| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-21652: ipvlan: Fix use-after-free in ipvlan_get_iflink(). |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ipvlan: Fix use-after-free in ipvlan_get_iflink(). |
| |
| syzbot presented an use-after-free report [0] regarding ipvlan and |
| linkwatch. |
| |
| ipvlan does not hold a refcnt of the lower device unlike vlan and |
| macvlan. |
| |
| If the linkwatch work is triggered for the ipvlan dev, the lower dev |
| might have already been freed, resulting in UAF of ipvlan->phy_dev in |
| ipvlan_get_iflink(). |
| |
| We can delay the lower dev unregistration like vlan and macvlan by |
| holding the lower dev's refcnt in dev->netdev_ops->ndo_init() and |
| releasing it in dev->priv_destructor(). |
| |
| Jakub pointed out calling .ndo_XXX after unregister_netdevice() has |
| returned is error prone and suggested [1] addressing this UAF in the |
| core by taking commit 750e51603395 ("net: avoid potential UAF in |
| default_operstate()") further. |
| |
| Let's assume unregistering devices DOWN and use RCU protection in |
| default_operstate() not to race with the device unregistration. |
| |
| [0]: |
| BUG: KASAN: slab-use-after-free in ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353 |
| Read of size 4 at addr ffff0000d768c0e0 by task kworker/u8:35/6944 |
| |
| CPU: 0 UID: 0 PID: 6944 Comm: kworker/u8:35 Not tainted 6.13.0-rc2-g9bc5c9515b48 #12 4c3cb9e8b4565456f6a355f312ff91f4f29b3c47 |
| Hardware name: linux,dummy-virt (DT) |
| Workqueue: events_unbound linkwatch_event |
| Call trace: |
| show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:484 (C) |
| __dump_stack lib/dump_stack.c:94 [inline] |
| dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120 |
| print_address_description mm/kasan/report.c:378 [inline] |
| print_report+0x16c/0x6f0 mm/kasan/report.c:489 |
| kasan_report+0xc0/0x120 mm/kasan/report.c:602 |
| __asan_report_load4_noabort+0x20/0x30 mm/kasan/report_generic.c:380 |
| ipvlan_get_iflink+0x84/0x88 drivers/net/ipvlan/ipvlan_main.c:353 |
| dev_get_iflink+0x7c/0xd8 net/core/dev.c:674 |
| default_operstate net/core/link_watch.c:45 [inline] |
| rfc2863_policy+0x144/0x360 net/core/link_watch.c:72 |
| linkwatch_do_dev+0x60/0x228 net/core/link_watch.c:175 |
| __linkwatch_run_queue+0x2f4/0x5b8 net/core/link_watch.c:239 |
| linkwatch_event+0x64/0xa8 net/core/link_watch.c:282 |
| process_one_work+0x700/0x1398 kernel/workqueue.c:3229 |
| process_scheduled_works kernel/workqueue.c:3310 [inline] |
| worker_thread+0x8c4/0xe10 kernel/workqueue.c:3391 |
| kthread+0x2b0/0x360 kernel/kthread.c:389 |
| ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 |
| |
| Allocated by task 9303: |
| kasan_save_stack mm/kasan/common.c:47 [inline] |
| kasan_save_track+0x30/0x68 mm/kasan/common.c:68 |
| kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568 |
| poison_kmalloc_redzone mm/kasan/common.c:377 [inline] |
| __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394 |
| kasan_kmalloc include/linux/kasan.h:260 [inline] |
| __do_kmalloc_node mm/slub.c:4283 [inline] |
| __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4289 |
| __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:650 |
| alloc_netdev_mqs+0xb4/0x1118 net/core/dev.c:11209 |
| rtnl_create_link+0x2b8/0xb60 net/core/rtnetlink.c:3595 |
| rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3771 |
| __rtnl_newlink net/core/rtnetlink.c:3896 [inline] |
| rtnl_newlink+0x122c/0x15c0 net/core/rtnetlink.c:4011 |
| rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6901 |
| netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2542 |
| rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6928 |
| netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] |
| netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1347 |
| netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1891 |
| sock_sendmsg_nosec net/socket.c:711 [inline] |
| __sock_sendmsg net/socket.c:726 [inline] |
| __sys_sendto+0x2ec/0x438 net/socket.c:2197 |
| __do_sys_sendto net/socket.c:2204 [inline] |
| __se_sys_sendto net/socket.c:2200 [inline] |
| __arm64_sys_sendto+0xe4/0x110 net/socket.c:2200 |
| __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] |
| invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49 |
| el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132 |
| do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151 |
| el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744 |
| el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762 |
| el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600 |
