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

net: tipc: prevent possible null deref of link

2020-12-21T12:28:18+00:00

[ Upstream commit 0398ba9e5a4b5675aa571e0445689d3c2e499c2d ] `tipc_node_apply_property` does a null check on a `tipc_link_entry` pointer but also accesses the same pointer out of the null check block. This triggers a warning on Coverity Static Analyzer because we're implying that `e->link` can BE null. Move "Update MTU for node link entry" line into if block to make sure that we're not in a state that `e->link` is null. Signed-off-by: Cengiz Can Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

tipc: fix incompatible mtu of transmission

2020-12-08T09:42:01+00:00

[ Upstream commit 0643334902fcdc770e2d9555811200213339a3f6 ] In commit 682cd3cf946b6 ("tipc: confgiure and apply UDP bearer MTU on running links"), we introduced a function to change UDP bearer MTU and applied this new value across existing per-link. However, we did not apply this new MTU value at node level. This lead to packet dropped at link level if its size is greater than new MTU value. To fix this issue, we also apply this new MTU value for node level. Fixes: 682cd3cf946b6 ("tipc: confgiure and apply UDP bearer MTU on running links") Acked-by: Jon Maloy Signed-off-by: Hoang Le Link: https://lore.kernel.org/r/20201130025544.3602-1-hoang.h.le@dektech.com.au Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

tipc: fix NULL pointer dereference in tipc_named_rcv

2020-10-29T09:10:51+00:00

[ Upstream commit 7b50ee3dad2581dc022b4e32e55964d4fcdccf20 ] In the function node_lost_contact(), we call __skb_queue_purge() without grabbing the list->lock. This can cause to a race-condition why processing the list 'namedq' in calling path tipc_named_rcv()->tipc_named_dequeue(). [] BUG: kernel NULL pointer dereference, address: 0000000000000000 [] #PF: supervisor read access in kernel mode [] #PF: error_code(0x0000) - not-present page [] PGD 7ca63067 P4D 7ca63067 PUD 6c553067 PMD 0 [] Oops: 0000 [#1] SMP NOPTI [] CPU: 1 PID: 15 Comm: ksoftirqd/1 Tainted: G O 5.9.0-rc6+ #2 [] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS [...] [] RIP: 0010:tipc_named_rcv+0x103/0x320 [tipc] [] Code: 41 89 44 24 10 49 8b 16 49 8b 46 08 49 c7 06 00 00 00 [...] [] RSP: 0018:ffffc900000a7c58 EFLAGS: 00000282 [] RAX: 00000000000012ec RBX: 0000000000000000 RCX: ffff88807bde1270 [] RDX: 0000000000002c7c RSI: 0000000000002c7c RDI: ffff88807b38f1a8 [] RBP: ffff88807b006288 R08: ffff88806a367800 R09: ffff88806a367900 [] R10: ffff88806a367a00 R11: ffff88806a367b00 R12: ffff88807b006258 [] R13: ffff88807b00628a R14: ffff888069334d00 R15: ffff88806a434600 [] FS: 0000000000000000(0000) GS:ffff888079480000(0000) knlGS:0[...] [] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [] CR2: 0000000000000000 CR3: 0000000077320000 CR4: 00000000000006e0 [] Call Trace: [] ? tipc_bcast_rcv+0x9a/0x1a0 [tipc] [] tipc_rcv+0x40d/0x670 [tipc] [] ? _raw_spin_unlock+0xa/0x20 [] tipc_l2_rcv_msg+0x55/0x80 [tipc] [] __netif_receive_skb_one_core+0x8c/0xa0 [] process_backlog+0x98/0x140 [] net_rx_action+0x13a/0x420 [] __do_softirq+0xdb/0x316 [] ? smpboot_thread_fn+0x2f/0x1e0 [] ? smpboot_thread_fn+0x74/0x1e0 [] ? smpboot_thread_fn+0x14e/0x1e0 [] run_ksoftirqd+0x1a/0x40 [] smpboot_thread_fn+0x149/0x1e0 [] ? sort_range+0x20/0x20 [] kthread+0x131/0x150 [] ? kthread_unuse_mm+0xa0/0xa0 [] ret_from_fork+0x22/0x30 [] Modules linked in: veth tipc(O) ip6_udp_tunnel udp_tunnel [...] [] CR2: 0000000000000000 [] ---[ end trace 65c276a8e2e2f310 ]--- To fix this, we need to grab the lock of the 'namedq' list on both path calling. Fixes: cad2929dc432 ("tipc: update a binding service via broadcast") Acked-by: Jon Maloy Signed-off-by: Hoang Huu Le Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman

