Specifically, if two threads were doing concurrent lookups and the existing
gateway was marked down, the the first thread would drop a reference on the
gateway route and then unlock the "root" route while it tried to allocate
a new route. The second thread could then also drop a reference on the
same gateway route resulting in a reference underflow. Fix this by
clearing the gateway route pointer after dropping the reference count but
before dropping the lock. Secondly, in this same case, the second thread
would overwrite the gateway route pointer w/o free'ing a reference to the
route installed by the first thread. In practice this would probably just
fix a lost reference that would result in a route never being freed.
This fixes panics observed in rt_check() and rtexpunge().
MFC after: 1 week
PR: kern/112490
Insight from: mehuljv at yahoo.com
Reviewed by: ru (found the "not-setting it to NULL" part)
Tested by: several
- In rt_check() remove the senderr() macro and the "bad" label. They
used to simplify code, but now aren't.
- Remove extra RT_LOCK_ASSERT() in rt_setgate(). The RT_REMREF macro
does this.
- In rtfree() convert panics to KASSERTs.
- Strict the routing API: rtfree() should be called only in a case
when we are completely sure we've got the last reference on the
rtentry. In all other cases RTFREE_LOCKED() macro should be used.
If the reference isn't the last one spit out a warning printf.
Correct the only(?) case for this in rt_check().
- Fix typos in comments.
at the start of rtalloc1(). This backs out part of revs 1.83 and 1.85.
Profiling on an i386 showed that that for sending tiny packets using
bge, -current takes 7 bzero()s where RELENG_4 takes only 1, and that
bzero()ing is now the dominant overhead (10-12%, up from 1%, but
profiling overestimated this a bit). This commit backs out 2 of the
6 extra bzero()s (1 in each of 2 calls per packet to rtalloc1()). They
were the largest ones by byte count (48 bytes each) but perhaps not
by time (small misaligned ones might take longer).
255.255.255.0, and a default route with gateway x.x.x.1. Now if
the address mask is changed to something more specific, e.g.,
255.255.255.128, then after the mask change the default gateway
is no longer reachable.
Since the default route is still present in the routing table,
when the output code tries to resolve the address of the default
gateway in function rt_check(), again, the default route will be
returned by rtalloc1(). Because the lock is currently held on the
rtentry structure, one more attempt to hold the lock will trigger
a crash due to "lock recursed on non-recursive mutex ..."
This is a general problem. The fix checks for the above condition
so that an existing route entry is not mistaken for a new cloned
route. Approriately, an ENETUNREACH error is returned back to the
caller
Approved by: andre
gateways which are unreachable except through the default router. For
example, assuming there is a default route configured, and inserting
a route
"route add 64.102.54.0/24 60.80.1.1"
is currently allowed even when 60.80.1.1 is only reachable through
the default route. However, an error is thrown when this route is
utilized, say,
"ping 64.102.54.1" will return an error
This type of route insertion should be disallowed becasue:
1) Let's say that somehow our code allowed this packet to flow to
the default router, and the default router knows the next hop is
60.80.1.1, then the question is why bother inserting this route in
the 1st place, just simply use the default route.
2) Since we're not talking about source routing here, the default
router could very well choose a different path than using 60.80.1.1
for the next hop, again it defeats the purpose of adding this route.
Reviewed by: ru, gnn, bz
Approved by: andre
destination. These checks are needed so we do not install
a route looking like this:
(0) 192.0.2.200 UH tun0 =>
When removing this route the kernel will start to walk
the address space which looks like a hang on 64bit platforms
because it'll take ages while on 32bit you should see a panic
when kernel debugging options are turned on.
The problem is in rtrequest1:
if (netmask) {
rt_maskedcopy(dst, ndst, netmask);
} else
bcopy(dst, ndst, dst->sa_len);
In both cases the len might be 0 if the application forgot to
set it. If so ndst will be all-zero leading to above
mentioned strange routes.
This is an application error but we must not fail/hang/panic
because of this.
Looks ok: gnn
No objections: net@ (silence)
MFC after: 8 weeks
rather than in ifindex_table[]; all (except one) accesses are
through ifp anyway. IF_LLADDR() works faster, and all (except
one) ifaddr_byindex() users were converted to use ifp->if_addr.
- Stop storing a (pointer to) Ethernet address in "struct arpcom",
and drop the IFP2ENADDR() macro; all users have been converted
to use IF_LLADDR() instead.
- Rearrange code so that in a case of failure the affected
route is not changed. Otherwise, a bogus rtentry will be
left and later rt_check() can recurse on its lock. [1]
- Remove comment about protocol cloning.
- Fix two places where rtentry mutex was recursed on, because
accessed via two different pointers, that were actually pointing
to the same rtentry in some cases. [1]
- Return EADDRINUSE instead of bogus EDQUOT, in case when gateway
uses the same route. [2]
Reported & tested by: ps, Andrej Zverev <az inec.ru> [1]
PR: kern/64090 [2]
- rt0 passed to rt_check() must not be NULL, assert this.
- rt returned by rt_check() must be valid locked rtentry,
if no error occured.
o Modify callers, so that they never pass NULL rt0
to rt_check().
