From nobody Fri Dec 19 18:47:03 2025 Received: from mx0b-0064b401.pphosted.com (mx0b-0064b401.pphosted.com [205.220.178.238]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E94F438DDB; Fri, 18 Apr 2025 01:25:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.178.238 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744939516; cv=none; b=HpChLu1wKt6iRw7W13kjlrS9sFv2em5r9FQDU7PsBXpDyI5f8ptdHK91kpzZscUV+sxmkZ2WhA/vu79JMaUCpPK2KHz0Swd4n4IbAAriPGWyh1Mib/0vbIME74l93k+AdY9Bq/2dpLWCBmzfUWiWf/KBAPXsNt255g0jS7YaYlE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744939516; c=relaxed/simple; bh=Pzb2r00wnq8Ee0+602c09KcWkGB3jnFjn2OjMWlrACg=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=hI9NjmMEid/D7zagiJWL/0xnGkE4kxjWlFFJRwGAPYw37315/J8L+gdOeU04q2M99v4wgfaVaYjcWS4oaJuvrlTms234jnPar822TqvBsHtHUNZ3iZKeB8G5CXIAo/+L3NBgwST3P1QUY3i+XtYZdo9/oz7l3Sb2S9g/GYlkNLg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com; spf=pass smtp.mailfrom=windriver.com; arc=none smtp.client-ip=205.220.178.238 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=windriver.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=windriver.com Received: from pps.filterd (m0250811.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 53I0pgLv032617; Fri, 18 Apr 2025 01:24:17 GMT Received: from ala-exchng02.corp.ad.wrs.com (ala-exchng02.wrs.com [147.11.82.254]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 45ydd1q582-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Fri, 18 Apr 2025 01:24:16 +0000 (GMT) Received: from ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) by ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.43; Thu, 17 Apr 2025 18:24:15 -0700 Received: from pek-lpg-core1.wrs.com (147.11.136.210) by ALA-EXCHNG02.corp.ad.wrs.com (147.11.82.254) with Microsoft SMTP Server id 15.1.2507.43 via Frontend Transport; Thu, 17 Apr 2025 18:24:10 -0700 From: To: , CC: , , , , , , , , , , , , , , , Subject: [PATCH 5.15.y] net: defer final 'struct net' free in netns dismantle Date: Fri, 18 Apr 2025 09:24:09 +0800 Message-ID: <20250418012409.2059897-1-jianqi.ren.cn@windriver.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-ORIG-GUID: LZQcCXxRCoyVPrJ1MGLCQvgJ72NDD0sG X-Proofpoint-GUID: LZQcCXxRCoyVPrJ1MGLCQvgJ72NDD0sG X-Authority-Analysis: v=2.4 cv=HecUTjE8 c=1 sm=1 tr=0 ts=6801a9c0 cx=c_pps a=K4BcnWQioVPsTJd46EJO2w==:117 a=K4BcnWQioVPsTJd46EJO2w==:17 a=XR8D0OoHHMoA:10 a=VwQbUJbxAAAA:8 a=pGLkceISAAAA:8 a=bC-a23v3AAAA:8 a=1XWaLZrsAAAA:8 a=P8mRVJMrAAAA:8 a=20KFwNOVAAAA:8 a=vggBfdFIAAAA:8 a=t7CeM3EgAAAA:8 a=sogmP-z4RixR6Pyh5rEA:9 a=-FEs8UIgK8oA:10 a=FO4_E8m0qiDe52t0p3_H:22 a=Vc1QvrjMcIoGonisw6Ob:22 a=FdTzh2GWekK77mhwV6Dw:22 X-Sensitive_Customer_Information: Yes X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-17_07,2025-04-17_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 phishscore=0 malwarescore=0 priorityscore=1501 spamscore=0 bulkscore=0 adultscore=0 mlxlogscore=999 impostorscore=0 suspectscore=0 clxscore=1015 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.21.0-2502280000 definitions=main-2504180007 Content-Type: text/plain; charset="utf-8" From: Eric Dumazet [ Upstream commit 0f6ede9fbc747e2553612271bce108f7517e7a45 ] Ilya reported a slab-use-after-free in dst_destroy [1] Issue is in xfrm6_net_init() and xfrm4_net_init() : They copy xfrm[46]_dst_ops_template into net->xfrm.xfrm[46]_dst_ops. But net structure might be freed before all the dst callbacks are called. So when dst_destroy() calls later : if (dst->ops->destroy) dst->ops->destroy(dst); dst->ops points to the old net->xfrm.xfrm[46]_dst_ops, which has been freed. See a relevant issue fixed in : ac888d58869b ("net: do not delay dst_entries_add() in dst_release()") A fix is to queue the 'struct net' to be freed after one another cleanup_net() round (and existing rcu_barrier()) [1] BUG: KASAN: slab-use-after-free in dst_destroy (net/core/dst.c:112) Read of size 8 at addr ffff8882137ccab0 by task swapper/37/0 Dec 03 05:46:18 kernel: CPU: 37 UID: 0 PID: 0 Comm: swapper/37 Kdump: loaded Not tainted 6.12.0 #67 Hardware