kernel/linux.git/net/tipc/discover.c, branch linux-5.9.y

net: tipc: kerneldoc fixes

2020-07-14T00:20:40+00:00

Simple fixes which require no deep knowledge of the code. Cc: Jon Maloy Cc: Ying Xue Signed-off-by: Andrew Lunn Acked-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix use-after-free in tipc_disc_rcv()

2019-12-11T01:45:04+00:00

In the function 'tipc_disc_rcv()', the 'msg_peer_net_hash()' is called to read the header data field but after the message skb has been freed, that might result in a garbage value... This commit fixes it by defining a new local variable to store the data first, just like the other header fields' handling. Fixes: f73b12812a3d ("tipc: improve throughput between nodes in netns") Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: improve throughput between nodes in netns

2019-10-30T00:55:38+00:00

Currently, TIPC transports intra-node user data messages directly socket to socket, hence shortcutting all the lower layers of the communication stack. This gives TIPC very good intra node performance, both regarding throughput and latency. We now introduce a similar mechanism for TIPC data traffic across network namespaces located in the same kernel. On the send path, the call chain is as always accompanied by the sending node's network name space pointer. However, once we have reliably established that the receiving node is represented by a namespace on the same host, we just replace the namespace pointer with the receiving node/namespace's ditto, and follow the regular socket receive patch though the receiving node. This technique gives us a throughput similar to the node internal throughput, several times larger than if we let the traffic go though the full network stacks. As a comparison, max throughput for 64k messages is four times larger than TCP throughput for the same type of traffic. To meet any security concerns, the following should be noted. - All nodes joining a cluster are supposed to have been be certified and authenticated by mechanisms outside TIPC. This is no different for nodes/namespaces on the same host; they have to auto discover each other using the attached interfaces, and establish links which are supervised via the regular link monitoring mechanism. Hence, a kernel local node has no other way to join a cluster than any other node, and have to obey to policies set in the IP or device layers of the stack. - Only when a sender has established with 100% certainty that the peer node is located in a kernel local namespace does it choose to let user data messages, and only those, take the crossover path to the receiving node/namespace. - If the receiving node/namespace is removed, its namespace pointer is invalidated at all peer nodes, and their neighbor link monitoring will eventually note that this node is gone. - To ensure the "100% certainty" criteria, and prevent any possible spoofing, received discovery messages must contain a proof that the sender knows a common secret. We use the hash mix of the sending node/namespace for this purpose, since it can be accessed directly by all other namespaces in the kernel. Upon reception of a discovery message, the receiver checks this proof against all the local namespaces'hash_mix:es. If it finds a match, that, along with a matching node id and cluster id, this is deemed sufficient proof that the peer node in question is in a local namespace, and a wormhole can be opened. - We should also consider that TIPC is intended to be a cluster local IPC mechanism (just like e.g. UNIX sockets) rather than a network protocol, and hence we think it can justified to allow it to shortcut the lower protocol layers. Regarding traceability, we should notice that since commit 6c9081a3915d ("tipc: add loopback device tracking") it is possible to follow the node internal packet flow by just activating tcpdump on the loopback interface. This will be true even for this mechanism; by activating tcpdump on the involved nodes' loopback interfaces their inter-name space messaging can easily be tracked. v2: - update 'net' pointer when node left/rejoined v3: - grab read/write lock when using node ref obj v4: - clone traffics between netns to loopback Suggested-by: Jon Maloy Acked-by: Jon Maloy Signed-off-by: Hoang Le Signed-off-by: David S. Miller

