================================================================== BUG: KASAN: use-after-free in ipgre_header+0x3af/0x3c0 net/ipv4/ip_gre.c:856 Write of size 2 at addr ffff88816b700004 by task syz-executor.5/9697 CPU: 1 PID: 9697 Comm: syz-executor.5 Not tainted 6.5.0-rc3-syzkaller-00020-gaf2e19389c2c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:364 [inline] print_report+0xc4/0x620 mm/kasan/report.c:475 kasan_report+0xda/0x110 mm/kasan/report.c:588 ipgre_header+0x3af/0x3c0 net/ipv4/ip_gre.c:856 dev_hard_header include/linux/netdevice.h:3144 [inline] neigh_connected_output+0x3b8/0x5d0 net/core/neighbour.c:1576 neigh_output include/net/neighbour.h:544 [inline] ip_finish_output2+0x70a/0x24b0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:292 [inline] ip_mc_output+0x241/0x720 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:458 [inline] ip_local_out+0xaf/0x190 net/ipv4/ip_output.c:127 iptunnel_xmit+0x61a/0xa30 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1e09/0x3350 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x63c/0x910 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4910 [inline] netdev_start_xmit include/linux/netdevice.h:4924 [inline] xmit_one net/core/dev.c:3537 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3553 __dev_queue_xmit+0xa55/0x3f20 net/core/dev.c:4203 dev_queue_xmit include/linux/netdevice.h:3088 [inline] neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:544 [inline] ip_finish_output2+0x70a/0x24b0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:292 [inline] ip_mc_output+0x241/0x720 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:458 [inline] ip_local_out+0xaf/0x190 net/ipv4/ip_output.c:127 iptunnel_xmit+0x61a/0xa30 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1e09/0x3350 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x63c/0x910 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4910 [inline] netdev_start_xmit include/linux/netdevice.h:4924 [inline] xmit_one net/core/dev.c:3537 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3553 __dev_queue_xmit+0xa55/0x3f20 net/core/dev.c:4203 dev_queue_xmit include/linux/netdevice.h:3088 [inline] neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:544 [inline] ip_finish_output2+0x70a/0x24b0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:292 [inline] ip_mc_output+0x241/0x720 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:458 [inline] ip_local_out+0xaf/0x190 net/ipv4/ip_output.c:127 iptunnel_xmit+0x61a/0xa30 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1e09/0x3350 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x63c/0x910 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4910 [inline] netdev_start_xmit include/linux/netdevice.h:4924 [inline] xmit_one net/core/dev.c:3537 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3553 __dev_queue_xmit+0xa55/0x3f20 net/core/dev.c:4203 dev_queue_xmit include/linux/netdevice.h:3088 [inline] neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:544 [inline] ip_finish_output2+0x70a/0x24b0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:292 [inline] ip_mc_output+0x241/0x720 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:458 [inline] ip_local_out+0xaf/0x190 net/ipv4/ip_output.c:127 iptunnel_xmit+0x61a/0xa30 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1e09/0x3350 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x63c/0x910 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4910 [inline] netdev_start_xmit include/linux/netdevice.h:4924 [inline] xmit_one net/core/dev.c:3537 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3553 __dev_queue_xmit+0xa55/0x3f20 net/core/dev.c:4203 dev_queue_xmit include/linux/netdevice.h:3088 [inline] neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:544 [inline] ip_finish_output2+0x70a/0x24b0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:292 [inline] ip_mc_output+0x241/0x720 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:458 [inline] ip_local_out+0xaf/0x190 net/ipv4/ip_output.c:127 iptunnel_xmit+0x61a/0xa30 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1e09/0x3350 net/ipv4/ip_tunnel.c:831 ipgre_xmit+0x63c/0x910 net/ipv4/ip_gre.c:662 __netdev_start_xmit include/linux/netdevice.h:4910 [inline] netdev_start_xmit include/linux/netdevice.h:4924 [inline] xmit_one net/core/dev.c:3537 [inline] dev_hard_start_xmit+0x13d/0x6c0 net/core/dev.c:3553 __dev_queue_xmit+0xa55/0x3f20 net/core/dev.c:4203 dev_queue_xmit include/linux/netdevice.h:3088 [inline] neigh_connected_output+0x42c/0x5d0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:544 [inline] ip_finish_output2+0x70a/0x24b0 net/ipv4/ip_output.c:230 __ip_finish_output net/ipv4/ip_output.c:308 [inline] __ip_finish_output+0x38b/0x640 net/ipv4/ip_output.c:290 ip_finish_output+0x31/0x280 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:292 [inline] ip_mc_output+0x241/0x720 net/ipv4/ip_output.c:417 dst_output include/net/dst.h:458 [inline] ip_local_out net/ipv4/ip_output.c:127 [inline] ip_send_skb+0xd3/0x250 net/ipv4/ip_output.c:1477 udp_send_skb+0x731/0x1470 net/ipv4/udp.c:979 udp_sendmsg+0x1de3/0x2a50 net/ipv4/udp.c:1261 inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:830 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0xd9/0x180 net/socket.c:748 ____sys_sendmsg+0x2ac/0x940 net/socket.c:2494 ___sys_sendmsg+0x135/0x1d0 net/socket.c:2548 __sys_sendmmsg+0x2a5/0x450 net/socket.c:2627 __compat_sys_sendmmsg net/compat.c:360 [inline] __do_compat_sys_sendmmsg net/compat.c:367 [inline] __se_compat_sys_sendmmsg net/compat.c:364 [inline] __ia32_compat_sys_sendmmsg+0x9d/0x100 net/compat.c:364 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x61/0xe0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f8e579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f895ac EFLAGS: 00000292 ORIG_RAX: 0000000000000159 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020007fc0 RDX: 000000000800001d RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the physical page: page:ffffea0005adc000 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16b700 flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 057ff00000000000 ffffea0005adc008 ffffea0005adc008 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?) Memory state around the buggy address: ffff88816b6fff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88816b6fff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88816b700000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88816b700080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88816b700100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi