CVE-2025-21653

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute<br /> <br /> syzbot found that TCA_FLOW_RSHIFT attribute was not validated.<br /> Right shitfing a 32bit integer is undefined for large shift values.<br /> <br /> UBSAN: shift-out-of-bounds in net/sched/cls_flow.c:329:23<br /> shift exponent 9445 is too large for 32-bit type &amp;#39;u32&amp;#39; (aka &amp;#39;unsigned int&amp;#39;)<br /> CPU: 1 UID: 0 PID: 54 Comm: kworker/u8:3 Not tainted 6.13.0-rc3-syzkaller-00180-g4f619d518db9 #0<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024<br /> Workqueue: ipv6_addrconf addrconf_dad_work<br /> Call Trace:<br /> <br /> __dump_stack lib/dump_stack.c:94 [inline]<br /> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120<br /> ubsan_epilogue lib/ubsan.c:231 [inline]<br /> __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468<br /> flow_classify+0x24d5/0x25b0 net/sched/cls_flow.c:329<br /> tc_classify include/net/tc_wrapper.h:197 [inline]<br /> __tcf_classify net/sched/cls_api.c:1771 [inline]<br /> tcf_classify+0x420/0x1160 net/sched/cls_api.c:1867<br /> sfb_classify net/sched/sch_sfb.c:260 [inline]<br /> sfb_enqueue+0x3ad/0x18b0 net/sched/sch_sfb.c:318<br /> dev_qdisc_enqueue+0x4b/0x290 net/core/dev.c:3793<br /> __dev_xmit_skb net/core/dev.c:3889 [inline]<br /> __dev_queue_xmit+0xf0e/0x3f50 net/core/dev.c:4400<br /> dev_queue_xmit include/linux/netdevice.h:3168 [inline]<br /> neigh_hh_output include/net/neighbour.h:523 [inline]<br /> neigh_output include/net/neighbour.h:537 [inline]<br /> ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236<br /> iptunnel_xmit+0x55d/0x9b0 net/ipv4/ip_tunnel_core.c:82<br /> udp_tunnel_xmit_skb+0x262/0x3b0 net/ipv4/udp_tunnel_core.c:173<br /> geneve_xmit_skb drivers/net/geneve.c:916 [inline]<br /> geneve_xmit+0x21dc/0x2d00 drivers/net/geneve.c:1039<br /> __netdev_start_xmit include/linux/netdevice.h:5002 [inline]<br /> netdev_start_xmit include/linux/netdevice.h:5011 [inline]<br /> xmit_one net/core/dev.c:3590 [inline]<br /> dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606<br /> __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434