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2021-07-25net/sched: act_ct: remove and free nf_table callbacksLouis Peens1-0/+11
commit 77ac5e40c44eb78333fbc38482d61fc2af7dda0a upstream. When cleaning up the nf_table in tcf_ct_flow_table_cleanup_work there is no guarantee that the callback list, added to by nf_flow_table_offload_add_cb, is empty. This means that it is possible that the flow_block_cb memory allocated will be lost. Fix this by iterating the list and freeing the flow_block_cb entries before freeing the nf_table entry (via freeing ct_ft). Fixes: 978703f42549 ("netfilter: flowtable: Add API for registering to flow table events") Signed-off-by: Louis Peens <louis.peens@corigine.com> Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com> Signed-off-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25net/sched: act_ct: fix err check for nf_conntrack_confirmwenxu1-1/+2
commit 8955b90c3cdad199137809aac8ccbbb585355913 upstream. The confirm operation should be checked. If there are any failed, the packet should be dropped like in ovs and netfilter. Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct") Signed-off-by: wenxu <wenxu@ucloud.cn> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25netfilter: ctnetlink: suspicious RCU usage in ctnetlink_dump_helpinfoVasily Averin1-0/+3
commit c23a9fd209bc6f8c1fa6ee303fdf037d784a1627 upstream. Two patches listed below removed ctnetlink_dump_helpinfo call from under rcu_read_lock. Now its rcu_dereference generates following warning: ============================= WARNING: suspicious RCU usage 5.13.0+ #5 Not tainted ----------------------------- net/netfilter/nf_conntrack_netlink.c:221 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 stack backtrace: CPU: 1 PID: 2251 Comm: conntrack Not tainted 5.13.0+ #5 Call Trace: dump_stack+0x7f/0xa1 ctnetlink_dump_helpinfo+0x134/0x150 [nf_conntrack_netlink] ctnetlink_fill_info+0x2c2/0x390 [nf_conntrack_netlink] ctnetlink_dump_table+0x13f/0x370 [nf_conntrack_netlink] netlink_dump+0x10c/0x370 __netlink_dump_start+0x1a7/0x260 ctnetlink_get_conntrack+0x1e5/0x250 [nf_conntrack_netlink] nfnetlink_rcv_msg+0x613/0x993 [nfnetlink] netlink_rcv_skb+0x50/0x100 nfnetlink_rcv+0x55/0x120 [nfnetlink] netlink_unicast+0x181/0x260 netlink_sendmsg+0x23f/0x460 sock_sendmsg+0x5b/0x60 __sys_sendto+0xf1/0x160 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x36/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 49ca022bccc5 ("netfilter: ctnetlink: don't dump ct extensions of unconfirmed conntracks") Fixes: 0b35f6031a00 ("netfilter: Remove duplicated rcu_read_lock.") Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Reviewed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-25net: ipv6: fix return value of ip6_skb_dst_mtuVadim Fedorenko1-1/+1
commit 40fc3054b45820c28ea3c65e2c86d041dc244a8a upstream. Commit 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE") introduced ip6_skb_dst_mtu with return value of signed int which is inconsistent with actually returned values. Also 2 users of this function actually assign its value to unsigned int variable and only __xfrm6_output assigns result of this function to signed variable but actually uses as unsigned in further comparisons and calls. Change this function to return unsigned int value. Fixes: 628a5c561890 ("[INET]: Add IP(V6)_PMTUDISC_RPOBE") Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20SUNRPC: prevent port reuse on transports which don't request it.NeilBrown1-1/+2
[ Upstream commit bc1c56e9bbe92766d017efb5f0a0c71f80da5570 ] If an RPC client is created without RPC_CLNT_CREATE_REUSEPORT, it should not reuse the source port when a TCP connection is re-established. This is currently implemented by preventing the source port being recorded after a successful connection (the call to xs_set_srcport()). However the source port is also recorded after a successful bind in xs_bind(). This may not be needed at all and certainly is not wanted when RPC_CLNT_CREATE_REUSEPORT wasn't requested. So avoid that assignment when xprt.reuseport is not set. With this change, NFSv4.1 and later mounts use a different port number on each connection. This is helpful with some firewalls which don't cope well with port reuse. Signed-off-by: NeilBrown <neilb@suse.de> Fixes: e6237b6feb37 ("NFSv4.1: Don't rebind to the same source port when reconnecting to the server") Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20net: bridge: multicast: fix MRD advertisement router port marking raceNikolay Aleksandrov1-0/+4
commit 000b7287b67555fee39d39fff75229dedde0dcbf upstream. When an MRD advertisement is received on a bridge port with multicast snooping enabled, we mark it as a router port automatically, that includes adding that port to the router port list. The multicast lock protects that list, but it is not acquired in the MRD advertisement case leading to a race condition, we need to take it to fix the race. Cc: stable@vger.kernel.org Cc: linus.luessing@c0d3.blue Fixes: 4b3087c7e37f ("bridge: Snoop Multicast Router Advertisements") Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20net: bridge: multicast: fix PIM hello router port marking raceNikolay Aleksandrov1-0/+2