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: update a binding service via broadcast

2020-06-17T15:53:34+00:00

Currently, updating binding table (add service binding to name table/withdraw a service binding) is being sent over replicast. However, if we are scaling up clusters to > 100 nodes/containers this method is less affection because of looping through nodes in a cluster one by one. It is worth to use broadcast to update a binding service. This way, the binding table can be updated on all peer nodes in one shot. Broadcast is used when all peer nodes, as indicated by a new capability flag TIPC_NAMED_BCAST, support reception of this message type. Four problems need to be considered when introducing this feature. 1) When establishing a link to a new peer node we still update this by a unicast 'bulk' update. This may lead to race conditions, where a later broadcast publication/withdrawal bypass the 'bulk', resulting in disordered publications, or even that a withdrawal may arrive before the corresponding publication. We solve this by adding an 'is_last_bulk' bit in the last bulk messages so that it can be distinguished from all other messages. Only when this message has arrived do we open up for reception of broadcast publications/withdrawals. 2) When a first legacy node is added to the cluster all distribution will switch over to use the legacy 'replicast' method, while the opposite happens when the last legacy node leaves the cluster. This entails another risk of message disordering that has to be handled. We solve this by adding a sequence number to the broadcast/replicast messages, so that disordering can be discovered and corrected. Note however that we don't need to consider potential message loss or duplication at this protocol level. 3) Bulk messages don't contain any sequence numbers, and will always arrive in order. Hence we must exempt those from the sequence number control and deliver them unconditionally. We solve this by adding a new 'is_bulk' bit in those messages so that they can be recognized. 4) Legacy messages, which don't contain any new bits or sequence numbers, but neither can arrive out of order, also need to be exempt from the initial synchronization and sequence number check, and delivered unconditionally. Therefore, we add another 'is_not_legacy' bit to all new messages so that those can be distinguished from legacy messages and the latter delivered directly. v1->v2: - fix warning issue reported by kbuild test robot - add santiy check to drop the publication message with a sequence number that is lower than the agreed synch point Signed-off-by: kernel test robot Signed-off-by: Hoang Huu Le Acked-by: Jon Maloy Signed-off-by: David S. Miller

Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv"

2020-06-02T22:13:46+00:00

This reverts commit de058420767df21e2b6b0f3bb36d1616fb962032. There is no actual tipc_node refcnt leak as stated in the above commit. The refcnt is hold carefully for the case of an asynchronous decryption (i.e. -EINPROGRESS/-EBUSY and skb = NULL is returned), so that the node object cannot be freed in the meantime. The counter will be re-balanced when the operation's callback arrives with the decrypted buffer if any. In other cases, e.g. a synchronous crypto the counter will be decreased immediately when it is done. Now with that commit, a kernel panic will occur when there is no node found (i.e. n = NULL) in the 'tipc_rcv()' or a premature release of the node object. This commit solves the issues by reverting the said commit, but keeping one valid case that the 'skb_linearize()' is failed. Acked-by: Jon Maloy Signed-off-by: Tuong Lien Tested-by: Hoang Le Signed-off-by: David S. Miller

