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linux/include/net/sctp/sctp.h
David S. Miller 676d23690f net: Fix use after free by removing length arg from sk_data_ready callbacks. 
Several spots in the kernel perform a sequence like:

	skb_queue_tail(&sk->s_receive_queue, skb);
	sk->sk_data_ready(sk, skb->len);

But at the moment we place the SKB onto the socket receive queue it
can be consumed and freed up.  So this skb->len access is potentially
to freed up memory.

Furthermore, the skb->len can be modified by the consumer so it is
possible that the value isn't accurate.

And finally, no actual implementation of this callback actually uses
the length argument.  And since nobody actually cared about it's
value, lots of call sites pass arbitrary values in such as '0' and
even '1'.

So just remove the length argument from the callback, that way there
is no confusion whatsoever and all of these use-after-free cases get
fixed as a side effect.

Based upon a patch by Eric Dumazet and his suggestion to audit this
issue tree-wide.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-11 16:15:36 -04:00

598 lines
18 KiB
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/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2001, 2004
* Copyright (c) 1999-2000 Cisco, Inc.
* Copyright (c) 1999-2001 Motorola, Inc.
* Copyright (c) 2001-2003 Intel Corp.
*
* This file is part of the SCTP kernel implementation
*
* The base lksctp header.
*
* This SCTP 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.
*
* This SCTP 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, see
* <http://www.gnu.org/licenses/>.
*
* 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>
* Xingang Guo <xingang.guo@intel.com>
* Jon Grimm <jgrimm@us.ibm.com>
* Daisy Chang <daisyc@us.ibm.com>
* Sridhar Samudrala <sri@us.ibm.com>
* Ardelle Fan <ardelle.fan@intel.com>
* Ryan Layer <rmlayer@us.ibm.com>
* Kevin Gao <kevin.gao@intel.com>
*/
#ifndef __net_sctp_h__
#define __net_sctp_h__
/* Header Strategy.
* Start getting some control over the header file depencies:
* includes
* constants
* structs
* prototypes
* macros, externs, and inlines
*
* Move test_frame specific items out of the kernel headers
* and into the test frame headers. This is not perfect in any sense
* and will continue to evolve.
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/tty.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/idr.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ipv6.h>
#include <net/ip6_route.h>
#endif
#include <asm/uaccess.h>
#include <asm/page.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/sctp/structs.h>
#include <net/sctp/constants.h>
#ifdef CONFIG_IP_SCTP_MODULE
#define SCTP_PROTOSW_FLAG 0
#else /* static! */
#define SCTP_PROTOSW_FLAG INET_PROTOSW_PERMANENT
#endif
/*
* Function declarations.
*/
/*
* sctp/protocol.c
*/
int sctp_copy_local_addr_list(struct net *, struct sctp_bind_addr *,
sctp_scope_t, gfp_t gfp, int flags);
struct sctp_pf *sctp_get_pf_specific(sa_family_t family);
int sctp_register_pf(struct sctp_pf *, sa_family_t);
void sctp_addr_wq_mgmt(struct net *, struct sctp_sockaddr_entry *, int);
/*
* sctp/socket.c
*/
int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb);
int sctp_inet_listen(struct socket *sock, int backlog);
void sctp_write_space(struct sock *sk);
void sctp_data_ready(struct sock *sk);
unsigned int sctp_poll(struct file *file, struct socket *sock,
poll_table *wait);
void sctp_sock_rfree(struct sk_buff *skb);
void sctp_copy_sock(struct sock *newsk, struct sock *sk,
struct sctp_association *asoc);
extern struct percpu_counter sctp_sockets_allocated;
int sctp_asconf_mgmt(struct sctp_sock *, struct sctp_sockaddr_entry *);
/*
* sctp/primitive.c
*/
int sctp_primitive_ASSOCIATE(struct net *, struct sctp_association *, void *arg);
int sctp_primitive_SHUTDOWN(struct net *, struct sctp_association *, void *arg);
int sctp_primitive_ABORT(struct net *, struct sctp_association *, void *arg);
