// SPDX-License-Identifier: GPL-2.0-or-later
/* SCTP kernel 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 implementation
*
* This abstraction represents an SCTP endpoint.
*
* Please send any bug reports or fixes you make to the
* email address(es):
* lksctp developers <linux-sctp@vger.kernel.org>
*
* 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>
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/random.h> /* get_random_bytes() */
#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 net *net = sock_net(sk);
struct sctp_hmac_algo_param *auth_hmacs = NULL;
struct sctp_chunks_param *auth_chunks = NULL;
struct sctp_shared_key *null_key;
int err;
ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
if (!ep->digest)
return NULL;
ep->auth_enable = net->sctp.auth_enable;
if (ep->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(struct_size(auth_hmacs, hmac_ids,
SCTP_AUTH_NUM_HMACS), gfp);
if (!auth_hmacs)
goto nomem;
auth_chunks = kzalloc(sizeof(*auth_chunks) +
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(struct sctp_paramhdr) + 2);
auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
/* Initialize the CHUNKS parameter */
auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
auth_chunks->param_hdr.length =
htons(sizeof(struct sctp_paramhdr));
/* If the Add-IP functionality is enabled, we must
* authenticate, ASCONF and ASCONF-ACK chunks
*/
if (net->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(struct sctp_paramhdr) + 2);
}
/* Allocate and initialize transorms arrays for supported
* HMACs.
*/
err = sctp_auth_init_hmacs(ep, gfp);
if (err)
goto nomem;
}
/* Initialize the base structure. */
/* What type of endpoint are we? */
ep->base.type = SCTP_EP_TYPE_SOCKET;
/* Initialize the basic object fields. */
refcount_set(&ep->base.refcnt, 1);
ep->base.dead = false;
/* 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);
/* Create the lists of associations. */
INIT_LIST_HEAD(&ep->asocs);
/* Use SCTP specific send buffer space queues. */
ep->sndbuf_policy = net->sctp.sndbuf_policy;
sk->sk_data_ready = sctp_data_ready;
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 = net->sctp.rcvbuf_policy;
/* Initialize the secret key used with cookie. */
get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
/* SCTP-AUTH extensions*/
INIT_LIST_HEAD(&ep->endpoint_shared_keys);
null_key = sctp_auth_shkey_create(0, gfp);
if (!null_key)
goto nomem_shkey;
list_add(&null_key->key_list, &ep->endpoint_shared_keys);
/* 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;
ep->prsctp_enable = net->sctp.prsctp_enable;
ep->reconf_enable = net->sctp.reconf_enable;
/* Remember who we are attached to. */
ep->base.sk = sk;
sock_hold(ep->base.sk);
return ep;
nomem_shkey:
sctp_auth_destroy_hmacs(ep->auth_hmacs);
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 = kzalloc(sizeof(*ep), gfp);
if (!ep)
goto fail;
if (!sctp_endpoint_init(ep, sk, gfp))
goto fail_init;
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 = true;
inet_sk_set_state(ep->base.sk, 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)
{
struct sock *sk;
if (unlikely(!ep->base.dead)) {
WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
return;
}
/* 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);
memset(ep->secret_key, 0, sizeof(ep->secret_key));
sk = ep->base.sk;
/* Remove and free the port */
if (sctp_sk(sk)->bind_hash)
sctp_put_port(sk);
sctp_sk(sk)->ep = NULL;
/* Give up our hold on the sock */
sock_put(sk);
kfree(ep);
SCTP_DBG_OBJCNT_DEC(ep);
}
/* Hold a reference to an endpoint. */
void sctp_endpoint_hold(struct sctp_endpoint *ep)
{
refcount_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 (refcount_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,
struct net *net,
const union sctp_addr *laddr)
{
struct sctp_endpoint *retval = NULL;
if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
net_eq(sock_net(ep->base.sk), net)) {
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 lookup the transport from hashtable at first, then get association
* through t->assoc.
*/
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 = NULL;
struct sctp_transport *t;
*transport = NULL;
/* If the local port is not set, there can't be any associations
* on this endpoint.
*/
if (!ep->base.bind_addr.port)
return NULL;
rcu_read_lock();
t = sctp_epaddr_lookup_transport(ep, paddr);
if (!t)
goto out;
*transport = t;
asoc = t->asoc;
out:
rcu_read_unlock();
return asoc;
}
/* Look for any peeled off association from the endpoint that matches the
* given peer address.
*/
bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
const union sctp_addr *paddr)
{
struct sctp_sockaddr_entry *addr;
struct sctp_bind_addr *bp;
struct net *net = sock_net(ep->base.sk);
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(net, &addr->a, paddr))
return true;
}
return false;
}
/* 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 net *net;
struct sctp_transport *transport;
struct sctp_chunk *chunk;
struct sctp_inq *inqueue;
union sctp_subtype subtype;
enum sctp_state state;
int error = 0;
int first_time = 1; /* is this the first time through the loop */
if (ep->base.dead)
return;
asoc = NULL;
inqueue = &ep->base.inqueue;
sk = ep->base.sk;
net = sock_net(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(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
if (asoc)
asoc->stats.ictrlchunks++;
}
if (chunk->transport)
chunk->transport->last_time_heard = ktime_get();
error = sctp_do_sm(net, 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;
}
}
