Revision 73223e4e2e3867ebf033a5a8eb2e5df0158ccc99 authored by zhong jiang on 18 August 2017, 22:16:24 UTC, committed by Linus Torvalds on 18 August 2017, 22:32:02 UTC
I hit a use after free issue when executing trinity and repoduced it with KASAN enabled. The related call trace is as follows. BUG: KASan: use after free in SyS_get_mempolicy+0x3c8/0x960 at addr ffff8801f582d766 Read of size 2 by task syz-executor1/798 INFO: Allocated in mpol_new.part.2+0x74/0x160 age=3 cpu=1 pid=799 __slab_alloc+0x768/0x970 kmem_cache_alloc+0x2e7/0x450 mpol_new.part.2+0x74/0x160 mpol_new+0x66/0x80 SyS_mbind+0x267/0x9f0 system_call_fastpath+0x16/0x1b INFO: Freed in __mpol_put+0x2b/0x40 age=4 cpu=1 pid=799 __slab_free+0x495/0x8e0 kmem_cache_free+0x2f3/0x4c0 __mpol_put+0x2b/0x40 SyS_mbind+0x383/0x9f0 system_call_fastpath+0x16/0x1b INFO: Slab 0xffffea0009cb8dc0 objects=23 used=8 fp=0xffff8801f582de40 flags=0x200000000004080 INFO: Object 0xffff8801f582d760 @offset=5984 fp=0xffff8801f582d600 Bytes b4 ffff8801f582d750: ae 01 ff ff 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ Object ffff8801f582d760: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk Object ffff8801f582d770: 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkk. Redzone ffff8801f582d778: bb bb bb bb bb bb bb bb ........ Padding ffff8801f582d8b8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ Memory state around the buggy address: ffff8801f582d600: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801f582d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8801f582d700: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fc !shared memory policy is not protected against parallel removal by other thread which is normally protected by the mmap_sem. do_get_mempolicy, however, drops the lock midway while we can still access it later. Early premature up_read is a historical artifact from times when put_user was called in this path see https://lwn.net/Articles/124754/ but that is gone since 8bccd85ffbaf ("[PATCH] Implement sys_* do_* layering in the memory policy layer."). but when we have the the current mempolicy ref count model. The issue was introduced accordingly. Fix the issue by removing the premature release. Link: http://lkml.kernel.org/r/1502950924-27521-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> [2.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent da094e4
bind_addr.c
/* SCTP kernel implementation
* (C) Copyright IBM Corp. 2001, 2003
* Copyright (c) Cisco 1999,2000
* Copyright (c) Motorola 1999,2000,2001
* Copyright (c) La Monte H.P. Yarroll 2001
*
* This file is part of the SCTP kernel implementation.
*
* A collection class to handle the storage of transport addresses.
*
* 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>
* Karl Knutson <karl@athena.chicago.il.us>
* Jon Grimm <jgrimm@us.ibm.com>
* Daisy Chang <daisyc@us.ibm.com>
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/if_inet6.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
/* Forward declarations for internal helpers. */
static int sctp_copy_one_addr(struct net *, struct sctp_bind_addr *,
union sctp_addr *, sctp_scope_t scope, gfp_t gfp,
int flags);
static void sctp_bind_addr_clean(struct sctp_bind_addr *);
/* First Level Abstractions. */
/* Copy 'src' to 'dest' taking 'scope' into account. Omit addresses
* in 'src' which have a broader scope than 'scope'.
*/
int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
const struct sctp_bind_addr *src,
sctp_scope_t scope, gfp_t gfp,
int flags)
{
struct sctp_sockaddr_entry *addr;
int error = 0;
/* All addresses share the same port. */
dest->port = src->port;
/* Extract the addresses which are relevant for this scope. */
list_for_each_entry(addr, &src->address_list, list) {
error = sctp_copy_one_addr(net, dest, &addr->a, scope,
gfp, flags);
if (error < 0)
goto out;
}
/* If there are no addresses matching the scope and
* this is global scope, try to get a link scope address, with
* the assumption that we must be sitting behind a NAT.