commit 04bef83a3358946bfc98a5ecebd1b0003d83d882 upstream. When a PIM hello packet is received on a bridge port with multicast snooping enabled, we mark it as a router port automatically, that includes adding that port the router port list. The multicast lock protects that list, but it is not acquired in the PIM message case leading to a race condition, we need to take it to fix the race. Cc: stable@vger.kernel.org Fixes: 91b02d3d133b ("bridge: mcast: add router port on PIM hello message") Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-19sctp: add size validation when walking chunksMarcelo Ricardo Leitner1-1/+1
[ Upstream commit 50619dbf8db77e98d821d615af4f634d08e22698 ] The first chunk in a packet is ensured to be present at the beginning of sctp_rcv(), as a packet needs to have at least 1 chunk. But the second one, may not be completely available and ch->length can be over uninitialized memory. Fix here is by only trying to walk on the next chunk if there is enough to hold at least the header, and then proceed with the ch->length validation that is already there. Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19sctp: validate from_addr_param returnMarcelo Ricardo Leitner5-25/+43
[ Upstream commit 0c5dc070ff3d6246d22ddd931f23a6266249e3db ] Ilja reported that, simply putting it, nothing was validating that from_addr_param functions were operating on initialized memory. That is, the parameter itself was being validated by sctp_walk_params, but it doesn't check for types and their specific sizes and it could be a 0-length one, causing from_addr_param to potentially work over the next parameter or even uninitialized memory. The fix here is to, in all calls to from_addr_param, check if enough space is there for the wanted IP address type. Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19Bluetooth: mgmt: Fix the command returns garbage parameter valueTedd Ho-Jeong An1-0/+2
[ Upstream commit 02ce2c2c24024aade65a8d91d6a596651eaf2d0a ] When the Get Device Flags command fails, it returns the error status with the parameters filled with the garbage values. Although the parameters are not used, it is better to fill with zero than the random values. Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19Bluetooth: L2CAP: Fix invalid access on ECRED Connection responseLuiz Augusto von Dentz1-2/+2
[ Upstream commit de895b43932cb47e69480540be7eca289af24f23 ] The use of l2cap_chan_del is not safe under a loop using list_for_each_entry. Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19Bluetooth: L2CAP: Fix invalid access if ECRED Reconfigure failsLuiz Augusto von Dentz1-2/+2
[ Upstream commit 1fa20d7d4aad02206e84b74915819fbe9f81dab3 ] The use of l2cap_chan_del is not safe under a loop using list_for_each_entry. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19Bluetooth: Shutdown controller after workqueues are flushed or cancelledKai-Heng Feng1-8/+8
[ Upstream commit 0ea9fd001a14ebc294f112b0361a4e601551d508 ] Rfkill block and unblock Intel USB Bluetooth [8087:0026] may make it stops working: [ 509.691509] Bluetooth: hci0: HCI reset during shutdown failed [ 514.897584] Bluetooth: hci0: MSFT filter_enable is already on [ 530.044751] usb 3-10: reset full-speed USB device number 5 using xhci_hcd [ 545.660350] usb 3-10: device descriptor read/64, error -110 [ 561.283530] usb 3-10: device descriptor read/64, error -110 [ 561.519682] usb 3-10: reset full-speed USB device number 5 using xhci_hcd [ 566.686650] Bluetooth: hci0: unexpected event for opcode 0x0500 [ 568.752452] Bluetooth: hci0: urb 0000000096cd309b failed to resubmit (113) [ 578.797955] Bluetooth: hci0: Failed to read MSFT supported features (-110) [ 586.286565] Bluetooth: hci0: urb 00000000c522f633 failed to resubmit (113) [ 596.215302] Bluetooth: hci0: Failed to read MSFT supported features (-110) Or kernel panics because other workqueues already freed skb: [ 2048.663763] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 2048.663775] #PF: supervisor read access in kernel mode [ 2048.663779] #PF: error_code(0x0000) - not-present page [ 2048.663782] PGD 0 P4D 0 [ 2048.663787] Oops: 0000 [#1] SMP NOPTI [ 2048.663793] CPU: 3 PID: 4491 Comm: rfkill Tainted: G W 5.13.0-rc1-next-20210510+ #20 [ 2048.663799] Hardware name: HP HP EliteBook 850 G8 Notebook PC/8846, BIOS T76 Ver. 01.01.04 12/02/2020 [ 2048.663801] RIP: 0010:__skb_ext_put+0x6/0x50 [ 2048.663814] Code: 8b 1b 48 85 db 75 db 5b 41 5c 5d c3 be 01 00 00 00 e8 de 13 c0 ff eb e7 be 02 00 00 00 e8 d2 13 c0 ff eb db 0f 1f 44 00 00 55 <8b> 07 48 89 e5 83 f8 01 74 14 b8 ff ff ff ff f0 0f c1 07 83 f8 01 [ 2048.663819] RSP: 0018:ffffc1d105b6fd80 EFLAGS: 00010286 [ 2048.663824] RAX: 0000000000000000 RBX: ffff9d9ac5649000 RCX: 0000000000000000 [ 2048.663827] RDX: ffffffffc0d1daf6 RSI: 0000000000000206 RDI: 0000000000000000 [ 2048.663830] RBP: ffffc1d105b6fd98 R08: 0000000000000001 R09: ffff9d9ace8ceac0 [ 2048.663834] R10: ffff9d9ace8ceac0 R11: 0000000000000001 R12: ffff9d9ac5649000 [ 2048.663838] R13: 0000000000000000 R14: 00007ffe0354d650 R15: 0000000000000000 [ 2048.663843] FS: 00007fe02ab19740(0000) GS:ffff9d9e5f8c0000(0000) knlGS:0000000000000000 [ 2048.663849] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2048.663853] CR2: 0000000000000000 CR3: 0000000111a52004 CR4: 0000000000770ee0 [ 2048.663856] PKRU: 55555554 [ 2048.663859] Call Trace: [ 2048.663865] ? skb_release_head_state+0x5e/0x80 [ 2048.663873] kfree_skb+0x2f/0xb0 [ 2048.663881] btusb_shutdown_intel_new+0x36/0x60 [btusb] [ 2048.663905] hci_dev_do_close+0x48c/0x5e0 [bluetooth] [ 2048.663954] ? __cond_resched+0x1a/0x50 [ 2048.663962] hci_rfkill_set_block+0x56/0xa0 [bluetooth] [ 2048.664007] rfkill_set_block+0x98/0x170 [ 2048.664016] rfkill_fop_write+0x136/0x1e0 [ 2048.664022] vfs_write+0xc7/0x260 [ 2048.664030] ksys_write+0xb1/0xe0 [ 2048.664035] ? exit_to_user_mode_prepare+0x37/0x1c0 [ 2048.664042] __x64_sys_write+0x1a/0x20 [ 2048.664048] do_syscall_64+0x40/0xb0 [ 2048.664055] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 2048.664060] RIP: 0033:0x7fe02ac23c27 [ 2048.664066] Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 [ 2048.664070] RSP: 002b:00007ffe0354d638 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 2048.664075] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fe02ac23c27 [ 2048.664078] RDX: 0000000000000008 RSI: 00007ffe0354d650 RDI: 0000000000000003 [ 2048.664081] RBP: 0000000000000000 R08: 0000559b05998440 R09: 0000559b05998440 [ 2048.664084] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 [ 2048.664086] R13: 0000000000000000 R14: ffffffff00000000 R15: 00000000ffffffff So move the shutdown callback to a place where workqueues are either flushed or cancelled to resolve the issue. Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19Bluetooth: Fix alt settings for incoming SCO with transparent coding formatKiran K1-3/+3
[ Upstream commit 06d213d8a89a6f55b708422c3dda2b22add10748 ] For incoming SCO connection with transparent coding format, alt setting of CVSD is getting applied instead of Transparent. Before fix: < HCI Command: Accept Synchron.. (0x01|0x0029) plen 21 #2196 [hci0] 321.342548 Address: 1C:CC:D6:E2:EA:80 (Xiaomi Communications Co Ltd) Transmit bandwidth: 8000 Receive bandwidth: 8000 Max latency: 13 Setting: 0x0003 Input Coding: Linear Input Data Format: 1's complement Input Sample Size: 8-bit # of bits padding at MSB: 0 Air Coding Format: Transparent Data Retransmission effort: Optimize for link quality (0x02) Packet type: 0x003f HV1 may be used HV2 may be used HV3 may be used EV3 may be used EV4 may be used EV5 may be used > HCI Event: Command Status (0x0f) plen 4 #2197 [hci0] 321.343585 Accept Synchronous Connection Request (0x01|0x0029) ncmd 1 Status: Success (0x00) > HCI Event: Synchronous Connect Comp.. (0x2c) plen 17 #2198 [hci0] 321.351666 Status: Success (0x00) Handle: 257 Address: 1C:CC:D6:E2:EA:80 (Xiaomi Communications Co Ltd) Link type: eSCO (0x02) Transmission interval: 0x0c Retransmission window: 0x04 RX packet length: 60 TX packet length: 60 Air mode: Transparent (0x03) ........ > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2336 [hci0] 321.383655 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #2337 [hci0] 321.389558 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2338 [hci0] 321.393615 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2339 [hci0] 321.393618 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2340 [hci0] 321.393618 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #2341 [hci0] 321.397070 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2342 [hci0] 321.403622 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2343 [hci0] 321.403625 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2344 [hci0] 321.403625 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2345 [hci0] 321.403625 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #2346 [hci0] 321.404569 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #2347 [hci0] 321.412091 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2348 [hci0] 321.413626 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2349 [hci0] 321.413630 > SCO Data RX: Handle 257 flags 0x00 dlen 48 #2350 [hci0] 321.413630 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #2351 [hci0] 321.419674 After fix: < HCI Command: Accept Synchronou.. (0x01|0x0029) plen 21 #309 [hci0] 49.439693 Address: 1C:CC:D6:E2:EA:80 (Xiaomi Communications Co Ltd) Transmit bandwidth: 8000 Receive bandwidth: 8000 Max latency: 13 Setting: 0x0003 Input Coding: Linear Input Data Format: 1's complement Input Sample Size: 8-bit # of bits padding at MSB: 0 Air Coding Format: Transparent Data Retransmission effort: Optimize for link quality (0x02) Packet type: 0x003f HV1 may be used HV2 may be used HV3 may be used EV3 may be used EV4 may be used EV5 may be used > HCI Event: Command Status (0x0f) plen 4 #310 [hci0] 49.440308 Accept Synchronous Connection Request (0x01|0x0029) ncmd 1 Status: Success (0x00) > HCI Event: Synchronous Connect Complete (0x2c) plen 17 #311 [hci0] 49.449308 