1. Copy a NULL-terminated string into a fixed-length buffer, and
2. copyout that buffer to userland,
we really ought to
0. Zero the entire buffer
first.
Security: FreeBSD-SA-05:08.kmem
from divert sockets.
- Remove div_disconnect() method, since it shouldn't be called now.
- Remove div_abort() method. It was never called directly, since protocol
doesn't have listen queue. It was called only from div_disconnect(),
which is removed now.
Reviewed by: rwatson, maxim
Approved by: julian (mentor)
MT5 after: 1 week
MT4 after: 1 month
and has been broken twice:
- in the beginning of div_output() replace KASSERT with assignment, as
it was in rev. 1.83. [1] [to be MFCed]
- refactor changes introduced in rev. 1.100: do not prepend a new tag
unconditionally. Before doing this check whether we have one. [2]
A small note for all hacking in this area:
when divert socket is not a real userland, but ng_ksocket(4), we receive
_the same_ mbufs, that we transmitted to socket. These mbufs have rcvif,
the tags we've put on them. And we should treat them correctly.
Discussed with: mlaier [1]
Silence from: green [2]
Reviewed by: maxim
Approved by: julian (mentor)
MFC after: 1 week
protocols: it is possible for sockets to be created and attached
to the divert protocol between the test for sockets present and
successful unload of the registration handler. We will need to
explore more mature APIs for unregistering the protocol and then
draining consumers, or an atomic test-and-unregister mechanism.
of protocols. The call to divert_packet() is done through a function pointer. All
semantics of IPDIVERT remain intact. If IPDIVERT is not loaded ipfw will refuse to
install divert rules and natd will complain about 'protocol not supported'. Once
it is loaded both will work and accept rules and open the divert socket. The module
can only be unloaded if no divert sockets are open. It does not close any divert
sockets when an unload is requested but will return EBUSY instead.
and preserves the ipfw ABI. The ipfw core packet inspection and filtering
functions have not been changed, only how ipfw is invoked is different.
However there are many changes how ipfw is and its add-on's are handled:
In general ipfw is now called through the PFIL_HOOKS and most associated
magic, that was in ip_input() or ip_output() previously, is now done in
ipfw_check_[in|out]() in the ipfw PFIL handler.
IPDIVERT is entirely handled within the ipfw PFIL handlers. A packet to
be diverted is checked if it is fragmented, if yes, ip_reass() gets in for
reassembly. If not, or all fragments arrived and the packet is complete,
divert_packet is called directly. For 'tee' no reassembly attempt is made
and a copy of the packet is sent to the divert socket unmodified. The
original packet continues its way through ip_input/output().
ipfw 'forward' is done via m_tag's. The ipfw PFIL handlers tag the packet
with the new destination sockaddr_in. A check if the new destination is a
local IP address is made and the m_flags are set appropriately. ip_input()
and ip_output() have some more work to do here. For ip_input() the m_flags
are checked and a packet for us is directly sent to the 'ours' section for
further processing. Destination changes on the input path are only tagged
and the 'srcrt' flag to ip_forward() is set to disable destination checks
and ICMP replies at this stage. The tag is going to be handled on output.
ip_output() again checks for m_flags and the 'ours' tag. If found, the
packet will be dropped back to the IP netisr where it is going to be picked
up by ip_input() again and the directly sent to the 'ours' section. When
only the destination changes, the route's 'dst' is overwritten with the
new destination from the forward m_tag. Then it jumps back at the route
lookup again and skips the firewall check because it has been marked with
M_SKIP_FIREWALL. ipfw 'forward' has to be compiled into the kernel with
'option IPFIREWALL_FORWARD' to enable it.
DUMMYNET is entirely handled within the ipfw PFIL handlers. A packet for
a dummynet pipe or queue is directly sent to dummynet_io(). Dummynet will
then inject it back into ip_input/ip_output() after it has served its time.
Dummynet packets are tagged and will continue from the next rule when they
hit the ipfw PFIL handlers again after re-injection.
BRIDGING and IPFW_ETHER are not changed yet and use ipfw_chk() directly as
they did before. Later this will be changed to dedicated ETHER PFIL_HOOKS.
More detailed changes to the code:
conf/files
Add netinet/ip_fw_pfil.c.
conf/options
Add IPFIREWALL_FORWARD option.
modules/ipfw/Makefile
Add ip_fw_pfil.c.
net/bridge.c
Disable PFIL_HOOKS if ipfw for bridging is active. Bridging ipfw
is still directly invoked to handle layer2 headers and packets would
get a double ipfw when run through PFIL_HOOKS as well.
netinet/ip_divert.c
Removed divert_clone() function. It is no longer used.
netinet/ip_dummynet.[ch]
Neither the route 'ro' nor the destination 'dst' need to be stored
while in dummynet transit. Structure members and associated macros
are removed.
netinet/ip_fastfwd.c
Removed all direct ipfw handling code and replace it with the new
'ipfw forward' handling code.
