6.6-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit 9593172d93b9f91c362baec4643003dc29802929 ]
syzkaller reported a use-after-free in geneve_find_dev() [0] without repro.
geneve_configure() links struct geneve_dev.next to net_generic(net, geneve_net_id)->geneve_list.
The net here could differ from dev_net(dev) if IFLA_NET_NS_PID, IFLA_NET_NS_FD, or IFLA_TARGET_NETNSID is set.
When dev_net(dev) is dismantled, geneve_exit_batch_rtnl() finally calls unregister_netdevice_queue() for each dev in the netns, and later the dev is freed.
However, its geneve_dev.next is still linked to the backend UDP socket netns.
Then, use-after-free will occur when another geneve dev is created in the netns.
Let's call geneve_dellink() instead in geneve_destroy_tunnels().
[0]: BUG: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline] BUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343 Read of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441
CPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24 dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (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_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379 geneve_find_dev drivers/net/geneve.c:1295 [inline] geneve_configure+0x234/0x858 drivers/net/geneve.c:1343 geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634 rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568 ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622 __sys_sendmsg net/socket.c:2654 [inline] __do_sys_sendmsg net/socket.c:2659 [inline] __se_sys_sendmsg net/socket.c:2657 [inline] __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657 __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
Allocated by task 13247: 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:4298 [inline] __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304 __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645 alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470 rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604 rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780 __rtnl_newlink net/core/rtnetlink.c:3906 [inline] rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021 rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911 netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543 rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:713 [inline] __sock_sendmsg net/socket.c:728 [inline] ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568 ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622 __sys_sendmsg net/socket.c:2654 [inline] __do_sys_sendmsg net/socket.c:2659 [inline] __se_sys_sendmsg net/socket.c:2657 [inline] __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657 __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 45: 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:2353 [inline] slab_free mm/slub.c:4613 [inline] kfree+0x140/0x420 mm/slub.c:4761 kvfree+0x4c/0x68 mm/util.c:688 netdev_release+0x94/0xc8 net/core/net-sysfs.c:2065 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+0xe5c/0xfc8 net/core/dev.c:11185 rtnl_unlock+0x20/0x38 net/core/rtnetlink.c:151 cleanup_net+0x4fc/0x8c0 net/core/net_namespace.c:648 process_one_work+0x700/0x1398 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x8c4/0xe10 kernel/workqueue.c:3398 kthread+0x4bc/0x608 kernel/kthread.c:464 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862
The buggy address belongs to the object at ffff000054d6e000 which belongs to the cache kmalloc-cg-4k of size 4096 The buggy address is located 3620 bytes inside of freed 4096-byte region [ffff000054d6e000, ffff000054d6f000)
The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x94d68 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 memcg:ffff000016276181 flags: 0x3fffe0000000040(head|node=0|zone=0|lastcpupid=0x1ffff) page_type: f5(slab) raw: 03fffe0000000040 ffff0000c000f500 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000040004 00000001f5000000 ffff000016276181 head: 03fffe0000000040 ffff0000c000f500 dead000000000122 0000000000000000 head: 0000000000000000 0000000000040004 00000001f5000000 ffff000016276181 head: 03fffe0000000003 fffffdffc1535a01 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: ffff000054d6ed00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff000054d6ed80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff000054d6ee00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^ ffff000054d6ee80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff000054d6ef00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
Fixes: 2d07dc79fe04 ("geneve: add initial netdev driver for GENEVE tunnels") Reported-by: syzkaller syzkaller@googlegroups.com Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20250213043354.91368-1-kuniyu@amazon.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/geneve.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index b939d4711c59b..c2066f19295d4 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -1966,16 +1966,11 @@ static void geneve_destroy_tunnels(struct net *net, struct list_head *head) /* gather any geneve devices that were moved into this ns */ for_each_netdev_safe(net, dev, aux) if (dev->rtnl_link_ops == &geneve_link_ops) - unregister_netdevice_queue(dev, head); + geneve_dellink(dev, head);
/* now gather any other geneve devices that were created in this ns */ - list_for_each_entry_safe(geneve, next, &gn->geneve_list, next) { - /* If geneve->dev is in the same netns, it was already added - * to the list by the previous loop. - */ - if (!net_eq(dev_net(geneve->dev), net)) - unregister_netdevice_queue(geneve->dev, head); - } + list_for_each_entry_safe(geneve, next, &gn->geneve_list, next) + geneve_dellink(geneve->dev, head); }
static void __net_exit geneve_exit_batch_net(struct list_head *net_list)