xfrm_state_afinfo_lock can be read-locked from bh context, so take it
in a bh-safe manner in xfrm_state_register_afinfo() and
xfrm_state_unregister_afinfo(). Found by the lock validator.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
xfrm typemap->lock may be used in softirq context, so all write_lock()
uses must be softirq-safe.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Send aevent immediately if we have sent nothing since last timer and
this is the first packet.
Fixes a corner case when packet threshold is very high, the timer low
and a very low packet rate input which is bursty.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes the *_decap_state structures which were previously
used to share state between input/post_input. This is no longer
needed.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
When xfrm_user isn't loaded xfrm_nl is NULL, which makes IPsec crash because
xfrm_aevent_is_on passes the NULL pointer to netlink_has_listeners as socket.
A second problem is that the xfrm_nl pointer is not cleared when the socket
is releases at module unload time.
Protect references of xfrm_nl from outside of xfrm_user by RCU, check
that the socket is present in xfrm_aevent_is_on and set it to NULL
when unloading xfrm_user.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
First, it warns when PAGE_SIZE >= 64K because the ctx_len
field is 16-bits.
Secondly, if there are any real length limitations it can
be verified by the security layer security_xfrm_state_alloc()
call.
Signed-off-by: David S. Miller <davem@davemloft.net>
This is similar to the SA expire insertion patch - only it inserts
expires for SP.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch allows a user to insert SA expires. This is useful to
do on an HA backup for the case of byte counts but may not be very
useful for the case of time based expiry.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
This introduces a feature similar to the one described in RFC 2367:
"
... the application needing an SA sends a PF_KEY
SADB_ACQUIRE message down to the Key Engine, which then either
returns an error or sends a similar SADB_ACQUIRE message up to one or
more key management applications capable of creating such SAs.
...
...
The third is where an application-layer consumer of security
associations (e.g. an OSPFv2 or RIPv2 daemon) needs a security
association.
Send an SADB_ACQUIRE message from a user process to the kernel.
<base, address(SD), (address(P),) (identity(SD),) (sensitivity,)
proposal>
The kernel returns an SADB_ACQUIRE message to registered
sockets.
<base, address(SD), (address(P),) (identity(SD),) (sensitivity,)
proposal>
The user-level consumer waits for an SADB_UPDATE or SADB_ADD
message for its particular type, and then can use that
association by using SADB_GET messages.
"
An app such as OSPF could then use ipsec KM to get keys
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch provides the core functionality needed for sync events
for ipsec. Derived work of Krisztian KOVACS <hidden@balabit.hu>
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
The only reason post_input exists at all is that it gives us the
potential to adjust the checksums incrementally in future which
we ought to do.
However, after thinking about it for a bit we can adjust the
checksums without using this post_input stuff at all. The crucial
point is that only the inner-most NAT-T SA needs to be considered
when adjusting checksums. What's more, the checksum adjustment
comes down to a single u32 due to the linearity of IP checksums.
We just happen to have a spare u32 lying around in our skb structure :)
When ip_summed is set to CHECKSUM_NONE on input, the value of skb->csum
is currently unused. All we have to do is to make that the checksum
adjustment and voila, there goes all the post_input and decap structures!
I've left in the decap data structures for now since it's intricately
woven into the sec_path stuff. We can kill them later too.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
We often just do an atomic_dec(&x->refcnt) on an xfrm_state object
because we know there is more than 1 reference remaining and thus
we can elide the heavier xfrm_state_put() call.
Do this behind an inline function called __xfrm_state_put() so that is
more obvious and also to allow us to more cleanly add refcount
debugging later.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The bridge-netfilter code attaches a fake dst_entry with dst->ops == NULL
to purely bridged packets. When these packets are SNATed and a policy
lookup is done, xfrm_lookup crashes because it tries to dereference
dst->ops.
Change xfrm_lookup not to dereference dst->ops before checking for the
DST_NOXFRM flag and set this flag in the fake dst_entry.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Problem discovered and initial patch by Olaf Kirch:
there's a problem with IPsec that has been bugging some of our users
for the last couple of kernel revs. Every now and then, IPsec will
freeze the machine completely. This is with openswan user land,
and with kernels up to and including 2.6.16-rc2.
