[....] Starting OpenBSD Secure Shell server: sshd[ 18.636524] random: sshd: uninitialized urandom read (32 bytes read, 31 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. [ 18.810087] random: sshd: uninitialized urandom read (32 bytes read, 31 bits of entropy available) [ 18.990323] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.091538] random: sshd: uninitialized urandom read (32 bytes read, 123 bits of entropy available) [ 20.248172] random: sshd: uninitialized urandom read (32 bytes read, 127 bits of entropy available) [ 20.351426] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.9' (ECDSA) to the list of known hosts. executing program [ 25.897855] ================================================================== [ 25.905230] BUG: KASAN: use-after-free in l2tp_session_queue_purge+0xe8/0x100 [ 25.912480] Read of size 4 at addr ffff8800ae24c780 by task syzkaller038915/3739 [ 25.919983] [ 25.921585] CPU: 1 PID: 3739 Comm: syzkaller038915 Not tainted 4.4.125-g38f41ec #63 [ 25.929367] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 25.938697] 0000000000000000 fc531750cd0a9857 ffff8800ad617cc0 ffffffff81d067bd [ 25.946676] ffffea0002b89300 ffff8800ae24c780 0000000000000000 ffff8800ae24c780 [ 25.954647] ffffffff82ded950 ffff8800ad617cf8 ffffffff814fea83 ffff8800ae24c780 [ 25.962608] Call Trace: [ 25.965167] [] dump_stack+0xc1/0x124 [ 25.970499] [] ? sock_release+0x1e0/0x1e0 [ 25.976266] [] print_address_description+0x73/0x260 [ 25.982908] [] ? sock_release+0x1e0/0x1e0 [ 25.988677] [] kasan_report+0x285/0x370 [ 25.994270] [] ? l2tp_session_queue_purge+0xe8/0x100 [ 26.000989] [] __asan_report_load4_noabort+0x14/0x20 [ 26.007711] [] l2tp_session_queue_purge+0xe8/0x100 [ 26.014259] [] ? sock_release+0x1e0/0x1e0 [ 26.020024] [] pppol2tp_release+0x1ff/0x310 [ 26.025964] [] sock_release+0x8d/0x1e0 [ 26.031471] [] sock_close+0x16/0x20 [ 26.036713] [] __fput+0x233/0x6d0 [ 26.041782] [] ____fput+0x15/0x20 [ 26.046861] [] task_work_run+0x104/0x180 [ 26.052539] [] exit_to_usermode_loop+0x13d/0x160 [ 26.058914] [] syscall_return_slowpath+0x1b5/0x1f0 [ 26.065460] [] int_ret_from_sys_call+0x25/0xa3 [ 26.071656] [ 26.073253] Allocated by task 3738: [ 26.076845] [] save_stack_trace+0x26/0x50 [ 26.082729] [] save_stack+0x43/0xd0 [ 26.088094] [] kasan_kmalloc+0xad/0xe0 [ 26.093721] [] __kmalloc+0x124/0x320 [ 26.099170] [] l2tp_session_create+0x39/0x10f0 [ 26.105483] [] pppol2tp_connect+0x10fc/0x1930 [ 26.111713] [] SYSC_connect+0x1b6/0x310 [ 26.117423] [] SyS_connect+0x24/0x30 [ 26.122880] [] entry_SYSCALL_64_fastpath+0x22/0x9e [ 26.129546] [ 26.131143] Freed by task 3738: [ 26.134387] [] save_stack_trace+0x26/0x50 [ 26.140272] [] save_stack+0x43/0xd0 [ 26.145636] [] kasan_slab_free+0x72/0xc0 [ 26.151429] [] kfree+0xfc/0x300 [ 26.156444] [] l2tp_session_free+0x170/0x200 [ 26.162594] [] l2tp_tunnel_closeall+0x2d1/0x3b0 [ 26.168995] [] l2tp_udp_encap_destroy+0x8b/0xf0 [ 26.175396] [] udpv6_destroy_sock+0xb1/0xd0 [ 26.181449] [] sk_common_release+0x6b/0x300 [ 26.187508] [] udp_lib_close+0x15/0x20 [ 26.193132] [] inet_release+0xfa/0x1d0 [ 26.198752] [] inet6_release+0x50/0x70 [ 26.204380] [] sock_release+0x8d/0x1e0 [ 26.210002] [] sock_close+0x16/0x20 [ 26.215369] [] __fput+0x233/0x6d0 [ 26.220555] [] ____fput+0x15/0x20 [ 26.225749] [] task_work_run+0x104/0x180 [ 26.231545] [] exit_to_usermode_loop+0x13d/0x160 [ 26.238038] [] syscall_return_slowpath+0x1b5/0x1f0 [ 26.244701] [] int_ret_from_sys_call+0x25/0xa3 [ 26.251021] [ 26.252619] The buggy address belongs to the object at ffff8800ae24c780 [ 26.252619] which belongs to the cache kmalloc-512 of size 512 [ 26.265242] The buggy address is located 0 bytes inside of [ 26.265242] 512-byte region [ffff8800ae24c780, ffff8800ae24c980) [ 26.276910] The buggy address belongs to the page: SeaBIOS (version 1.8.2-20171130_102032-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 0x000f2350: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304 Booting from Hard Disk 0... early console in decompress_kernel input_data: 0x00000000039c926e input_len: 0x0000000001427f53 output: 0x0000000001000000 output_len: 0x0000000003ddca40 run_size: 0x0000000005516000 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 4.4.125-g38f41ec (syzkaller@ci) (gcc version 7.1.1 20170620 (GCC) ) #63 SMP PREEMPT Thu Mar 29 12:42:13 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 0x000f23d0-0x000f23df] mapped at [ffff8800000f23d0] [ 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 0x00000000000F2390 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 1671620716 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: 6581380K/7863876K available (40445K kernel code, 6140K rwdata, 8816K rodata, 1852K init, 23632K bss, 1282496K 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 [ 1.129756] Calibrating delay loop (skipped) preset value.. 