CVE-2025-21858

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> geneve: Fix use-after-free in geneve_find_dev().<br /> <br /> syzkaller reported a use-after-free in geneve_find_dev() [0]<br /> without repro.<br /> <br /> geneve_configure() links struct geneve_dev.next to<br /> net_generic(net, geneve_net_id)-&gt;geneve_list.<br /> <br /> The net here could differ from dev_net(dev) if IFLA_NET_NS_PID,<br /> IFLA_NET_NS_FD, or IFLA_TARGET_NETNSID is set.<br /> <br /> When dev_net(dev) is dismantled, geneve_exit_batch_rtnl() finally<br /> calls unregister_netdevice_queue() for each dev in the netns,<br /> and later the dev is freed.<br /> <br /> However, its geneve_dev.next is still linked to the backend UDP<br /> socket netns.<br /> <br /> Then, use-after-free will occur when another geneve dev is created<br /> in the netns.<br /> <br /> Let&amp;#39;s call geneve_dellink() instead in geneve_destroy_tunnels().<br /> <br /> [0]:<br /> BUG: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline]<br /> BUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343<br /> Read of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441<br /> <br /> CPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24 dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d<br /> Hardware name: linux,dummy-virt (DT)<br /> Call trace:<br /> show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (C)<br /> __dump_stack lib/dump_stack.c:94 [inline]<br /> dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120<br /> print_address_description mm/kasan/report.c:378 [inline]<br /> print_report+0x16c/0x6f0 mm/kasan/report.c:489<br /> kasan_report+0xc0/0x120 mm/kasan/report.c:602<br /> __asan_report_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379<br /> geneve_find_dev drivers/net/geneve.c:1295 [inline]<br /> geneve_configure+0x234/0x858 drivers/net/geneve.c:1343<br /> geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634<br /> rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795<br /> __rtnl_newlink net/core/rtnetlink.c:3906 [inline]<br /> rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021<br /> rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911<br /> netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543<br /> rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938<br /> netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]<br /> netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348<br /> netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892<br /> sock_sendmsg_nosec net/socket.c:713 [inline]<br /> __sock_sendmsg net/socket.c:728 [inline]<br /> ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568<br /> ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622<br /> __sys_sendmsg net/socket.c:2654 [inline]<br /> __do_sys_sendmsg net/socket.c:2659 [inline]<br /> __se_sys_sendmsg net/socket.c:2657 [inline]<br /> __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657<br /> __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]<br /> invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49<br /> el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132<br /> do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151<br /> el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744<br /> el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762<br /> el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600<br /> <br /> Allocated by task 13247:<br /> kasan_save_stack mm/kasan/common.c:47 [inline]<br /> kasan_save_track+0x30/0x68 mm/kasan/common.c:68<br /> kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568<br /> poison_kmalloc_redzone mm/kasan/common.c:377 [inline]<br /> __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394<br /> kasan_kmalloc include/linux/kasan.h:260 [inline]<br /> __do_kmalloc_node mm/slub.c:4298 [inline]<br /> __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304<br /> __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645<br /> alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470<br /> rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604<br /> rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780<br /> __rtnl_newlink net/core/rtnetlink.c:3906 [inline]<br /> rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021<br /> rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911<br /> netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543<br /> rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938<br /> netlink_unicast_kernel net/netlink/af_n<br /> ---truncated---