Status: Success (0x00) Handle: 257 Address: 1C:CC:D6:E2:EA:80 (Xiaomi Communications Co Ltd) Link type: eSCO (0x02) Transmission interval: 0x0c Retransmission window: 0x04 RX packet length: 60 TX packet length: 60 Air mode: Transparent (0x03) < SCO Data TX: Handle 257 flags 0x00 dlen 60 #312 [hci0] 49.450421 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #313 [hci0] 49.457927 > HCI Event: Max Slots Change (0x1b) plen 3 #314 [hci0] 49.460345 Handle: 256 Max slots: 5 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #315 [hci0] 49.465453 > SCO Data RX: Handle 257 flags 0x00 dlen 60 #316 [hci0] 49.470502 > SCO Data RX: Handle 257 flags 0x00 dlen 60 #317 [hci0] 49.470519 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #318 [hci0] 49.472996 > SCO Data RX: Handle 257 flags 0x00 dlen 60 #319 [hci0] 49.480412 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #320 [hci0] 49.480492 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #321 [hci0] 49.487989 > SCO Data RX: Handle 257 flags 0x00 dlen 60 #322 [hci0] 49.490303 < SCO Data TX: Handle 257 flags 0x00 dlen 60 #323 [hci0] 49.495496 > SCO Data RX: Handle 257 flags 0x00 dlen 60 #324 [hci0] 49.500304 > SCO Data RX: Handle 257 flags 0x00 dlen 60 #325 [hci0] 49.500311 Signed-off-by: Kiran K <kiran.k@intel.com> Signed-off-by: Lokendra Singh <lokendra.singh@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19Bluetooth: Fix the HCI to MGMT status conversion tableYu Liu1-0/+3
[ Upstream commit 4ef36a52b0e47c80bbfd69c0cce61c7ae9f541ed ] 0x2B, 0x31 and 0x33 are reserved for future use but were not present in the HCI to MGMT conversion table, this caused the conversion to be incorrect for the HCI status code greater than 0x2A. Reviewed-by: Miao-chen Chou <mcchou@chromium.org> Signed-off-by: Yu Liu <yudiliu@google.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19net: ip: avoid OOM kills with large UDP sends over loopbackJakub Kicinski2-29/+35
[ Upstream commit 6d123b81ac615072a8525c13c6c41b695270a15d ] Dave observed number of machines hitting OOM on the UDP send path. The workload seems to be sending large UDP packets over loopback. Since loopback has MTU of 64k kernel will try to allocate an skb with up to 64k of head space. This has a good chance of failing under memory pressure. What's worse if the message length is <32k the allocation may trigger an OOM killer. This is entirely avoidable, we can use an skb with page frags. af_unix solves a similar problem by limiting the head length to SKB_MAX_ALLOC. This seems like a good and simple approach. It means that UDP messages > 16kB will now use fragments if underlying device supports SG, if extra allocator pressure causes regressions in real workloads we can switch to trying the large allocation first and falling back. v4: pre-calculate all the additions to alloclen so we can be sure it won't go over order-2 Reported-by: Dave Jones <dsj@fb.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19mac80211: consider per-CPU statistics if presentJohannes Berg1-8/+3
[ Upstream commit d656a4c6ead6c3f252b2f2532bc9735598f7e317 ] If we have been keeping per-CPU statistics, consider them regardless of USES_RSS, because we may not actually fill those, for example in non-fast-RX cases when the connection is not compatible with fast-RX. If we didn't fill them, the additional data will be zero and not affect anything, and if we did fill them then it's more correct to consider them. This fixes an issue in mesh mode where some statistics are not updated due to USES_RSS being set, but fast-RX isn't used. Reported-by: Thiraviyam Mariyappan <tmariyap@codeaurora.org> Link: https://lore.kernel.org/r/20210610220814.13b35f5797c5.I511e9b33c5694e0d6cef4b6ae755c873d7c22124@changeid Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19cfg80211: fix default HE tx bitrate mask in 2G bandPing-Ke Shih1-5/+4
[ Upstream commit 9df66d5b9f45c39b3925d16e8947cc10009b186d ] In 2G band, a HE sta can only supports HT and HE, but not supports VHT. In this case, default HE tx bitrate mask isn't filled, when we use iw to set bitrates without any parameter. Signed-off-by: Ping-Ke Shih <pkshih@realtek.com> Link: https://lore.kernel.org/r/20210609075944.51130-1-pkshih@realtek.com Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19wireless: wext-spy: Fix out-of-bounds warningGustavo A. R. Silva1-7/+7
[ Upstream commit e93bdd78406da9ed01554c51e38b2a02c8ef8025 ] Fix the following out-of-bounds warning: net/wireless/wext-spy.c:178:2: warning: 'memcpy' offset [25, 28] from the object at 'threshold' is out of the bounds of referenced subobject 'low' with type 'struct iw_quality' at offset 20 [-Warray-bounds] The problem is that the original code is trying to copy data into a couple of struct members adjacent to each other in a single call to memcpy(). This causes a legitimate compiler warning because memcpy() overruns the length of &threshold.low and &spydata->spy_thr_low. As these are just a couple of struct members, fix this by using direct assignments, instead of memcpy(). This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210422200032.GA168995@embeddedor Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19vsock: notify server to shutdown when client has pending signalLongpeng(Mike)1-1/+1
