From 5c3e82fe159622e46e91458c1a6509c321a62820 Mon Sep 17 00:00:00 2001 From: Qiujun Huang Date: Fri, 27 Mar 2020 11:07:51 +0800 Subject: sctp: fix refcount bug in sctp_wfree We should iterate over the datamsgs to move all chunks(skbs) to newsk. The following case cause the bug: for the trouble SKB, it was in outq->transmitted list sctp_outq_sack sctp_check_transmitted SKB was moved to outq->sacked list then throw away the sack queue SKB was deleted from outq->sacked (but it was held by datamsg at sctp_datamsg_to_asoc So, sctp_wfree was not called here) then migrate happened sctp_for_each_tx_datachunk( sctp_clear_owner_w); sctp_assoc_migrate(); sctp_for_each_tx_datachunk( sctp_set_owner_w); SKB was not in the outq, and was not changed to newsk finally __sctp_outq_teardown sctp_chunk_put (for another skb) sctp_datamsg_put __kfree_skb(msg->frag_list) sctp_wfree (for SKB) SKB->sk was still oldsk (skb->sk != asoc->base.sk). Reported-and-tested-by: syzbot+cea71eec5d6de256d54d@syzkaller.appspotmail.com Signed-off-by: Qiujun Huang Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/socket.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) (limited to 'net/sctp') diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 1b56fc440606..757740115e93 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -147,29 +147,44 @@ static void sctp_clear_owner_w(struct sctp_chunk *chunk) skb_orphan(chunk->skb); } +#define traverse_and_process() \ +do { \ + msg = chunk->msg; \ + if (msg == prev_msg) \ + continue; \ + list_for_each_entry(c, &msg->chunks, frag_list) { \ + if ((clear && asoc->base.sk == c->skb->sk) || \ + (!clear && asoc->base.sk != c->skb->sk)) \ + cb(c); \ + } \ + prev_msg = msg; \ +} while (0) + static void sctp_for_each_tx_datachunk(struct sctp_association *asoc, + bool clear, void (*cb)(struct sctp_chunk *)) { + struct sctp_datamsg *msg, *prev_msg = NULL; struct sctp_outq *q = &asoc->outqueue; + struct sctp_chunk *chunk, *c; struct sctp_transport *t; - struct sctp_chunk *chunk; list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) list_for_each_entry(chunk, &t->transmitted, transmitted_list) - cb(chunk); + traverse_and_process(); list_for_each_entry(chunk, &q->retransmit, transmitted_list) - cb(chunk); + traverse_and_process(); list_for_each_entry(chunk, &q->sacked, transmitted_list) - cb(chunk); + traverse_and_process(); list_for_each_entry(chunk, &q->abandoned, transmitted_list) - cb(chunk); + traverse_and_process(); list_for_each_entry(chunk, &q->out_chunk_list, list) - cb(chunk); + traverse_and_process(); } static void sctp_for_each_rx_skb(struct sctp_association *asoc, struct sock *sk, @@ -9574,9 +9589,9 @@ static int sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, * paths won't try to lock it and then oldsk. */ lock_sock_nested(newsk, SINGLE_DEPTH_NESTING); - sctp_for_each_tx_datachunk(assoc, sctp_clear_owner_w); + sctp_for_each_tx_datachunk(assoc, true, sctp_clear_owner_w); sctp_assoc_migrate(assoc, newsk); - sctp_for_each_tx_datachunk(assoc, sctp_set_owner_w); + sctp_for_each_tx_datachunk(assoc, false, sctp_set_owner_w); /* If the association on the newsk is already closed before accept() * is called, set RCV_SHUTDOWN flag. -- cgit v1.2.3 From 582eea230536a6f104097dd46205822005d5fe3a Mon Sep 17 00:00:00 2001 From: Marcelo Ricardo Leitner Date: Thu, 26 Mar 2020 20:47:46 -0300 Subject: sctp: fix possibly using a bad saddr with a given dst Under certain circumstances, depending on the order of addresses on the interfaces, it could be that sctp_v[46]_get_dst() would return a dst with a mismatched struct flowi. For example, if when walking through the bind addresses and the first one is not a match, it saves the dst as a fallback (added in 410f03831c07), but not the flowi. Then if the next one is also not a match, the previous dst will be returned but with the flowi information for the 2nd address, which is wrong. The fix is to use a locally stored flowi that can be used for such attempts, and copy it to the parameter only in case it is a possible match, together with the corresponding dst entry. The patch updates IPv6 code mostly just to be in sync. Even though the issue is also present there, it fallback is not expected to work with IPv6. Fixes: 410f03831c07 ("sctp: add routing output fallback") Reported-by: Jin Meng Signed-off-by: Marcelo Ricardo Leitner Tested-by: Xin Long Signed-off-by: David S. Miller --- net/sctp/ipv6.c | 20 ++++++++++++++------ net/sctp/protocol.c | 28 +++++++++++++++++++--------- 2 files changed, 33 insertions(+), 15 deletions(-) (limited to 'net/sctp') diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index bc734cfaa29e..c87af430107a 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -228,7 +228,8 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, { struct sctp_association *asoc = t->asoc; struct dst_entry *dst = NULL; - struct flowi6 *fl6 = &fl->u.ip6; + struct flowi _fl; + struct flowi6 *fl6 = &_fl.u.ip6; struct sctp_bind_addr *bp; struct ipv6_pinfo *np = inet6_sk(sk); struct sctp_sockaddr_entry *laddr; @@ -238,7 +239,7 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, enum sctp_scope scope; __u8 matchlen = 0; - memset(fl6, 0, sizeof(struct flowi6)); + memset(&_fl, 0, sizeof(_fl)); fl6->daddr = daddr->v6.sin6_addr; fl6->fl6_dport = daddr->v6.sin6_port; fl6->flowi6_proto = IPPROTO_SCTP; @@ -276,8 +277,11 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, rcu_read_unlock(); dst = ip6_dst_lookup_flow(sock_net(sk), sk, fl6, final_p); - if (!asoc || saddr) + if (!asoc || saddr) { + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); goto out; + } bp = &asoc->base.bind_addr; scope = sctp_scope(daddr); @@ -300,6 +304,8 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if ((laddr->a.sa.sa_family == AF_INET6) && (sctp_v6_cmp_addr(&dst_saddr, &laddr->a))) { rcu_read_unlock(); + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); goto out; } } @@ -338,6 +344,8 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if (!IS_ERR_OR_NULL(dst)) dst_release(dst); dst = bdst; + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); break; } @@ -351,6 +359,8 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, dst_release(dst); dst = bdst; matchlen = bmatchlen; + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); } rcu_read_unlock(); @@ -359,14 +369,12 @@ out: struct rt6_info *rt; rt = (struct rt6_info *)dst; - t->dst = dst; t->dst_cookie = rt6_get_cookie(rt); pr_debug("rt6_dst:%pI6/%d rt6_src:%pI6\n", &rt->rt6i_dst.addr, rt->rt6i_dst.plen, - &fl6->saddr); + &fl->u.ip6.saddr); } else { t->dst = NULL; - pr_debug("no route\n"); } } diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index 78af2fcf90cc..092d1afdee0d 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -409,7 +409,8 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, { struct sctp_association *asoc = t->asoc; struct rtable *rt; - struct flowi4 *fl4 = &fl->u.ip4; + struct flowi _fl; + struct flowi4 *fl4 = &_fl.u.ip4; struct sctp_bind_addr *bp; struct sctp_sockaddr_entry *laddr; struct dst_entry *dst = NULL; @@ -419,7 +420,7 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, if (t->dscp & SCTP_DSCP_SET_MASK) tos = t->dscp & SCTP_DSCP_VAL_MASK; - memset(fl4, 0x0, sizeof(struct flowi4)); + memset(&_fl, 0x0, sizeof(_fl)); fl4->daddr = daddr->v4.sin_addr.s_addr; fl4->fl4_dport = daddr->v4.sin_port; fl4->flowi4_proto = IPPROTO_SCTP; @@ -438,8 +439,11 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, &fl4->saddr); rt = ip_route_output_key(sock_net(sk), fl4); - if (!IS_ERR(rt)) + if (!IS_ERR(rt)) { dst = &rt->dst; + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); + } /* If there is no association or if a source address is passed, no * more validation is required. @@ -502,27 +506,33 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, odev = __ip_dev_find(sock_net(sk), laddr->a.v4.sin_addr.s_addr, false); if (!odev || odev->ifindex != fl4->flowi4_oif) { - if (!dst) + if (!dst) { dst = &rt->dst; - else + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); + } else { dst_release(&rt->dst); + } continue; } dst_release(dst); dst = &rt->dst; + t->dst = dst; + memcpy(fl, &_fl, sizeof(_fl)); break; } out_unlock: rcu_read_unlock(); out: - t->dst = dst; - if (dst) + if (dst) { pr_debug("rt_dst:%pI4, rt_src:%pI4\n", - &fl4->daddr, &fl4->saddr); - else + &fl->u.ip4.daddr, &fl->u.ip4.saddr); + } else { + t->dst = NULL; pr_debug("no route\n"); + } } /* For v4, the source address is cached in the route entry(dst). So no need -- cgit v1.2.3