kernel/git/next/linux-next.git/net/sched/act_api.c, branch stable

net/sched: add get_fill_size callbacks for actions missing them

2026-08-20T19:16:43+00:00

Several tc actions - act_police, act_bpf, act_pedit, act_ife, act_sample, act_ct, act_ctinfo and act_tunnel_key among them - provide no get_fill_size() callback, so tcf_action_fill_size() falls back to tcf_action_shared_attrs_size() which does not account for the action-specific netlink attributes emitted inside TCA_ACT_OPTIONS by their dump functions. When an RTM_NEWACTION request with NLM_F_ECHO (or an RTNLGRP_TC listener) creates several actions, tcf_add_notify_msg() allocates the echo skb from this underestimated size. When this happens, the act_api code fails to add all of the fields to the netlink message and, thus, fails to send it. Issue is that, when that happens, this failure doesn't stop the action instances from being added. So any user watching these events will be under the false impression that no actions were created at all. For example, act_pedit overruns with 32 actions of four munge keys each, act_police with 32 policers once the optional rate/peakrate/result/avrate attributes are present. To fix this, add the missing get_fill_size callbacks returning the worst-case size of each action's dump attributes, following the pattern used by act_gact/act_skbedit/act_vlan. Also widen the TCA_GACT_TM accounting in tcf_action_shared_attrs_size() to nla_total_size_64bit(), since actions dump their tcf_t with nla_put_64bit(), which may be preceded by an NLA_PAD attribute. Note: We only provided fixes for the actions we reproduced this bug with as of today. We can send a separate hardening patch for the remaining actions to net-next later. The other pre-existing issues, pointed out by Clashiko [1], will be fixed in upcoming patches. [1] https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260810164357.1653956-1-victor%40mojatatu.com Fixes: 4e76e75d6aba ("net sched actions: calculate add/delete event message size") Reported-by: Vega Acked-by: Jamal Hadi Salim Signed-off-by: Victor Nogueira Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260816201327.2435335-1-victor@mojatatu.com Signed-off-by: Jakub Kicinski

net/sched: act_api: fix TOCTOU NULL deref on a->goto_chain

2026-08-12T01:21:46+00:00

tcf_action_exec() handles TC_ACT_GOTO_CHAIN by first checking rcu_access_pointer(a->goto_chain) and then calling tcf_action_goto_chain_exec(), which does a second, independent rcu_dereference_bh(a->goto_chain) read and immediately dereferences chain->filter_chain. A concurrent tcf_action_set_ctrlact() (e.g. the gact replace path) can clear a->goto_chain between the two reads, so the second read returns NULL and tcf_action_goto_chain_exec() dereferences NULL. Fix the race by doing a single rcu_dereference_bh() read of a->goto_chain in tcf_action_exec(), checking it once for NULL, and passing the resulting chain pointer into tcf_action_goto_chain_exec(). This turns the split check/use into a single check/use on one value. Fixes: ee3bbfe806cd ("net/sched: let actions use RCU to access 'goto_chain'") Reported-by: vega@nebusec.ai Tested-by: Victor Nogueira Signed-off-by: Jamal Hadi Salim Reviewed-by: Davide Caratti Link: https://patch.msgid.link/20260809090928.868186-1-jhs@mojatatu.com Signed-off-by: Jakub Kicinski

