From: Xin Long lucien.xin@gmail.com
[ Upstream commit 312434617cb16be5166316cf9d08ba760b1042a1 ]
This patch is to fix a data-race reported by syzbot:
BUG: KCSAN: data-race in sctp_assoc_migrate / sctp_hash_obj
write to 0xffff8880b67c0020 of 8 bytes by task 18908 on cpu 1: sctp_assoc_migrate+0x1a6/0x290 net/sctp/associola.c:1091 sctp_sock_migrate+0x8aa/0x9b0 net/sctp/socket.c:9465 sctp_accept+0x3c8/0x470 net/sctp/socket.c:4916 inet_accept+0x7f/0x360 net/ipv4/af_inet.c:734 __sys_accept4+0x224/0x430 net/socket.c:1754 __do_sys_accept net/socket.c:1795 [inline] __se_sys_accept net/socket.c:1792 [inline] __x64_sys_accept+0x4e/0x60 net/socket.c:1792 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9
read to 0xffff8880b67c0020 of 8 bytes by task 12003 on cpu 0: sctp_hash_obj+0x4f/0x2d0 net/sctp/input.c:894 rht_key_get_hash include/linux/rhashtable.h:133 [inline] rht_key_hashfn include/linux/rhashtable.h:159 [inline] rht_head_hashfn include/linux/rhashtable.h:174 [inline] head_hashfn lib/rhashtable.c:41 [inline] rhashtable_rehash_one lib/rhashtable.c:245 [inline] rhashtable_rehash_chain lib/rhashtable.c:276 [inline] rhashtable_rehash_table lib/rhashtable.c:316 [inline] rht_deferred_worker+0x468/0xab0 lib/rhashtable.c:420 process_one_work+0x3d4/0x890 kernel/workqueue.c:2269 worker_thread+0xa0/0x800 kernel/workqueue.c:2415 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
It was caused by rhashtable access asoc->base.sk when sctp_assoc_migrate is changing its value. However, what rhashtable wants is netns from asoc base.sk, and for an asoc, its netns won't change once set. So we can simply fix it by caching netns since created.
Fixes: d6c0256a60e6 ("sctp: add the rhashtable apis for sctp global transport hashtable") Reported-by: syzbot+e3b35fe7918ff0ee474e@syzkaller.appspotmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Acked-by: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Signed-off-by: Jakub Kicinski jakub.kicinski@netronome.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/sctp/structs.h | 3 +++ net/sctp/associola.c | 1 + net/sctp/endpointola.c | 1 + net/sctp/input.c | 4 ++-- 4 files changed, 7 insertions(+), 2 deletions(-)
--- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -1202,6 +1202,9 @@ struct sctp_ep_common { /* What socket does this endpoint belong to? */ struct sock *sk;
+ /* Cache netns and it won't change once set */ + struct net *net; + /* This is where we receive inbound chunks. */ struct sctp_inq inqueue;
--- a/net/sctp/associola.c +++ b/net/sctp/associola.c @@ -81,6 +81,7 @@ static struct sctp_association *sctp_ass /* Discarding const is appropriate here. */ asoc->ep = (struct sctp_endpoint *)ep; asoc->base.sk = (struct sock *)sk; + asoc->base.net = sock_net(sk);
sctp_endpoint_hold(asoc->ep); sock_hold(asoc->base.sk); --- a/net/sctp/endpointola.c +++ b/net/sctp/endpointola.c @@ -163,6 +163,7 @@ static struct sctp_endpoint *sctp_endpoi
/* Remember who we are attached to. */ ep->base.sk = sk; + ep->base.net = sock_net(sk); sock_hold(ep->base.sk);
return ep; --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -812,7 +812,7 @@ static inline int sctp_hash_cmp(struct r return err;
asoc = t->asoc; - if (!net_eq(sock_net(asoc->base.sk), x->net)) + if (!net_eq(asoc->base.net, x->net)) goto out; if (x->ep) { if (x->ep != asoc->ep) @@ -835,7 +835,7 @@ static inline u32 sctp_hash_obj(const vo { const struct sctp_transport *t = data; const union sctp_addr *paddr = &t->ipaddr; - const struct net *net = sock_net(t->asoc->base.sk); + const struct net *net = t->asoc->base.net; u16 lport = htons(t->asoc->base.bind_addr.port); u32 addr;