At the moment ifconfig(8) sets address of `inet` family if no
address family specified and some unrecognized parameter given.
This has security and UX implications:
Because inet addresses mix with other ifconfig(8) parameters,
a misspelled parameter will be assumed to be an inet address.
Since it is possible to set an inet address from a hostname,
gethostbyname(3) will eventually look up this parameter as
an address via DNS. One may run something like
`ifconfig iwm0 wpakeysecretpassword` and `wpakeysecretpassword`
will be sent over the wire.
If a user misspelled a parameter they have to wait for undefined
amount of time for DNS lookup to finish (DNS server may not be
available).
This patch is to make address family a required parameter when
setting an address.
Index: ifconfig.8
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.8,v
retrieving revision 1.288
diff -u -p -r1.288 ifconfig.8
--- ifconfig.8 14 Sep 2017 13:02:12 -0000 1.288
+++ ifconfig.8 22 Oct 2017 15:25:45 -0000
@@ -41,11 +41,13 @@
.Nm ifconfig
.Op Fl AaC
.Op Ar interface
-.Op Ar address_family
+.Oo
+.Ar address_family
.Oo
.Ar address
.Op Ar dest_address
.Oc
+.Oc
.Op Ar parameters
.Sh DESCRIPTION
The
@@ -108,8 +110,6 @@ interfaces).
.It Ar address_family
Specifies the address family
which affects interpretation of the remaining parameters.
-Since an interface can receive transmissions in differing protocols
-with different naming schemes, specifying the address family is
recommended.
The address or protocol families currently
supported are
.Dq inet
Index: ifconfig.c
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.c,v
retrieving revision 1.348
diff -u -p -r1.348 ifconfig.c
--- ifconfig.c 29 Aug 2017 21:10:20 -0000 1.348
+++ ifconfig.c 22 Oct 2017 15:25:46 -0000
@@ -677,14 +677,15 @@ main(int argc, char *argv[])
errx(1, "interface name '%s' too long", *argv);
argc--, argv++;
if (argc > 0) {
- for (afp = rafp = afs; rafp->af_name; rafp++)
+ for (rafp = afs; rafp->af_name; rafp++)
if (strcmp(rafp->af_name, *argv) == 0) {
afp = rafp;
argc--;
argv++;
break;
}
- rafp = afp;
+ if (!afp)
+ errx(1, "invalid address family: %s", *argv);
af = ifr.ifr_addr.sa_family = rafp->af_af;
}
if (Cflag) {