int sctp_primitive_SEND(struct net *, struct sctp_association *, void *arg);
int sctp_primitive_REQUESTHEARTBEAT(struct net *, struct sctp_association *, void *arg);
int sctp_primitive_ASCONF(struct net *, struct sctp_association *, void *arg);
/*
* sctp/input.c
*/
int sctp_rcv(struct sk_buff *skb);
void sctp_v4_err(struct sk_buff *skb, u32 info);
void sctp_hash_established(struct sctp_association *);
void sctp_unhash_established(struct sctp_association *);
void sctp_hash_endpoint(struct sctp_endpoint *);
void sctp_unhash_endpoint(struct sctp_endpoint *);
struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *,
struct sctphdr *, struct sctp_association **,
struct sctp_transport **);
void sctp_err_finish(struct sock *, struct sctp_association *);
void sctp_icmp_frag_needed(struct sock *, struct sctp_association *,
struct sctp_transport *t, __u32 pmtu);
void sctp_icmp_redirect(struct sock *, struct sctp_transport *,
struct sk_buff *);
void sctp_icmp_proto_unreachable(struct sock *sk,
struct sctp_association *asoc,
struct sctp_transport *t);
void sctp_backlog_migrate(struct sctp_association *assoc,
struct sock *oldsk, struct sock *newsk);
/*
* sctp/proc.c
*/
int sctp_snmp_proc_init(struct net *net);
void sctp_snmp_proc_exit(struct net *net);
int sctp_eps_proc_init(struct net *net);
void sctp_eps_proc_exit(struct net *net);
int sctp_assocs_proc_init(struct net *net);
void sctp_assocs_proc_exit(struct net *net);
int sctp_remaddr_proc_init(struct net *net);
void sctp_remaddr_proc_exit(struct net *net);
/*
* Module global variables
*/
/*
* sctp/protocol.c
*/
extern struct kmem_cache *sctp_chunk_cachep __read_mostly;
extern struct kmem_cache *sctp_bucket_cachep __read_mostly;
/*
* Section: Macros, externs, and inlines
*/
/* SCTP SNMP MIB stats handlers */
#define SCTP_INC_STATS(net, field) SNMP_INC_STATS((net)->sctp.sctp_statistics, field)
#define SCTP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->sctp.sctp_statistics, field)
#define SCTP_INC_STATS_USER(net, field) SNMP_INC_STATS_USER((net)->sctp.sctp_statistics, field)
#define SCTP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->sctp.sctp_statistics, field)
/* sctp mib definitions */
enum {
SCTP_MIB_NUM = 0,
SCTP_MIB_CURRESTAB, /* CurrEstab */
SCTP_MIB_ACTIVEESTABS, /* ActiveEstabs */
SCTP_MIB_PASSIVEESTABS, /* PassiveEstabs */
SCTP_MIB_ABORTEDS, /* Aborteds */
SCTP_MIB_SHUTDOWNS, /* Shutdowns */
SCTP_MIB_OUTOFBLUES, /* OutOfBlues */
SCTP_MIB_CHECKSUMERRORS, /* ChecksumErrors */
SCTP_MIB_OUTCTRLCHUNKS, /* OutCtrlChunks */
SCTP_MIB_OUTORDERCHUNKS, /* OutOrderChunks */
SCTP_MIB_OUTUNORDERCHUNKS, /* OutUnorderChunks */
SCTP_MIB_INCTRLCHUNKS, /* InCtrlChunks */
SCTP_MIB_INORDERCHUNKS, /* InOrderChunks */
SCTP_MIB_INUNORDERCHUNKS, /* InUnorderChunks */
SCTP_MIB_FRAGUSRMSGS, /* FragUsrMsgs */
SCTP_MIB_REASMUSRMSGS, /* ReasmUsrMsgs */
SCTP_MIB_OUTSCTPPACKS, /* OutSCTPPacks */
SCTP_MIB_INSCTPPACKS, /* InSCTPPacks */
SCTP_MIB_T1_INIT_EXPIREDS,
SCTP_MIB_T1_COOKIE_EXPIREDS,
SCTP_MIB_T2_SHUTDOWN_EXPIREDS,
SCTP_MIB_T3_RTX_EXPIREDS,
SCTP_MIB_T4_RTO_EXPIREDS,
SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS,
SCTP_MIB_DELAY_SACK_EXPIREDS,
SCTP_MIB_AUTOCLOSE_EXPIREDS,
SCTP_MIB_T1_RETRANSMITS,
SCTP_MIB_T3_RETRANSMITS,
SCTP_MIB_PMTUD_RETRANSMITS,
SCTP_MIB_FAST_RETRANSMITS,
SCTP_MIB_IN_PKT_SOFTIRQ,
SCTP_MIB_IN_PKT_BACKLOG,
SCTP_MIB_IN_PKT_DISCARDS,
SCTP_MIB_IN_DATA_CHUNK_DISCARDS,
__SCTP_MIB_MAX
};
#define SCTP_MIB_MAX __SCTP_MIB_MAX
struct sctp_mib {
unsigned long mibs[SCTP_MIB_MAX];
};
/* helper function to track stats about max rto and related transport */
static inline void sctp_max_rto(struct sctp_association *asoc,
struct sctp_transport *trans)
{
if (asoc->stats.max_obs_rto < (__u64)trans->rto) {
asoc->stats.max_obs_rto = trans->rto;
memset(&asoc->stats.obs_rto_ipaddr, 0,
sizeof(struct sockaddr_storage));
memcpy(&asoc->stats.obs_rto_ipaddr, &trans->ipaddr,
trans->af_specific->sockaddr_len);
}
}
/*
* Macros for keeping a global reference of object allocations.
