From: Jianbo Liu <jianbol@nvidia.com> stable inclusion from stable-v6.6.152 commit 4d1fc1d990f81ee8b4168fdfac2e8e9fedc4e3d4 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18291 CVE: CVE-2026-74700 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 2ecd487b670fcbb1ad4893fff1af4aafdecb6023 ] The filter counter is updated under the protection of cb_lock in the cited commit. While waiting for the lock, it's possible the filter is being deleted by other thread, and thus causes UAF when dump it. Fix this issue by moving tcf_block_filter_cnt_update() after tfilter_put(). ================================================================== BUG: KASAN: slab-use-after-free in fl_dump_key+0x1d3e/0x20d0 [cls_flower] Read of size 4 at addr ffff88814f864000 by task tc/2973 CPU: 7 PID: 2973 Comm: tc Not tainted 6.9.0-rc2_for_upstream_debug_2024_04_02_12_41 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x7e/0xc0 print_report+0xc1/0x600 ? __virt_addr_valid+0x1cf/0x390 ? fl_dump_key+0x1d3e/0x20d0 [cls_flower] ? fl_dump_key+0x1d3e/0x20d0 [cls_flower] kasan_report+0xb9/0xf0 ? fl_dump_key+0x1d3e/0x20d0 [cls_flower] fl_dump_key+0x1d3e/0x20d0 [cls_flower] ? lock_acquire+0x1c2/0x530 ? fl_dump+0x172/0x5c0 [cls_flower] ? lockdep_hardirqs_on_prepare+0x400/0x400 ? fl_dump_key_options.part.0+0x10f0/0x10f0 [cls_flower] ? do_raw_spin_lock+0x12d/0x270 ? spin_bug+0x1d0/0x1d0 fl_dump+0x21d/0x5c0 [cls_flower] ? fl_tmplt_dump+0x1f0/0x1f0 [cls_flower] ? nla_put+0x15f/0x1c0 tcf_fill_node+0x51b/0x9a0 ? tc_skb_ext_tc_enable+0x150/0x150 ? __alloc_skb+0x17b/0x310 ? __build_skb_around+0x340/0x340 ? down_write+0x1b0/0x1e0 tfilter_notify+0x1a5/0x390 ? fl_terse_dump+0x400/0x400 [cls_flower] tc_new_tfilter+0x963/0x2170 ? tc_del_tfilter+0x1490/0x1490 ? print_usage_bug.part.0+0x670/0x670 ? lock_downgrade+0x680/0x680 ? security_capable+0x51/0x90 ? tc_del_tfilter+0x1490/0x1490 rtnetlink_rcv_msg+0x75e/0xac0 ? if_nlmsg_stats_size+0x4c0/0x4c0 ? lockdep_set_lock_cmp_fn+0x190/0x190 ? __netlink_lookup+0x35e/0x6e0 netlink_rcv_skb+0x12c/0x360 ? if_nlmsg_stats_size+0x4c0/0x4c0 ? netlink_ack+0x15e0/0x15e0 ? lockdep_hardirqs_on_prepare+0x400/0x400 ? netlink_deliver_tap+0xcd/0xa60 ? netlink_deliver_tap+0xcd/0xa60 ? netlink_deliver_tap+0x1c9/0xa60 netlink_unicast+0x43e/0x700 ? netlink_attachskb+0x750/0x750 ? lock_acquire+0x1c2/0x530 ? __might_fault+0xbb/0x170 netlink_sendmsg+0x749/0xc10 ? netlink_unicast+0x700/0x700 ? __might_fault+0xbb/0x170 ? netlink_unicast+0x700/0x700 __sock_sendmsg+0xc5/0x190 ____sys_sendmsg+0x534/0x6b0 ? import_iovec+0x7/0x10 ? kernel_sendmsg+0x30/0x30 ? __copy_msghdr+0x3c0/0x3c0 ? entry_SYSCALL_64_after_hwframe+0x46/0x4e ? lock_acquire+0x1c2/0x530 ? __virt_addr_valid+0x116/0x390 ___sys_sendmsg+0xeb/0x170 ? __virt_addr_valid+0x1ca/0x390 ? copy_msghdr_from_user+0x110/0x110 ? __delete_object+0xb8/0x100 ? __virt_addr_valid+0x1cf/0x390 ? do_sys_openat2+0x102/0x150 ? lockdep_hardirqs_on_prepare+0x284/0x400 ? do_sys_openat2+0x102/0x150 ? __fget_light+0x53/0x1d0 ? sockfd_lookup_light+0x1a/0x150 __sys_sendmsg+0xb5/0x140 ? __sys_sendmsg_sock+0x20/0x20 ? lock_downgrade+0x680/0x680 do_syscall_64+0x70/0x140 entry_SYSCALL_64_after_hwframe+0x46/0x4e RIP: 0033:0x7f98e3713367 Code: 0e 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b9 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 RSP: 002b:00007ffc74a64608 