From: Xin Long <lucien.xin@xxxxxxxxx>
[ Upstream commit 63dfb7938b13fa2c2fbcb45f34d065769eb09414 ]
syzbot reported a memory leak:
BUG: memory leak, unreferenced object 0xffff888120b3d380 (size 64):
backtrace:
[...] slab_alloc mm/slab.c:3319 [inline]
[...] kmem_cache_alloc+0x13f/0x2c0 mm/slab.c:3483
[...] sctp_bucket_create net/sctp/socket.c:8523 [inline]
[...] sctp_get_port_local+0x189/0x5a0 net/sctp/socket.c:8270
[...] sctp_do_bind+0xcc/0x200 net/sctp/socket.c:402
[...] sctp_bindx_add+0x4b/0xd0 net/sctp/socket.c:497
[...] sctp_setsockopt_bindx+0x156/0x1b0 net/sctp/socket.c:1022
[...] sctp_setsockopt net/sctp/socket.c:4641 [inline]
[...] sctp_setsockopt+0xaea/0x2dc0 net/sctp/socket.c:4611
[...] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3147
[...] __sys_setsockopt+0x10f/0x220 net/socket.c:2084
[...] __do_sys_setsockopt net/socket.c:2100 [inline]
It was caused by when sending msgs without binding a port, in the path:
inet_sendmsg() -> inet_send_prepare() -> inet_autobind() ->
.get_port/sctp_get_port(), sp->bind_hash will be set while bp->port is
not. Later when binding another port by sctp_setsockopt_bindx(), a new
bucket will be created as bp->port is not set.
sctp's autobind is supposed to call sctp_autobind() where it does all
things including setting bp->port. Since sctp_autobind() is called in
sctp_sendmsg() if the sk is not yet bound, it should have skipped the
auto bind.
THis patch is to avoid calling inet_autobind() in inet_send_prepare()
by changing sctp_prot .no_autobind with true, also remove the unused
.get_port.
Reported-by: syzbot+d44f7bbebdea49dbc84a@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/sctp/socket.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -8313,7 +8313,7 @@ struct proto sctp_prot = {
.backlog_rcv = sctp_backlog_rcv,
.hash = sctp_hash,
.unhash = sctp_unhash,
- .get_port = sctp_get_port,
+ .no_autobind = true,
.obj_size = sizeof(struct sctp_sock),
.sysctl_mem = sysctl_sctp_mem,
.sysctl_rmem = sysctl_sctp_rmem,
@@ -8352,7 +8352,7 @@ struct proto sctpv6_prot = {
.backlog_rcv = sctp_backlog_rcv,
.hash = sctp_hash,
.unhash = sctp_unhash,
- .get_port = sctp_get_port,
+ .no_autobind = true,
.obj_size = sizeof(struct sctp6_sock),
.sysctl_mem = sysctl_sctp_mem,
.sysctl_rmem = sysctl_sctp_rmem,
