[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 33.556897] random: sshd: uninitialized urandom read (32 bytes read) [ 33.925683] kauditd_printk_skb: 9 callbacks suppressed [ 33.925692] audit: type=1400 audit(1569009642.467:35): avc: denied { map } for pid=6846 comm="bash" path="/bin/bash" dev="sda1" ino=1457 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 [ 33.982241] random: sshd: uninitialized urandom read (32 bytes read) [ 34.506130] random: sshd: uninitialized urandom read (32 bytes read) [ 34.688259] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.1.4' (ECDSA) to the list of known hosts. [ 41.233561] random: sshd: uninitialized urandom read (32 bytes read) executing program [ 41.365015] audit: type=1400 audit(1569009649.907:36): avc: denied { map } for pid=6859 comm="syz-executor103" path="/root/syz-executor103342751" 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 [ 41.394369] ================================================================== [ 41.401957] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x1ae/0x200 [ 41.409664] Read of size 2 at addr ffff88809162da70 by task syz-executor103/6859 [ 41.417683] [ 41.419405] CPU: 0 PID: 6859 Comm: syz-executor103 Not tainted 4.14.145 #0 [ 41.426409] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.435909] Call Trace: [ 41.438582] dump_stack+0x138/0x197 [ 41.442304] ? svc_udp_recvfrom+0x298/0xe00 [ 41.446617] ? tcp_init_tso_segs+0x1ae/0x200 [ 41.451112] print_address_description.cold+0x7c/0x1dc [ 41.456372] ? tcp_init_tso_segs+0x1ae/0x200 [ 41.460763] kasan_report.cold+0xa9/0x2af [ 41.465248] __asan_report_load2_noabort+0x14/0x20 [ 41.470163] tcp_init_tso_segs+0x1ae/0x200 [ 41.474378] ? tcp_tso_segs+0x7d/0x1c0 [ 41.478247] tcp_write_xmit+0x15e/0x4960 [ 41.482306] ? tcp_v6_md5_lookup+0x23/0x30 [ 41.486521] ? tcp_established_options+0x2c5/0x420 [ 41.491693] ? tcp_current_mss+0x1dc/0x2f0 [ 41.495917] ? __alloc_skb+0x3ee/0x500 [ 41.499822] __tcp_push_pending_frames+0xa6/0x260 [ 41.504939] tcp_send_fin+0x17e/0xc40 [ 41.508831] tcp_close+0xcc8/0xfb0 [ 41.512460] ? lock_acquire+0x16f/0x430 [ 41.516418] ? ip_mc_drop_socket+0x1d6/0x230 [ 41.520815] inet_release+0xec/0x1c0 [ 41.524599] inet6_release+0x53/0x80 [ 41.528293] __sock_release+0xce/0x2b0 [ 41.532180] ? __sock_release+0x2b0/0x2b0 [ 41.536403] sock_close+0x1b/0x30 [ 41.539854] __fput+0x275/0x7a0 [ 41.543117] ____fput+0x16/0x20 [ 41.546466] task_work_run+0x114/0x190 [ 41.550558] do_exit+0x7df/0x2c10 [ 41.554116] ? mm_update_next_owner+0x5d0/0x5d0 [ 41.559129] ? up_read+0x1a/0x40 [ 41.562486] ? __do_page_fault+0x358/0xb80 [ 41.566709] do_group_exit+0x111/0x330 [ 41.570606] SyS_exit_group+0x1d/0x20 [ 41.574485] ? do_group_exit+0x330/0x330 [ 41.578537] do_syscall_64+0x1e8/0x640 [ 41.582490] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.587503] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 41.592896] RIP: 0033:0x43ee48 [ 41.596108] RSP: 002b:00007ffe44c5ad78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 41.603820] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee48 [ 41.611074] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 41.618328] RBP: 00000000004be648 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 41.625591] R10: 0000000020000001 R11: 0000000000000246 R12: 0000000000000001 [ 41.632842] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 41.640101] [ 41.641719] Allocated by task 6859: [ 41.645328] save_stack_trace+0x16/0x20 [ 41.649281] save_stack+0x45/0xd0 [ 41.652721] kasan_kmalloc+0xce/0xf0 [ 41.656410] kasan_slab_alloc+0xf/0x20 [ 41.660305] kmem_cache_alloc_node+0x144/0x780 [ 41.665256] __alloc_skb+0x9c/0x500 [ 41.668877] sk_stream_alloc_skb+0xb3/0x780 [ 41.673201] tcp_sendmsg_locked+0xf61/0x3200 [ 41.677739] tcp_sendmsg+0x30/0x50 [ 41.682201] inet_sendmsg+0x122/0x500 [ 41.686030] sock_sendmsg+0xce/0x110 [ 41.689741] SYSC_sendto+0x206/0x310 [ 41.693622] SyS_sendto+0x40/0x50 [ 41.697243] do_syscall_64+0x1e8/0x640 [ 41.701144] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 41.706318] [ 41.707928] Freed by task 6859: [ 41.711209] save_stack_trace+0x16/0x20 [ 41.715169] save_stack+0x45/0xd0 [ 41.718954] kasan_slab_free+0x75/0xc0 [ 