I managed to debug this a little, and what happens is that we end
up looping in xfrm_lookup, and never get out. With a bit of debug
printks added, I can this happening:
ip_route_output_flow calls xfrm_lookup
xfrm_find_bundle returns NULL (apparently we're in the
middle of negotiating a new SA or something)
We therefore call xfrm_tmpl_resolve. This returns EAGAIN
We go to sleep, waiting for a policy update.
Then we loop back to the top
Apparently, the dst_orig that was passed into xfrm_lookup
has been dropped from the routing table (obsolete=2)
This leads to the endless loop, because we now create
a new bundle, check the new bundle and find it's stale
(stale_bundle -> xfrm_bundle_ok -> dst_check() return 0)
People have been testing with the patch below, which seems to fix the
problem partially. They still see connection hangs however (things
only clear up when they start a new ping or new ssh). So the patch
is obvsiouly not sufficient, and something else seems to go wrong.
I'm grateful for any hints you may have...
I suggest that we simply bail out always. If the dst decides to die
on us later on, the packet will be dropped anyway. So there is no
great urgency to retry here. Once we have the proper resolution
queueing, we can then do the retry again.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Olaf Kirch <okir@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
A bunch of asm/bug.h includes are both not needed (since it will get
pulled anyway) and bogus (since they are done too early). Removed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This changes some simple "if (x) BUG();" statements to "BUG_ON(x);"
Signed-off-by: Kris Katterjohn <kjak@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Handle NAT of decapsulated IPsec packets by reconstructing the struct flowi
of the original packet from the conntrack information for IPsec policy
checks.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_route_me_harder doesn't use the port numbers of the xfrm lookup and
uses ip_route_input for non-local addresses which doesn't do a xfrm
lookup, ip6_route_me_harder doesn't do a xfrm lookup at all.
Use xfrm_decode_session and do the lookup manually, make sure both
only do the lookup if the packet hasn't been transformed already.
Makeing sure the lookup only happens once needs a new field in the
IP6CB, which exceeds the size of skb->cb. The size of skb->cb is
increased to 48b. Apparently the IPv6 mobile extensions need some
more room anyway.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch contains two corrections to the LSM-IPsec Nethooks patches
previously applied.
(1) free a security context on a failed insert via xfrm_user
interface in xfrm_add_policy. Memory leak.
(2) change the authorization of the allocation of a security context
in a xfrm_policy or xfrm_state from both relabelfrom and relabelto
to setcontext.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch series implements per packet access control via the
extension of the Linux Security Modules (LSM) interface by hooks in
the XFRM and pfkey subsystems that leverage IPSec security
associations to label packets. Extensions to the SELinux LSM are
included that leverage the patch for this purpose.
This patch implements the changes necessary to the XFRM subsystem,
pfkey interface, ipv4/ipv6, and xfrm_user interface to restrict a
socket to use only authorized security associations (or no security
association) to send/receive network packets.
Patch purpose:
The patch is designed to enable access control per packets based on
the strongly authenticated IPSec security association. Such access
controls augment the existing ones based on network interface and IP
address. The former are very coarse-grained, and the latter can be
spoofed. By using IPSec, the system can control access to remote
hosts based on cryptographic keys generated using the IPSec mechanism.
This enables access control on a per-machine basis or per-application
if the remote machine is running the same mechanism and trusted to
enforce the access control policy.
Patch design approach:
The overall approach is that policy (xfrm_policy) entries set by
user-level programs (e.g., setkey for ipsec-tools) are extended with a
security context that is used at policy selection time in the XFRM
subsystem to restrict the sockets that can send/receive packets via
security associations (xfrm_states) that are built from those
policies.
A presentation available at
www.selinux-symposium.org/2005/presentations/session2/2-3-jaeger.pdf
from the SELinux symposium describes the overall approach.