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000047eae0 RCX: 00007f98e3713367 RDX: 0000000000000000 RSI: 00007ffc74a64670 RDI: 0000000000000003 RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000 R10: 00007f98e360c5e8 R11: 0000000000000246 R12: 00007ffc74a6a508 R13: 00000000660d518d R14: 0000000000484a80 R15: 00007ffc74a6a50b </TASK> Allocated by task 2973: kasan_save_stack+0x20/0x40 kasan_save_track+0x10/0x30 __kasan_kmalloc+0x77/0x90 fl_change+0x27a6/0x4540 [cls_flower] tc_new_tfilter+0x879/0x2170 rtnetlink_rcv_msg+0x75e/0xac0 netlink_rcv_skb+0x12c/0x360 netlink_unicast+0x43e/0x700 netlink_sendmsg+0x749/0xc10 __sock_sendmsg+0xc5/0x190 ____sys_sendmsg+0x534/0x6b0 ___sys_sendmsg+0xeb/0x170 __sys_sendmsg+0xb5/0x140 do_syscall_64+0x70/0x140 entry_SYSCALL_64_after_hwframe+0x46/0x4e Freed by task 283: kasan_save_stack+0x20/0x40 kasan_save_track+0x10/0x30 kasan_save_free_info+0x37/0x50 poison_slab_object+0x105/0x190 __kasan_slab_free+0x11/0x30 kfree+0x111/0x340 process_one_work+0x787/0x1490 worker_thread+0x586/0xd30 kthread+0x2df/0x3b0 ret_from_fork+0x2d/0x70 ret_from_fork_asm+0x11/0x20 Last potentially related work creation: kasan_save_stack+0x20/0x40 __kasan_record_aux_stack+0x9b/0xb0 insert_work+0x25/0x1b0 __queue_work+0x640/0xc90 rcu_work_rcufn+0x42/0x70 rcu_core+0x6a9/0x1850 __do_softirq+0x264/0x88f Second to last potentially related work creation: kasan_save_stack+0x20/0x40 __kasan_record_aux_stack+0x9b/0xb0 __call_rcu_common.constprop.0+0x6f/0xac0 queue_rcu_work+0x56/0x70 fl_mask_put+0x20d/0x270 [cls_flower] __fl_delete+0x352/0x6b0 [cls_flower] fl_delete+0x97/0x160 [cls_flower] tc_del_tfilter+0x7d1/0x1490 rtnetlink_rcv_msg+0x75e/0xac0 netlink_rcv_skb+0x12c/0x360 netlink_unicast+0x43e/0x700 netlink_sendmsg+0x749/0xc10 __sock_sendmsg+0xc5/0x190 ____sys_sendmsg+0x534/0x6b0 ___sys_sendmsg+0xeb/0x170 __sys_sendmsg+0xb5/0x140 do_syscall_64+0x70/0x140 entry_SYSCALL_64_after_hwframe+0x46/0x4e Fixes: 2081fd3445fe ("net: sched: cls_api: add filter counter") Signed-off-by: Jianbo Liu <jianbol@nvidia.com> Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com> Tested-by: Asbjørn Sloth Tønnesen <ast@fiberby.net> Signed-off-by: David S. Miller <davem@davemloft.net> Stable-dep-of: a347304b2ca1 ("net/sched: cls_api: Always acquire rtnl_lock when destroying locked classifiers") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Dong Chenchen <dongchenchen2@huawei.com> --- net/sched/cls_api.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index f16cfc23014b..1eedeaf42729 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -2384,22 +2384,22 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n, if (!rtnl_held) flags |= TCA_ACT_FLAGS_NO_RTNL; if (is_qdisc_ingress(parent)) flags |= TCA_ACT_FLAGS_AT_INGRESS; if (is_ingress_or_clsact(block, q)) flags |= TCA_ACT_FLAGS_AT_INGRESS_OR_CLSACT; err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh, flags, extack); if (err == 0) { - tcf_block_filter_cnt_update(block, &tp->counted, true); tfilter_notify(net, skb, n, tp, block, q, parent, fh, RTM_NEWTFILTER, false, rtnl_held, extack); tfilter_put(tp, fh); + tcf_block_filter_cnt_update(block, &tp->counted, true); /* q pointer is NULL for shared blocks */ if (q) q->flags &= ~TCQ_F_CAN_BYPASS; } errout: if (err && tp_created) tcf_chain_tp_delete_empty(chain, tp, rtnl_held, NULL); errout_tp: -- 2.43.0