From 89e23277f9c16df6f9f9c1a1a07f8f132339c15c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 11 Jan 2024 19:49:13 +0000 Subject: mptcp: mptcp_parse_option() fix for MPTCPOPT_MP_JOIN mptcp_parse_option() currently sets OPTIONS_MPTCP_MPJ, for the three possible cases handled for MPTCPOPT_MP_JOIN option. OPTIONS_MPTCP_MPJ is the combination of three flags: - OPTION_MPTCP_MPJ_SYN - OPTION_MPTCP_MPJ_SYNACK - OPTION_MPTCP_MPJ_ACK This is a problem, because backup, join_id, token, nonce and/or hmac fields could be left uninitialized in some cases. Distinguish the three cases, as following patches will need this step. Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Signed-off-by: Eric Dumazet Cc: Florian Westphal Cc: Peter Krystad Cc: Matthieu Baerts Cc: Mat Martineau Cc: Geliang Tang Reviewed-by: Simon Horman Acked-by: Paolo Abeni Reviewed-by: Mat Martineau Link: https://lore.kernel.org/r/20240111194917.4044654-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/mptcp/options.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index c53914012d01..d2527d189a79 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -123,8 +123,8 @@ static void mptcp_parse_option(const struct sk_buff *skb, break; case MPTCPOPT_MP_JOIN: - mp_opt->suboptions |= OPTIONS_MPTCP_MPJ; if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { + mp_opt->suboptions |= OPTION_MPTCP_MPJ_SYN; mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; mp_opt->join_id = *ptr++; mp_opt->token = get_unaligned_be32(ptr); @@ -135,6 +135,7 @@ static void mptcp_parse_option(const struct sk_buff *skb, mp_opt->backup, mp_opt->join_id, mp_opt->token, mp_opt->nonce); } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { + mp_opt->suboptions |= OPTION_MPTCP_MPJ_SYNACK; mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; mp_opt->join_id = *ptr++; mp_opt->thmac = get_unaligned_be64(ptr); @@ -145,11 +146,10 @@ static void mptcp_parse_option(const struct sk_buff *skb, mp_opt->backup, mp_opt->join_id, mp_opt->thmac, mp_opt->nonce); } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { + mp_opt->suboptions |= OPTION_MPTCP_MPJ_ACK; ptr += 2; memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); pr_debug("MP_JOIN hmac"); - } else { - mp_opt->suboptions &= ~OPTIONS_MPTCP_MPJ; } break; -- cgit From c1665273bdc7c201766c65e561c06711f2e050dc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 11 Jan 2024 19:49:14 +0000 Subject: mptcp: strict validation before using mp_opt->hmac mp_opt->hmac contains uninitialized data unless OPTION_MPTCP_MPJ_ACK was set in mptcp_parse_option(). We must refine the condition before we call subflow_hmac_valid(). Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Signed-off-by: Eric Dumazet Cc: Florian Westphal Cc: Peter Krystad Cc: Matthieu Baerts Cc: Mat Martineau Cc: Geliang Tang Reviewed-by: Simon Horman Acked-by: Paolo Abeni Reviewed-by: Mat Martineau Link: https://lore.kernel.org/r/20240111194917.4044654-3-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/mptcp/subflow.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 3eacd04e7099..bb05477006a6 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -788,7 +788,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, } else if (subflow_req->mp_join) { mptcp_get_options(skb, &mp_opt); - if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ) || + if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK) || !subflow_hmac_valid(req, &mp_opt) || !mptcp_can_accept_new_subflow(subflow_req->msk)) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC); -- cgit From be1d9d9d38da922bd4beeec5b6dd821ff5a1dfeb Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 11 Jan 2024 19:49:15 +0000 Subject: mptcp: use OPTION_MPTCP_MPJ_SYNACK in subflow_finish_connect() subflow_finish_connect() uses four fields (backup, join_id, thmac, none) that may contain garbage unless OPTION_MPTCP_MPJ_SYNACK has been set in mptcp_parse_option() Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Signed-off-by: Eric Dumazet Cc: Florian Westphal Cc: Peter Krystad Cc: Matthieu Baerts Cc: Mat Martineau Cc: Geliang Tang Reviewed-by: Simon Horman Acked-by: Paolo Abeni Reviewed-by: Mat Martineau Link: https://lore.kernel.org/r/20240111194917.4044654-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/mptcp/subflow.