*/
#ifdef CONFIG_SCTP_DBG_OBJCNT
extern atomic_t sctp_dbg_objcnt_sock;
extern atomic_t sctp_dbg_objcnt_ep;
extern atomic_t sctp_dbg_objcnt_assoc;
extern atomic_t sctp_dbg_objcnt_transport;
extern atomic_t sctp_dbg_objcnt_chunk;
extern atomic_t sctp_dbg_objcnt_bind_addr;
extern atomic_t sctp_dbg_objcnt_bind_bucket;
extern atomic_t sctp_dbg_objcnt_addr;
extern atomic_t sctp_dbg_objcnt_ssnmap;
extern atomic_t sctp_dbg_objcnt_datamsg;
extern atomic_t sctp_dbg_objcnt_keys;
/* Macros to atomically increment/decrement objcnt counters. */
#define SCTP_DBG_OBJCNT_INC(name) \
atomic_inc(&sctp_dbg_objcnt_## name)
#define SCTP_DBG_OBJCNT_DEC(name) \
atomic_dec(&sctp_dbg_objcnt_## name)
#define SCTP_DBG_OBJCNT(name) \
atomic_t sctp_dbg_objcnt_## name = ATOMIC_INIT(0)
/* Macro to help create new entries in in the global array of
* objcnt counters.
*/
#define SCTP_DBG_OBJCNT_ENTRY(name) \
{.label= #name, .counter= &sctp_dbg_objcnt_## name}
void sctp_dbg_objcnt_init(struct net *);
void sctp_dbg_objcnt_exit(struct net *);
#else
#define SCTP_DBG_OBJCNT_INC(name)
#define SCTP_DBG_OBJCNT_DEC(name)
static inline void sctp_dbg_objcnt_init(struct net *net) { return; }
static inline void sctp_dbg_objcnt_exit(struct net *net) { return; }
#endif /* CONFIG_SCTP_DBG_OBJCOUNT */
#if defined CONFIG_SYSCTL
void sctp_sysctl_register(void);
void sctp_sysctl_unregister(void);
int sctp_sysctl_net_register(struct net *net);
void sctp_sysctl_net_unregister(struct net *net);
#else
static inline void sctp_sysctl_register(void) { return; }
static inline void sctp_sysctl_unregister(void) { return; }
static inline int sctp_sysctl_net_register(struct net *net) { return 0; }
static inline void sctp_sysctl_net_unregister(struct net *net) { return; }
#endif
/* Size of Supported Address Parameter for 'x' address types. */
#define SCTP_SAT_LEN(x) (sizeof(struct sctp_paramhdr) + (x) * sizeof(__u16))
#if IS_ENABLED(CONFIG_IPV6)
void sctp_v6_pf_init(void);
void sctp_v6_pf_exit(void);
int sctp_v6_protosw_init(void);
void sctp_v6_protosw_exit(void);
int sctp_v6_add_protocol(void);
void sctp_v6_del_protocol(void);
#else /* #ifdef defined(CONFIG_IPV6) */
static inline void sctp_v6_pf_init(void) { return; }
static inline void sctp_v6_pf_exit(void) { return; }
static inline int sctp_v6_protosw_init(void) { return 0; }
static inline void sctp_v6_protosw_exit(void) { return; }
static inline int sctp_v6_add_protocol(void) { return 0; }
static inline void sctp_v6_del_protocol(void) { return; }
#endif /* #if defined(CONFIG_IPV6) */
/* Map an association to an assoc_id. */
static inline sctp_assoc_t sctp_assoc2id(const struct sctp_association *asoc)
{
return asoc ? asoc->assoc_id : 0;
}
/* Look up the association by its id. */
struct sctp_association *sctp_id2assoc(struct sock *sk, sctp_assoc_t id);
int sctp_do_peeloff(struct sock *sk, sctp_assoc_t id, struct socket **sockp);
/* A macro to walk a list of skbs. */
#define sctp_skb_for_each(pos, head, tmp) \
skb_queue_walk_safe(head, pos, tmp)
/* A helper to append an entire skb list (list) to another (head). */
static inline void sctp_skb_list_tail(struct sk_buff_head *list,
struct sk_buff_head *head)
{
unsigned long flags;
spin_lock_irqsave(&head->lock, flags);
spin_lock(&list->lock);
skb_queue_splice_tail_init(list, head);
spin_unlock(&list->lock);
spin_unlock_irqrestore(&head->lock, flags);
}
/**
* sctp_list_dequeue - remove from the head of the queue
* @list: list to dequeue from
*
* Remove the head of the list. The head item is
* returned or %NULL if the list is empty.
