From e7579d5d5b3298f7e888ed07ac16bfb7174c135a Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Mon, 21 Dec 2020 22:07:25 +0100 Subject: net: mptcp: cap forward allocation to 1M the following syzkaller reproducer: r0 = socket$inet_mptcp(0x2, 0x1, 0x106) bind$inet(r0, &(0x7f0000000080)={0x2, 0x4e24, @multicast2}, 0x10) connect$inet(r0, &(0x7f0000000480)={0x2, 0x4e24, @local}, 0x10) sendto$inet(r0, &(0x7f0000000100)="f6", 0xffffffe7, 0xc000, 0x0, 0x0) systematically triggers the following warning: WARNING: CPU: 2 PID: 8618 at net/core/stream.c:208 sk_stream_kill_queues+0x3fa/0x580 Modules linked in: CPU: 2 PID: 8618 Comm: syz-executor Not tainted 5.10.0+ #334 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/04 RIP: 0010:sk_stream_kill_queues+0x3fa/0x580 Code: df 48 c1 ea 03 0f b6 04 02 84 c0 74 04 3c 03 7e 40 8b ab 20 02 00 00 e9 64 ff ff ff e8 df f0 81 2 RSP: 0018:ffffc9000290fcb0 EFLAGS: 00010293 RAX: ffff888011cb8000 RBX: 0000000000000000 RCX: ffffffff86eecf0e RDX: 0000000000000000 RSI: ffffffff86eecf6a RDI: 0000000000000005 RBP: 0000000000000e28 R08: ffff888011cb8000 R09: fffffbfff1f48139 R10: ffffffff8fa409c7 R11: fffffbfff1f48138 R12: ffff8880215e6220 R13: ffffffff8fa409c0 R14: ffffc9000290fd30 R15: 1ffff92000521fa2 FS: 00007f41c78f4800(0000) GS:ffff88802d000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f95c803d088 CR3: 0000000025ed2000 CR4: 00000000000006f0 Call Trace: __mptcp_destroy_sock+0x4f5/0x8e0 mptcp_close+0x5e2/0x7f0 inet_release+0x12b/0x270 __sock_release+0xc8/0x270 sock_close+0x18/0x20 __fput+0x272/0x8e0 task_work_run+0xe0/0x1a0 exit_to_user_mode_prepare+0x1df/0x200 syscall_exit_to_user_mode+0x19/0x50 entry_SYSCALL_64_after_hwframe+0x44/0xa9 userspace programs provide arbitrarily high values of 'len' in sendmsg(): this is causing integer overflow of 'amount'. Cap forward allocation to 1 megabyte: higher values are not really useful. Suggested-by: Paolo Abeni Fixes: e93da92896bc ("mptcp: implement wmem reservation") Signed-off-by: Davide Caratti Link: https://lore.kernel.org/r/3334d00d8b2faecafdfab9aa593efcbf61442756.1608584474.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/mptcp/protocol.c') diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 09b19aa2f205..6628d8d74203 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -877,6 +877,9 @@ static void __mptcp_wmem_reserve(struct sock *sk, int size) struct mptcp_sock *msk = mptcp_sk(sk); WARN_ON_ONCE(msk->wmem_reserved); + if (WARN_ON_ONCE(amount < 0)) + amount = 0; + if (amount <= sk->sk_forward_alloc) goto reserve; @@ -1587,7 +1590,7 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL)) return -EOPNOTSUPP; - mptcp_lock_sock(sk, __mptcp_wmem_reserve(sk, len)); + mptcp_lock_sock(sk, __mptcp_wmem_reserve(sk, min_t(size_t, 1 << 20, len))); timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); -- cgit v1.2.3 From 20bc80b6f582ad1151c52ca09ab66b472768c9c8 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 12 Jan 2021 18:25:23 +0100 Subject: mptcp: more strict state checking for acks Syzkaller found a way to trigger division by zero in mptcp_subflow_cleanup_rbuf(). The current checks implemented into tcp_can_send_ack() are too week, let's be more accurate. Reported-by: Christoph Paasch Fixes: ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling") Fixes: fd8976790a6c ("mptcp: be careful on MPTCP-level ack.") Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/mptcp/protocol.c') diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 6628d8d74203..2ff8c7caf74f 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -427,7 +427,7 @@ static bool mptcp_subflow_active(struct mptcp_subflow_context *subflow) static bool tcp_can_send_ack(const struct sock *ssk) { return !((1 << inet_sk_state_load(ssk)) & - (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE)); + (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_TIME_WAIT | TCPF_CLOSE | TCPF_LISTEN)); } static void mptcp_send_ack(struct mptcp_sock *msk) -- cgit v1.2.3 From 76e2a55d16259b51116767b28b19d759bff43f72 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 12 Jan 2021 18:25:24 +0100 Subject: mptcp: better msk-level shutdown. Instead of re-implementing most of inet_shutdown, re-use such helper, and implement the MPTCP-specific bits at the 'proto' level. The msk-level disconnect() can now be invoked, lets provide a suitable implementation. As a side effect, this fixes bad state management for listener sockets. The latter could lead to division by 0 oops since commit ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling"). Fixes: 43b54c6ee382 ("mptcp: Use full MPTCP-level disconnect state machine") Fixes: ea4ca586b16f ("mptcp: refine MPTCP-level ack scheduling") Signed-off-by: Paolo Abeni Reviewed-by: Mat Martineau Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 62 ++++++++++++++-------------------------------------- 1 file changed, 17 insertions(+), 45 deletions(-) (limited to 'net/mptcp/protocol.c') diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 2ff8c7caf74f..81faeff8f3bb 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2642,11 +2642,12 @@ static void mptcp_copy_inaddrs(struct sock *msk, const struct sock *ssk) static int mptcp_disconnect(struct sock *sk, int flags) { - /* Should never be called. - * inet_stream_connect() calls ->disconnect, but that - * refers to the subflow socket, not the mptcp one. - */ - WARN_ON_ONCE(1); + struct mptcp_subflow_context *subflow; + struct mptcp_sock *msk = mptcp_sk(sk); + + __mptcp_flush_join_list(msk); + mptcp_for_each_subflow(msk, subflow) + tcp_disconnect(mptcp_subflow_tcp_sock(subflow), flags); return 0; } @@ -3089,6 +3090,14 @@ bool mptcp_finish_join(struct sock *ssk) return true; } +static void mptcp_shutdown(struct sock *sk, int how) +{ + pr_debug("sk=%p, how=%d", sk, how); + + if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) + __mptcp_wr_shutdown(sk); +} + static struct proto mptcp_prot = { .name = "MPTCP", .owner = THIS_MODULE, @@ -3098,7 +3107,7 @@ static struct proto mptcp_prot = { .accept = mptcp_accept, .setsockopt = mptcp_setsockopt, .getsockopt = mptcp_getsockopt, - .shutdown = tcp_shutdown, + .shutdown = mptcp_shutdown, .destroy = mptcp_destroy, .sendmsg = mptcp_sendmsg, .recvmsg = mptcp_recvmsg, @@ -3344,43 +3353,6 @@ static __poll_t mptcp_poll(struct file *file, struct socket *sock, return mask; } -static int mptcp_shutdown(struct socket *sock, int how) -{ - struct mptcp_sock *msk = mptcp_sk(sock->sk); - struct sock *sk = sock->sk; - int ret = 0; - - pr_debug("sk=%p, how=%d", msk, how); - - lock_sock(sk); - - how++; - if ((how & ~SHUTDOWN_MASK) || !how) { - ret = -EINVAL; - goto out_unlock; - } - - if (sock->state == SS_CONNECTING) { - if ((1 << sk->sk_state) & - (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE)) - sock->state = SS_DISCONNECTING; - else - sock->state = SS_CONNECTED; - } - - sk->sk_shutdown |= how; - if ((how & SEND_SHUTDOWN) && mptcp_close_state(sk)) - __mptcp_wr_shutdown(sk); - - /* Wake up anyone sleeping in poll. */ - sk->sk_state_change(sk); - -out_unlock: - release_sock(sk); - - return ret; -} - static const struct proto_ops mptcp_stream_ops = { .family = PF_INET, .owner = THIS_MODULE, @@ -3394,7 +3366,7 @@ static const struct proto_ops mptcp_stream_ops = { .ioctl = inet_ioctl, .gettstamp = sock_gettstamp, .listen = mptcp_listen, - .shutdown = mptcp_shutdown, + .shutdown = inet_shutdown, .setsockopt = sock_common_setsockopt, .getsockopt = sock_common_getsockopt, .sendmsg = inet_sendmsg, @@ -3444,7 +3416,7 @@ static const struct proto_ops mptcp_v6_stream_ops = { .ioctl = inet6_ioctl, .gettstamp = sock_gettstamp, .listen = mptcp_listen, - .shutdown = mptcp_shutdown, + .shutdown = inet_shutdown, .setsockopt = sock_common_setsockopt, .getsockopt = sock_common_getsockopt, .sendmsg = inet6_sendmsg, -- cgit v1.2.3 From 13a9499e833387fcc7a53915bbe5cddf3c336b59 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 14 Jan 2021 16:37:37 +0100 Subject: mptcp: fix locking in mptcp_disconnect() tcp_disconnect() expects the caller acquires the sock lock, but mptcp_disconnect() is not doing that. Add the missing required lock. Reported-by: Eric Dumazet Fixes: 76e2a55d1625 ("mptcp: better msk-level shutdown.") Signed-off-by: Paolo Abeni Link: https://lore.kernel.org/r/f818e82b58a556feeb71dcccc8bf1c87aafc6175.1610638176.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski --- net/mptcp/protocol.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'net/mptcp/protocol.c') diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 81faeff8f3bb..f998a077c7dd 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2646,8 +2646,13 @@ static int mptcp_disconnect(struct sock *sk, int flags) struct mptcp_sock *msk = mptcp_sk(sk); __mptcp_flush_join_list(msk); - mptcp_for_each_subflow(msk, subflow) - tcp_disconnect(mptcp_subflow_tcp_sock(subflow), flags); + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); + + lock_sock(ssk); + tcp_disconnect(ssk, flags); + release_sock(ssk); + } return 0; } -- cgit v1.2.3