6.6-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ 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@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Florian Westphal fw@strlen.de Cc: Peter Krystad peter.krystad@linux.intel.com Cc: Matthieu Baerts matttbe@kernel.org Cc: Mat Martineau martineau@kernel.org Cc: Geliang Tang geliang.tang@linux.dev Reviewed-by: Simon Horman horms@kernel.org Acked-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Link: https://lore.kernel.org/r/20240111194917.4044654-5-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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;