net/sched: act_pedit: fix TOCTOU heap OOB write in tc offload

2026-07-06T10:52:01+00:00

There is a TOCTOU race condition in flower lockless approach between sizing a flow_rule buffer and filling it. zdi-disclosures@trendmicro.com reports: The cls_flower classifier operates with TCF_PROTO_OPS_DOIT_UNLOCKED (fl_change runs without RTNL), while RTM_NEWACTION holds RTNL, so the independent locking domains make the race reachable in practice. KASAN confirms: BUG: KASAN: slab-out-of-bounds in tcf_pedit_offload_act_setup+0x81b/0x930 Write of size 4 at addr ffff888001f27520 by task poc-toctou/312 The buggy address is located 0 bytes to the right of allocated 288-byte region [ffff888001f27400, ffff888001f27520) (cache kmalloc-512) Note: The result is a heap OOB write attacker-controlled content into the adjacent slab object (requires CAP_NET_ADMIN). The fix introduces reading tcfp_nkeys under act->tcfa_lock in all places using a new tcf_pedit_nkeys_locked() which replaces the old tcf_pedit_nkeys(). Additionally we close the remaining TOCTOU window between the sizing read and the fill reads by more careful accounting. Rather than silently truncating the key count, which leads to incorrect action semantics offloaded to hardware and secondary OOB writes if the remaining capacity is zero or consumed by prior actions, we enforce remaining capacity checks and return -ENOSPC if the required space exceeds the remaining capacity. Fixes: 71d0ed7079df ("net/act_pedit: Support using offset relative to the conventional network headers") Reported-by: zdi-disclosures@trendmicro.com Tested-by: Victor Nogueira Signed-off-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260701161912.125355-1-jhs@mojatatu.com Signed-off-by: Paolo Abeni

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2026-06-04T22:29:04+00:00

Cross-merge networking fixes after downstream PR (net-7.1-rc7). Silent conflicts: net/wireless/nl80211.c cb9959ab5f99 ("wifi: cfg80211: enforce HE/EHT cap/oper consistency") a384ae969902 ("wifi: cfg80211: move AP HT/VHT/... operation to beacon info") https://lore.kernel.org/aiGJDaHV4UlCexIQ@sirena.org.uk Conflicts: drivers/net/wireless/intel/iwlwifi/mld/ap.c a342c99cb70d ("wifi: iwlwifi: mld: honor BSS_CHANGED_BEACON_ENABLED") 9bf1b409afc7 ("wifi: iwlwifi: mld: send tx power constraints before link activation") https://lore.kernel.org/ah2bfedhV45ZxMO8@sirena.org.uk drivers/net/wireless/intel/iwlwifi/pcie/drv.c 093305d801fa ("wifi: iwlwifi: pcie: simplify the resume flow if fast resume is not used") e2323929a68a ("wifi: iwlwifi: pcie: add debug print for resume flow if powered off") https://lore.kernel.org/ah2bfedhV45ZxMO8@sirena.org.uk Adjacent changes: drivers/net/ethernet/airoha/airoha_eth.c b38cae85d1c4 ("net: airoha: Fix use-after-free in metadata dst teardown") ec6c391bcca7 ("net: airoha: Introduce airoha_gdm_dev struct") drivers/net/ethernet/microchip/lan743x_main.c 8173d22b211f ("net: lan743x: permit VLAN-tagged packets up to configured MTU") e3c6508a46f5 ("net: lan743x: avoid netdev-based logging before netdev registration") Signed-off-by: Jakub Kicinski

net/sched: act_api: use RCU with deferred freeing for action lifecycle

2026-06-01T23:52:08+00:00

When NEWTFILTER and DELFILTER are run concurrently it is possible to create a race with an associated action. Let's illustrate with CPU0 running NEWTFILTER and CPU1 running DELFILTER: 0: mutex_lock() <-- holds the idr lock 0: rcu_read_lock() 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR) 0: mutex_unlock() <-- releases the idr lock 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) <-- Action removed from IDR 1: mutex_unlock() <-- mutex released allowing us to delete the action 1: tcf_action_cleanup(p); kfree(p) <-- Kfrees p immediately, no deferral 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- ouch, UAF p points to freed memory This patch fixes the race condition between NEWTFILTER and DELFILTER by adding struct rcu_head to tc_action used in the deferral and introducing a call_rcu() in the delete path to defer the final kfree(). Note: this is a revert of commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu") but also modernization/simplification to directly use kfree_rcu(). Let's illustrate the new restored code path: 0: rcu_read_lock() 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) 1: mutex_unlock() 1: call_rcu(&p->tcfa_rcu, tcf_action_rcu_free) <-- defer kfree after grace period 0: p = idr_find(idr, index) 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- fails, refcnt already 0 1: rcu_read_unlock() <-- release so freeing can run after grace period After CPU1 calls idr_remove(), the object is no longer reachable through the IDR. CPU0's subsequent idr_find() will return NULL, and even if it still held a stale pointer, the immediate kfree() is now deferred until after the RCU grace period, so no UAF can occur. Fixes: d7fb60b9cafb ("net_sched: get rid of tcfa_rcu") Suggested-by: Jakub Kicinski Reported-by: Kyle Zeng Tested-by: Victor Nogueira Tested-by: syzbot@syzkaller.appspotmail.com Signed-off-by: Jamal Hadi Salim Tested-by: Kyle Zeng Reviewed-by: Pedro Tammela Reviewed-by: Eric Dumazet Reviewed-by: Victor Nogueira Link: https://patch.msgid.link/20260531160812.68020-1-jhs@mojatatu.com Signed-off-by: Jakub Kicinski

