random: cc1: uninitialized urandom read (8 bytes read) audit: type=1400 audit(1538170847.614:9): avc: denied { map } for pid=1808 comm="syz-execprog" path="/root/syzkaller-shm048756115" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:file_t:s0 tclass=file permissive=1 ip (2693) used greatest stack depth: 23520 bytes left audit: type=1400 audit(1538170852.644:10): avc: denied { prog_load } for pid=4025 comm="syz-executor3" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1 ================================================================== BUG: KASAN: slab-out-of-bounds in bpf_skb_proto_xlat net/core/filter.c:2150 [inline] BUG: KASAN: slab-out-of-bounds in ____bpf_skb_change_proto net/core/filter.c:2188 [inline] BUG: KASAN: slab-out-of-bounds in bpf_skb_change_proto+0xd7d/0x1100 net/core/filter.c:2163 Read of size 2 at addr ffff8801ca80bc78 by task syz-executor3/4029 CPU: 1 PID: 4029 Comm: syz-executor3 Not tainted 4.14.72+ #11 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_address_description+0x60/0x22b mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409 bpf_skb_proto_xlat net/core/filter.c:2150 [inline] ____bpf_skb_change_proto net/core/filter.c:2188 [inline] bpf_skb_change_proto+0xd7d/0x1100 net/core/filter.c:2163 ___bpf_prog_run+0x248e/0x5c70 kernel/bpf/core.c:1012 Allocated by task 4024: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc.part.1+0x4f/0xd0 mm/kasan/kasan.c:551 slab_post_alloc_hook mm/slab.h:442 [inline] slab_alloc_node mm/slub.c:2723 [inline] slab_alloc mm/slub.c:2731 [inline] kmem_cache_alloc+0xe4/0x2b0 mm/slub.c:2736 kmem_cache_alloc_node include/linux/slab.h:361 [inline] __alloc_skb+0xd8/0x550 net/core/skbuff.c:193 alloc_skb include/linux/skbuff.h:980 [inline] netlink_dump+0x21b/0xa60 net/netlink/af_netlink.c:2183 __netlink_dump_start+0x4e4/0x750 net/netlink/af_netlink.c:2299 netlink_dump_start include/linux/netlink.h:217 [inline] rtnetlink_rcv_msg+0x6db/0xb30 net/core/rtnetlink.c:4225 netlink_rcv_skb+0x130/0x390 net/netlink/af_netlink.c:2432 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline] netlink_unicast+0x46d/0x620 net/netlink/af_netlink.c:1312 netlink_sendmsg+0x664/0xbe0 net/netlink/af_netlink.c:1877 sock_sendmsg_nosec net/socket.c:645 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:655 SYSC_sendto net/socket.c:1762 [inline] SyS_sendto+0x211/0x340 net/socket.c:1730 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 4024: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:524 slab_free_hook mm/slub.c:1389 [inline] slab_free_freelist_hook mm/slub.c:1410 [inline] slab_free mm/slub.c:2966 [inline] kmem_cache_free+0x12d/0x350 mm/slub.c:2988 kfree_skbmem+0x9e/0x100 net/core/skbuff.c:582 __kfree_skb net/core/skbuff.c:642 [inline] consume_skb+0xc9/0x330 net/core/skbuff.c:701 skb_free_datagram+0x15/0xd0 net/core/datagram.c:331 netlink_recvmsg+0x569/0xd10 net/netlink/af_netlink.c:1956 sock_recvmsg_nosec net/socket.c:818 [inline] sock_recvmsg+0xc0/0x100 net/socket.c:825 ___sys_recvmsg+0x242/0x510 net/socket.c:2220 __sys_recvmsg+0xc7/0x170 net/socket.c:2265 SYSC_recvmsg net/socket.c:2277 [inline] SyS_recvmsg+0x27/0x40 net/socket.c:2272 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8801ca80bb40 which belongs to the cache skbuff_head_cache of size 224 The buggy address is located 88 bytes to the right of 224-byte region [ffff8801ca80bb40, ffff8801ca80bc20) The buggy address belongs to the page: page:ffffea00072a02c0 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000100(slab) raw: 4000000000000100 0000000000000000 0000000000000000 00000001800c000c raw: ffffea00072e4dc0 0000000500000005 ffff8801dab70200 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ca80bb00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801ca80bb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8801ca80bc00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8801ca80bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ca80bd00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc ==================================================================