name: Red Hat KVM/RHEL, BIOS 1.16.1-1.el9 04/01/2014 Call Trace: dump_stack_lvl (lib/dump_stack.c:124) print_address_description.constprop.0 (mm/kasan/report.c:378) ? dst_destroy (net/core/dst.c:112) print_report (mm/kasan/report.c:489) ? dst_destroy (net/core/dst.c:112) ? kasan_addr_to_slab (mm/kasan/common.c:37) kasan_report (mm/kasan/report.c:603) ? dst_destroy (net/core/dst.c:112) ? rcu_do_batch (kernel/rcu/tree.c:2567) dst_destroy (net/core/dst.c:112) rcu_do_batch (kernel/rcu/tree.c:2567) ? __pfx_rcu_do_batch (kernel/rcu/tree.c:2491) ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4339 kernel/locking= /lockdep.c:4406) rcu_core (kernel/rcu/tree.c:2825) handle_softirqs (kernel/softirq.c:554) __irq_exit_rcu (kernel/softirq.c:589 kernel/softirq.c:428 kernel/softirq.c:= 637) irq_exit_rcu (kernel/softirq.c:651) sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1049 arch/x86/kern= el/apic/apic.c:1049) asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702) RIP: 0010:default_idle (./arch/x86/include/asm/irqflags.h:37 ./arch/x86/inc= lude/asm/irqflags.h:92 arch/x86/kernel/process.c:743) Code: 00 4d 29 c8 4c 01 c7 4c 29 c2 e9 6e ff ff ff 90 90 90 90 90 90 90 90 = 90 90 90 90 90 90 90 90 66 90 0f 00 2d c7 c9 27 00 fb f4 c3 cc cc cc c= c 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 RSP: 0018:ffff888100d2fe00 EFLAGS: 00000246 RAX: 00000000001870ed RBX: 1ffff110201a5fc2 RCX: ffffffffb61a3e46 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffb3d4d123 RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed11c7e1835d R10: ffff888e3f0c1aeb R11: 0000000000000000 R12: 0000000000000000 R13: ffff888100d20000 R14: dffffc0000000000 R15: 0000000000000000 ? ct_kernel_exit.constprop.0 (kernel/context_tracking.c:148) ? cpuidle_idle_call (kernel/sched/idle.c:186) default_idle_call (./include/linux/cpuidle.h:143 kernel/sched/idle.c:118) cpuidle_idle_call (kernel/sched/idle.c:186) ? __pfx_cpuidle_idle_call (kernel/sched/idle.c:168) ? lock_release (kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5848) ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4347 kernel/locking= /lockdep.c:4406) ? tsc_verify_tsc_adjust (arch/x86/kernel/tsc_sync.c:59) do_idle (kernel/sched/idle.c:326) cpu_startup_entry (kernel/sched/idle.c:423 (discriminator 1)) start_secondary (arch/x86/kernel/smpboot.c:202 arch/x86/kernel/smpboot.c:28= 2) ? __pfx_start_secondary (arch/x86/kernel/smpboot.c:232) ? soft_restart_cpu (arch/x86/kernel/head_64.S:452) common_startup_64 (arch/x86/kernel/head_64.S:414) Dec 03 05:46:18 kernel: Allocated by task 12184: kasan_save_stack (mm/kasan/common.c:48) kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 = mm/kasan/common.c:69) __kasan_slab_alloc (mm/kasan/common.c:319 mm/kasan/common.c:345) kmem_cache_alloc_noprof (mm/slub.c:4085 mm/slub.c:4134 mm/slub.c:4141) copy_net_ns (net/core/net_namespace.c:421 net/core/net_namespace.c:480) create_new_namespaces (kernel/nsproxy.c:110) unshare_nsproxy_namespaces (kernel/nsproxy.c:228 (discriminator 4)) ksys_unshare (kernel/fork.c:3313) __x64_sys_unshare (kernel/fork.c:3382) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Dec 03 05:46:18 kernel: Freed by task 11: kasan_save_stack (mm/kasan/common.c:48) kasan_save_track (./arch/x86/include/asm/current.h:49 mm/kasan/common.c:60 = mm/kasan/common.c:69) kasan_save_free_info (mm/kasan/generic.c:582) __kasan_slab_free (mm/kasan/common.c:271) kmem_cache_free (mm/slub.c:4579 mm/slub.c:4681) cleanup_net (net/core/net_namespace.c:456 net/core/net_namespace.c:446 net/= core/net_namespace.c:647) process_one_work (kernel/workqueue.c:3229) worker_thread (kernel/workqueue.c:3304 kernel/workqueue.c:3391) kthread (kernel/kthread.c:389) ret_from_fork (arch/x86/kernel/process.c:147) ret_from_fork_asm (arch/x86/entry/entry_64.S:257) Dec 03 05:46:18 kernel: Last potentially related work creation: kasan_save_stack (mm/kasan/common.c:48) __kasan_record_aux_stack (mm/kasan/generic.c:541) insert_work (./include/linux/instrumented.h:68 ./include/asm-generic/bitops= /instrumented-non-atomic.h:141 