freebsd stable - Oct 2017 - ppp routing bug ?

On 10/26/2017 12:01 PM, Eugene Grosbein wrote:
> 
> I would re-run ppp under ktrace to make sure while having "route
monitor" running around.
> Then compare pids with kdump output.
I wonder if I copied and pasted from 2 different test sessions. Anyways,
same PID when I re-ran the test and more importantly the same results
(see pid.txt). The HOST flag is missing for some reason when the route
is added by ppp vs via the shell

29597 is the ppp process


the borked route monitor looks like

got message of size 124 on Thu Oct 26 12:21:12 2017
RTM_ADD: Add Route: len 124, pid: 29597, seq 2, errno 0,
flags:<UP,GATEWAY,DONE,STATIC>
locks:  inits:
sockaddrs: <DST,GATEWAY>
 192.168.134.2 64.7.128.7


got message of size 196 on Thu Oct 26 12:21:13 2017
RTM_CHANGE: Change Metrics or flags: len 196, pid: 29597, seq 5, errno
0, flags:<UP,DONE,STATIC>
locks:  inits: <mtu>
sockaddrs: <DST,GATEWAY,IFP,IFA>
 192.168.134.2 64.7.128.7 tun0 98-159-244-185.agas1a-dynamic.dsl.sentex.ca

vs the one that works

got message of size 124 on Thu Oct 26 12:21:13 2017
RTM_ADD: Add Route: len 124, pid: 29877, seq 1, errno 0,
flags:<UP,GATEWAY,HOST,DONE,STATIC>
locks:  inits:
sockaddrs: <DST,GATEWAY>
 192.168.136.1 64.7.128.7


got message of size 196 on Thu Oct 26 12:21:13 2017
RTM_CHANGE: Change Metrics or flags: len 196, pid: 29597, seq 8, errno
0, flags:<UP,DONE,STATIC>
locks:  inits: <mtu>
sockaddrs: <DST,GATEWAY,IFP,IFA>
 192.168.136.1 64.7.128.7 tun0 98-159-244-185.agas1a-dynamic.dsl.sentex.ca

> 
>> I diffed the source to ppp from 10 vs 11 and nothing has really
changed.
>>  Perhaps routing API changes that ppp was relying on ?
> 
> It seems so.
> 
> 
> 

-- 
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada   http://www.tancsa.com/
-------------- next part --------------
grep pid route.txt2 
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_ADD: Add Route: len 204, pid: 0, seq 0, errno 0,
flags:<UP,HOST,STATIC>
RTM_ADD: Add Route: len 276, pid: 0, seq 0, errno 0, flags:<UP,DONE>
RTM_ADD: Add Route: len 176, pid: 29594, seq 1, errno 0,
flags:<UP,GATEWAY,DONE,STATIC>
RTM_DELETE: Delete Route: len 204, pid: 0, seq 0, errno 0,
flags:<HOST,STATIC>
RTM_DELETE: Delete Route: len 276, pid: 0, seq 0, errno 0, flags:<DONE>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_GET: Report Metrics: len 180, pid: 29769, seq 1, errno 3,
flags:<UP,GATEWAY,STATIC>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_ADD: Add Route: len 164, pid: 0, seq 0, errno 0,
flags:<UP,HOST,PINNED>
RTM_ADD: Add Route: len 124, pid: 29597, seq 2, errno 0,
flags:<UP,GATEWAY,DONE,STATIC>
RTM_ADD: Add Route: len 140, pid: 29597, seq 3, errno 0,
flags:<UP,GATEWAY,DONE,STATIC>
RTM_ADD: Add Route: len 140, pid: 29874, seq 1, errno 0,
flags:<UP,GATEWAY,DONE,STATIC>
RTM_ADD: Add Route: len 124, pid: 29877, seq 1, errno 0,
flags:<UP,GATEWAY,HOST,DONE,STATIC>
RTM_ADD: Add Route: len 140, pid: 29884, seq 1, errno 0,
flags:<UP,GATEWAY,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 236, pid: 29597, seq 4, errno 0,
flags:<UP,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 196, pid: 29597, seq 5, errno 0,
flags:<UP,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 212, pid: 29597, seq 6, errno 0,
flags:<UP,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 212, pid: 29597, seq 7, errno 0,
flags:<UP,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 196, pid: 29597, seq 8, errno 0,
flags:<UP,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 212, pid: 29597, seq 9, errno 0,
flags:<UP,DONE,STATIC>
RTM_CHANGE: Change Metrics or flags: len 260, pid: 29597, seq 10, errno 51,
flags:<UP,STATIC>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>
RTM_MISS: Lookup failed on this address: len 108, pid: 0, seq 0, errno 0,
flags:<DONE>

27.10.2017 1:04, Mike Tancsa ?????:
> On 10/26/2017 12:01 PM, Eugene Grosbein wrote:
>>
>> I would re-run ppp under ktrace to make sure while having "route
monitor" running around.
>> Then compare pids with kdump output.
> 
> I wonder if I copied and pasted from 2 different test sessions. Anyways,
> same PID when I re-ran the test and more importantly the same results
> (see pid.txt). The HOST flag is missing for some reason when the route
> is added by ppp vs via the shell
> 
> 29597 is the ppp process
> 
> 
> the borked route monitor looks like
> 
> got message of size 124 on Thu Oct 26 12:21:12 2017
> RTM_ADD: Add Route: len 124, pid: 29597, seq 2, errno 0,
> flags:<UP,GATEWAY,DONE,STATIC>
> locks:  inits:
> sockaddrs: <DST,GATEWAY>
>  192.168.134.2 64.7.128.7
> 
> 
> got message of size 196 on Thu Oct 26 12:21:13 2017
> RTM_CHANGE: Change Metrics or flags: len 196, pid: 29597, seq 5, errno
> 0, flags:<UP,DONE,STATIC>
> locks:  inits: <mtu>
> sockaddrs: <DST,GATEWAY,IFP,IFA>
>  192.168.134.2 64.7.128.7 tun0 98-159-244-185.agas1a-dynamic.dsl.sentex.ca
> 
> vs the one that works
> 
> got message of size 124 on Thu Oct 26 12:21:13 2017
> RTM_ADD: Add Route: len 124, pid: 29877, seq 1, errno 0,
> flags:<UP,GATEWAY,HOST,DONE,STATIC>
> locks:  inits:
> sockaddrs: <DST,GATEWAY>
>  192.168.136.1 64.7.128.7
> 
> 
> got message of size 196 on Thu Oct 26 12:21:13 2017
> RTM_CHANGE: Change Metrics or flags: len 196, pid: 29597, seq 8, errno
> 0, flags:<UP,DONE,STATIC>
> locks:  inits: <mtu>
> sockaddrs: <DST,GATEWAY,IFP,IFA>
>  192.168.136.1 64.7.128.7 tun0 98-159-244-185.agas1a-dynamic.dsl.sentex.ca
That makes sense: ppp send bogus request to the routing socket and
the request has not RTF_HOST flag nor RTA_NETMASK address.
It seems, earlier kernel code masked this bug somehow but it does not now.

Anyway, we have two bugs here: ppp sending bad request and kernel having
no enough checks for this somehow.

Fixing ppp part would be easy. Please try this patch:

--- usr.sbin/ppp/route.c.orig        2017-02-15 13:06:48.606161000 +0700
+++ usr.sbin/ppp/route.c     2017-10-27 05:14:44.006142000 +0700
@@ -801,8 +801,10 @@ rt_Set(struct bundle *bundle, int cmd, c
   if (!ncprange_ishost(dst)) {
     cp += memcpy_roundup(cp, &samask, samask.ss_len);
     rtmes.m_rtm.rtm_addrs |= RTA_NETMASK;
   }
+  else
+    rtmes.m_rtm.rtm_flags |= RTF_HOST;

   nb = cp - (char *)&rtmes;
   rtmes.m_rtm.rtm_msglen = nb;
   wb = ID0write(s, &rtmes, nb);
@@ -905,8 +907,10 @@ rt_Update(struct bundle *bundle, const s
   if (mask) {
     rtmes.m_rtm.rtm_addrs |= RTA_NETMASK;
     p += memcpy_roundup(p, mask, mask->sa_len);
   }
+  else
+    rtmes.m_rtm.rtm_flags |= RTF_HOST;

   if (ifa && ifp && ifp->sa_family == AF_LINK) {
     rtmes.m_rtm.rtm_addrs |= RTA_IFP;
     p += memcpy_roundup(p, ifp, ifp->sa_len);