netinet/ip_fw.h
Removed 'ro' and 'dst' from struct ip_fw_args.
netinet/ip_fw2.c
(Re)moved some global variables and the module handling.
netinet/ip_fw_pfil.c
New file containing the ipfw PFIL handlers and module initialization.
netinet/ip_input.c
Removed all direct ipfw handling code and replace it with the new
'ipfw forward' handling code. ip_forward() does not longer require
the 'next_hop' struct sockaddr_in argument. Disable early checks
if 'srcrt' is set.
netinet/ip_output.c
Removed all direct ipfw handling code and replace it with the new
'ipfw forward' handling code.
netinet/ip_var.h
Add ip_reass() as general function. (Used from ipfw PFIL handlers
for IPDIVERT.)
netinet/raw_ip.c
Directly check if ipfw and dummynet control pointers are active.
netinet/tcp_input.c
Rework the 'ipfw forward' to local code to work with the new way of
forward tags.
netinet/tcp_sack.c
Remove include 'opt_ipfw.h' which is not needed here.
sys/mbuf.h
Remove m_claim_next() macro which was exclusively for ipfw 'forward'
and is no longer needed.
Approved by: re (scottl)
for structures with timers in them. It might be that a timer might fire
even when the associated structure has already been free'd. Having type-
stable storage in this case is beneficial for graceful failure handling and
debugging.
Discussed with: bosko, tegge, rwatson
make it fully self-contained.
o ip_reass() now returns a new mbuf with the reassembled packet and ip->ip_len
including the IP header.
o Computation of the delayed checksum is moved into divert_packet().
Reviewed by: silby
associated with performing a wakeup on the socket buffer:
- When performing an sbappend*() followed by a so[rw]wakeup(), explicitly
acquire the socket buffer lock and use the _locked() variants of both
calls. Note that the _locked() sowakeup() versions unlock the mutex on
return. This is done in uipc_send(), divert_packet(), mroute
socket_send(), raw_append(), tcp_reass(), tcp_input(), and udp_append().
- When the socket buffer lock is dropped before a sowakeup(), remove the
explicit unlock and use the _locked() sowakeup() variant. This is done
in soisdisconnecting(), soisdisconnected() when setting the can't send/
receive flags and dropping data, and in uipc_rcvd() which adjusting
back-pressure on the sockets.
For UNIX domain sockets running mpsafe with a contention-intensive SMP
mysql benchmark, this results in a 1.6% query rate improvement due to
reduce mutex costs.
SOCK_LOCK(so):
- Hold socket lock over calls to MAC entry points reading or
manipulating socket labels.
- Assert socket lock in MAC entry point implementations.
- When externalizing the socket label, first make a thread-local
copy while holding the socket lock, then release the socket lock
to externalize to userspace.
the syscall arguments and does the suser() permission check, and
kern_mlock(), which does the resource limit checking and calls
vm_map_wire(). Split munlock() in a similar way.
Enable the RLIMIT_MEMLOCK checking code in kern_mlock().
Replace calls to vslock() and vsunlock() in the sysctl code with
calls to kern_mlock() and kern_munlock() so that the sysctl code
will obey the wired memory limits.
Nuke the vslock() and vsunlock() implementations, which are no
longer used.
Add a member to struct sysctl_req to track the amount of memory
that is wired to handle the request.
Modify sysctl_wire_old_buffer() to return an error if its call to
kern_mlock() fails. Only wire the minimum of the length specified
in the sysctl request and the length specified in its argument list.
It is recommended that sysctl handlers that use sysctl_wire_old_buffer()
should specify reasonable estimates for the amount of data they
want to return so that only the minimum amount of memory is wired
no matter what length has been specified by the request.
Modify the callers of sysctl_wire_old_buffer() to look for the
error return.
Modify sysctl_old_user to obey the wired buffer length and clean up
its implementation.
Reviewed by: bms
them mostly with packet tags (one case is handled by using an mbuf flag
since the linkage between "caller" and "callee" is direct and there's no
need to incur the overhead of a packet tag).
This is (mostly) work from: sam
Silence from: -arch
Approved by: bms(mentor), sam, rwatson
the routing table. Move all usage and references in the tcp stack
from the routing table metrics to the tcp hostcache.
It caches measured parameters of past tcp sessions to provide better
initial start values for following connections from or to the same
source or destination. Depending on the network parameters to/from
the remote host this can lead to significant speedups for new tcp
connections after the first one because they inherit and shortcut
the learning curve.
tcp_hostcache is designed for multiple concurrent access in SMP
environments with high contention and is hash indexed by remote
ip address.
It removes significant locking requirements from the tcp stack with
regard to the routing table.
Reviewed by: sam (mentor), bms
Reviewed by: -net, -current, core@kame.net (IPv6 parts)
Approved by: re (scottl)
the MAC label referenced from 'struct socket' in the IPv4 and
IPv6-based protocols. This permits MAC labels to be checked during
network delivery operations without dereferencing inp->inp_socket
to get to so->so_label, which will eventually avoid our having to
grab the socket lock during delivery at the network layer.
