len;
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cmp->cmsg_level = SOL_SOCKET;
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cmp->cmsg_type = SCM_CREDS;
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sc->sc_uid = p->p_cred->p_ruid;
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sc->sc_euid = p->p_ucred->cr_uid;
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sc->sc_gid = p->p_cred->p_rgid;
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sc->sc_egid = p->p_ucred->cr_gid;
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sc->sc_ngroups = p->p_ucred->cr_ngroups;
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for (i = 0; i < sc->sc_ngroups; i++)
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sc->sc_groups[i] = p->p_ucred->cr_groups[i];
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/*
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* If a control message already exists, append us to the end.
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*/
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if (control != NULL) {
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for (n = control; n->m_next != NULL; n = n->m_next)
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;
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n->m_next = m;
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} else
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control = m;
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return (control);
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}
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int unp_defer, unp_gcing;
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extern struct domain unixdomain;
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