stanonik@nprdc.arpa (Ron Stanonik) (12/16/85)
Description:
Ioctl's can affect the wrong interface if you have interfaces
with similar names; eg, sl and slip. The problem is that
ifunit(name), in sys/net/if.c, bcmp's its argument
to each interface name, but doesn't compare lengths. So,
sl, being a prefix of slip, matches. (I feel as though I've
seen a fix for this, but couldn't find it.) By the way, 4.3BSD
seems to have the same bug.
Repeat-By:
We have two serial interfaces, "sl" from rick@seismo.arpa,
and "slip" from ks@purdue-ecn.arpa. The "slip" interface
was if_attach'ed first. Ifconfig'ing "sl" clobbered the
"slip" interface.
Fix:
--- if.c Mon Dec 16 12:04:59 1985
***************
*** 184,190
{
register char *cp;
register struct ifnet *ifp;
! int unit;
for (cp = name; cp < name + IFNAMSIZ && *cp; cp++)
if (*cp >= '0' && *cp <= '9')
--- 184,190 -----
{
register char *cp;
register struct ifnet *ifp;
! int unit, len;
for (cp = name; cp < name + IFNAMSIZ && *cp; cp++)
if (*cp >= '0' && *cp <= '9')
***************
*** 192,197
if (*cp == '\0' || cp == name + IFNAMSIZ)
return ((struct ifnet *)0);
unit = *cp - '0', *cp = 0;
for (ifp = ifnet; ifp; ifp = ifp->if_next) {
if (bcmp(ifp->if_name, name, (unsigned)(cp - name)))
continue;
--- 192,198 -----
if (*cp == '\0' || cp == name + IFNAMSIZ)
return ((struct ifnet *)0);
unit = *cp - '0', *cp = 0;
+ len = (int)(cp - name);
for (ifp = ifnet; ifp; ifp = ifp->if_next) {
if (strlen(ifp->if_name) != len || bcmp(ifp->if_name, name, len))
continue;
***************
*** 193,199
return ((struct ifnet *)0);
unit = *cp - '0', *cp = 0;
for (ifp = ifnet; ifp; ifp = ifp->if_next) {
! if (bcmp(ifp->if_name, name, (unsigned)(cp - name)))
continue;
if (unit == ifp->if_unit)
break;
--- 194,200 -----
unit = *cp - '0', *cp = 0;
len = (int)(cp - name);
for (ifp = ifnet; ifp; ifp = ifp->if_next) {
! if (strlen(ifp->if_name) != len || bcmp(ifp->if_name, name, len))
continue;
if (unit == ifp->if_unit)
break;