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index bb05477006a6..103ff5471993 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -506,7 +506,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) } else if (subflow->request_join) { u8 hmac[SHA256_DIGEST_SIZE]; - if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPJ)) { + if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_SYNACK)) { subflow->reset_reason = MPTCP_RST_EMPTCP; goto do_reset; } -- cgit From 66ff70df1a919a066942844bb095d6fcb748d78d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 11 Jan 2024 19:49:16 +0000 Subject: mptcp: use OPTION_MPTCP_MPJ_SYN in subflow_check_req() 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 Signed-off-by: Eric Dumazet Cc: Florian Westphal Cc: Peter Krystad Cc: Matthieu Baerts Cc: Mat Martineau Cc: Geliang Tang Reviewed-by: Simon Horman Acked-by: Paolo Abeni Reviewed-by: Mat Martineau Link: https://lore.kernel.org/r/20240111194917.4044654-5-edumazet@google.com Signed-off-by: Jakub Kicinski --- 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 103ff5471993..13039ac8d1ab 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; -- cgit From 724b00c12957973656d312dce2a110c75ae2c680 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 11 Jan 2024 19:49:17 +0000 Subject: mptcp: refine opt_mp_capable determination OPTIONS_MPTCP_MPC is a combination of three flags. It would be better to be strict about testing what flag is expected, at least for code readability. mptcp_parse_option() already makes the distinction. - subflow_check_req() should use OPTION_MPTCP_MPC_SYN. - mptcp_subflow_init_cookie_req() should use OPTION_MPTCP_MPC_ACK. - subflow_finish_connect() should use OPTION_MPTCP_MPC_SYNACK - subflow_syn_recv_sock should use OPTION_MPTCP_MPC_ACK Suggested-by: Paolo Abeni Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Acked-by: Paolo Abeni Reviewed-by: Mat Martineau Fixes: 74c7dfbee3e1 ("mptcp: consolidate in_opt sub-options fields in a bitmask") Link: https://lore.kernel.org/r/20240111194917.4044654-6-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/mptcp/subflow.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 13039ac8d1ab..1117d1e84274 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -157,7 +157,7 @@ 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_capable = !!(mp_opt.suboptions & OPTION_MPTCP_MPC_SYN); opt_mp_join = !!(mp_opt.suboptions & OPTION_MPTCP_MPJ_SYN); if (opt_mp_capable) { SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVE); @@ -254,7 +254,7 @@ int mptcp_subflow_init_cookie_req(struct request_sock *req, subflow_init_req(req, sk_listener); mptcp_get_options(skb, &mp_opt); - opt_mp_capable = !!(mp_opt.suboptions & OPTIONS_MPTCP_MPC); + opt_mp_capable = !!(mp_opt.suboptions & OPTION_MPTCP_MPC_ACK); opt_mp_join = !!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK); if (opt_mp_capable && opt_mp_join) return -EINVAL; @@ -486,7 +486,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) mptcp_get_options(skb, &mp_opt); if (subflow->request_mptcp) { - if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) { + if (!(mp_opt.suboptions & OPTION_MPTCP_MPC_SYNACK)) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPCAPABLEACTIVEFALLBACK); mptcp_do_fallback(sk); @@ -783,7 +783,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, * options. */ mptcp_get_options(skb, &mp_opt); - if (!(mp_opt.suboptions & OPTIONS_MPTCP_MPC)) + if (!(mp_opt.suboptions & OPTION_MPTCP_MPC_ACK)) fallback = true; } else if (subflow_req->mp_join) { -- cgit