user/sven/linux.git/net/tipc/socket.h, branch v4.20

tipc: call start and done ops directly in __tipc_nl_compat_dumpit()

2018-09-07T04:49:18Z

__tipc_nl_compat_dumpit() uses a netlink_callback on stack, so the only way to align it with other ->dumpit() call path is calling tipc_dump_start() and tipc_dump_done() directly inside it. Otherwise ->dumpit() would always get NULL from cb->args[]. But tipc_dump_start() uses sock_net(cb->skb->sk) to retrieve net pointer, the cb->skb here doesn't set skb->sk, the net pointer is saved in msg->net instead, so introduce a helper function __tipc_dump_start() to pass in msg->net. Ying pointed out cb->args[0...3] are already used by other callbacks on this call path, so we can't use cb->args[0] any more, use cb->args[4] instead. Fixes: 9a07efa9aea2 ("tipc: switch to rhashtable iterator") Reported-and-tested-by: syzbot+e93a2c41f91b8e2c7d9b@syzkaller.appspotmail.com Cc: Jon Maloy Cc: Ying Xue Signed-off-by: Cong Wang Acked-by: Ying Xue Signed-off-by: David S. Miller

tipc: switch to rhashtable iterator

2018-08-30T01:04:54Z

syzbot reported a use-after-free in tipc_group_fill_sock_diag(), where tipc_group_fill_sock_diag() still reads tsk->group meanwhile tipc_group_delete() just deletes it in tipc_release(). tipc_nl_sk_walk() aims to lock this sock when walking each sock in the hash table to close race conditions with sock changes like this one, by acquiring tsk->sk.sk_lock.slock spinlock, unfortunately this doesn't work at all. All non-BH call path should take lock_sock() instead to make it work. tipc_nl_sk_walk() brutally iterates with raw rht_for_each_entry_rcu() where RCU read lock is required, this is the reason why lock_sock() can't be taken on this path. This could be resolved by switching to rhashtable iterator API's, where taking a sleepable lock is possible. Also, the iterator API's are friendly for restartable calls like diag dump, the last position is remembered behind the scence, all we need to do here is saving the iterator into cb->args[]. I tested this with parallel tipc diag dump and thousands of tipc socket creation and release, no crash or memory leak. Reported-by: syzbot+b9c8f3ab2994b7cd1625@syzkaller.appspotmail.com Cc: Jon Maloy Cc: Ying Xue Signed-off-by: Cong Wang Signed-off-by: David S. Miller

tipc: use the right skb in tipc_sk_fill_sock_diag()

2018-04-08T16:34:29Z

Commit 4b2e6877b879 ("tipc: Fix namespace violation in tipc_sk_fill_sock_diag") tried to fix the crash but failed, the crash is still 100% reproducible with it. In tipc_sk_fill_sock_diag(), skb is the diag dump we are filling, it is not correct to retrieve its NETLINK_CB(), instead, like other protocol diag, we should use NETLINK_CB(cb->skb).sk here. Reported-by: Fixes: 4b2e6877b879 ("tipc: Fix namespace violation in tipc_sk_fill_sock_diag") Fixes: c30b70deb5f4 (tipc: implement socket diagnostics for AF_TIPC) Cc: GhantaKrishnamurthy MohanKrishna Cc: Jon Maloy Cc: Ying Xue Signed-off-by: Cong Wang Signed-off-by: David S. Miller

tipc: implement socket diagnostics for AF_TIPC

2018-03-22T18:43:35Z

This commit adds socket diagnostics capability for AF_TIPC in netlink family NETLINK_SOCK_DIAG in a new kernel module (diag.ko). The following are key design considerations: - config TIPC_DIAG has default y, like INET_DIAG. - only requests with flag NLM_F_DUMP is supported (dump all). - tipc_sock_diag_req message is introduced to send filter parameters. - the response attributes are of TLV, some nested. To avoid exposing data structures between diag and tipc modules and avoid code duplication, the following additions are required: - export tipc_nl_sk_walk function to reuse socket iterator. - export tipc_sk_fill_sock_diag to fill the tipc diag attributes. - create a sock_diag response message in __tipc_add_sock_diag defined in diag.c and use the above exported tipc_sk_fill_sock_diag to fill response. Acked-by: Jon Maloy Acked-by: Ying Xue Signed-off-by: GhantaKrishnamurthy MohanKrishna Signed-off-by: Parthasarathy Bhuvaragan Signed-off-by: David S. Miller

