linux/net/sctp/endpointola.c
Vlad Yasevich bbd0d59809 [SCTP]: Implement the receive and verification of AUTH chunk
This patch implements the receive path needed to process authenticated
chunks.  Add ability to process the AUTH chunk and handle edge cases
for authenticated COOKIE-ECHO as well.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:51:31 -07:00

483 lines
13 KiB
C

/* SCTP kernel reference Implementation
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
* Copyright (c) 2001-2002 International Business Machines, Corp.
* Copyright (c) 2001 Intel Corp.
* Copyright (c) 2001 Nokia, Inc.
* Copyright (c) 2001 La Monte H.P. Yarroll
*
* This file is part of the SCTP kernel reference Implementation
*
* This abstraction represents an SCTP endpoint.
*
* This file is part of the implementation of the add-IP extension,
* based on <draft-ietf-tsvwg-addip-sctp-02.txt> June 29, 2001,
* for the SCTP kernel reference Implementation.
*
* The SCTP reference implementation is free software;
* you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* The SCTP reference implementation is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* ************************
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU CC; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <lksctp-developers@lists.sourceforge.net>
*
* Or submit a bug report through the following website:
* http://www.sf.net/projects/lksctp
*
* Written or modified by:
* La Monte H.P. Yarroll <piggy@acm.org>
* Karl Knutson <karl@athena.chicago.il.us>
* Jon Grimm <jgrimm@austin.ibm.com>
* Daisy Chang <daisyc@us.ibm.com>
* Dajiang Zhang <dajiang.zhang@nokia.com>
*
* Any bugs reported given to us we will try to fix... any fixes shared will
* be incorporated into the next SCTP release.
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/random.h> /* get_random_bytes() */
#include <linux/crypto.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
/* Forward declarations for internal helpers. */
static void sctp_endpoint_bh_rcv(struct work_struct *work);
/*
* Initialize the base fields of the endpoint structure.
*/
static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
struct sock *sk,
gfp_t gfp)
{
struct sctp_hmac_algo_param *auth_hmacs = NULL;
struct sctp_chunks_param *auth_chunks = NULL;
struct sctp_shared_key *null_key;
int err;
memset(ep, 0, sizeof(struct sctp_endpoint));
ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
if (!ep->digest)
return NULL;
if (sctp_auth_enable) {
/* Allocate space for HMACS and CHUNKS authentication
* variables. There are arrays that we encode directly
* into parameters to make the rest of the operations easier.
*/
auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
if (!auth_hmacs)
goto nomem;
auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
SCTP_NUM_CHUNK_TYPES, gfp);
if (!auth_chunks)
goto nomem;
/* Initialize the HMACS parameter.
* SCTP-AUTH: Section 3.3
* Every endpoint supporting SCTP chunk authentication MUST
* support the HMAC based on the SHA-1 algorithm.
*/
auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
auth_hmacs->param_hdr.length =
htons(sizeof(sctp_paramhdr_t) + 2);
auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
/* Initialize the CHUNKS parameter */
auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
/* If the Add-IP functionality is enabled, we must
* authenticate, ASCONF and ASCONF-ACK chunks
*/
if (sctp_addip_enable) {
auth_chunks->chunks[0] = SCTP_CID_ASCONF;
auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
auth_chunks->param_hdr.length =
htons(sizeof(sctp_paramhdr_t) + 2);
}
}
/* Initialize the base structure. */
/* What type of endpoint are we? */
ep->base.type = SCTP_EP_TYPE_SOCKET;
/* Initialize the basic object fields. */
atomic_set(&ep->base.refcnt, 1);
ep->base.dead = 0;
ep->base.malloced = 1;
/* Create an input queue. */
sctp_inq_init(&ep->base.inqueue);
/* Set its top-half handler */
sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
/* Initialize the bind addr area */
sctp_bind_addr_init(&ep->base.bind_addr, 0);
/* Remember who we are attached to. */
ep->base.sk = sk;
sock_hold(ep->base.sk);
/* Create the lists of associations. */
INIT_LIST_HEAD(&ep->asocs);
/* Use SCTP specific send buffer space queues. */
ep->sndbuf_policy = sctp_sndbuf_policy;
sk->sk_write_space = sctp_write_space;
sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
/* Get the receive buffer policy for this endpoint */
ep->rcvbuf_policy = sctp_rcvbuf_policy;
/* Initialize the secret key used with cookie. */
get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
ep->last_key = ep->current_key = 0;
ep->key_changed_at = jiffies;
/* SCTP-AUTH extensions*/
INIT_LIST_HEAD(&ep->endpoint_shared_keys);
null_key = sctp_auth_shkey_create(0, GFP_KERNEL);
if (!null_key)
goto nomem;
list_add(&null_key->key_list, &ep->endpoint_shared_keys);
/* Allocate and initialize transorms arrays for suported HMACs. */
err = sctp_auth_init_hmacs(ep, gfp);
if (err)
goto nomem_hmacs;
/* Add the null key to the endpoint shared keys list and
* set the hmcas and chunks pointers.
