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

net/sched: act_api: release all action references on NEWACTION failure

2026-09-10T16:06:05+00:00

When a batched RTM_NEWACTION request replaces an existing action, tcf_idr_check_alloc() takes a temporary reference on it. If a later action fails to initialize, tcf_action_destroy() uses strict release semantics to clean up the actions initialized so far. For an action bound to a filter, the strict check returns -EPERM without dropping the temporary reference. This error also makes tcf_action_destroy() return before releasing subsequent entries. Any new action initialized between the bound action and the failing entry is leaked together with its reserved IDR slot, preventing reuse of its index. Use tcf_idr_release() to drop each reference held by the batch without rejecting bound actions. This allows cleanup to continue through all initialized entries and preserves the module reference release when an action is destroyed. Explicit action deletion and flushing retain their separate bind-count checks. Fixes: 55334a5db5cd ("net_sched: act: refuse to remove bound action outside") Cc: stable@vger.kernel.org Signed-off-by: Xuanqiang Luo Reviewed-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260909070336.32979-2-xuanqiang.luo@linux.dev Signed-off-by: Jakub Kicinski

net/sched: act_api: fix skb sizing and action leak on reoffload delete

2026-08-28T22:56:06+00:00

tcf_reoffload_del_notify_msg() sizes the RTM_DELACTION skb with tcf_action_fill_size(action) alone. Unlike every other notification path it never wraps that in tcf_action_full_attrs_size(), so the nlmsg_put() header, struct tcamsg and the TCA_ACT_TAB nest that tca_get_fill() emits - 24 bytes on x86_64 - are not budgeted. As long as the single action stays well under NLMSG_GOODSIZE the floor in alloc_skb() hides this, but once its fill size crosses NLMSG_GOODSIZE the allocation is exactly 24 bytes short and tca_get_fill() runs out of tailroom. That is now easy to reach for an offloadable act_pedit with a large tcfp_nkeys, which commit 8e2efb3f45a5 ("net/sched: add get_fill_size callbacks for actions missing them") started accounting for properly. When that happens tcf_reoffload_del_notify() returns early, before tcf_idr_release_unsafe(), and tcf_action_reoffload_cb() discards the return value: if (tc_act_skip_sw(p->tcfa_flags) && !tc_act_in_hw(p)) tcf_reoffload_del_notify(net, p); The action has just lost its last hardware instance and is skip_sw, so it is left installed while processing no packets, and with no notification to tell userspace about it. An -ENOBUFS from alloc_skb() gets the same treatment. Fix this by budgeting the message header the way the add and delete paths do, and release the action even when the notification cannot be built - dropping the notification is strictly better than leaking a dead action, and there is no caller left to report the error to. Fixes: 13926d19a11e ("flow_offload: add reoffload process to update hw_count") Reported-by: Sashiko Closes: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260810164357.1653956-1-victor%40mojatatu.com Acked-by: Jamal Hadi Salim Signed-off-by: Victor Nogueira Reviewed-by: Pedro Tammela Link: https://patch.msgid.link/20260824153903.4143642-4-victor@mojatatu.com Signed-off-by: Jakub Kicinski

net/sched: act_api: size the RTM_GETACTION reply from the actions

2026-08-28T22:56:06+00:00

tca_action_gd() already walks every requested action and accumulates attr_size += tcf_action_fill_size(act), then wraps the result in tcf_action_full_attrs_size(). For RTM_DELACTION that value is handed to tcf_del_notify_msg(), which allocates max(attr_size, NLMSG_GOODSIZE). For RTM_GETACTION it is silently discarded and tcf_get_notify() allocates a fixed NLMSG_GOODSIZE skb instead. Any action whose dump exceeds that fixed budget therefore cannot be read back. For example, act_pedit overruns the budget with 32 actions of four munge keys each, act_police with 32 policers once the optional rate/peakrate/result/avrate attributes are present Fix this by passing attr_size through and allocate the reply the way the add and delete paths do. Note on exposure: RTM_GETACTION is the only one of the three action commands that is not capability checked - tc_ctl_action() requires CAP_NET_ADMIN for RTM_NEWACTION and RTM_DELACTION only - so this turns a fixed NLMSG_GOODSIZE reply into a user sized allocation on an unprivileged path. It is bounded by TCA_ACT_MAX_PRIO actions per request, and tca_action_gd() does not reject duplicate indices, so a single large action can be requested 32 times; an act_bpf program near BPF_MAXINSNS is about 32KB of dump, or roughly 1MB for one request. Creating such an action still requires CAP_NET_ADMIN, and the add and delete paths have sized their skbs this way since the Fixes commit. Should this ever need bounding, GFP_KERNEL_ACCOUNT would charge the reply to the caller's memcg. Fixes: 4e76e75d6aba ("net sched actions: calculate add/delete event message size") Reported-by: Sashiko Closes: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260810164357.1653956-1-victor%40mojatatu.com Acked-by: Jamal Hadi Salim Signed-off-by: Victor Nogueira Link: https://patch.msgid.link/20260824153903.4143642-3-victor@mojatatu.com Signed-off-by: Jakub Kicinski

net/sched: act_api: budget all shared attributes in notify skbs

2026-08-28T22:56:05+00:00

tcf_action_shared_attrs_size() is supposed to return an upper bound on the netlink attributes every action dump emits outside of TCA_ACT_OPTIONS, so that tcf_add_notify_msg(), tcf_del_notify_msg() and friends can allocate an skb large enough for the reply. It has fallen behind the dump path and is now an underestimate for every single action. Attributes, such as, TCA_ACT_IN_HW_COUNT and TCA_STATS_BASIC_HW are emitted unconditionally and never accounted for. TCA_STATS_PKT64, TCA_ACT_USED_HW_STATS, TCA_STATS_RATE_EST, TCA_STATS_RATE_EST64 require specific conditions, but are also not accounted for. Fix the issue by budgeting all of them so that we have a legitimate upper bound. Even tough for of them require specific conditions, they are cheap so, to avoid overcomplicating, we opted to account for them unconditionally as well to account for a real worst case scenario. Fixes: 4e76e75d6aba ("net sched actions: calculate add/delete event message size") Reported-by: Sashiko Closes: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260810164357.1653956-1-victor%40mojatatu.com Acked-by: Jamal Hadi Salim Signed-off-by: Victor Nogueira Link: https://patch.msgid.link/20260824153903.4143642-2-victor@mojatatu.com Signed-off-by: Jakub Kicinski

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