*/
static inline struct list_head *sctp_list_dequeue(struct list_head *list)
{
struct list_head *result = NULL;
if (list->next != list) {
result = list->next;
list->next = result->next;
list->next->prev = list;
INIT_LIST_HEAD(result);
}
return result;
}
/* SCTP version of skb_set_owner_r. We need this one because
* of the way we have to do receive buffer accounting on bundled
* chunks.
*/
static inline void sctp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
{
struct sctp_ulpevent *event = sctp_skb2event(skb);
skb_orphan(skb);
skb->sk = sk;
skb->destructor = sctp_sock_rfree;
atomic_add(event->rmem_len, &sk->sk_rmem_alloc);
/*
* This mimics the behavior of skb_set_owner_r
*/
sk->sk_forward_alloc -= event->rmem_len;
}
/* Tests if the list has one and only one entry. */
static inline int sctp_list_single_entry(struct list_head *head)
{
return (head->next != head) && (head->next == head->prev);
}
/* Generate a random jitter in the range of -50% ~ +50% of input RTO. */
static inline __s32 sctp_jitter(__u32 rto)
{
static __u32 sctp_rand;
__s32 ret;
/* Avoid divide by zero. */
if (!rto)
rto = 1;
sctp_rand += jiffies;
sctp_rand ^= (sctp_rand << 12);
sctp_rand ^= (sctp_rand >> 20);
/* Choose random number from 0 to rto, then move to -50% ~ +50%
* of rto.
*/
ret = sctp_rand % rto - (rto >> 1);
return ret;
}
/* Break down data chunks at this point. */
static inline int sctp_frag_point(const struct sctp_association *asoc, int pmtu)
{
struct sctp_sock *sp = sctp_sk(asoc->base.sk);
int frag = pmtu;
frag -= sp->pf->af->net_header_len;
frag -= sizeof(struct sctphdr) + sizeof(struct sctp_data_chunk);
if (asoc->user_frag)
frag = min_t(int, frag, asoc->user_frag);
frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN);
return frag;
}
static inline void sctp_assoc_pending_pmtu(struct sock *sk, struct sctp_association *asoc)
{
sctp_assoc_sync_pmtu(sk, asoc);
asoc->pmtu_pending = 0;
}
/* Walk through a list of TLV parameters. Don't trust the
* individual parameter lengths and instead depend on
* the chunk length to indicate when to stop. Make sure
* there is room for a param header too.