[ Upstream commit c7ff9cff70601ea19245d997bb977344663434c7 ] The client's sk_state will be set to TCP_ESTABLISHED if the server replay the client's connect request. However, if the client has pending signal, its sk_state will be set to TCP_CLOSE without notify the server, so the server will hold the corrupt connection. client server 1. sk_state=TCP_SYN_SENT | 2. call ->connect() | 3. wait reply | | 4. sk_state=TCP_ESTABLISHED | 5. insert to connected list | 6. reply to the client 7. sk_state=TCP_ESTABLISHED | 8. insert to connected list | 9. *signal pending* <--------------------- the user kill client 10. sk_state=TCP_CLOSE | client is exiting... | 11. call ->release() | virtio_transport_close if (!(sk->sk_state == TCP_ESTABLISHED || sk->sk_state == TCP_CLOSING)) return true; *return at here, the server cannot notice the connection is corrupt* So the client should notify the peer in this case. Cc: David S. Miller <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Jorgen Hansen <jhansen@vmware.com> Cc: Norbert Slusarek <nslusarek@gmx.net> Cc: Andra Paraschiv <andraprs@amazon.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: David Brazdil <dbrazdil@google.com> Cc: Alexander Popov <alex.popov@linux.com> Suggested-by: Stefano Garzarella <sgarzare@redhat.com> Link: https://lkml.org/lkml/2021/5/17/418 Signed-off-by: lixianming <lixianming5@huawei.com> Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19net: sched: fix error return code in tcf_del_walker()Yang Yingliang1-1/+2
[ Upstream commit 55d96f72e8ddc0a294e0b9c94016edbb699537e1 ] When nla_put_u32() fails, 'ret' could be 0, it should return error code in tcf_del_walker(). Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19xfrm: Fix error reporting in xfrm_state_construct.Steffen Klassert1-14/+14
[ Upstream commit 6fd06963fa74197103cdbb4b494763127b3f2f34 ] When memory allocation for XFRMA_ENCAP or XFRMA_COADDR fails, the error will not be reported because the -ENOMEM assignment to the err variable is overwritten before. Fix this by moving these two in front of the function so that memory allocation failures will be reported. Reported-by: Tobias Brunner <tobias@strongswan.org> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19net: bridge: mrp: Update ring transitions.Horatiu Vultur1-4/+2
[ Upstream commit fcb34635854a5a5814227628867ea914a9805384 ] According to the standard IEC 62439-2, the number of transitions needs to be counted for each transition 'between' ring state open and ring state closed and not from open state to closed state. Therefore fix this for both ring and interconnect ring. Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19net: tcp better handling of reordering then loss casesYuchung Cheng1-19/+26
[ Upstream commit a29cb6914681a55667436a9eb7a42e28da8cf387 ] This patch aims to improve the situation when reordering and loss are ocurring in the same flight of packets. Previously the reordering would first induce a spurious recovery, then the subsequent ACK may undo the cwnd (based on the timestamps e.g.). However the current loss recovery does not proceed to invoke RACK to install a reordering timer. If some packets are also lost, this may lead to a long RTO-based recovery. An example is https://groups.google.com/g/bbr-dev/c/OFHADvJbTEI The solution is to after reverting the recovery, always invoke RACK to either mount the RACK timer to fast retransmit after the reordering window, or restarts the recovery if new loss is identified. Hence it is possible the sender may go from Recovery to Disorder/Open to Recovery again in one ACK. Reported-by: mingkun bian <bianmingkun@gmail.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19ipv6: use prandom_u32() for ID generationWilly Tarreau1-23/+5
[ Upstream commit 62f20e068ccc50d6ab66fdb72ba90da2b9418c99 ] This is a complement to commit aa6dd211e4b1 ("inet: use bigger hash table for IP ID generation"), but focusing on some specific aspects of IPv6. Contary to IPv4, IPv6 only uses packet IDs with fragments, and with a minimum MTU of 1280, it's much less easy to force a remote peer to produce many fragments to explore its ID sequence. In addition packet IDs are 32-bit in IPv6, which further complicates their analysis. On the other hand, it is often easier to choose among plenty of possible source addresses and partially work around the bigger hash table the commit above permits, which leaves IPv6 partially exposed to some possibilities of remote analysis at the risk of weakening some protocols like DNS if some IDs can be predicted with a good enough probability. Given the wide range of permitted IDs, the risk of collision is extremely low so there's no need to rely on the positive increment algorithm that is shared with the IPv4 code via ip_idents_reserve(). We have a fast PRNG, so let's simply call prandom_u32() and be done with it. Performance measurements at 10 Gbps couldn't show any difference with the previous code, even when using a single core, because due to the large fragments, we're limited to only ~930 kpps at 10 Gbps and the cost of the random generation is completely offset by other operations and by the network transfer time. In addition, this change removes the need to update a shared entry in the idents table so it may even end up being slightly faster on large scale systems where this matters. The risk of at least one collision here is about 1/80 million among 10 IDs, 1/850k among 100 IDs, and still only 1/8.5k among 1000 IDs, which remains very low compared to IPv4 where all IDs are reused every 4 to 80ms on a 10 Gbps flow depending on packet sizes. Reported-by: Amit Klein <aksecurity@gmail.com> Signed-off-by: Willy Tarreau <w@1wt.eu> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20210529110746.6796-1-w@1wt.eu Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19net/sched: cls_api: increase max_reclassify_loopDavide Caratti1-1/+1
[ Upstream commit 05ff8435e50569a0a6b95e5ceaea43696e8827ab ] modern userspace applications, like OVN, can configure the TC datapath to "recirculate" packets several times. If more than 4 "recirculation" rules are configured, packets can be dropped by __tcf_classify(). Changing the maximum number of reclassifications (from 4 to 16) should be sufficient to prevent drops in most use cases, and guard against loops at the same time. Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-19net: Treat __napi_schedule_irqoff() as __napi_schedule() on PREEMPT_RTSebastian Andrzej Siewior1-2/+9
[ Upstream commit 8380c81d5c4fced6f4397795a5ae65758272bbfd ] __napi_schedule_irqoff() is an optimized version of __napi_schedule() which can be used where it is known that interrupts are disabled, e.g. in interrupt-handlers, spin_lock_irq() sections or hrtimer callbacks. On PREEMPT_RT enabled kernels this assumptions is not true. Force- threaded interrupt handlers and spinlocks are not disabling interrupts and the NAPI hrtimer callback is forced into softirq context which runs with interrupts enabled as well. Chasing all usage sites of __napi_schedule_irqoff() is a whack-a-mole game so make __napi_schedule_irqoff() invoke __napi_schedule() for PREEMPT_RT kernels. The callers of ____napi_schedule() in the networking core have been audited and are correct on PREEMPT_RT kernels as well. Reported-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14net: tipc: fix FB_MTU eat two pagesMenglong Dong3-11/+11
[ Upstream commit 0c6de0c943dbb42831bf7502eb5c007f71e752d2 ] FB_MTU is used in 'tipc_msg_build()' to alloc smaller skb when memory allocation fails, which can avoid unnecessary sending failures. The value of FB_MTU now is 3744, and the data size will be: (3744 + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + \ SKB_DATA_ALIGN(BUF_HEADROOM + BUF_TAILROOM + 3)) which is larger than one page(4096), and two pages will be allocated. To avoid it, replace '3744' with a calculation: (PAGE_SIZE - SKB_DATA_ALIGN(BUF_OVERHEAD) - \ SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) What's more, alloc_skb_fclone() will call SKB_DATA_ALIGN for data size, and it's not necessary to make alignment for buf_size in tipc_buf_acquire(). So, just remove it. Fixes: 4c94cc2d3d57 ("tipc: fall back to smaller MTU if allocation of local send skb fails") Signed-off-by: Menglong Dong <dong.menglong@zte.com.cn> Acked-by: Jon Maloy <jmaloy@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14net: sched: fix warning in tcindex_alloc_perfect_hashPavel Skripkin1-1/+1
[ Upstream commit 3f2db250099f46988088800052cdf2332c7aba61 ] Syzbot reported warning in tcindex_alloc_perfect_hash. The problem was in too big cp->hash, which triggers warning in kmalloc. Since cp->hash comes from userspace, there is no need to warn if value is not correct Fixes: b9a24bb76bf6 ("net_sched: properly handle failure case of tcf_exts_init()") Reported-and-tested-by: syzbot+1071ad60cd7df39fdadb@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Acked-by: Cong Wang <cong.wang@bytedance.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14net: lwtunnel: handle MTU calculation in forwadingVadim Fedorenko1-1/+2
[ Upstream commit fade56410c22cacafb1be9f911a0afd3701d8366 ] Commit 14972cbd34ff ("net: lwtunnel: Handle fragmentation") moved fragmentation logic away from lwtunnel by carry encap headroom and use it in output MTU calculation. But the forwarding part was not covered and created difference in MTU for output and forwarding and further to silent drops on ipv4 forwarding path. Fix it by taking into account lwtunnel encap headroom. The same commit also introduced difference in how to treat RTAX_MTU in IPv4 and IPv6 where latter explicitly removes lwtunnel encap headroom from route MTU. Make IPv4 version do the same. Fixes: 14972cbd34ff ("net: lwtunnel: Handle fragmentation") Suggested-by: David Ahern <dsahern@gmail.com> Signed-off-by: Vadim Fedorenko <vfedorenko@novek.ru> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14Bluetooth: Fix handling of HCI_LE_Advertising_Set_Terminated eventLuiz Augusto von Dentz1-1/+12