tipc: fix lockdep warning when reinitilaizing sockets

2018-11-18T06:01:31+00:00

We get the following warning: [ 47.926140] 32-bit node address hash set to 2010a0a [ 47.927202] [ 47.927433] ================================ [ 47.928050] WARNING: inconsistent lock state [ 47.928661] 4.19.0+ #37 Tainted: G E [ 47.929346] -------------------------------- [ 47.929954] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 47.930116] swapper/3/0 [HC0[0]:SC1[3]:HE1:SE0] takes: [ 47.930116] 00000000af8bc31e (&(&ht->lock)->rlock){+.?.}, at: rhashtable_walk_enter+0x36/0xb0 [ 47.930116] {SOFTIRQ-ON-W} state was registered at: [ 47.930116] _raw_spin_lock+0x29/0x60 [ 47.930116] rht_deferred_worker+0x556/0x810 [ 47.930116] process_one_work+0x1f5/0x540 [ 47.930116] worker_thread+0x64/0x3e0 [ 47.930116] kthread+0x112/0x150 [ 47.930116] ret_from_fork+0x3a/0x50 [ 47.930116] irq event stamp: 14044 [ 47.930116] hardirqs last enabled at (14044): [] __local_bh_enable_ip+0x7a/0xf0 [ 47.938117] hardirqs last disabled at (14043): [] __local_bh_enable_ip+0x41/0xf0 [ 47.938117] softirqs last enabled at (14028): [] irq_enter+0x5e/0x60 [ 47.938117] softirqs last disabled at (14029): [] irq_exit+0xb5/0xc0 [ 47.938117] [ 47.938117] other info that might help us debug this: [ 47.938117] Possible unsafe locking scenario: [ 47.938117] [ 47.938117] CPU0 [ 47.938117] ---- [ 47.938117] lock(&(&ht->lock)->rlock); [ 47.938117] [ 47.938117] lock(&(&ht->lock)->rlock); [ 47.938117] [ 47.938117] *** DEADLOCK *** [ 47.938117] [ 47.938117] 2 locks held by swapper/3/0: [ 47.938117] #0: 0000000062c64f90 ((&d->timer)){+.-.}, at: call_timer_fn+0x5/0x280 [ 47.938117] #1: 00000000ee39619c (&(&d->lock)->rlock){+.-.}, at: tipc_disc_timeout+0xc8/0x540 [tipc] [ 47.938117] [ 47.938117] stack backtrace: [ 47.938117] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G E 4.19.0+ #37 [ 47.938117] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 47.938117] Call Trace: [ 47.938117] [ 47.938117] dump_stack+0x5e/0x8b [ 47.938117] print_usage_bug+0x1ed/0x1ff [ 47.938117] mark_lock+0x5b5/0x630 [ 47.938117] __lock_acquire+0x4c0/0x18f0 [ 47.938117] ? lock_acquire+0xa6/0x180 [ 47.938117] lock_acquire+0xa6/0x180 [ 47.938117] ? rhashtable_walk_enter+0x36/0xb0 [ 47.938117] _raw_spin_lock+0x29/0x60 [ 47.938117] ? rhashtable_walk_enter+0x36/0xb0 [ 47.938117] rhashtable_walk_enter+0x36/0xb0 [ 47.938117] tipc_sk_reinit+0xb0/0x410 [tipc] [ 47.938117] ? mark_held_locks+0x6f/0x90 [ 47.938117] ? __local_bh_enable_ip+0x7a/0xf0 [ 47.938117] ? lockdep_hardirqs_on+0x20/0x1a0 [ 47.938117] tipc_net_finalize+0xbf/0x180 [tipc] [ 47.938117] tipc_disc_timeout+0x509/0x540 [tipc] [ 47.938117] ? call_timer_fn+0x5/0x280 [ 47.938117] ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc] [ 47.938117] ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc] [ 47.938117] call_timer_fn+0xa1/0x280 [ 47.938117] ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc] [ 47.938117] run_timer_softirq+0x1f2/0x4d0 [ 47.938117] __do_softirq+0xfc/0x413 [ 47.938117] irq_exit+0xb5/0xc0 [ 47.938117] smp_apic_timer_interrupt+0xac/0x210 [ 47.938117] apic_timer_interrupt+0xf/0x20 [ 47.938117] [ 47.938117] RIP: 0010:default_idle+0x1c/0x140 [ 47.938117] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 55 53 65 8b 2d d8 2b 74 65 0f 1f 44 00 00 e8 c6 2c 8b ff fb f4 <65> 8b 2d c5 2b 74 65 0f 1f 44 00 00 5b 5d 41 5c c3 65 8b 05 b4 2b [ 47.938117] RSP: 0018:ffffaf6ac0207ec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 [ 47.938117] RAX: ffff8f5b3735e200 RBX: 0000000000000003 RCX: 0000000000000001 [ 47.938117] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8f5b3735e200 [ 47.938117] RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000 [ 47.938117] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 47.938117] R13: 0000000000000000 R14: ffff8f5b3735e200 R15: ffff8f5b3735e200 [ 47.938117] ? default_idle+0x1a/0x140 [ 47.938117] do_idle+0x1bc/0x280 [ 47.938117] cpu_startup_entry+0x19/0x20 [ 47.938117] start_secondary+0x187/0x1c0 [ 47.938117] secondary_startup_64+0xa4/0xb0 The reason seems to be that tipc_net_finalize()->tipc_sk_reinit() is calling the function rhashtable_walk_enter() within a timer interrupt. We fix this by executing tipc_net_finalize() in work queue context. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix correct setting of message type in second discoverer