net/sched: add qstats_cpu_drop_inc() helper

2026-05-05T01:59:07+00:00

1) Using this_cpu_inc() is better than going through this_cpu_ptr(): - Single instruction on x86. - Store tearing prevention. 2) Change tcf_action_update_stats() to use this_cpu_add(). 3) Add WRITE_ONCE() to __qdisc_qstats_drop() and qstats_drop_inc() in preparation for lockless "tc qdisc show". $ scripts/bloat-o-meter -t vmlinux.old vmlinux.new add/remove: 0/0 grow/shrink: 3/17 up/down: 72/-216 (-144) Function old new delta dualpi2_enqueue_skb 462 511 +49 tcf_ife_act 1061 1077 +16 taprio_enqueue 613 620 +7 codel_qdisc_enqueue 149 143 -6 tcf_vlan_act 684 676 -8 tcf_skbedit_act 626 618 -8 tcf_police_act 725 717 -8 tcf_mpls_act 1297 1289 -8 tcf_gate_act 310 302 -8 tcf_gact_act 222 214 -8 tcf_csum_act 2438 2430 -8 tcf_bpf_act 709 701 -8 tcf_action_update_stats 124 115 -9 pie_qdisc_enqueue 865 856 -9 pfifo_enqueue 116 107 -9 choke_enqueue 2069 2059 -10 plug_enqueue 139 128 -11 bfifo_enqueue 121 110 -11 tcf_nat_act 1501 1489 -12 gred_enqueue 1743 1668 -75 Total: Before=24388609, After=24388465, chg -0.00% Signed-off-by: Eric Dumazet Reviewed-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260501135916.2566766-1-edumazet@google.com Signed-off-by: Jakub Kicinski

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

net/sched: act_api: avoid dereferencing ERR_PTR in tcf_idrinfo_destroy

2026-01-07T01:27:18+00:00

syzbot reported a crash in tc_act_in_hw() during netns teardown where tcf_idrinfo_destroy() passed an ERR_PTR(-EBUSY) value as a tc_action pointer, leading to an invalid dereference. Guard against ERR_PTR entries when iterating the action IDR so teardown does not call tc_act_in_hw() on an error pointer. Fixes: 84a7d6797e6a ("net/sched: acp_api: no longer acquire RTNL in tc_action_net_exit()") Link: https://syzkaller.appspot.com/bug?extid=8f1c492ffa4644ff3826 Reported-by: syzbot+8f1c492ffa4644ff3826@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=8f1c492ffa4644ff3826 Signed-off-by: Shivani Gupta Link: https://patch.msgid.link/20260105005905.243423-1-shivani07g@gmail.com Signed-off-by: Jakub Kicinski

net_sched: act: remove tcfa_qstats

2025-09-02T22:52:24+00:00

tcfa_qstats is currently only used to hold drops and overlimits counters. tcf_action_inc_drop_qstats() and tcf_action_inc_overlimit_qstats() currently acquire a->tcfa_lock to increment these counters. Switch to two atomic_t to get lock-free accounting. Signed-off-by: Eric Dumazet Reviewed-by: Jamal Hadi Salim Link: https://patch.msgid.link/20250901093141.2093176-1-edumazet@google.com Signed-off-by: Jakub Kicinski