41.723025] kmem_cache_free+0x83/0x2b0 [ 41.727114] kfree_skbmem+0x8d/0x120 [ 41.730813] __kfree_skb+0x1e/0x30 [ 41.734450] tcp_remove_empty_skb.part.0+0x231/0x2e0 [ 41.739785] tcp_sendmsg_locked+0x1ced/0x3200 [ 41.744474] tcp_sendmsg+0x30/0x50 [ 41.748005] inet_sendmsg+0x122/0x500 [ 41.752008] sock_sendmsg+0xce/0x110 [ 41.755706] SYSC_sendto+0x206/0x310 [ 41.759428] SyS_sendto+0x40/0x50 [ 41.762879] do_syscall_64+0x1e8/0x640 [ 41.766889] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 41.772083] [ 41.773767] The buggy address belongs to the object at ffff88809162da40 [ 41.773767] which belongs to the cache skbuff_fclone_cache of size 472 [ 41.787266] The buggy address is located 48 bytes inside of [ 41.787266] 472-byte region [ffff88809162da40, ffff88809162dc18) [ 41.799274] The buggy address belongs to the page: [ 41.804193] page:ffffea0002458b40 count:1 mapcount:0 mapping:ffff88809162d040 index:0x0 [ 41.812717] flags: 0x1fffc0000000100(slab) [ 41.817525] raw: 01fffc0000000100 ffff88809162d040 0000000000000000 0000000100000006 [ 41.826061] raw: ffffea000270a420 ffff8880a9dfd048 ffff88821b7573c0 0000000000000000 [ 41.833943] page dumped because: kasan: bad access detected [ 41.842531] [ 41.844188] Memory state around the buggy address: [ 41.849101] ffff88809162d900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 41.856749] ffff88809162d980: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc [ 41.864463] >ffff88809162da00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb [ 41.871831] ^ [ 41.878932] ffff88809162da80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.886412] ffff88809162db00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 41.893774] ================================================================== [ 41.901219] Disabling lock debugging due to kernel taint [ 41.910350] Kernel panic - not syncing: panic_on_warn set ... [ 41.910350] [ 41.918065] CPU: 0 PID: 6859 Comm: syz-executor103 Tainted: G B 4.14.145 #0 [ 41.926295] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.935725] Call Trace: [ 41.938394] dump_stack+0x138/0x197 [ 41.942012] ? tcp_init_tso_segs+0x1ae/0x200 [ 41.946533] panic+0x1f2/0x426 [ 41.949714] ? add_taint.cold+0x16/0x16 [ 41.953689] ? ___preempt_schedule+0x16/0x18 [ 41.958137] kasan_end_report+0x47/0x4f [ 41.962282] kasan_report.cold+0x130/0x2af [ 41.966509] __asan_report_load2_noabort+0x14/0x20 [ 41.971428] tcp_init_tso_segs+0x1ae/0x200 [ 41.975640] ? tcp_tso_segs+0x7d/0x1c0 [ 41.979515] tcp_write_xmit+0x15e/0x4960 [ 41.983558] ? tcp_v6_md5_lookup+0x23/0x30 [ 41.987850] ? tcp_established_options+0x2c5/0x420 [ 41.992775] ? tcp_current_mss+0x1dc/0x2f0 [ 41.997595] ? __alloc_skb+0x3ee/0x500 [ 42.001593] __tcp_push_pending_frames+0xa6/0x260 [ 42.006578] tcp_send_fin+0x17e/0xc40 [ 42.010369] tcp_close+0xcc8/0xfb0 [ 42.014002] ? lock_acquire+0x16f/0x430 [ 42.017960] ? ip_mc_drop_socket+0x1d6/0x230 [ 42.022386] inet_release+0xec/0x1c0 [ 42.026206] inet6_release+0x53/0x80 [ 42.030056] __sock_release+0xce/0x2b0 [ 42.033952] ? __sock_release+0x2b0/0x2b0 [ 42.038098] sock_close+0x1b/0x30 [ 42.041550] __fput+0x275/0x7a0 [ 42.044856] ____fput+0x16/0x20 [ 42.048147] task_work_run+0x114/0x190 [ 42.052035] do_exit+0x7df/0x2c10 [ 42.055474] ? mm_update_next_owner+0x5d0/0x5d0 [ 42.060130] ? up_read+0x1a/0x40 [ 42.063487] ? __do_page_fault+0x358/0xb80 [ 42.067701] do_group_exit+0x111/0x330 [ 42.071574] SyS_exit_group+0x1d/0x20 [ 42.075353] ? do_group_exit+0x330/0x330 [ 42.079393] do_syscall_64+0x1e8/0x640 [ 42.083347] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.089011] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 42.094194] RIP: 0033:0x43ee48 [ 42.097361] RSP: 002b:00007ffe44c5ad78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 42.105148] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ee48 [ 42.112398] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 42.119736] RBP: 00000000004be648 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 42.126984] R10: 0000000020000001 R11: 0000000000000246 R12: 0000000000000001 [ 42.134258] R13: 00000000006d0180 R14: 0000000000000000 R15: 0000000000000000 [ 42.143380] Kernel Offset: disabled [ 42.147009] Rebooting in 86400 seconds..