2018-07-07T10:49:01+00:00

The duplicate address discovery protocol is not safe against two discoverers running in parallel. The one executing first after the trial period is over will set the node address and change its own message type to DSC_REQ_MSG. The one executing last may find that the node address is already set, and never change message type, with the result that its links may never be established. In this commmit we ensure that the message type always is set correctly after the trial period is over. Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: correct discovery message handling during address trial period

2018-07-07T10:49:01+00:00

With the duplicate address discovery protocol for tipc nodes addresses we introduced a one second trial period before a node is allocated a hash number to use as address. Unfortunately, we miss to handle the case when a regular LINK REQUEST/ RESPONSE arrives from a cluster node during the trial period. Such messages are not ignored as they should be, leading to links setup attempts while the node still has no address. Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: tipc_disc_addr_trial_msg() can be static

2018-03-26T01:21:43+00:00

Fixes: 25b0b9c4e835 ("tipc: handle collisions of 32-bit node address hash values") Signed-off-by: Fengguang Wu Acked-by: Jon Maloy jon.maloy@ericsson.com Signed-off-by: David S. Miller

tipc: handle collisions of 32-bit node address hash values

2018-03-23T17:12:18+00:00

When a 32-bit node address is generated from a 128-bit identifier, there is a risk of collisions which must be discovered and handled. We do this as follows: - We don't apply the generated address immediately to the node, but do instead initiate a 1 sec trial period to allow other cluster members to discover and handle such collisions. - During the trial period the node periodically sends out a new type of message, DSC_TRIAL_MSG, using broadcast or emulated broadcast, to all the other nodes in the cluster. - When a node is receiving such a message, it must check that the presented 32-bit identifier either is unused, or was used by the very same peer in a previous session. In both cases it accepts the request by not responding to it. - If it finds that the same node has been up before using a different address, it responds with a DSC_TRIAL_FAIL_MSG containing that address. - If it finds that the address has already been taken by some other node, it generates a new, unused address and returns it to the requester. - During the trial period the requesting node must always be prepared to accept a failure message, i.e., a message where a peer suggests a different (or equal) address to the one tried. In those cases it must apply the suggested value as trial address and restart the trial period. This algorithm ensures that in the vast majority of cases a node will have the same address before and after a reboot. If a legacy user configures the address explicitly, there will be no trial period and messages, so this protocol addition is completely backwards compatible. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: add 128-bit node identifier

2018-03-23T17:12:18+00:00

We add a 128-bit node identity, as an alternative to the currently used 32-bit node address. For the sake of compatibility and to minimize message header changes we retain the existing 32-bit address field. When not set explicitly by the user, this field will be filled with a hash value generated from the much longer node identity, and be used as a shorthand value for the latter. We permit either the address or the identity to be set by configuration, but not both, so when the address value is set by a legacy user the corresponding 128-bit node identity is generated based on the that value. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller

tipc: remove direct accesses to own_addr field in struct tipc_net

2018-03-23T17:12:18+00:00

As a preparation to changing the addressing structure of TIPC we replace all direct accesses to the tipc_net::own_addr field with the function dedicated for this, tipc_own_addr(). There are no changes to program logics in this commit. Acked-by: Ying Xue Signed-off-by: Jon Maloy Signed-off-by: David S. Miller