This change introduces 'struct inpcb' as a labeled object to the
MAC Framework, along with the normal circus of entry points:
initialization, creation from socket, destruction, as well as a
delivery access control check.
For most policies, the inpcb label will simply be a cache of the
socket label, so a new protocol switch method is introduced,
pr_sosetlabel() to notify protocols that the socket layer label
has been updated so that the cache can be updated while holding
appropriate locks. Most protocols implement this using
pru_sosetlabel_null(), but IPv4/IPv6 protocols using inpcbs use
the the worker function in_pcbsosetlabel(), which calls into the
MAC Framework to perform a cache update.
Biba, LOMAC, and MLS implement these entry points, as do the stub
policy, and test policy.
Reviewed by: sam, bms
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
do not have mh_nextpkt initialized. Somtimes what's there is "1", and the
ip_input() code pukes trying to m_free() it, rendering divert sockets and
such broken.
This really underscores the need to get rid of MT_TAG.
Reviewed by: rwatson
o pickup Giant in divert_packet to protect sbappendaddr since it
can be entered through MPSAFE callouts or through ip_input when
mpsafenet is 1
o add missing locking on output
o add locking to abort and shutdown
o add a ctlinput handler to invalidate held routing table references
on an ICMP redirect (may not be needed)
Supported by: FreeBSD Foundation
if_xname, if_dname, and if_dunit. if_xname is the name of the interface
and if_dname/unit are the driver name and instance.
This change paves the way for interface renaming and enhanced pseudo
device creation and configuration symantics.
Approved By: re (in principle)
Reviewed By: njl, imp
Tested On: i386, amd64, sparc64
Obtained From: NetBSD (if_xname)
of asserting that an mbuf has a packet header. Use it instead of hand-
rolled versions wherever applicable.
Submitted by: Hiten Pandya <hiten@unixdaemons.com>
This allows socket() to return an error when the kernel is not built
with IPDIVERT, and doesn't prevent future applications from using the
"borrowed" IP protocol number. The sysctl net.inet.raw.olddiverterror
controls whether opening a socket with the "borrowed" IP protocol
fails with an accompanying kernel printf; this code should last only a
couple of releases.
Approved by: re
o instead of a list of mbufs use a list of m_tag structures a la openbsd
o for netgraph et. al. extend the stock openbsd m_tag to include a 32-bit
ABI/module number cookie
o for openbsd compatibility define a well-known cookie MTAG_ABI_COMPAT and
use this in defining openbsd-compatible m_tag_find and m_tag_get routines
o rewrite KAME use of aux mbufs in terms of packet tags
o eliminate the most heavily used aux mbufs by adding an additional struct
inpcb parameter to ip_output and ip6_output to allow the IPsec code to
locate the security policy to apply to outbound packets
o bump __FreeBSD_version so code can be conditionalized
o fixup ipfilter's call to ip_output based on __FreeBSD_version
Reviewed by: julian, luigi (silent), -arch, -net, darren
Approved by: julian, silence from everyone else
Obtained from: openbsd (mostly)
MFC after: 1 month
kernel access control.
Invoke the MAC framework to label mbuf created using divert sockets.
These labels may later be used for access control on delivery to
another socket, or to an interface.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI LAbs
packet forwarding state ("annotations") during ip processing.
The code is considerably cleaner now.
The variables removed by this change are:
ip_divert_cookie used by divert sockets
ip_fw_fwd_addr used for transparent ip redirection
last_pkt used by dynamic pipes in dummynet
Removal of the first two has been done by carrying the annotations
into volatile structs prepended to the mbuf chains, and adding
appropriate code to add/remove annotations in the routines which
make use of them, i.e. ip_input(), ip_output(), tcp_input(),
bdg_forward(), ether_demux(), ether_output_frame(), div_output().
On passing, remove a bug in divert handling of fragmented packet.
Now it is the fragment at offset 0 which sets the divert status of
the whole packet, whereas formerly it was the last incoming fragment
to decide.
Removal of last_pkt required a change in the interface of ip_fw_chk()
and dummynet_io(). On passing, use the same mechanism for dummynet
annotations and for divert/forward annotations.
option IPFIREWALL_FORWARD is effectively useless, the code to
implement it is very small and is now in by default to avoid the
obfuscation of conditionally compiled code.
NOTES:
* there is at least one global variable left, sro_fwd, in ip_output().
I am not sure if/how this can be removed.
* I have deliberately avoided gratuitous style changes in this commit
to avoid cluttering the diffs. Minor stule cleanup will likely be
necessary
* this commit only focused on the IP layer. I am sure there is a
number of global variables used in the TCP and maybe UDP stack.
* despite the number of files touched, there are absolutely no API's
or data structures changed by this commit (except the interfaces of
ip_fw_chk() and dummynet_io(), which are internal anyways), so
an MFC is quite safe and unintrusive (and desirable, given the
improved readability of the code).
MFC after: 10 days