[ Upstream commit 23837a6d7a1a61818ed94a6b8af552d6cf7d32d5 ] Error status of this event means that it has ended due reasons other than a connection: 'If advertising has terminated as a result of the advertising duration elapsing, the Status parameter shall be set to the error code Advertising Timeout (0x3C).' 'If advertising has terminated because the Max_Extended_Advertising_Events was reached, the Status parameter shall be set to the error code Limit Reached (0x43).' Fixes: acf0aeae431a0 ("Bluetooth: Handle ADv set terminated event") Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14Bluetooth: Fix Set Extended (Scan Response) DataLuiz Augusto von Dentz1-22/+29
[ Upstream commit c9ed0a7077306f9d41d74fb006ab5dbada8349c5 ] These command do have variable length and the length can go up to 251, so this changes the struct to not use a fixed size and then when creating the PDU only the actual length of the data send to the controller. Fixes: a0fb3726ba551 ("Bluetooth: Use Set ext adv/scan rsp data if controller supports") Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14Bluetooth: Fix not sending Set Extended Scan ResponseLuiz Augusto von Dentz1-8/+6
[ Upstream commit a76a0d365077711594ce200a9553ed6d1ff40276 ] Current code is actually failing on the following tests of mgmt-tester because get_adv_instance_scan_rsp_len did not account for flags that cause scan response data to be included resulting in non-scannable instance when in fact it should be scannable. Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14Bluetooth: mgmt: Fix slab-out-of-bounds in tlv_data_is_validLuiz Augusto von Dentz1-0/+3
[ Upstream commit 799acb9347915bfe4eac0ff2345b468f0a1ca207 ] This fixes parsing of LTV entries when the length is 0. Found with: tools/mgmt-tester -s "Add Advertising - Success (ScRsp only)" Add Advertising - Success (ScRsp only) - run Sending Add Advertising (0x003e) Test condition added, total 1 [ 11.004577] ================================================================== [ 11.005292] BUG: KASAN: slab-out-of-bounds in tlv_data_is_valid+0x87/0xe0 [ 11.005984] Read of size 1 at addr ffff888002c695b0 by task mgmt-tester/87 [ 11.006711] [ 11.007176] [ 11.007429] Allocated by task 87: [ 11.008151] [ 11.008438] The buggy address belongs to the object at ffff888002c69580 [ 11.008438] which belongs to the cache kmalloc-64 of size 64 [ 11.010526] The buggy address is located 48 bytes inside of [ 11.010526] 64-byte region [ffff888002c69580, ffff888002c695c0) [ 11.012423] The buggy address belongs to the page: [ 11.013291] [ 11.013544] Memory state around the buggy address: [ 11.014359] ffff888002c69480: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 11.015453] ffff888002c69500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 11.016232] >ffff888002c69580: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc [ 11.017010] ^ [ 11.017547] ffff888002c69600: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc [ 11.018296] ffff888002c69680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 11.019116] ================================================================== Fixes: 2bb36870e8cb2 ("Bluetooth: Unify advertising instance flags check") Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14bpfilter: Specify the log level for the kmsg messageGary Lin1-1/+1
[ Upstream commit a196fa78a26571359740f701cf30d774eb8a72cb ] Per the kmsg document [0], if we don't specify the log level with a prefix "<N>" in the message string, the default log level will be applied to the message. Since the default level could be warning(4), this would make the log utility such as journalctl treat the message, "Started bpfilter", as a warning. To avoid confusion, this commit adds the prefix "<5>" to make the message always a notice. [0] https://www.kernel.org/doc/Documentation/ABI/testing/dev-kmsg Fixes: 36c4357c63f3 ("net: bpfilter: print umh messages to /dev/kmsg") Reported-by: Martin Loviska <mloviska@suse.com> Signed-off-by: Gary Lin <glin@suse.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Dmitrii Banshchikov <me@ubique.spb.ru> Link: https://lore.kernel.org/bpf/20210623040918.8683-1-glin@suse.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14ipv6: fix out-of-bound access in ip6_parse_tlv()Eric Dumazet1-14/+13
[ Upstream commit 624085a31c1ad6a80b1e53f686bf6ee92abbf6e8 ] First problem is that optlen is fetched without checking there is more than one byte to parse. Fix this by taking care of IPV6_TLV_PAD1 before fetching optlen (under appropriate sanity checks against len) Second problem is that IPV6_TLV_PADN checks of zero padding are performed before the check of remaining length. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: c1412fce7ecc ("net/ipv6/exthdrs.c: Strict PadN option checking") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14bpf: Do not change gso_size during bpf_skb_change_proto()Maciej Żenczykowski1-4/+0