*/
if (list_empty(&dest->address_list) && (SCTP_SCOPE_GLOBAL == scope)) {
list_for_each_entry(addr, &src->address_list, list) {
error = sctp_copy_one_addr(net, dest, &addr->a,
SCTP_SCOPE_LINK, gfp,
flags);
if (error < 0)
goto out;
}
}
out:
if (error)
sctp_bind_addr_clean(dest);
return error;
}
/* Exactly duplicate the address lists. This is necessary when doing
* peer-offs and accepts. We don't want to put all the current system
* addresses into the endpoint. That's useless. But we do want duplicat
* the list of bound addresses that the older endpoint used.
*/
int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
const struct sctp_bind_addr *src,
gfp_t gfp)
{
struct sctp_sockaddr_entry *addr;
int error = 0;
/* All addresses share the same port. */
dest->port = src->port;
list_for_each_entry(addr, &src->address_list, list) {
error = sctp_add_bind_addr(dest, &addr->a, sizeof(addr->a),
1, gfp);
if (error < 0)
break;
}
return error;
}
/* Initialize the SCTP_bind_addr structure for either an endpoint or
* an association.
*/
void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
{
INIT_LIST_HEAD(&bp->address_list);
bp->port = port;
}
/* Dispose of the address list. */
static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
{
struct sctp_sockaddr_entry *addr, *temp;
/* Empty the bind address list. */
list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
list_del_rcu(&addr->list);
kfree_rcu(addr, rcu);
SCTP_DBG_OBJCNT_DEC(addr);
}
}
/* Dispose of an SCTP_bind_addr structure */
void sctp_bind_addr_free(struct sctp_bind_addr *bp)
{
/* Empty the bind address list. */
sctp_bind_addr_clean(bp);
}
/* Add an address to the bind address list in the SCTP_bind_addr structure. */
int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
int new_size, __u8 addr_state, gfp_t gfp)
{
struct sctp_sockaddr_entry *addr;
/* Add the address to the bind address list. */
addr = kzalloc(sizeof(*addr), gfp);
if (!addr)
return -ENOMEM;
memcpy(&addr->a, new, min_t(size_t, sizeof(*new), new_size));
/* Fix up the port if it has not yet been set.
* Both v4 and v6 have the port at the same offset.
*/
if (!addr->a.v4.sin_port)
addr->a.v4.sin_port = htons(bp->port);
addr->state = addr_state;
addr->valid = 1;
INIT_LIST_HEAD(&addr->list);
/* We always hold a socket lock when calling this function,
* and that acts as a writer synchronizing lock.
*/
list_add_tail_rcu(&addr->list, &bp->address_list);
SCTP_DBG_OBJCNT_INC(addr);
return 0;
}
/* Delete an address from the bind address list in the SCTP_bind_addr
* structure.
*/
int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
{
struct sctp_sockaddr_entry *addr, *temp;
int found = 0;
/* We hold the socket lock when calling this function,
* and that acts as a writer synchronizing lock.
*/
list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
/* Found the exact match. */
found = 1;
addr->valid = 0;
list_del_rcu(&addr->list);
break;
}
}
if (found) {
kfree_rcu(addr, rcu);
SCTP_DBG_OBJCNT_DEC(addr);
return 0;
}
return -EINVAL;
}
/* Create a network byte-order representation of all the addresses
* formated as SCTP parameters.
*
* The second argument is the return value for the length.
*/
union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
int *addrs_len,
gfp_t gfp)
{
union sctp_params addrparms;
union sctp_params retval;
int addrparms_len;
union sctp_addr_param rawaddr;
int len;
struct sctp_sockaddr_entry *addr;
struct list_head *pos;
struct sctp_af *af;
addrparms_len = 0;
len = 0;
/* Allocate enough memory at once. */
list_for_each(pos, &bp->address_list) {
len += sizeof(union sctp_addr_param);
}
/* Don't even bother embedding an address if there
* is only one.