Patch implementation details:
On output, the policy retrieved (via xfrm_policy_lookup or
xfrm_sk_policy_lookup) must be authorized for the security context of
the socket and the same security context is required for resultant
security association (retrieved or negotiated via racoon in
ipsec-tools). This is enforced in xfrm_state_find.
On input, the policy retrieved must also be authorized for the socket
(at __xfrm_policy_check), and the security context of the policy must
also match the security association being used.
The patch has virtually no impact on packets that do not use IPSec.
The existing Netfilter (outgoing) and LSM rcv_skb hooks are used as
before.
Also, if IPSec is used without security contexts, the impact is
minimal. The LSM must allow such policies to be selected for the
combination of socket and remote machine, but subsequent IPSec
processing proceeds as in the original case.
Testing:
The pfkey interface is tested using the ipsec-tools. ipsec-tools have
been modified (a separate ipsec-tools patch is available for version
0.5) that supports assignment of xfrm_policy entries and security
associations with security contexts via setkey and the negotiation
using the security contexts via racoon.
The xfrm_user interface is tested via ad hoc programs that set
security contexts. These programs are also available from me, and
contain programs for setting, getting, and deleting policy for testing
this interface. Testing of sa functions was done by tracing kernel
behavior.
Signed-off-by: Trent Jaeger <tjaeger@cse.psu.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The problem is that when new policies are inserted, sockets do not see
the update (but all new route lookups do).
This bug is related to the SA insertion stale route issue solved
recently, and this policy visibility problem can be fixed in a similar
way.
The fix is to flush out the bundles of all policies deeper than the
policy being inserted. Consider beginning state of "outgoing"
direction policy list:
policy A --> policy B --> policy C --> policy D
First, realize that inserting a policy into a list only potentially
changes IPSEC routes for that direction. Therefore we need not bother
considering the policies for other directions. We need only consider
the existing policies in the list we are doing the inserting.
Consider new policy "B'", inserted after B.
policy A --> policy B --> policy B' --> policy C --> policy D
Two rules:
1) If policy A or policy B matched before the insertion, they
appear before B' and thus would still match after inserting
B'
2) Policy C and D, now "shadowed" and after policy B', potentially
contain stale routes because policy B' might be selected
instead of them.
Therefore we only need flush routes assosciated with policies
appearing after a newly inserted policy, if any.
Signed-off-by: David S. Miller <davem@davemloft.net>
When we insert a new xfrm_state which potentially
subsumes an existing one, make sure all cached
bundles are flushed so that the new SA is used
immediately.
Signed-off-by: David S. Miller <davem@davemloft.net>
Most netlink families make no use of the done() callback, making
it optional gets rid of all unnecessary dummy implementations.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
From: Jesper Juhl <jesper.juhl@gmail.com>
This is the net/ part of the big kfree cleanup patch.
Remove pointless checks for NULL prior to calling kfree() in net/.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Now that we've switched over to storing MTUs in the xfrm_dst entries,
we no longer need the dst's get_mss methods. This patch gets rid of
them.
It also documents the fact that our MTU calculation is not optimal
for ESP.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
- added typedef unsigned int __nocast gfp_t;
- replaced __nocast uses for gfp flags with gfp_t - it gives exactly
the same warnings as far as sparse is concerned, doesn't change
generated code (from gcc point of view we replaced unsigned int with
typedef) and documents what's going on far better.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Here is a patch that adds a helper called xfrm_policy_id2dir to
document the fact that the policy direction can be and is derived
from the index.
This is based on a patch by YOSHIFUJI Hideaki and 210313105@suda.edu.cn.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix implicit nocast warnings in xfrm code:
net/xfrm/xfrm_policy.c:232:47: warning: implicit cast to nocast type
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch puts mostly read only data in the right section
(read_mostly), to help sharing of these data between CPUS without
memory ping pongs.
