random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) random: sshd: uninitialized urandom read (32 bytes read) audit: type=1400 audit(1569001542.764:36): avc: denied { map } for pid=6900 comm="syz-executor573" path="/root/syz-executor573485886" dev="sda1" ino=16484 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: use-after-free in tcp_skb_pcount include/net/tcp.h:911 [inline] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 net/ipv4/tcp_output.c:1790 Read of size 2 at addr ffff88809f99d2f0 by task syz-executor573/6900 CPU: 1 PID: 6900 Comm: syz-executor573 Not tainted 4.14.145 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x138/0x197 lib/dump_stack.c:53 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428 tcp_skb_pcount include/net/tcp.h:911 [inline] tcp_init_tso_segs+0x1ae/0x200 net/ipv4/tcp_output.c:1790 tcp_write_xmit+0x15e/0x4960 net/ipv4/tcp_output.c:2330 __tcp_push_pending_frames+0xa6/0x260 net/ipv4/tcp_output.c:2563 tcp_send_fin+0x17e/0xc40 net/ipv4/tcp_output.c:3115 tcp_close+0xcc8/0xfb0 net/ipv4/tcp.c:2221 inet_release+0xec/0x1c0 net/ipv4/af_inet.c:425 inet6_release+0x53/0x80 net/ipv6/af_inet6.c:450 __sock_release+0xce/0x2b0 net/socket.c:602 sock_close+0x1b/0x30 net/socket.c:1139 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x7df/0x2c10 kernel/exit.c:874 do_group_exit+0x111/0x330 kernel/exit.c:977 SYSC_exit_group kernel/exit.c:988 [inline] SyS_exit_group+0x1d/0x20 kernel/exit.c:986 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x43ee88 RSP: 002b:00007ffc016a0828 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee88 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004be688 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000020000004 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6900: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3642 __alloc_skb+0x9c/0x500 net/core/skbuff.c:193 alloc_skb_fclone include/linux/skbuff.h:1022 [inline] sk_stream_alloc_skb+0xb3/0x780 net/ipv4/tcp.c:855 tcp_sendmsg_locked+0xf61/0x3200 net/ipv4/tcp.c:1301 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1457 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 SYSC_sendto+0x206/0x310 net/socket.c:1763 SyS_sendto+0x40/0x50 net/socket.c:1731 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 6900: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x83/0x2b0 mm/slab.c:3758 kfree_skbmem+0x8d/0x120 net/core/skbuff.c:607 __kfree_skb+0x1e/0x30 net/core/skbuff.c:646 sk_wmem_free_skb include/net/sock.h:1416 [inline] tcp_remove_empty_skb.part.0+0x231/0x2e0 net/ipv4/tcp.c:929 tcp_remove_empty_skb net/ipv4/tcp.c:925 [inline] tcp_sendmsg_locked+0x1ced/0x3200 net/ipv4/tcp.c:1435 tcp_sendmsg+0x30/0x50 net/ipv4/tcp.c:1457 inet_sendmsg+0x122/0x500 net/ipv4/af_inet.c:762 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xce/0x110 net/socket.c:656 SYSC_sendto+0x206/0x310 net/socket.c:1763 SyS_sendto+0x40/0x50 net/socket.c:1731 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff88809f99d2c0 which belongs to the cache skbuff_fclone_cache of size 472 The buggy address is located 48 bytes inside of 472-byte region [ffff88809f99d2c0, ffff88809f99d498) The buggy address belongs to the page: page:ffffea00027e6740 count:1 mapcount:0 mapping:ffff88809f99d040 index:0x0 flags: 0x1fffc0000000100(slab) raw: 01fffc0000000100 ffff88809f99d040 0000000000000000 0000000100000006 raw: ffffea00029b8120 ffff8880a9e1bd48 ffff8880a9e19a80 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809f99d180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809f99d200: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809f99d280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff88809f99d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809f99d380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================