*/
ep->auth_hmacs_list = auth_hmacs;
ep->auth_chunk_list = auth_chunks;
return ep;
nomem_hmacs:
sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
nomem:
/* Free all allocations */
kfree(auth_hmacs);
kfree(auth_chunks);
kfree(ep->digest);
return NULL;
}
/* Create a sctp_endpoint with all that boring stuff initialized.
* Returns NULL if there isn't enough memory.
*/
struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
{
struct sctp_endpoint *ep;
/* Build a local endpoint. */
ep = t_new(struct sctp_endpoint, gfp);
if (!ep)
goto fail;
if (!sctp_endpoint_init(ep, sk, gfp))
goto fail_init;
ep->base.malloced = 1;
SCTP_DBG_OBJCNT_INC(ep);
return ep;
fail_init:
kfree(ep);
fail:
return NULL;
}
/* Add an association to an endpoint. */
void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
struct sctp_association *asoc)
{
struct sock *sk = ep->base.sk;
/* If this is a temporary association, don't bother
* since we'll be removing it shortly and don't
* want anyone to find it anyway.
*/
if (asoc->temp)
return;
/* Now just add it to our list of asocs */
list_add_tail(&asoc->asocs, &ep->asocs);
/* Increment the backlog value for a TCP-style listening socket. */
if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
sk->sk_ack_backlog++;
}
/* Free the endpoint structure. Delay cleanup until
* all users have released their reference count on this structure.
*/
void sctp_endpoint_free(struct sctp_endpoint *ep)
{
ep->base.dead = 1;
ep->base.sk->sk_state = SCTP_SS_CLOSED;
/* Unlink this endpoint, so we can't find it again! */
sctp_unhash_endpoint(ep);
sctp_endpoint_put(ep);
}
/* Final destructor for endpoint. */
static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
{
SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
/* Free up the HMAC transform. */
crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
/* Free the digest buffer */
kfree(ep->digest);
/* SCTP-AUTH: Free up AUTH releated data such as shared keys
* chunks and hmacs arrays that were allocated
*/
sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
kfree(ep->auth_hmacs_list);
kfree(ep->auth_chunk_list);
/* AUTH - Free any allocated HMAC transform containers */
sctp_auth_destroy_hmacs(ep->auth_hmacs);
/* Cleanup. */
sctp_inq_free(&ep->base.inqueue);
sctp_bind_addr_free(&ep->base.bind_addr);
/* Remove and free the port */
if (sctp_sk(ep->base.sk)->bind_hash)
sctp_put_port(ep->base.sk);
/* Give up our hold on the sock. */
if (ep->base.sk)
sock_put(ep->base.sk);
/* Finally, free up our memory. */
if (ep->base.malloced) {
kfree(ep);
SCTP_DBG_OBJCNT_DEC(ep);
}
}
/* Hold a reference to an endpoint. */
void sctp_endpoint_hold(struct sctp_endpoint *ep)
{
atomic_inc(&ep->base.refcnt);
}
/* Release a reference to an endpoint and clean up if there are
* no more references.
*/
void sctp_endpoint_put(struct sctp_endpoint *ep)
{
if (atomic_dec_and_test(&ep->base.refcnt))
sctp_endpoint_destroy(ep);
}
/* Is this the endpoint we are looking for? */
struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
const union sctp_addr *laddr)
{
struct sctp_endpoint *retval = NULL;
if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
sctp_sk(ep->base.sk)))
retval = ep;
}
return retval;
}
/* Find the association that goes with this chunk.
