Date: Fri, 24 May 1996 09:15:18 +0200 (SAT) From: R Bezuidenhout <rbezuide@mikom.csir.co.za> To: hackers@freebsd.org Cc: wollman@freebsd.org Subject: Panic: route add -net !! Message-ID: <199605240715.JAA13069@zibbi.mikom.csir.co.za>
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Hi all
One of our customers tried the following on a machine running
2.1-STABLE and got a kernel panic. I also tried this on a local
machine, which fictious IP numbers :) and got the same result:
/etc/hosts
12.12.12.12 ddd.csir.co.za ddd
13.13.13.0 ccc.csir.co.za ccc
Now!!
duzi# route add -net ccc ddd
This causes the system to panic. I know that the 13.13.13.0 entry
should actually be in the /etc/networks file, I have tested that
and that seems to work fine, no panic. I know that putting the
network entry in the hosts file is wrong, but I think it should
not cause a kernel panic.
If you use exactly the same command, but substitute the IP numbers
e.g. route add -net 13.13.13.0 12.12.12.12
then it works fine.
I traced the problem through /sbin/route and saw that the problem
occurs in the following section:
/usr/src/sbin/route/route.c
line 137:
NEXTADDR(RTA_IFP, so_ifp);
NEXTADDR(RTA_IFA, so_ifa);
rtm.rtm_msglen = l = cp - (char *)&m_rtmsg;
if (verbose)
print_rtmsg(&rtm, l);
if (debugonly)
return (0);
if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
perror("writing to routing socket");
return (-1);
}
When the write(s, (char *)&m_rtmsg, l)) is done it causes the panic.
I've compared it with the one using IP numbers instead of aliases
and there seems to be a netmask entry missing in &rtm (the verbose
printing)
I traced this to /usr/src/sbin/route/route.c
line 852
if (((val = inet_addr(s)) != -1) &&
(which != RTA_DST || forcenet == 0)) {
su->sin.sin_addr.s_addr = val;
if (inet_lnaof(su->sin.sin_addr) != INADDR_ANY)
return (1);
else {
val = ntohl(val);
goto netdone;
}
}
if ((val = inet_network(s)) != -1 ||
((np = getnetbyname(s)) != NULL && (val = np->n_net) != 0)) {
netdone:
if (which == RTA_DST)
inet_makenetandmask(val, &su->sin);
return (0);
}
hp = gethostbyname(s);
if (hp) {
*hpp = hp;
su->sin.sin_family = hp->h_addrtype;
bcopy(hp->h_addr, (char *)&su->sin.sin_addr, hp->h_length);
return (1);
When using aliases the first two if statements fail and ends up at
hp = gethostbyname(s);
... the call works fine but no netmask is added like in the second
if with
inet_makenetandmask(val, &su->sin);
When using IP numbers the second if is true and
inet_makenetandmask(val, &su->sin);
is executed and a netmask added.
If I use the aliases BUT add -netmask 255.255.255.0 at the end, the
call succeeds and there is no panic.
I'm not sure if this should be fixed in /sbin/route or a check added
in the kernel.
Next follows the panic log written by the kernel:
May 23 15:24:39 duzi /kernel: Fatal trap 12: page fault while in kernel mode
May 23 15:24:41 duzi /kernel: fault virtual address = 0x4
May 23 15:24:42 duzi /kernel: fault code = supervisor read, page
not present
May 23 15:24:42 duzi /kernel: instruction pointer = 0x8:0xf0133523
May 23 15:24:43 duzi /kernel: code segment = base 0x0, limit 0xffff
f, type 0x1b
May 23 15:24:43 duzi /kernel: = DPL 0, pres 1, def32 1, gran 1
May 23 15:24:44 duzi /kernel: processor eflags = interrupt enabled, resume, IOP
L = 0
May 23 15:24:44 duzi /kernel: current process = 13407 (route)
May 23 15:24:45 duzi /kernel: interrupt mask =
May 23 15:24:45 duzi /kernel: panic: page fault
May 23 15:24:45 duzi /kernel:
And with nm /kernel
earch_m
f013265c T _rn_refines
f01326f0 T _rn_lookup
f0132744 t _rn_satsifies_leaf
f01327b4 T _rn_match
f0132924 T _rn_newpair
f013297c T _rn_insert
f0132ac8 T _rn_addmask
f0132d10 t _rn_lexobetter
f0132d70 t _rn_new_radix_mask
f0132e1c T _rn_addroute
f0133184 T _rn_delete
f01334ec T _rn_walktree_from ***** looks like this is it !!!
f01335f8 T _rn_walktree
f01336a0 T _rn_inithead
f01337a4 T _rn_init
f0133880 F raw_cb.o
f0133880 T _raw_attach
f01338ec T _raw_detach
f013392c T _raw_disconnect
f0133950 F raw_usrreq.o
f0133950 T _raw_init
f013396c T _raw_input
f0133ab8 T _raw_ctlinput
f0133ac8 T _raw_usrreq
Thanx Reinier
########################################################################
# #
# Reinier Bezuidenhout Company: Mikomtek CSIR, ZA #
# #
# Network Engineer - NetSec development team #
# #
# Current Projects: NetSec - Secure Platform firewall system #
# http://www.mikom.csir.co.za #
# #
# E-mail: rbezuide@mikom.csir.co.za #
# #
########################################################################
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