*/
#define sctp_walk_params(pos, chunk, member)\
_sctp_walk_params((pos), (chunk), ntohs((chunk)->chunk_hdr.length), member)
#define _sctp_walk_params(pos, chunk, end, member)\
for (pos.v = chunk->member;\
pos.v <= (void *)chunk + end - ntohs(pos.p->length) &&\
ntohs(pos.p->length) >= sizeof(sctp_paramhdr_t);\
pos.v += WORD_ROUND(ntohs(pos.p->length)))
#define sctp_walk_errors(err, chunk_hdr)\
_sctp_walk_errors((err), (chunk_hdr), ntohs((chunk_hdr)->length))
#define _sctp_walk_errors(err, chunk_hdr, end)\
for (err = (sctp_errhdr_t *)((void *)chunk_hdr + \
sizeof(sctp_chunkhdr_t));\
(void *)err <= (void *)chunk_hdr + end - ntohs(err->length) &&\
ntohs(err->length) >= sizeof(sctp_errhdr_t); \
err = (sctp_errhdr_t *)((void *)err + WORD_ROUND(ntohs(err->length))))
#define sctp_walk_fwdtsn(pos, chunk)\
_sctp_walk_fwdtsn((pos), (chunk), ntohs((chunk)->chunk_hdr->length) - sizeof(struct sctp_fwdtsn_chunk))
#define _sctp_walk_fwdtsn(pos, chunk, end)\
for (pos = chunk->subh.fwdtsn_hdr->skip;\
(void *)pos <= (void *)chunk->subh.fwdtsn_hdr->skip + end - sizeof(struct sctp_fwdtsn_skip);\
pos++)
/* Round an int up to the next multiple of 4. */
#define WORD_ROUND(s) (((s)+3)&~3)
/* External references. */
extern struct proto sctp_prot;
extern struct proto sctpv6_prot;
void sctp_put_port(struct sock *sk);
extern struct idr sctp_assocs_id;
extern spinlock_t sctp_assocs_id_lock;
/* Static inline functions. */
/* Convert from an IP version number to an Address Family symbol. */
static inline int ipver2af(__u8 ipver)
{
switch (ipver) {
case 4:
return AF_INET;
case 6:
return AF_INET6;
default:
return 0;
}
}
/* Convert from an address parameter type to an address family. */
static inline int param_type2af(__be16 type)
{
switch (type) {
case SCTP_PARAM_IPV4_ADDRESS:
return AF_INET;
case SCTP_PARAM_IPV6_ADDRESS:
return AF_INET6;
default:
return 0;
}
}
/* Warning: The following hash functions assume a power of two 'size'. */
/* This is the hash function for the SCTP port hash table. */
static inline int sctp_phashfn(struct net *net, __u16 lport)
{
return (net_hash_mix(net) + lport) & (sctp_port_hashsize - 1);
}
/* This is the hash function for the endpoint hash table. */
static inline int sctp_ep_hashfn(struct net *net, __u16 lport)
{
return (net_hash_mix(net) + lport) & (sctp_ep_hashsize - 1);
}
/* This is the hash function for the association hash table. */
static inline int sctp_assoc_hashfn(struct net *net, __u16 lport, __u16 rport)
{
int h = (lport << 16) + rport + net_hash_mix(net);
h ^= h>>8;
return h & (sctp_assoc_hashsize - 1);
}
/* This is the hash function for the association hash table. This is
* not used yet, but could be used as a better hash function when
* we have a vtag.
*/
static inline int sctp_vtag_hashfn(__u16 lport, __u16 rport, __u32 vtag)
{
int h = (lport << 16) + rport;
h ^= vtag;
return h & (sctp_assoc_hashsize - 1);
}
#define sctp_for_each_hentry(epb, head) \
hlist_for_each_entry(epb, head, node)
/* Is a socket of this style? */
#define sctp_style(sk, style) __sctp_style((sk), (SCTP_SOCKET_##style))
static inline int __sctp_style(const struct sock *sk, sctp_socket_type_t style)
{
return sctp_sk(sk)->type == style;
}
/* Is the association in this state? */
#define sctp_state(asoc, state) __sctp_state((asoc), (SCTP_STATE_##state))
static inline int __sctp_state(const struct sctp_association *asoc,
sctp_state_t state)
{
return asoc->state == state;
}
/* Is the socket in this state? */
#define sctp_sstate(sk, state) __sctp_sstate((sk), (SCTP_SS_##state))
static inline int __sctp_sstate(const struct sock *sk, sctp_sock_state_t state)
{
return sk->sk_state == state;
}
/* Map v4-mapped v6 address back to v4 address */
static inline void sctp_v6_map_v4(union sctp_addr *addr)
{
addr->v4.sin_family = AF_INET;
addr->v4.sin_port = addr->v6.sin6_port;
addr->v4.sin_addr.s_addr = addr->v6.sin6_addr.s6_addr32[3];
}
/* Map v4 address to v4-mapped v6 address */
static inline void sctp_v4_map_v6(union sctp_addr *addr)
{
addr->v6.sin6_family = AF_INET6;
addr->v6.sin6_port = addr->v4.sin_port;
addr->v6.sin6_addr.s6_addr32[3] = addr->v4.sin_addr.s_addr;
addr->v6.sin6_addr.s6_addr32[0] = 0;
addr->v6.sin6_addr.s6_addr32[1] = 0;
addr->v6.sin6_addr.s6_addr32[2] = htonl(0x0000ffff);
}
/* The cookie is always 0 since this is how it's used in the
* pmtu code.
*/
static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport *t)
{
if (t->dst && !dst_check(t->dst, t->dst_cookie)) {
dst_release(t->dst);
t->dst = NULL;
}
return t->dst;
}
#endif /* __net_sctp_h__ */
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