* We do a linear search of the associations for this endpoint.
* We return the matching transport address too.
*/
static struct sctp_association *__sctp_endpoint_lookup_assoc(
const struct sctp_endpoint *ep,
const union sctp_addr *paddr,
struct sctp_transport **transport)
{
int rport;
struct sctp_association *asoc;
struct list_head *pos;
rport = ntohs(paddr->v4.sin_port);
list_for_each(pos, &ep->asocs) {
asoc = list_entry(pos, struct sctp_association, asocs);
if (rport == asoc->peer.port) {
*transport = sctp_assoc_lookup_paddr(asoc, paddr);
if (*transport)
return asoc;
}
}
*transport = NULL;
return NULL;
}
/* Lookup association on an endpoint based on a peer address. BH-safe. */
struct sctp_association *sctp_endpoint_lookup_assoc(
const struct sctp_endpoint *ep,
const union sctp_addr *paddr,
struct sctp_transport **transport)
{
struct sctp_association *asoc;
sctp_local_bh_disable();
asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
sctp_local_bh_enable();
return asoc;
}
/* Look for any peeled off association from the endpoint that matches the
* given peer address.
*/
int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
const union sctp_addr *paddr)
{
struct sctp_sockaddr_entry *addr;
struct sctp_bind_addr *bp;
bp = &ep->base.bind_addr;
/* This function is called with the socket lock held,
* so the address_list can not change.
*/
list_for_each_entry(addr, &bp->address_list, list) {
if (sctp_has_association(&addr->a, paddr))
return 1;
}
return 0;
}
/* Do delayed input processing. This is scheduled by sctp_rcv().
* This may be called on BH or task time.
*/
static void sctp_endpoint_bh_rcv(struct work_struct *work)
{
struct sctp_endpoint *ep =
container_of(work, struct sctp_endpoint,
base.inqueue.immediate);
struct sctp_association *asoc;
struct sock *sk;
struct sctp_transport *transport;
struct sctp_chunk *chunk;
struct sctp_inq *inqueue;
sctp_subtype_t subtype;
sctp_state_t state;
int error = 0;
int first_time = 1; /* is this the first time through the looop */
if (ep->base.dead)
return;
asoc = NULL;
inqueue = &ep->base.inqueue;
sk = ep->base.sk;
while (NULL != (chunk = sctp_inq_pop(inqueue))) {
subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
/* If the first chunk in the packet is AUTH, do special
* processing specified in Section 6.3 of SCTP-AUTH spec
*/
if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
struct sctp_chunkhdr *next_hdr;
next_hdr = sctp_inq_peek(inqueue);
if (!next_hdr)
goto normal;
/* If the next chunk is COOKIE-ECHO, skip the AUTH
* chunk while saving a pointer to it so we can do
* Authentication later (during cookie-echo
* processing).
*/
if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
chunk->auth_chunk = skb_clone(chunk->skb,
GFP_ATOMIC);
chunk->auth = 1;
continue;
}
}
normal:
/* We might have grown an association since last we
* looked, so try again.
*
* This happens when we've just processed our
* COOKIE-ECHO chunk.
*/
if (NULL == chunk->asoc) {
asoc = sctp_endpoint_lookup_assoc(ep,
sctp_source(chunk),
&transport);
chunk->asoc = asoc;
chunk->transport = transport;
}
state = asoc ? asoc->state : SCTP_STATE_CLOSED;
if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
continue;
/* Remember where the last DATA chunk came from so we
* know where to send the SACK.
*/
if (asoc && sctp_chunk_is_data(chunk))
asoc->peer.last_data_from = chunk->transport;
else
SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
if (chunk->transport)
chunk->transport->last_time_heard = jiffies;
error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
ep, asoc, chunk, GFP_ATOMIC);
if (error && chunk)
chunk->pdiscard = 1;
/* Check to see if the endpoint is freed in response to
* the incoming chunk. If so, get out of the while loop.
*/
if (!sctp_sk(sk)->ep)
break;
if (first_time)
first_time = 0;
}
}