tipc: redesign connection-level flow control

2016-05-03T19:51:16Z

There are two flow control mechanisms in TIPC; one at link level that handles network congestion, burst control, and retransmission, and one at connection level which' only remaining task is to prevent overflow in the receiving socket buffer. In TIPC, the latter task has to be solved end-to-end because messages can not be thrown away once they have been accepted and delivered upwards from the link layer, i.e, we can never permit the receive buffer to overflow. Currently, this algorithm is message based. A counter in the receiving socket keeps track of number of consumed messages, and sends a dedicated acknowledge message back to the sender for each 256 consumed message. A counter at the sending end keeps track of the sent, not yet acknowledged messages, and blocks the sender if this number ever reaches 512 unacknowledged messages. When the missing acknowledge arrives, the socket is then woken up for renewed transmission. This works well for keeping the message flow running, as it almost never happens that a sender socket is blocked this way. A problem with the current mechanism is that it potentially is very memory consuming. Since we don't distinguish between small and large messages, we have to dimension the socket receive buffer according to a worst-case of both. I.e., the window size must be chosen large enough to sustain a reasonable throughput even for the smallest messages, while we must still consider a scenario where all messages are of maximum size. Hence, the current fix window size of 512 messages and a maximum message size of 66k results in a receive buffer of 66 MB when truesize(66k) = 131k is taken into account. It is possible to do much better. This commit introduces an algorithm where we instead use 1024-byte blocks as base unit. This unit, always rounded upwards from the actual message size, is used when we advertise windows as well as when we count and acknowledge transmitted data. The advertised window is based on the configured receive buffer size in such a way that even the worst-case truesize/msgsize ratio always is covered. Since the smallest possible message size (from a flow control viewpoint) now is 1024 bytes, we can safely assume this ratio to be less than four, which is the value we are now using. This way, we have been able to reduce the default receive buffer size from 66 MB to 2 MB with maintained performance. In order to keep this solution backwards compatible, we introduce a new capability bit in the discovery protocol, and use this throughout the message sending/reception path to always select the right unit. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: clean up socket layer message reception

2015-07-26T23:31:50Z

When a message is received in a socket, one of the call chains tipc_sk_rcv()->tipc_sk_enqueue()->filter_rcv()(->tipc_sk_proto_rcv()) or tipc_sk_backlog_rcv()->filter_rcv()(->tipc_sk_proto_rcv()) are followed. At each of these levels we may encounter situations where the message may need to be rejected, or a new message produced for transfer back to the sender. Despite recent improvements, the current code for doing this is perceived as awkward and hard to follow. Leveraging the two previous commits in this series, we now introduce a more uniform handling of such situations. We let each of the functions in the chain itself produce/reverse the message to be returned to the sender, but also perform the actual forwarding. This simplifies the necessary logics within each function. Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix netns refcnt leak

2015-03-18T02:11:26Z

When the TIPC module is loaded, we launch a topology server in kernel space, which in its turn is creating TIPC sockets for communication with topology server users. Because both the socket's creator and provider reside in the same module, it is necessary that the TIPC module's reference count remains zero after the server is started and the socket created; otherwise it becomes impossible to perform "rmmod" even on an idle module. Currently, we achieve this by defining a separate "tipc_proto_kern" protocol struct, that is used only for kernel space socket allocations. This structure has the "owner" field set to NULL, which restricts the module reference count from being be bumped when sk_alloc() for local sockets is called. Furthermore, we have defined three kernel-specific functions, tipc_sock_create_local(), tipc_sock_release_local() and tipc_sock_accept_local(), to avoid the module counter being modified when module local sockets are created or deleted. This has worked well until we introduced name space support. However, after name space support was introduced, we have observed that a reference count leak occurs, because the netns counter is not decremented in tipc_sock_delete_local(). This commit remedies this problem. But instead of just modifying tipc_sock_delete_local(), we eliminate the whole parallel socket handling infrastructure, and start using the regular sk_create_kern(), kernel_accept() and sk_release_kernel() calls. Since those functions manipulate the module counter, we must now compensate for that by explicitly decrementing the counter after module local sockets are created, and increment it just before calling sk_release_kernel(). Fixes: a62fbccecd62 ("tipc: make subscriber server support net namespace") Signed-off-by: Ying Xue Reviewed-by: Jon Maloy Reviewed-by: Erik Hugne Reported-by: Cong Wang Tested-by: Erik Hugne Signed-off-by: David S. Miller

tipc: convert legacy nl socket dump to nl compat

2015-02-09T21:20:48Z

Convert socket (port) listing to compat dumpit call. If a socket (port) has publications a second dumpit call is issued to collect them and format then into the legacy buffer before continuing to process the sockets (ports). Command converted in this patch: TIPC_CMD_SHOW_PORTS Signed-off-by: Richard Alpe Reviewed-by: Erik Hugne Reviewed-by: Ying Xue Reviewed-by: Jon Maloy Signed-off-by: David S. Miller

tipc: eliminate race condition at multicast reception

2015-02-06T00:00:03Z

In a previous commit in this series we resolved a race problem during unicast message reception. Here, we resolve the same problem at multicast reception. We apply the same technique: an input queue serializing the delivery of arriving buffers. The main difference is that here we do it in two steps. First, the broadcast link feeds arriving buffers into the tail of an arrival queue, which head is consumed at the socket level, and where destination lookup is performed. Second, if the lookup is successful, the resulting buffer clones are fed into a second queue, the input queue. This queue is consumed at reception in the socket just like in the unicast case. Both queues are protected by the same lock, -the one of the input queue. Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: simplify socket multicast reception

2015-02-06T00:00:03Z

The structure 'tipc_port_list' is used to collect port numbers representing multicast destination socket on a receiving node. The list is not based on a standard linked list, and is in reality optimized for the uncommon case that there are more than one multicast destinations per node. This makes the list handling unecessarily complex, and as a consequence, even the socket multicast reception becomes more complex. In this commit, we replace 'tipc_port_list' with a new 'struct tipc_plist', which is based on a standard list. We give the new list stack (push/pop) semantics, someting that simplifies the implementation of the function tipc_sk_mcast_rcv(). Reviewed-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller