[....] Starting file context maintaining daemon: restorecond[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.517310] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.946522] random: sshd: uninitialized urandom read (32 bytes read, 40 bits of entropy available) [ 25.241884] random: sshd: uninitialized urandom read (32 bytes read, 40 bits of entropy available) [ 26.235161] random: sshd: uninitialized urandom read (32 bytes read, 112 bits of entropy available) [ 26.412022] random: sshd: uninitialized urandom read (32 bytes read, 116 bits of entropy available) Warning: Permanently added '10.128.10.4' (ECDSA) to the list of known hosts. [ 31.786832] random: sshd: uninitialized urandom read (32 bytes read, 120 bits of entropy available) 2018/02/28 09:36:19 parsed 1 programs 2018/02/28 09:36:19 executed programs: 0 [ 32.124282] IPVS: Creating netns size=2552 id=1 2018/02/28 09:36:24 executed programs: 83 [ 39.736675] ================================================================== [ 39.744078] BUG: KASAN: use-after-free in pppol2tp_session_destruct+0xee/0x110 [ 39.751407] Read of size 4 at addr ffff8800b4f45680 by task syz-executor0/4169 [ 39.758730] [ 39.760329] CPU: 0 PID: 4169 Comm: syz-executor0 Not tainted 4.4.118-g239a415 #26 [ 39.767917] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 39.777241] 0000000000000000 1f58595b5d7bb9c5 ffff8800bafffc20 ffffffff81d0402d [ 39.785208] ffffea0002d3d100 ffff8800b4f45680 0000000000000000 ffff8800b4f45680 [ 39.793173] ffffffff82de7c80 ffff8800bafffc58 ffffffff814fe103 ffff8800b4f45680 [ 39.801159] Call Trace: [ 39.803718] [] dump_stack+0xc1/0x124 [ 39.809052] [] ? sock_release+0x1e0/0x1e0 [ 39.814817] [] print_address_description+0x73/0x260 [ 39.821461] [] ? sock_release+0x1e0/0x1e0 [ 39.827233] [] kasan_report+0x285/0x370 [ 39.832829] [] ? pppol2tp_session_destruct+0xee/0x110 [ 39.839636] [] __asan_report_load4_noabort+0x14/0x20 [ 39.846357] [] pppol2tp_session_destruct+0xee/0x110 [ 39.852989] [] ? pppol2tp_seq_start+0x4e0/0x4e0 [ 39.859276] [] sk_destruct+0x4a/0x4c0 [ 39.864694] [] __sk_free+0x57/0x230 [ 39.869936] [] sk_free+0x30/0x40 [ 39.874920] [] pppol2tp_release+0x27a/0x310 [ 39.880861] [] sock_release+0x8d/0x1e0 [ 39.886366] [] sock_close+0x16/0x20 [ 39.891612] [] __fput+0x233/0x6d0 [ 39.896702] [] ____fput+0x15/0x20 [ 39.901776] [] task_work_run+0x104/0x180 [ 39.907460] [] exit_to_usermode_loop+0x13d/0x160 [ 39.913833] [] do_fast_syscall_32+0x614/0x8a0 [ 39.919953] [] sysenter_flags_fixed+0xd/0x17 [ 39.925976] [ 39.927576] Allocated by task 4169: [ 39.931170] [] save_stack_trace+0x26/0x50 [ 39.937067] [] save_stack+0x43/0xd0 [ 39.942430] [] kasan_kmalloc+0xad/0xe0 [ 39.948069] [] __kmalloc+0x124/0x320 [ 39.953520] [] l2tp_session_create+0x39/0x10f0 [ 39.959838] [] pppol2tp_connect+0x10fc/0x1930 [ 39.966068] [] SYSC_connect+0x1b6/0x310 [ 39.971778] [] SyS_connect+0x24/0x30 [ 39.977222] [] do_fast_syscall_32+0x321/0x8a0 [ 39.983467] [] sysenter_flags_fixed+0xd/0x17 [ 39.989608] [ 39.991206] Freed by task 4170: [ 39.994454] [] save_stack_trace+0x26/0x50 [ 40.000335] [] save_stack+0x43/0xd0 [ 40.005693] [] kasan_slab_free+0x72/0xc0 [ 40.011488] [] kfree+0xfc/0x300 [ 40.016501] [] l2tp_session_free+0x170/0x200 [ 40.022641] [] l2tp_tunnel_closeall+0x2d1/0x3b0 [ 40.029042] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 40.035443] [] udpv6_destroy_sock+0xb1/0xd0 [ 40.041505] [] sk_common_release+0x6b/0x300 [ 40.047560] [] udp_lib_close+0x15/0x20 [ 40.053183] [] inet_release+0xfa/0x1d0 [ 40.058808] [] inet6_release+0x50/0x70 [ 40.064432] [] sock_release+0x8d/0x1e0 [ 40.070055] [] sock_close+0x16/0x20 [ 40.075414] [] __fput+0x233/0x6d0 [ 40.080604] [] ____fput+0x15/0x20 [ 40.085791] [] task_work_run+0x104/0x180 [ 40.091593] [] exit_to_usermode_loop+0x13d/0x160 [ 40.098084] [] do_fast_syscall_32+0x614/0x8a0 [ 40.104312] [] sysenter_flags_fixed+0xd/0x17 [ 40.110457] [ 40.112055] The buggy address belongs to the object at ffff8800b4f45680 [ 40.112055] which belongs to the cache kmalloc-512 of size 512 [ 40.124680] The buggy address is located 0 bytes inside of [ 40.124680] 512-byte region [ffff8800b4f45680, ffff8800b4f45880) [ 40.136347] The buggy address belongs to the page: [ 40.157599] BUG: unable to handle kernelSeaBIOS (version 1.8.2-20180102_145157-google) Total RAM Size = 0x00000001e0000000 = 7680 MiB CPUs found: 2 Max CPUs supported: 256 found virtio-scsi at 0:3 virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0 virtio-scsi blksize=512 sectors=4194304 = 2048 MiB drive 0x000f2330: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304 Booting from Hard Disk 0... early console in decompress_kernel input_data: 0x00000000037cb26e input_len: 0x0000000001423f0b output: 0x0000000001000000 output_len: 0x0000000003bdaa40 run_size: 0x0000000005310000 Decompressing Linux... Parsing ELF... done. Booting the kernel. [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Initializing cgroup subsys cpuacct [ 0.000000] Initializing cgroup subsys schedtune [ 0.000000] Linux version 4.4.118-g239a415 (syzkaller@ci) (gcc version 7.1.1 20170620 (GCC) ) #26 SMP PREEMPT Tue Feb 27 02:15:55 UTC 2018 [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz root=/dev/sda1 console=ttyS0 earlyprintk=serial vsyscall=native rodata=n ftrace_dump_on_oops=orig_cpu oops=panic panic_on_warn=1 nmi_watchdog=panic panic=86400 workqueue.watchdog_thresh=120 [ 0.000000] KERNEL supported cpus: [ 0.000000] Intel GenuineIntel [ 0.000000] AMD AuthenticAMD [ 0.000000] Centaur CentaurHauls [ 0.000000] x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256 [ 0.000000] x86/fpu: Supporting XSAVE feature 0x01: 'x87 floating point registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x02: 'SSE registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x04: 'AVX registers' [ 0.000000] x86/fpu: Enabled xstate features 0x7, context size is 832 bytes, using 'standard' format. [ 0.000000] x86/fpu: Using 'eager' FPU context switches. [ 0.000000] e820: BIOS-provided physical RAM map: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009fbff] usable [ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bfff2fff] usable [ 0.000000] BIOS-e820: [mem 0x00000000bfff3000-0x00000000bfffffff] reserved [ 0.000000] BIOS-e820: [mem 0x00000000fffbc000-0x00000000ffffffff] reserved [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000021fffffff] usable [ 0.000000] bootconsole [earlyser0] enabled [ 0.000000] NX (Execute Disable) protection: active [ 0.000000] SMBIOS 2.4 present. [ 0.000000] Hypervisor detected: KVM [ 0.000000] e820: last_pfn = 0x220000 max_arch_pfn = 0x400000000 [ 0.000000] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WC UC- WT [ 0.000000] e820: last_pfn = 0xbfff3 max_arch_pfn = 0x400000000 [ 0.000000] found SMP MP-table at [mem 0x000f23b0-0x000f23bf] mapped at [ffff8800000f23b0] [ 0.000000] Scanning 1 areas for low memory corruption [ 0.000000] Using GB pages for direct mapping [ 0.000000] ACPI: Early table checksum verification disabled [ 0.000000] ACPI: RSDP 0x00000000000F2370 000014 (v00 Google) [ 0.000000] ACPI: RSDT 0x00000000BFFF3430 000038 (v01 Google GOOGRSDT 00000001 GOOG 00000001) [ 0.000000] ACPI: FACP 0x00000000BFFFCF60 0000F4 (v02 Google GOOGFACP 00000001 GOOG 00000001) [ 0.000000] ACPI: DSDT 0x00000000BFFF3470 0017B2 (v01 Google GOOGDSDT 00000001 GOOG 00000001) [ 0.000000] ACPI: FACS 0x00000000BFFFCF00 000040 [ 0.000000] ACPI: FACS 0x00000000BFFFCF00 000040 [ 0.000000] ACPI: SSDT 0x00000000BFFF65F0 00690D (v01 Google GOOGSSDT 00000001 GOOG 00000001) [ 0.000000] ACPI: APIC 0x00000000BFFF5D10 000076 (v01 Google GOOGAPIC 00000001 GOOG 00000001) [ 0.000000] ACPI: WAET 0x00000000BFFF5CE0 000028 (v01 Google GOOGWAET 00000001 GOOG 00000001) [ 0.000000] ACPI: SRAT 0x00000000BFFF4C30 0000C8 (v01 Google GOOGSRAT 00000001 GOOG 00000001) [ 0.000000] kvm-clock: Using msrs 4b564d01 and 4b564d00 [ 0.000000] kvm-clock: cpu 0, msr 2:1fffd001, primary cpu clock [ 0.000000] kvm-clock: using sched offset of 2070332681 cycles [ 0.000000] clocksource: kvm-clock: mask: 0xffffffffffffffff max_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns [ 0.000000] Zone ranges: [ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff] [ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x000000021fffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000000001000-0x000000000009efff] [ 0.000000] node 0: [mem 0x0000000000100000-0x00000000bfff2fff] [ 0.000000] node 0: [mem 0x0000000100000000-0x000000021fffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000000001000-0x000000021fffffff] [ 0.000000] kasan: KernelAddressSanitizer initialized [ 0.000000] ACPI: PM-Timer IO Port: 0xb008 [ 0.000000] ACPI: LAPIC_NMI (acpi_id[0xff] dfl dfl lint[0x1]) [ 0.000000] IOAPIC[0]: apic_id 0, version 17, address 0xfec00000, GSI 0-23 [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 5 global_irq 5 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 10 global_irq 10 high level) [ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 11 global_irq 11 high level) [ 0.000000] Using ACPI (MADT) for SMP configuration information [ 0.000000] smpboot: Allowing 2 CPUs, 0 hotplug CPUs [ 0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff] [ 0.000000] PM: Registered nosave memory: [mem 0x0009f000-0x0009ffff] [ 0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000effff] [ 0.000000] PM: Registered nosave memory: [mem 0x000f0000-0x000fffff] [ 0.000000] PM: Registered nosave memory: [mem 0xbfff3000-0xbfffffff] [ 0.000000] PM: Registered nosave memory: [mem 0xc0000000-0xfffbbfff] [ 0.000000] PM: Registered nosave memory: [mem 0xfffbc000-0xffffffff] [ 0.000000] e820: [mem 0xc0000000-0xfffbbfff] available for PCI devices [ 0.000000] Booting paravirtualized kernel on KVM [ 0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 0.000000] setup_percpu: NR_CPUS:64 nr_cpumask_bits:64 nr_cpu_ids:2 nr_node_ids:1 [ 0.000000] PERCPU: Embedded 42 pages/cpu @ffff8801db200000 s134024 r8192 d29816 u1048576 [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 1935227 [ 0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz root=/dev/sda1 console=ttyS0 earlyprintk=serial vsyscall=native rodata=n ftrace_dump_on_oops=orig_cpu oops=panic panic_on_warn=1 nmi_watchdog=panic panic=86400 workqueue.watchdog_thresh=120 [ 0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes) [ 0.000000] Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes) [ 0.000000] Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes) [ 0.000000] Memory: 6581404K/7863876K available (40418K kernel code, 6136K rwdata, 8808K rodata, 1848K init, 23616K bss, 1282472K reserved, 0K cma-reserved) [ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1 [ 0.000000] Kernel/User page tables isolation: enabled [ 0.000000] Running RCU self tests [ 0.000000] Preemptible hierarchical RCU implementation. [ 0.000000] RCU lockdep checking is enabled. [ 0.000000] Build-time adjustment of leaf fanout to 64. [ 0.000000] RCU restricting CPUs from NR_CPUS=64 to nr_cpu_ids=2. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=2 [ 0.000000] NR_IRQS:4352 nr_irqs:440 16 [ 0.000000] console [ttyS0] enabled [ 0.000000] console [ttyS0] enabled [ 0.000000] bootconsole [earlyser0] disabled [ 0.000000] bootconsole [earlyser0] disabled [ 0.000000] Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar [ 0.000000] ... MAX_LOCKDEP_SUBCLASSES: 8 [ 0.000000] ... MAX_LOCK_DEPTH: 48 [ 0.000000] ... MAX_LOCKDEP_KEYS: 8191 [ 0.000000] ... CLASSHASH_SIZE: 4096 [ 0.000000] ... MAX_LOCKDEP_ENTRIES: 32768 [ 0.000000] ... MAX_LOCKDEP_CHAINS: 65536 [ 0.000000] ... CHAINHASH_SIZE: 32768 [ 0.000000] memory used by lock dependency info: 8159 kB [ 0.000000] per task-struct memory footprint: 1920 bytes [ 0.000000] tsc: Detected 2300.000 MHz processor [ 1.130566] Calibrating delay loop (skipped) preset value.. 4600.00 BogoMIPS (lpj=23000000) [ 1.131718] pid_max: default: 32768 minimum: 301 [ 1.132421] ACPI: Core revision 20150930 [ 1.551724] ACPI: 2 ACPI AML tables successfully acquired and loaded [ 1.553696] Security Framework initialized [ 1.554266] SELinux: Initializing. [ 1.554914] AppArmor: AppArmor disabled by boot time parameter [ 1.555828] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.556763] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.560456] Initializing cgroup subsys io [ 1.561063] Initializing cgroup subsys freezer [ 1.561710] Initializing cgroup subsys hugetlb [ 1.562332] Initializing cgroup subsys debug [ 1.563106] CPU: Physical Processor ID: 0 [ 1.564991] mce: CPU supports 32 MCE banks [ 1.565747] Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024 [ 1.566613] Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4 [ 1.567516] Spectre V2 : Vulnerable: Minimal generic ASM retpoline [ 1.570663] Freeing SMP alternatives memory: 44K [ 1.580284] ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1 [ 1.699915] smpboot: CPU0: Intel(R) Xeon(R) CPU @ 2.30GHz (family: 0x6, model: 0x3f, stepping: 0x0) [ 1.701371] Performance Events: unsupported p6 CPU model 63 no PMU driver, software events only. [ 1.790166] x86: Booting SMP configuration: [ 1.790813] .... node #0, CPUs: #1 [ 1.791579] kvm-clock: cpu 1, msr 2:1fffd041, secondary cpu clock [ 1.796233] x86: Booted up 1 node, 2 CPUs [ 1.796842] smpboot: Total of 2 processors activated (9200.00 BogoMIPS) [ 1.801345] devtmpfs: initialized [ 1.810621] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 1.812004] futex hash table entries: 512 (order: 4, 65536 bytes) [ 1.813559] xor: automatically using best checksumming function: [ 1.816931] kworker/u4:0 (21) used greatest stack depth: 27944 bytes left [ 1.909917] avx : 20398.400 MB/sec [ 1.910982] RTC time: 9:36:32, date: 02/28/18 [ 1.913663] NET: Registered protocol family 16 [ 1.914880] schedtune: init normalization constants... [ 1.915621] schedtune: no energy model data [ 1.916325] schedtune: disabled! [ 1.940074] cpuidle: using governor ladder [ 1.969946] cpuidle: using governor menu [ 1.971194] ACPI: bus type PCI registered [ 1.971760] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 [ 1.974475] PCI: Using configuration type 1 for base access [ 1.980863] kworker/u4:1 (55) used greatest stack depth: 27448 bytes left [ 2.124169] kworker/u4:2 (464) used greatest stack depth: 27080 bytes left [ 2.329834] raid6: sse2x1 gen() 4810 MB/s [ 2.499803] raid6: sse2x1 xor() 2683 MB/s [ 2.669778] raid6: sse2x2 gen() 7586 MB/s [ 2.839752] raid6: sse2x2 xor() 4349 MB/s [ 3.009721] raid6: sse2x4 gen() 9016 MB/s [ 3.179691] raid6: sse2x4 xor() 5691 MB/s [ 3.349662] raid6: avx2x1 gen() 9440 MB/s [ 3.519639] raid6: avx2x2 gen() 14684 MB/s [ 3.689606] raid6: avx2x4 gen() 19162 MB/s [ 3.690247] raid6: using algorithm avx2x4 gen() 19162 MB/s [ 3.690989] raid6: using avx2x2 recovery algorithm [ 3.692187] ACPI: Added _OSI(Module Device) [ 3.692781] ACPI: Added _OSI(Processor Device) [ 3.693406] ACPI: Added _OSI(3.0 _SCP Extensions) [ 3.694048] ACPI: Added _OSI(Processor Aggregator Device) [ 3.719458] ACPI: Executed 2 blocks of module-level executable AML code