6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 66ff70df1a919a066942844bb095d6fcb748d78d ]
syzbot reported that subflow_check_req() was using uninitialized data in
subflow_check_req() [1]
This is because mp_opt.token is only set when OPTION_MPTCP_MPJ_SYN is also set.
While we are are it, fix mptcp_subflow_init_cookie_req()
to test for OPTION_MPTCP_MPJ_ACK.
[1]
BUG: KMSAN: uninit-value in subflow_token_join_request net/mptcp/subflow.c:91 [inline]
BUG: KMSAN: uninit-value in subflow_check_req+0x1028/0x15d0 net/mptcp/subflow.c:209
subflow_token_join_request net/mptcp/subflow.c:91 [inline]
subflow_check_req+0x1028/0x15d0 net/mptcp/subflow.c:209
subflow_v6_route_req+0x269/0x410 net/mptcp/subflow.c:367
tcp_conn_request+0x153a/0x4240 net/ipv4/tcp_input.c:7164
subflow_v6_conn_request+0x3ee/0x510
tcp_rcv_state_process+0x2e1/0x4ac0 net/ipv4/tcp_input.c:6659
tcp_v6_do_rcv+0x11bf/0x1fe0 net/ipv6/tcp_ipv6.c:1669
tcp_v6_rcv+0x480b/0x4fb0 net/ipv6/tcp_ipv6.c:1900
ip6_protocol_deliver_rcu+0xda6/0x2a60 net/ipv6/ip6_input.c:438
ip6_input_finish net/ipv6/ip6_input.c:483 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
ip6_input+0x15d/0x430 net/ipv6/ip6_input.c:492
dst_input include/net/dst.h:461 [inline]
ip6_rcv_finish+0x5db/0x870 net/ipv6/ip6_input.c:79
NF_HOOK include/linux/netfilter.h:314 [inline]
ipv6_rcv+0xda/0x390 net/ipv6/ip6_input.c:310
__netif_receive_skb_one_core net/core/dev.c:5532 [inline]
__netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5646
netif_receive_skb_internal net/core/dev.c:5732 [inline]
netif_receive_skb+0x58/0x660 net/core/dev.c:5791
tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555
tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
call_write_iter include/linux/fs.h:2020 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x8ef/0x1490 fs/read_write.c:584
ksys_write+0x20f/0x4c0 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x93/0xd0 fs/read_write.c:646
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Local variable mp_opt created at:
subflow_check_req+0x6d/0x15d0 net/mptcp/subflow.c:145
subflow_v6_route_req+0x269/0x410 net/mptcp/subflow.c:367
CPU: 1 PID: 5924 Comm: syz-executor.3 Not tainted 6.7.0-rc8-syzkaller-00055-g5eff55d725a4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests")
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Florian Westphal <fw@xxxxxxxxx>
Cc: Peter Krystad <peter.krystad@xxxxxxxxxxxxxxx>
Cc: Matthieu Baerts <matttbe@xxxxxxxxxx>
Cc: Mat Martineau <martineau@xxxxxxxxxx>
Cc: Geliang Tang <geliang.tang@xxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240111194917.4044654-5-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/mptcp/subflow.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 5b37fee2a85a..93f43a5cce40 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -158,7 +158,7 @@ static int subflow_check_req(struct request_sock *req,
mptcp_get_options(skb, &mp_opt);
opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC);
- opt_mp_join = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ);
+ opt_mp_join = !!(mp_opt.suboptions & OPTION_MPTCP_MPJ_SYN);
if (opt_mp_capable) {
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE);
@@ -255,7 +255,7 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req,
mptcp_get_options(skb, &mp_opt);
opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC);
- opt_mp_join = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ);
+ opt_mp_join = !!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK);
if (opt_mp_capable && opt_mp_join)
return -EINVAL;
--
2.43.0
