/*
* userv service (or standalone program) for per-user IP subranges.
*
- * When invoked appropriately, it creates a point-to-point network
- * interface with specified parameters. It arranges for packets sent out
- * via that interface by the kernel to appear on its own stdout in SLIP or
- * CSLIP encoding, and packets injected into its own stdin to be given to
- * the kernel as if received on that interface. Optionally, additional
- * routes can be set up to arrange for traffic for other address ranges to
- * be routed through the new interface.
- *
* This is the service program, which is invoked as root from userv (or may
* be invoked firectly).
*
*
* The remaining arguments are supplied by the (untrusted) caller:
*
- * <local-addr>,<peer-addr>,<mtu>[,[<proto>]]
+ * <local-addr>,<peer-addr>,<mtu>[,[<proto>][,[<ifnamepat>]]]
*
* As for slattach. The only supported protocol is slip.
* Alternatively, set to `debug' to print debugging info and
* service program directly (not via userv), without needing to set up
* permissions in /etc/userv/ipif-networks.
*
+ * Only `*' permits interface name patterns other than the default
+ * value of `userv%d'.
+ *
* #...
*
* Comment. Blank lines are also ignored.
static const unsigned long gidmaxval= (unsigned long)((gid_t)-2);
static const char *const protos_ok[]= { "slip", 0 };
static const int signals[]= { SIGHUP, SIGINT, SIGTERM, 0 };
+static const char default_ifnamepat[]= "userv%d";
static const char *configstr, *proto;
static unsigned long localaddr, peeraddr, mtu;
static int localpming, peerpming;
-static int localallow, peerallow, allallow;
+static int localallow, peerallow, ifnameallow, allallow;
+static char *ifnamepat;
static int nexroutes;
static struct exroute {
unsigned long prefix, mask;
*argp= comma + 1;
} else {
len= strlen(start);
- *argp= start + len;
+ *argp= 0;
}
}
if (!len) {
case '*':
permit_begin();
permit_range(0UL,0UL,1,0);
+ ifnameallow= 1;
return;
case '#':
mtu= eat_number(&carg,"mtu", 576,65536, ",",0);
localallow= peerallow= 0;
- char *protostr = eat_optionalstr(&carg,"protocol","slip");
+ char *protostr= eat_optionalstr(&carg,"protocol","slip");
if (!strcmp(protostr,"debug")) {
proto= 0;
} else {
cprotop++);
if (!proto) fatal("invalid protocol");
}
+
+ ifnamepat= eat_optionalstr(&carg,"ifname pattern",default_ifnamepat);
addrnet_mustdiffer("local-addr",localaddr,~0UL, "peer-addr",peeraddr,~0UL);
sprintf(erwhatbuf, "route#%d", i);
checkallow(exroutes[i].allow, erwhatbuf, exroutes[i].prefixtxt, exroutes[i].masktxt);
}
+ if (!strcmp(ifnamepat,default_ifnamepat))
+ ifnameallow= 1;
+ if (!ifnameallow) {
+ fprintf(stderr,
+ "userv-ipif service: access denied for interface name %s\n",
+ ifnamepat);
+ allallow= 0;
+ }
if (!allallow) fatal("access denied");
}
}
static void createif(void) {
- static const char ifnamepat[]= "userv%d";
struct ifreq ifr;
int r;
memset(&ifr,0,sizeof(ifr));
ifr.ifr_flags= IFF_TUN | IFF_NO_PI;
- assert(sizeof(ifr.ifr_name) >= sizeof(ifnamepat));
+ assert(sizeof(ifr.ifr_name) >= strlen(ifnamepat)+1);
strcpy(ifr.ifr_name, ifnamepat);
tunfd= open("/dev/net/tun", O_RDWR);