================================================================== BUG: KASAN: slab-out-of-bounds in ip6_tnl_parse_tlv_enc_lim+0x5df/0x660 net/ipv6/ip6_tunnel.c:417 Read of size 1 at addr ffff8801bfe51287 by task syz-executor2/22789 CPU: 1 PID: 22789 Comm: syz-executor2 Not tainted 4.20.0-rc1+ #136 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x244/0x39d lib/dump_stack.c:113 print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 ip6_tnl_parse_tlv_enc_lim+0x5df/0x660 net/ipv6/ip6_tunnel.c:417 ip6ip6_tnl_xmit net/ipv6/ip6_tunnel.c:1348 [inline] ip6_tnl_start_xmit+0x49f/0x25a0 net/ipv6/ip6_tunnel.c:1412 __netdev_start_xmit include/linux/netdevice.h:4356 [inline] netdev_start_xmit include/linux/netdevice.h:4365 [inline] xmit_one net/core/dev.c:3252 [inline] dev_hard_start_xmit+0x295/0xc80 net/core/dev.c:3268 __dev_queue_xmit+0x2f71/0x3ad0 net/core/dev.c:3838 dev_queue_xmit+0x17/0x20 net/core/dev.c:3871 __bpf_tx_skb net/core/filter.c:2017 [inline] __bpf_redirect_common net/core/filter.c:2055 [inline] __bpf_redirect+0x5cf/0xb20 net/core/filter.c:2062 ____bpf_clone_redirect net/core/filter.c:2095 [inline] bpf_clone_redirect+0x2f6/0x490 net/core/filter.c:2067 bpf_prog_759a992c578a3894+0x5a3/0x1000 Allocated by task 22789: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 __do_kmalloc_node mm/slab.c:3684 [inline] __kmalloc_node_track_caller+0x50/0x70 mm/slab.c:3698 __kmalloc_reserve.isra.40+0x41/0xe0 net/core/skbuff.c:137 pskb_expand_head+0x230/0x10f0 net/core/skbuff.c:1460 skb_ensure_writable+0x3dd/0x640 net/core/skbuff.c:5073 __bpf_try_make_writable net/core/filter.c:1638 [inline] bpf_try_make_writable net/core/filter.c:1644 [inline] bpf_try_make_head_writable net/core/filter.c:1652 [inline] ____bpf_clone_redirect net/core/filter.c:2089 [inline] bpf_clone_redirect+0x14a/0x490 net/core/filter.c:2067 bpf_prog_759a992c578a3894+0x5a3/0x1000 Freed by task 20856: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3817 skb_free_head+0x99/0xc0 net/core/skbuff.c:550 skb_release_data+0x6a4/0x880 net/core/skbuff.c:570 skb_release_all+0x4a/0x60 net/core/skbuff.c:627 __kfree_skb net/core/skbuff.c:641 [inline] kfree_skb+0x1bb/0x580 net/core/skbuff.c:659 ip6_tnl_start_xmit+0xb0c/0x25a0 net/ipv6/ip6_tunnel.c:1426 __netdev_start_xmit include/linux/netdevice.h:4356 [inline] netdev_start_xmit include/linux/netdevice.h:4365 [inline] xmit_one net/core/dev.c:3252 [inline] dev_hard_start_xmit+0x295/0xc80 net/core/dev.c:3268 __dev_queue_xmit+0x2f71/0x3ad0 net/core/dev.c:3838 dev_queue_xmit+0x17/0x20 net/core/dev.c:3871 __bpf_tx_skb net/core/filter.c:2017 [inline] __bpf_redirect_common net/core/filter.c:2055 [inline] __bpf_redirect+0x5cf/0xb20 net/core/filter.c:2062 ____bpf_clone_redirect net/core/filter.c:2095 [inline] bpf_clone_redirect+0x2f6/0x490 net/core/filter.c:2067 0xffffffffa0040fd9 The buggy address belongs to the object at ffff8801bfe51080 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 7 bytes to the right of 512-byte region [ffff8801bfe51080, ffff8801bfe51280) The buggy address belongs to the page: page:ffffea0006ff9440 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 flags: 0x2fffc0000000200(slab) raw: 02fffc0000000200 ffffea0006f32448 ffffea0007218d88 ffff8801da800940 raw: 0000000000000000 ffff8801bfe51080 0000000100000006 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801bfe51180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801bfe51200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffff8801bfe51280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8801bfe51300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801bfe51380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================