kernel/workqueue.c:788 kernel/workqueue.c:79= 5 kernel/workqueue.c:2186) __queue_work (kernel/workqueue.c:2340) queue_work_on (kernel/workqueue.c:2391) xfrm_policy_insert (net/xfrm/xfrm_policy.c:1610) xfrm_add_policy (net/xfrm/xfrm_user.c:2116) xfrm_user_rcv_msg (net/xfrm/xfrm_user.c:3321) netlink_rcv_skb (net/netlink/af_netlink.c:2536) xfrm_netlink_rcv (net/xfrm/xfrm_user.c:3344) netlink_unicast (net/netlink/af_netlink.c:1316 net/netlink/af_netlink.c:134= 2) netlink_sendmsg (net/netlink/af_netlink.c:1886) sock_write_iter (net/socket.c:729 net/socket.c:744 net/socket.c:1165) vfs_write (fs/read_write.c:590 fs/read_write.c:683) ksys_write (fs/read_write.c:736) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Dec 03 05:46:18 kernel: Second to last potentially related work creation: kasan_save_stack (mm/kasan/common.c:48) __kasan_record_aux_stack (mm/kasan/generic.c:541) insert_work (./include/linux/instrumented.h:68 ./include/asm-generic/bitops= /instrumented-non-atomic.h:141 kernel/workqueue.c:788 kernel/workqueue.c:79= 5 kernel/workqueue.c:2186) __queue_work (kernel/workqueue.c:2340) queue_work_on (kernel/workqueue.c:2391) __xfrm_state_insert (./include/linux/workqueue.h:723 net/xfrm/xfrm_state.c:= 1150 net/xfrm/xfrm_state.c:1145 net/xfrm/xfrm_state.c:1513) xfrm_state_update (./include/linux/spinlock.h:396 net/xfrm/xfrm_state.c:194= 0) xfrm_add_sa (net/xfrm/xfrm_user.c:912) xfrm_user_rcv_msg (net/xfrm/xfrm_user.c:3321) netlink_rcv_skb (net/netlink/af_netlink.c:2536) xfrm_netlink_rcv (net/xfrm/xfrm_user.c:3344) netlink_unicast (net/netlink/af_netlink.c:1316 net/netlink/af_netlink.c:134= 2) netlink_sendmsg (net/netlink/af_netlink.c:1886) sock_write_iter (net/socket.c:729 net/socket.c:744 net/socket.c:1165) vfs_write (fs/read_write.c:590 fs/read_write.c:683) ksys_write (fs/read_write.c:736) do_syscall_64 (arch/x86/entry/common.c:52 arch/x86/entry/common.c:83) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Fixes: a8a572a6b5f2 ("xfrm: dst_entries_init() per-net dst_ops") Reported-by: Ilya Maximets Closes: https://lore.kernel.org/netdev/CANn89iKKYDVpB=3DMtmfH7nyv2p=3DrJWSL= edO5k7wSZgtY_tO8WQg@mail.gmail.com/T/#m02c98c3009fe66382b73cfb4db9cf1df6fab= 3fbf Signed-off-by: Eric Dumazet Acked-by: Paolo Abeni Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241204125455.3871859-1-edumazet@google.com Signed-off-by: Jakub Kicinski [Minor conflict resolved due to code context change.] Signed-off-by: Jianqi Ren Signed-off-by: He Zhe --- Verified the build test --- include/net/net_namespace.h | 1 + net/core/net_namespace.c | 21 ++++++++++++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index ff9ecc76d622..c3cc3a465955 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -80,6 +80,7 @@ struct net { * or to unregister pernet ops * (pernet_ops_rwsem write locked). */ + struct llist_node defer_free_list; struct llist_node cleanup_list; /* namespaces on death row */ =20 #ifdef CONFIG_KEYS diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 1e9e76c4ff5b..09ba69532273 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -440,11 +440,28 @@ static struct net *net_alloc(void) goto out; } =20 +static LLIST_HEAD(defer_free_list); + +static void net_complete_free(void) +{ + struct llist_node *kill_list; + struct net *net, *next; + + /* Get the list of namespaces to free from last round. */ + kill_list =3D llist_del_all(&defer_free_list); + + llist_for_each_entry_safe(net, next, kill_list, defer_free_list) + kmem_cache_free(net_cachep, net); + +} + static void net_free(struct net *net) { if (refcount_dec_and_test(&net->passive)) { kfree(rcu_access_pointer(net->gen)); - kmem_cache_free(net_cachep, net); + + /* Wait for an extra rcu_barrier() before final free. */ + llist_add(&net->defer_free_list, &defer_free_list); } } =20 @@ -628,6 +645,8 @@ static void cleanup_net(struct work_struct *work) */ rcu_barrier(); =20 + net_complete_free(); + /* Finally it is safe to free my network namespace structure */ list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) { list_del_init(&net->exit_list); --=20 2.34.1