Reviewed by: sam, ume (nd6.c)
route itself.
It fixes a bug where an IPv4 route for example has an IPv6 gateway
specified:
route add 10.1.1.1 -inet6 fe80::1%fxp0
Destination Gateway Flags Refs Use Netif Expire
10.1.1.1 fe80::1%fxp0 UGHS 0 0 fxp0
The fix rejects these illegal combinations:
route: writing to routing socket: Invalid argument
add host 10.1.1.1: gateway fe80::1%fxp0: Invalid argument
Reviewed by: KAME jinmei@isl.rdc.toshiba.co.jp
Reviewed by: andre (mentor)
Approved by: re
MFC after: 5
security.jail.allow_raw_sockets sysctl MIB is set to 1) where privileged
access to jails is given out, it is possible for prison root to manipulate
various network parameters which effect the host environment. This commit
plugs a number of security holes associated with the use of raw sockets
and prisons.
This commit makes the following changes:
- Add a comment to rtioctl warning developers that if they add
any ioctl commands, they should use super-user checks where necessary,
as it is possible for PRISON root to make it this far in execution.
- Add super-user checks for the execution of the SIOCGETVIFCNT
and SIOCGETSGCNT IP multicast ioctl commands.
- Add a super-user check to rip_ctloutput(). If the calling cred
is PRISON root, make sure the socket option name is IP_HDRINCL,
otherwise deny the request.
Although this patch corrects a number of security problems associated
with raw sockets and prisons, the warning in jail(8) should still
apply, and by default we should keep the default value of
security.jail.allow_raw_sockets MIB to 0 (or disabled) until
we are certain that we have tracked down all the problems.
Looking forward, we will probably want to eliminate the
references to curthread.
This may be a MFC candidate for RELENG_5.
Reviewed by: rwatson
Approved by: bmilekic (mentor)
called "rtentry".
This saves a considerable amount of kernel memory. R_Zmalloc previously
used 256 byte blocks (plus kmalloc overhead) whereas UMA only needs 132
bytes.
Idea from: OpenBSD
it checked for rt == NULL after dereferencing the pointer).
We never check for those events elsewhere, so probably these checks
might go away here as well.
Slightly simplify (and document) the logic for memory allocation
in rt_setgate().
The rest is mostly style changes -- replace 0 with NULL where appropriate,
remove the macro SA() that was only used once, remove some useless
debugging code in rt_fixchange, explain some odd-looking casts.
of an interface. No functional change.
On passing, comment a likely bug in net/rtsock.c:sysctl_ifmalist()
which, if confirmed, would deserve to be fixed and MFC'ed
the space occupied by a struct sockaddr when passed through a
routing socket.
Use it to replace the macro ROUNDUP(int), that does the same but
is redefined by every file which uses it, courtesy of
the School of Cut'n'Paste Programming(TM).
(partial) userland changes to follow.
accordingly. The define is left intact for ABI compatibility
with userland.
This is a pre-step for the introduction of tcp_hostcache. The
network stack remains fully useable with this change.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
routine that takes a locked routing table reference and removes all
references to the entry in the various data structures. This
eliminates instances of recursive locking and also closes races
where the lock on the entry had to be dropped prior to calling
rtrequest(RTM_DELETE). This also cleans up confusion where the
caller held a reference to an entry that might have been reclaimed
(and in some cases used that reference).
Supported by: FreeBSD Foundation
that covers updates to the contents. Note this is separate from holding
a reference and/or locking the routing table itself.
Other/related changes:
o rtredirect loses the final parameter by which an rtentry reference
may be returned; this was never used and added unwarranted complexity
for locking.
o minor style cleanups to routing code (e.g. ansi-fy function decls)
o remove the logic to bump the refcnt on the parent of cloned routes,
we assume the parent will remain as long as the clone; doing this avoids
a circularity in locking during delete
o convert some timeouts to MPSAFE callouts
Notes:
1. rt_mtx in struct rtentry is guarded by #ifdef _KERNEL as user-level
applications cannot/do-no know about mutex's. Doing this requires
that the mutex be the last element in the structure. A better solution
is to introduce an externalized version of struct rtentry but this is
a major task because of the intertwining of rtentry and other data
structures that are visible to user applications.
2. There are known LOR's that are expected to go away with forthcoming
work to eliminate many held references. If not these will be resolved
prior to release.
3. ATM changes are untested.
Sponsored by: FreeBSD Foundation
Obtained from: BSD/OS (partly)
o move route_cb to be private to rtsock.c
o replace global static route_proto by locals
o eliminate global #define shorthands for info references
o remove some register decls
o ansi-fy function decls
o move items to be close in scope to their usage
o add rt_dispatch function for dispatching the actual message
o cleanup tangled logic for doing all-but-me msg send
Support by: FreeBSD Foundation
when julian@ added it, but the commented out code had at least
one bug -- not freeing the allocated mbuf.
Anyway, this comment no longer applies as of revision 1.67, so
remove it.
the entry being removed (ret_nrt != NULL), increment the entry's
rt_refcnt like we do it for RTM_ADD and RTM_RESOLVE, rather than
messing around with 1->0 transitions for rtfree() all over.