*/
if (len == sizeof(union sctp_addr_param)) {
retval.v = NULL;
goto end_raw;
}
retval.v = kmalloc(len, gfp);
if (!retval.v)
goto end_raw;
addrparms = retval;
list_for_each_entry(addr, &bp->address_list, list) {
af = sctp_get_af_specific(addr->a.v4.sin_family);
len = af->to_addr_param(&addr->a, &rawaddr);
memcpy(addrparms.v, &rawaddr, len);
addrparms.v += len;
addrparms_len += len;
}
end_raw:
*addrs_len = addrparms_len;
return retval;
}
/*
* Create an address list out of the raw address list format (IPv4 and IPv6
* address parameters).
*/
int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
int addrs_len, __u16 port, gfp_t gfp)
{
union sctp_addr_param *rawaddr;
struct sctp_paramhdr *param;
union sctp_addr addr;
int retval = 0;
int len;
struct sctp_af *af;
/* Convert the raw address to standard address format */
while (addrs_len) {
param = (struct sctp_paramhdr *)raw_addr_list;
rawaddr = (union sctp_addr_param *)raw_addr_list;
af = sctp_get_af_specific(param_type2af(param->type));
if (unlikely(!af)) {
retval = -EINVAL;
sctp_bind_addr_clean(bp);
break;
}
af->from_addr_param(&addr, rawaddr, htons(port), 0);
if (sctp_bind_addr_state(bp, &addr) != -1)
goto next;
retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
SCTP_ADDR_SRC, gfp);
if (retval) {
/* Can't finish building the list, clean up. */
sctp_bind_addr_clean(bp);
break;
}
next:
len = ntohs(param->length);
addrs_len -= len;
raw_addr_list += len;
}
return retval;
}
/********************************************************************
* 2nd Level Abstractions
********************************************************************/
/* Does this contain a specified address? Allow wildcarding. */
int sctp_bind_addr_match(struct sctp_bind_addr *bp,
const union sctp_addr *addr,
struct sctp_sock *opt)
{
struct sctp_sockaddr_entry *laddr;
int match = 0;
rcu_read_lock();
list_for_each_entry_rcu(laddr, &bp->address_list, list) {
if (!laddr->valid)
continue;
if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
match = 1;
break;
}
}
rcu_read_unlock();
return match;
}
/* Does the address 'addr' conflict with any addresses in
* the bp.
*/
int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
const union sctp_addr *addr,
struct sctp_sock *bp_sp,
struct sctp_sock *addr_sp)
{
struct sctp_sockaddr_entry *laddr;
int conflict = 0;
struct sctp_sock *sp;
/* Pick the IPv6 socket as the basis of comparison
* since it's usually a superset of the IPv4.
* If there is no IPv6 socket, then default to bind_addr.
*/
if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
sp = bp_sp;
else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
sp = addr_sp;
else
sp = bp_sp;
rcu_read_lock();
list_for_each_entry_rcu(laddr, &bp->address_list, list) {
if (!laddr->valid)
continue;
conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
if (conflict)
break;
}
rcu_read_unlock();
return conflict;
}
/* Get the state of the entry in the bind_addr_list */
int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
const union sctp_addr *addr)
{
struct sctp_sockaddr_entry *laddr;
struct sctp_af *af;
int state = -1;
af = sctp_get_af_specific(addr->sa.sa_family);
if (unlikely(!af))
return state;
rcu_read_lock();
list_for_each_entry_rcu(laddr, &bp->address_list, list) {
if (!laddr->valid)
continue;
if (af->cmp_addr(&laddr->a, addr)) {
state = laddr->state;
break;
}
}
rcu_read_unlock();
return state;
}
/* Find the first address in the bind address list that is not present in
* the addrs packed array.
*/
union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr *bp,
const union sctp_addr *addrs,
int addrcnt,
struct sctp_sock *opt)
{
struct sctp_sockaddr_entry *laddr;
union sctp_addr *addr;
void *addr_buf;
struct sctp_af *af;
int i;
/* This is only called sctp_send_asconf_del_ip() and we hold
* the socket lock in that code patch, so that address list
* can't change.
