urandom_read: 1 callbacks suppressed random: sshd: uninitialized urandom read (32 bytes read) audit: type=1400 audit(1546193831.052:8): avc: denied { map } for pid=1783 comm="syz-executor910" path="/root/syz-executor910660043" dev="sda1" ino=16482 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 ================================================================== BUG: KASAN: slab-out-of-bounds in __ptr_ring_produce include/linux/ptr_ring.h:109 [inline] BUG: KASAN: slab-out-of-bounds in ptr_ring_produce include/linux/ptr_ring.h:132 [inline] BUG: KASAN: slab-out-of-bounds in skb_array_produce include/linux/skb_array.h:48 [inline] BUG: KASAN: slab-out-of-bounds in tun_net_xmit+0xf18/0x1010 drivers/net/tun.c:916 Read of size 8 at addr ffff8881c6efa650 by task syz-executor910/1786 CPU: 1 PID: 1786 Comm: syz-executor910 Not tainted 4.14.91+ #30 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 __ptr_ring_produce include/linux/ptr_ring.h:109 [inline] ptr_ring_produce include/linux/ptr_ring.h:132 [inline] skb_array_produce include/linux/skb_array.h:48 [inline] tun_net_xmit+0xf18/0x1010 drivers/net/tun.c:916 __netdev_start_xmit include/linux/netdevice.h:4030 [inline] netdev_start_xmit include/linux/netdevice.h:4039 [inline] xmit_one net/core/dev.c:3009 [inline] dev_hard_start_xmit+0x191/0x890 net/core/dev.c:3025 sch_direct_xmit+0x280/0x520 net/sched/sch_generic.c:186 __dev_xmit_skb net/core/dev.c:3218 [inline] __dev_queue_xmit+0x16fd/0x1f40 net/core/dev.c:3493 neigh_hh_output include/net/neighbour.h:490 [inline] neigh_output include/net/neighbour.h:498 [inline] ip6_finish_output2+0x1136/0x1f90 net/ipv6/ip6_output.c:120 ip6_finish_output+0x62e/0xb10 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:239 [inline] ip6_output+0x1dd/0x680 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:459 [inline] ip6_local_out+0x94/0x170 net/ipv6/output_core.c:176 ip6_send_skb+0x98/0x2e0 net/ipv6/ip6_output.c:1686 udp_v6_send_skb+0x4e3/0xe70 net/ipv6/udp.c:1081 udpv6_sendmsg+0x1f07/0x2510 net/ipv6/udp.c:1353 inet_sendmsg+0x168/0x540 net/ipv4/af_inet.c:781 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 RIP: 0033:0x441ba9 RSP: 002b:00007ffeef0893f8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441ba9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000008470 R08: 00000000200001c0 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000402990 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 1785: 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 __kmalloc+0x153/0x340 mm/slub.c:3760 __kmalloc_node include/linux/slab.h:356 [inline] kmalloc_node include/linux/slab.h:530 [inline] kvmalloc_node+0x42/0xd0 mm/util.c:397 kvmalloc include/linux/mm.h:531 [inline] kvmalloc_array include/linux/mm.h:547 [inline] __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:455 [inline] ptr_ring_resize_multiple include/linux/ptr_ring.h:613 [inline] skb_array_resize_multiple include/linux/skb_array.h:200 [inline] tun_queue_resize drivers/net/tun.c:2815 [inline] tun_device_event+0x450/0xc50 drivers/net/tun.c:2833 notifier_call_chain+0x114/0x1b0 kernel/notifier.c:93 call_netdevice_notifiers+0x6e/0xa0 net/core/dev.c:1687 dev_ifsioc+0x735/0x840 net/core/dev_ioctl.c:311 dev_ioctl+0x25f/0xce0 net/core/dev_ioctl.c:566 sock_do_ioctl+0x92/0xb0 net/socket.c:980 sock_ioctl+0x263/0x430 net/socket.c:1070 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x1a0/0x1030 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7e/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 0: (stack is not available) The buggy address belongs to the object at ffff8881c6efa648 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes to the right of 8-byte region [ffff8881c6efa648, ffff8881c6efa650) The buggy address belongs to the page: page:ffffea00071bbe80 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000100(slab) raw: 4000000000000100 0000000000000000 0000000000000000 0000000180aa00aa raw: dead000000000100 dead000000000200 ffff8881da803c00 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881c6efa500: fc fc fb fc fc fb fc fc fb fc fc fb fc fc fb fc ffff8881c6efa580: fc fb fc fc fb fc fc fb fc fc fb fc fc 00 fc fc >ffff8881c6efa600: 00 fc fc fb fc fc fb fc fc 00 fc fc fc fc fc fc ^ ffff8881c6efa680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881c6efa700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================