4600.00 BogoMIPS (lpj=23000000) [ 1.130907] pid_max: default: 32768 minimum: 301 [ 1.131612] ACPI: Core revision 20150930 [ 1.539829] ACPI: 2 ACPI AML tables successfully acquired and loaded [ 1.541746] Security Framework initialized [ 1.542316] SELinux: Initializing. [ 1.542964] AppArmor: AppArmor disabled by boot time parameter [ 1.543860] Mount-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.544818] Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes) [ 1.548453] Initializing cgroup subsys io [ 1.549149] Initializing cgroup subsys freezer [ 1.549797] Initializing cgroup subsys hugetlb [ 1.550432] Initializing cgroup subsys debug [ 1.551240] CPU: Physical Processor ID: 0 [ 1.552996] mce: CPU supports 32 MCE banks [ 1.553768] Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024 [ 1.554625] Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4 [ 1.555543] Spectre V2 : Vulnerable: Minimal generic ASM retpoline [ 1.558683] Freeing SMP alternatives memory: 44K [ 1.568031] ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1 [ 1.679107] smpboot: CPU0: Intel(R) Xeon(R) CPU @ 2.30GHz (family: 0x6, model: 0x3f, stepping: 0x0) [ 1.680598] Performance Events: unsupported p6 CPU model 63 no PMU driver, software events only. [ 1.769382] x86: Booting SMP configuration: [ 1.770109] .... node #0, CPUs: #1 [ 1.770887] kvm-clock: cpu 1, msr 2:1fffd041, secondary cpu clock [ 1.775668] x86: Booted up 1 node, 2 CPUs [ 1.776278] smpboot: Total of 2 processors activated (9200.00 BogoMIPS) [ 1.780907] devtmpfs: initialized [ 1.790229] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns [ 1.791635] futex hash table entries: 512 (order: 4, 65536 bytes) [ 1.793276] xor: automatically using best checksumming function: [ 1.806832] kworker/u4:0 (21) used greatest stack depth: 27944 bytes left [ 1.889126] avx : 21145.600 MB/sec [ 1.890261] RTC time: 3:45:10, date: 04/06/18 [ 1.892566] NET: Registered protocol family 16 [ 1.893687] schedtune: init normalization constants... [ 1.894407] schedtune: no energy model data [ 1.895010] schedtune: disabled! [ 1.929332] cpuidle: using governor ladder [ 1.959164] cpuidle: using governor menu [ 1.960463] ACPI: bus type PCI registered [ 1.961022] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 [ 1.963787] PCI: Using configuration type 1 for base access [ 1.977094] kworker/u4:1 (57) used greatest stack depth: 27448 bytes left [ 2.399135] raid6: sse2x1 gen() 4600 MB/s [ 2.569093] raid6: sse2x1 xor() 2523 MB/s [ 2.739086] raid6: sse2x2 gen() 7558 MB/s [ 2.909075] raid6: sse2x2 xor() 4312 MB/s [ 3.079073] raid6: sse2x4 gen() 8840 MB/s [ 3.249068] raid6: sse2x4 xor() 5680 MB/s [ 3.419062] raid6: avx2x1 gen() 9466 MB/s [ 3.589057] raid6: avx2x2 gen() 14582 MB/s [ 3.759043] raid6: avx2x4 gen() 19210 MB/s [ 3.759728] raid6: using algorithm avx2x4 gen() 19210 MB/s [ 3.760472] raid6: using avx2x2 recovery algorithm [ 3.761771] ACPI: Added _OSI(Module Device) [ 3.762400] ACPI: Added _OSI(Processor Device) [ 3.763029] ACPI: Added _OSI(3.0 _SCP Extensions) [ 3.763739] ACPI: Added _OSI(Processor Aggregator Device) [ 3.789432] ACPI: Executed 2 blocks of module-level executable AML code [ 4.638576] ACPI: Interpreter enabled [ 4.639528] ACPI: (supports S0 S3 S4 S5) [ 4.640092] ACPI: Using IOAPIC for interrupt routing [ 4.641244] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug [ 5.782727] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) [ 5.783724] acpi PNP0A03:00: _OSC: OS supports [ASPM ClockPM Segments MSI] [ 5.785054] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM [ 5.786078] acpi PNP0A03:00: fail to add MMCONFIG information, can't access extended PCI configuration space under this bridge. [ 5.811977] PCI host bridge to bus 0000:00 [ 5.812620] pci_bus 0000:00: root bus resource [io 0x0000-0x0cf7 window] [ 5.813605] pci_bus 0000:00: root bus resource [io 0x0d00-0xffff window] [ 5.814535] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff window] [ 5.815578] pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window] [ 5.816610] pci_bus 0000:00: root bus resource [bus 00-ff] [ 5.850362] pci 0000:00:01.3: quirk: [io 0xb000-0xb03f] claimed by PIIX4 ACPI [ 5.926892] ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11) [ 5.932634] ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11) [ 5.938135] ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11) [ 5.943590] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11) [ 5.946889] ACPI: PCI Interrupt Link [LNKS] (IRQs *9)