tipc: add support for broadcast rcv stats dumping

2020-05-26T22:16:52+00:00

This commit enables dumping the statistics of a broadcast-receiver link like the traditional 'broadcast-link' one (which is for broadcast- sender). The link dumping can be triggered via netlink (e.g. the iproute2/tipc tool) by the link flag - 'TIPC_NLA_LINK_BROADCAST' as the indicator. The name of a broadcast-receiver link of a specific peer will be in the format: 'broadcast-link:'. For example: Link Window:50 packets RX packets:7841 fragments:2408/440 bundles:0/0 TX packets:0 fragments:0/0 bundles:0/0 RX naks:0 defs:124 dups:0 TX naks:21 acks:0 retrans:0 Congestion link:0 Send queue max:0 avg:0 In addition, the broadcast-receiver link statistics can be reset in the usual way via netlink by specifying that link name in command. Note: the 'tipc_link_name_ext()' is removed because the link name can now be retrieved simply via the 'l->name'. Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: enable broadcast retrans via unicast

2020-05-26T22:16:52+00:00

In some environment, broadcast traffic is suppressed at high rate (i.e. a kind of bandwidth limit setting). When it is applied, TIPC broadcast can still run successfully. However, when it comes to a high load, some packets will be dropped first and TIPC tries to retransmit them but the packet retransmission is intentionally broadcast too, so making things worse and not helpful at all. This commit enables the broadcast retransmission via unicast which only retransmits packets to the specific peer that has really reported a gap i.e. not broadcasting to all nodes in the cluster, so will prevent from being suppressed, and also reduce some overheads on the other peers due to duplicates, finally improve the overall TIPC broadcast performance. Note: the functionality can be turned on/off via the sysctl file: echo 1 > /proc/sys/net/tipc/bc_retruni echo 0 > /proc/sys/net/tipc/bc_retruni Default is '0', i.e. the broadcast retransmission still works as usual. Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: introduce Gap ACK blocks for broadcast link

2020-05-26T22:16:52+00:00

As achieved through commit 9195948fbf34 ("tipc: improve TIPC throughput by Gap ACK blocks"), we apply the same mechanism for the broadcast link as well. The 'Gap ACK blocks' data field in a 'PROTOCOL/STATE_MSG' will consist of two parts built for both the broadcast and unicast types: 31 16 15 0 +-------------+-------------+-------------+-------------+ | bgack_cnt | ugack_cnt | len | +-------------+-------------+-------------+-------------+ - | gap | ack | | +-------------+-------------+-------------+-------------+ > bc gacks : : : | +-------------+-------------+-------------+-------------+ - | gap | ack | | +-------------+-------------+-------------+-------------+ > uc gacks : : : | +-------------+-------------+-------------+-------------+ - which is "automatically" backward-compatible. We also increase the max number of Gap ACK blocks to 128, allowing upto 64 blocks per type (total buffer size = 516 bytes). Besides, the 'tipc_link_advance_transmq()' function is refactored which is applicable for both the unicast and broadcast cases now, so some old functions can be removed and the code is optimized. With the patch, TIPC broadcast is more robust regardless of packet loss or disorder, latency, ... in the underlying network. Its performance is boost up significantly. For example, experiment with a 5% packet loss rate results: $ time tipc-pipe --mc --rdm --data_size 123 --data_num 1500000 real 0m 42.46s user 0m 1.16s sys 0m 17.67s Without the patch: $ time tipc-pipe --mc --rdm --data_size 123 --data_num 1500000 real 8m 27.94s user 0m 0.55s sys 0m 2.38s Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: Fix potential tipc_node refcnt leak in tipc_rcv

2020-04-18T20:24:20+00:00

tipc_rcv() invokes tipc_node_find() twice, which returns a reference of the specified tipc_node object to "n" with increased refcnt. When tipc_rcv() returns or a new object is assigned to "n", the original local reference of "n" becomes invalid, so the refcount should be decreased to keep refcount balanced. The issue happens in some paths of tipc_rcv(), which forget to decrease the refcnt increased by tipc_node_find() and will cause a refcnt leak. Fix this issue by calling tipc_node_put() before the original object pointed by "n" becomes invalid. Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: David S. Miller