On one of my production machine, tcp_statistics was sitting in a
heavily modified cache line, so *every* SNMP update had to force a
reload.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netlink_broadcast users must initialize NETLINK_CB(skb).dst_groups to the
destination group mask for netlink_recvmsg.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
- Remove bogus code for compiling netlink as module
- Add module refcounting support for modules implementing a netlink
protocol
- Add support for autoloading modules that implement a netlink protocol
as soon as someone opens a socket for that protocol
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Spotted by, and original patch by, Balazs Scheidler.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the protocol specific config options out to the specific protocols.
With this change net/Kconfig now starts to become readable and serve as a
good basis for further re-structuring.
The menu structure is left almost intact, except that indention is
fixed in most cases. Most visible are the INET changes where several
"depends on INET" are replaced with a single ifdef INET / endif pair.
Several new files were created to accomplish this change - they are
small but serve the purpose that config options are now distributed
out where they belongs.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds the xfrm_state_afinfo->init_flags hook which allows
each address family to perform any common initialisation that does
not require a corresponding destructor call.
It will be used subsequently to set the XFRM_STATE_NOPMTUDISC flag
in IPv4.
It also fixes up the error codes returned by xfrm_init_state.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: James Morris <jmorris@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds xfrm_init_state which is simply a wrapper that calls
xfrm_get_type and subsequently x->type->init_state. It also gets rid
of the unused args argument.
Abstracting it out allows us to add common initialisation code, e.g.,
to set family-specific flags.
The add_time setting in xfrm_user.c was deleted because it's already
set by xfrm_state_alloc.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: James Morris <jmorris@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch changes the format of the XFRM_MSG_DELSA and
XFRM_MSG_DELPOLICY notification so that the main message
sent is of the same format as that received by the kernel
if the original message was via netlink. This also means
that we won't lose the byid information carried in km_event.
Since this user interface is introduced by Jamal's patch
we can still afford to change it.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Small fixup to use netlink macros instead of hardcoding.
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Herbert Xu wrote:
> @@ -1254,6 +1326,7 @@ static int pfkey_add(struct sock *sk, st
> if (IS_ERR(x))
> return PTR_ERR(x);
>
> + xfrm_state_hold(x);
This introduces a leak when xfrm_state_add()/xfrm_state_update()
fail. We hold two references (one from xfrm_state_alloc(), one
from xfrm_state_hold()), but only drop one. We need to take the
reference because the reference from xfrm_state_alloc() can
be dropped by __xfrm_state_delete(), so the fix is to drop both
references on error. Same problem in xfrm_user.c.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch removes XFRM_SAP_* and converts them over to XFRM_MSG_*.
The netlink interface is meant to map directly onto the underlying
xfrm subsystem. Therefore rather than using a new independent
representation for the events we can simply use the existing ones
from xfrm_user.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch fixes policy deletion in xfrm_user so that it sets
km_event.data.byid. This puts xfrm_user on par with what af_key
does in this case.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch ensures that the hard state/policy expire notifications are
only sent when the state/policy is successfully removed from their
respective tables.
As it is, it's possible for a state/policy to both expire through
reaching a hard limit, as well as being deleted by the user.
Note that this behaviour isn't actually forbidden by RFC 2367.
However, it is a quality of implementation issue.
As an added bonus, the restructuring in this patch will help
eventually in moving the expire notifications from softirq
context into process context, thus improving their reliability.
One important side-effect from this change is that SAs reaching
their hard byte/packet limits are now deleted immediately, just
like SAs that have reached their hard time limits.
Previously they were announced immediately but only deleted after
30 seconds.
This is bad because it prevents the system from issuing an ACQUIRE
command until the existing state was deleted by the user or expires
after the time is up.
In the scenario where the expire notification was lost this introduces
a 30 second delay into the system for no good reason.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Heres the final patch.
What this patch provides
- netlink xfrm events
- ability to have events generated by netlink propagated to pfkey
and vice versa.
- fixes the acquire lets-be-happy-with-one-success issue
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[XFRM] Call dst_check() with appropriate cookie
This fixes infinite loop issue with IPv6 tunnel mode.
Signed-off-by: Kazunori Miyazawa <kazunori@miyazawa.org>
Signed-off-by: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
We need to verify that the payload contains enough data so that
attach_one_algo can copy alg_key_len bits from the payload.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
The variable alg_key_len is in bits and not bytes. The function
attach_one_algo is currently using it as if it were in bytes.