| |
| Freed by task 10200: |
| kasan_save_stack mm/kasan/common.c:47 [inline] |
| kasan_save_track+0x30/0x68 mm/kasan/common.c:68 |
| kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:582 |
| poison_slab_object mm/kasan/common.c:247 [inline] |
| __kasan_slab_free+0x48/0x68 mm/kasan/common.c:264 |
| kasan_slab_free include/linux/kasan.h:233 [inline] |
| slab_free_hook mm/slub.c:2338 [inline] |
| slab_free mm/slub.c:4598 [inline] |
| kfree+0x140/0x420 mm/slub.c:4746 |
| kvfree+0x4c/0x68 mm/util.c:693 |
| netdev_release+0x94/0xc8 net/core/net-sysfs.c:2034 |
| device_release+0x98/0x1c0 |
| kobject_cleanup lib/kobject.c:689 [inline] |
| kobject_release lib/kobject.c:720 [inline] |
| kref_put include/linux/kref.h:65 [inline] |
| kobject_put+0x2b0/0x438 lib/kobject.c:737 |
| netdev_run_todo+0xdd8/0xf48 net/core/dev.c:10924 |
| rtnl_unlock net/core/rtnetlink.c:152 [inline] |
| rtnl_net_unlock net/core/rtnetlink.c:209 [inline] |
| rtnl_dellink+0x484/0x680 net/core/rtnetlink.c:3526 |
| rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6901 |
| netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2542 |
| rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6928 |
| netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] |
| netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1347 |
| netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1891 |
| sock_sendmsg_nosec net/socket.c:711 [inline] |
| __sock_sendmsg net/socket.c:726 [inline] |
| ____sys_sendmsg+0x410/0x708 net/socket.c:2583 |
| ___sys_sendmsg+0x178/0x1d8 net/socket.c:2637 |
| __sys_sendmsg net/socket.c:2669 [inline] |
| __do_sys_sendmsg net/socket.c:2674 [inline] |
| __se_sys_sendmsg net/socket.c:2672 [inline] |
| __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2672 |
| __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] |
| invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49 |
| el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132 |
| do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151 |
| el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744 |
| el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762 |
| el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600 |
| |
| The buggy address belongs to the object at ffff0000d768c000 |
| which belongs to the cache kmalloc-cg-4k of size 4096 |
| The buggy address is located 224 bytes inside of |
| freed 4096-byte region [ffff0000d768c000, ffff0000d768d000) |
| |
| The buggy address belongs to the physical page: |
| page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117688 |
| head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 |
| memcg:ffff0000c77ef981 |
| flags: 0xbfffe0000000040(head|node=0|zone=2|lastcpupid=0x1ffff) |
| page_type: f5(slab) |
| raw: 0bfffe0000000040 ffff0000c000f500 dead000000000100 dead000000000122 |
| raw: 0000000000000000 0000000000040004 00000001f5000000 ffff0000c77ef981 |
| head: 0bfffe0000000040 ffff0000c000f500 dead000000000100 dead000000000122 |
| head: 0000000000000000 0000000000040004 00000001f5000000 ffff0000c77ef981 |
| head: 0bfffe0000000003 fffffdffc35da201 ffffffffffffffff 0000000000000000 |
| head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 |
| page dumped because: kasan: bad access detected |
| |
| Memory state around the buggy address: |
| ffff0000d768bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ffff0000d768c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| >ffff0000d768c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ^ |
| ffff0000d768c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| ffff0000d768c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb |
| |
| The Linux kernel CVE team has assigned CVE-2025-21652 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.2 with commit 8c55facecd7ade835287298ce325f930d888d8ec and fixed in 6.6.72 with commit ba9f7c16ec879c83bb4f80406773a911aace8267 |
| Issue introduced in 6.2 with commit 8c55facecd7ade835287298ce325f930d888d8ec and fixed in 6.12.10 with commit 52a24538d569f48e79d1a169a5d359d384152950 |
| Issue introduced in 6.2 with commit 8c55facecd7ade835287298ce325f930d888d8ec and fixed in 6.13 with commit cb358ff94154774d031159b018adf45e17673941 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-21652 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/core/link_watch.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/ba9f7c16ec879c83bb4f80406773a911aace8267 |
| https://git.kernel.org/stable/c/52a24538d569f48e79d1a169a5d359d384152950 |
| https://git.kernel.org/stable/c/cb358ff94154774d031159b018adf45e17673941 |