[ Upstream commit 364745fbe981a4370f50274475da4675661104df ] This is technically a backwards incompatible change in behaviour, but I'm going to argue that it is very unlikely to break things, and likely to fix *far* more then it breaks. In no particular order, various reasons follow: (a) I've long had a bug assigned to myself to debug a super rare kernel crash on Android Pixel phones which can (per stacktrace) be traced back to BPF clat IPv6 to IPv4 protocol conversion causing some sort of ugly failure much later on during transmit deep in the GSO engine, AFAICT precisely because of this change to gso_size, though I've never been able to manually reproduce it. I believe it may be related to the particular network offload support of attached USB ethernet dongle being used for tethering off of an IPv6-only cellular connection. The reason might be we end up with more segments than max permitted, or with a GSO packet with only one segment... (either way we break some assumption and hit a BUG_ON) (b) There is no check that the gso_size is > 20 when reducing it by 20, so we might end up with a negative (or underflowing) gso_size or a gso_size of 0. This can't possibly be good. Indeed this is probably somehow exploitable (or at least can result in a kernel crash) by delivering crafted packets and perhaps triggering an infinite loop or a divide by zero... As a reminder: gso_size (MSS) is related to MTU, but not directly derived from it: gso_size/MSS may be significantly smaller then one would get by deriving from local MTU. And on some NICs (which do loose MTU checking on receive, it may even potentially be larger, for example my work pc with 1500 MTU can receive 1520 byte frames [and sometimes does due to bugs in a vendor plat46 implementation]). Indeed even just going from 21 to 1 is potentially problematic because it increases the number of segments by a factor of 21 (think DoS, or some other crash due to too many segments). (c) It's always safe to not increase the gso_size, because it doesn't result in the max packet size increasing. So the skb_increase_gso_size() call was always unnecessary for correctness (and outright undesirable, see later). As such the only part which is potentially dangerous (ie. could cause backwards compatibility issues) is the removal of the skb_decrease_gso_size() call. (d) If the packets are ultimately destined to the local device, then there is absolutely no benefit to playing around with gso_size. It only matters if the packets will egress the device. ie. we're either forwarding, or transmitting from the device. (e) This logic only triggers for packets which are GSO. It does not trigger for skbs which are not GSO. It will not convert a non-GSO MTU sized packet into a GSO packet (and you don't even know what the MTU is, so you can't even fix it). As such your transmit path must *already* be able to handle an MTU 20 bytes larger then your receive path (for IPv4 to IPv6 translation) - and indeed 28 bytes larger due to IPv4 fragments. Thus removing the skb_decrease_gso_size() call doesn't actually increase the size of the packets your transmit side must be able to handle. ie. to handle non-GSO max-MTU packets, the IPv4/IPv6 device/ route MTUs must already be set correctly. Since for example with an IPv4 egress MTU of 1500, IPv4 to IPv6 translation will already build 1520 byte IPv6 frames, so you need a 1520 byte device MTU. This means if your IPv6 device's egress MTU is 1280, your IPv4 route must be 1260 (and actually 1252, because of the need to handle fragments). This is to handle normal non-GSO packets. Thus the reduction is simply not needed for GSO packets, because when they're correctly built, they will already be the right size. (f) TSO/GSO should be able to exactly undo GRO: the number of packets (TCP segments) should not be modified, so that TCP's MSS counting works correctly (this matters for congestion control). If protocol conversion changes the gso_size, then the number of TCP segments may increase or decrease. Packet loss after protocol conversion can result in partial loss of MSS segments that the sender sent. How's the sending TCP stack going to react to receiving ACKs/SACKs in the middle of the segments it sent? (g) skb_{decrease,increase}_gso_size() are already no-ops for GSO_BY_FRAGS case (besides triggering WARN_ON_ONCE). This means you already cannot guarantee that gso_size (and thus resulting packet MTU) is changed. ie. you must assume it won't be changed. (h) changing gso_size is outright buggy for UDP GSO packets, where framing matters (I believe that's also the case for SCTP, but it's already excluded by [g]). So the only remaining case is TCP, which also doesn't want it (see [f]). (i) see also the reasoning on the previous attempt at fixing this (commit fa7b83bf3b156c767f3e4a25bbf3817b08f3ff8e) which shows that the current behaviour causes TCP packet loss: In the forwarding path GRO -> BPF 6 to 4 -> GSO for TCP traffic, the coalesced packet payload can be > MSS, but < MSS + 20. bpf_skb_proto_6_to_4() will upgrade the MSS and it can be > the payload length. After then tcp_gso_segment checks for the payload length if it is <= MSS. The condition is causing the packet to be dropped. tcp_gso_