*/
list_for_each_entry(laddr, &bp->address_list, list) {
addr_buf = (union sctp_addr *)addrs;
for (i = 0; i < addrcnt; i++) {
addr = addr_buf;
af = sctp_get_af_specific(addr->v4.sin_family);
if (!af)
break;
if (opt->pf->cmp_addr(&laddr->a, addr, opt))
break;
addr_buf += af->sockaddr_len;
}
if (i == addrcnt)
return &laddr->a;
}
return NULL;
}
/* Copy out addresses from the global local address list. */
static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
union sctp_addr *addr,
sctp_scope_t scope, gfp_t gfp,
int flags)
{
int error = 0;
if (sctp_is_any(NULL, addr)) {
error = sctp_copy_local_addr_list(net, dest, scope, gfp, flags);
} else if (sctp_in_scope(net, addr, scope)) {
/* Now that the address is in scope, check to see if
* the address type is supported by local sock as
* well as the remote peer.
*/
if ((((AF_INET == addr->sa.sa_family) &&
(flags & SCTP_ADDR4_PEERSUPP))) ||
(((AF_INET6 == addr->sa.sa_family) &&
(flags & SCTP_ADDR6_ALLOWED) &&
(flags & SCTP_ADDR6_PEERSUPP))))
error = sctp_add_bind_addr(dest, addr, sizeof(*addr),
SCTP_ADDR_SRC, gfp);
}
return error;
}
/* Is this a wildcard address? */
int sctp_is_any(struct sock *sk, const union sctp_addr *addr)
{
unsigned short fam = 0;
struct sctp_af *af;
/* Try to get the right address family */
if (addr->sa.sa_family != AF_UNSPEC)
fam = addr->sa.sa_family;
else if (sk)
fam = sk->sk_family;
af = sctp_get_af_specific(fam);
if (!af)
return 0;
return af->is_any(addr);
}
/* Is 'addr' valid for 'scope'? */
int sctp_in_scope(struct net *net, const union sctp_addr *addr, sctp_scope_t scope)
{
sctp_scope_t addr_scope = sctp_scope(addr);
/* The unusable SCTP addresses will not be considered with
* any defined scopes.
*/
if (SCTP_SCOPE_UNUSABLE == addr_scope)
return 0;
/*
* For INIT and INIT-ACK address list, let L be the level of
* of requested destination address, sender and receiver
* SHOULD include all of its addresses with level greater
* than or equal to L.
*
* Address scoping can be selectively controlled via sysctl
* option
*/
switch (net->sctp.scope_policy) {
case SCTP_SCOPE_POLICY_DISABLE:
return 1;
case SCTP_SCOPE_POLICY_ENABLE:
if (addr_scope <= scope)
return 1;
break;
case SCTP_SCOPE_POLICY_PRIVATE:
if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
return 1;
break;
case SCTP_SCOPE_POLICY_LINK:
if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
return 1;
break;
default:
break;
}
return 0;
}
int sctp_is_ep_boundall(struct sock *sk)
{
struct sctp_bind_addr *bp;
struct sctp_sockaddr_entry *addr;
bp = &sctp_sk(sk)->ep->base.bind_addr;
if (sctp_list_single_entry(&bp->address_list)) {
addr = list_entry(bp->address_list.next,
struct sctp_sockaddr_entry, list);
if (sctp_is_any(sk, &addr->a))
return 1;
}
return 0;
}
/********************************************************************
* 3rd Level Abstractions
********************************************************************/
/* What is the scope of 'addr'? */
sctp_scope_t sctp_scope(const union sctp_addr *addr)
{
struct sctp_af *af;
af = sctp_get_af_specific(addr->sa.sa_family);
if (!af)
return SCTP_SCOPE_UNUSABLE;
return af->scope((union sctp_addr *)addr);
}
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