This causes it to read memory which may not be there.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
It looks like skb_cow_data() does not set
proper owner for newly created skb.
If we have several fragments for skb and some of them
are shared(?) or cloned (like in async IPsec) there
might be a situation when we require recreating skb and
thus using skb_copy() for it.
Newly created skb has neither a destructor nor a socket
assotiated with it, which must be copied from the old skb.
As far as I can see, current code sets destructor and socket
for the first one skb only and uses truesize of the first skb
only to increment sk_wmem_alloc value.
If above "analysis" is correct then attached patch fixes that.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
I found a bug that stopped IPsec/IPv6 from working. About
a month ago IPv6 started using rt6i_idev->dev on the cached socket dst
entries. If the cached socket dst entry is IPsec, then rt6i_idev will
be NULL.
Since we want to look at the rt6i_idev of the original route in this
case, the easiest fix is to store rt6i_idev in the IPsec dst entry just
as we do for a number of other IPv6 route attributes. Unfortunately
this means that we need some new code to handle the references to
rt6i_idev. That's why this patch is bigger than it would otherwise be.
I've also done the same thing for IPv4 since it is conceivable that
once these idev attributes start getting used for accounting, we
probably need to dereference them for IPv4 IPsec entries too.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
If we free up a partially processed packet because it's
skb->len dropped to zero, we need to decrement qlen because
we are dropping out of the top-level loop so it will do
the decrement for us.
Spotted by Herbert Xu.
Signed-off-by: David S. Miller <davem@davemloft.net>
The qlen should continue to decrement, even if we
pop partially processed SKBs back onto the receive queue.
Signed-off-by: David S. Miller <davem@davemloft.net>
Let's recap the problem. The current asynchronous netlink kernel
message processing is vulnerable to these attacks:
1) Hit and run: Attacker sends one or more messages and then exits
before they're processed. This may confuse/disable the next netlink
user that gets the netlink address of the attacker since it may
receive the responses to the attacker's messages.
Proposed solutions:
a) Synchronous processing.
b) Stream mode socket.
c) Restrict/prohibit binding.
2) Starvation: Because various netlink rcv functions were written
to not return until all messages have been processed on a socket,
it is possible for these functions to execute for an arbitrarily
long period of time. If this is successfully exploited it could
also be used to hold rtnl forever.
Proposed solutions:
a) Synchronous processing.
b) Stream mode socket.
Firstly let's cross off solution c). It only solves the first
problem and it has user-visible impacts. In particular, it'll
break user space applications that expect to bind or communicate
with specific netlink addresses (pid's).
So we're left with a choice of synchronous processing versus
SOCK_STREAM for netlink.
For the moment I'm sticking with the synchronous approach as
suggested by Alexey since it's simpler and I'd rather spend
my time working on other things.
However, it does have a number of deficiencies compared to the
stream mode solution:
1) User-space to user-space netlink communication is still vulnerable.
2) Inefficient use of resources. This is especially true for rtnetlink
since the lock is shared with other users such as networking drivers.
The latter could hold the rtnl while communicating with hardware which
causes the rtnetlink user to wait when it could be doing other things.
3) It is still possible to DoS all netlink users by flooding the kernel
netlink receive queue. The attacker simply fills the receive socket
with a single netlink message that fills up the entire queue. The
attacker then continues to call sendmsg with the same message in a loop.
Point 3) can be countered by retransmissions in user-space code, however
it is pretty messy.
In light of these problems (in particular, point 3), we should implement
stream mode netlink at some point. In the mean time, here is a patch
that implements synchronous processing.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Converts xfrm_msg_min and xfrm_dispatch to use c99 designated
initializers to make greping a little bit easier. Also replaces
two hardcoded message type with meaningful names.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use 'daddr' instead of &tmpl->id.daddr, since the latter
might be zero. Also, only perform the lookup when
tmpl->id.spi is non-zero.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Ingo Molnar