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
endpointola.c
/* 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.
*
* The 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.
*
* The 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@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(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(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);
}
}
/* 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);
/* 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 = 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;
list_add(&null_key->key_list, &ep->endpoint_shared_keys);
/* Allocate and initialize transorms arrays for supported 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;
ep->prsctp_enable = net->sctp.prsctp_enable;
ep->reconf_enable = net->sctp.reconf_enable;
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 = 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;
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)
{
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.
*/
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;
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 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 net *net;
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 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;
}
}
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