hashcat
Segmentation fault on NixOS
Describe the bug A segmentation fault is encountered if I run hashcat on NixOS with an Intel CPU.
To Reproduce For example I used the following AS-REP hash file:
[email protected]:72b67b5955b338756f7b547081ede581$d9e112aebab2e9dd2360b0746e9b718c1114e3e1e86aac9a24d809a226d67ee7636d2fc0ed83dd6afd0159a817438dce603baf18aece570c6820f9733c48f54ce0b9841d5b8cfab879e8581892e9ad61e055ca28fefd6aa81cf4cd443183f0d3b8020c68cce1b714932575d634f11d8329314b5eb20da93b15c9ed9c75f21a4b597ed8ae2ed75c5b4980918e046b4d0ec923fb02919f2ec3146ea4bc1af59fbbdc5c8fc0c3a8df64930c1ff48c58f6804268791610aba3355dd44127a0897666479ec7dbd0bfbc721ab1aa2dd09df12adf28b748c3969cbcfd1d7f72172d93112dec81ecf81d
Then I tried to crack the hash with hashcat using the wordlist rockyou.txt:
hashcat -a 0 -m 18200 svc-alfresco.hash /usr/share/wordlists/rockyou.txt
hashcat (6.2.6) starting
OpenCL API (OpenCL 2.0 LINUX) - Platform #1 [Intel(R) Corporation]
==================================================================
* Device #1: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz, 15938/31941 MB (3992 MB allocatable), 8MCU
Minimum password length supported by kernel: 0
Maximum password length supported by kernel: 256
Hashes: 1 digests; 1 unique digests, 1 unique salts
Bitmaps: 16 bits, 65536 entries, 0x0000ffff mask, 262144 bytes, 5/13 rotates
Rules: 1
Optimizers applied:
* Zero-Byte
* Not-Iterated
* Single-Hash
* Single-Salt
ATTENTION! Pure (unoptimized) backend kernels selected.
Pure kernels can crack longer passwords, but drastically reduce performance.
If you want to switch to optimized kernels, append -O to your commandline.
See the above message to find out about the exact limits.
Watchdog: Temperature abort trigger set to 90c
Initializing backend runtime for device #1. Please be patient...Stack dump:
0. Running pass 'Intel OpenCL Vectorizer' on module 'main'.
1. Running pass 'Intel OpenCL VectorizerCore' on function '@__Vectorized_.gpu_utf8_to_utf16'
2. Running pass 'Predicator' on function '@__Vectorized_.gpu_utf8_to_utf16'
[1] 9546 segmentation fault hashcat -a 0 -m 18200 svc-alfresco.hash /usr/share/wordlists/rockyou.txt
From the output above we can see a segmentation fault.
Expected behavior Hashcat is supposed to crack the hash without any issues. Instead a segfault happens.
Hardware/Compute device (please complete the following information):
- Compute device name: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz, 15938/31941 MB (3992 MB allocatable), 8MCU
- OpenCL/CUDA driver name: Intel(R) OpenCL
- OpenCL/CUDA driver version: 1.2.0.475
- OpenCL/CUDA driver source: installed on NixOS via nix:
{ config, lib, pkgs, modulesPath, ... }:
{
## Intel GPU config
# Set initramfs kernel modules
# Enable Intel video driver via early KMS
boot.initrd.kernelModules = [
"i915"
];
# X11 / Wayland settings
services.xserver = {
enable = true;
videoDrivers = [ "intel" ];
};
# Load libva driver for accelerated video
nixpkgs.config.packageOverrides = pkgs: {
intel-vaapi-driver = pkgs.intel-vaapi-driver.override { enableHybridCodec = true; };
};
# OpenGL settings
hardware.graphics = {
enable = true;
extraPackages = with pkgs; [
intel-media-driver # LIBVA_DRIVER_NAME=iHD
intel-vaapi-driver # LIBVA_DRIVER_NAME=i965 (older but works better for Firefox/Chromium)
libvdpau-va-gl
intel-ocl
intel-compute-runtime
ocl-icd
vpl-gpu-rt
];
extraPackages32 = with pkgs.pkgsi686Linux; [ intel-vaapi-driver ];
};
environment.sessionVariables = { LIBVA_DRIVER_NAME = "iHD"; }; # Force intel-media-driver
environment.variables = {
VDPAU_DRIVER = "va_gl";
};
}
Hashcat version (please complete the following information):
- OS: Linux
- Distribution: NixOS Unstable
- Version: 6.2.6
Diagnostic output compute devices:
❯ clinfo
Number of platforms 1
Platform Name Intel(R) OpenCL
Platform Vendor Intel(R) Corporation
Platform Version OpenCL 2.0 LINUX
Platform Profile FULL_PROFILE
Platform Extensions cl_khr_icd cl_khr_global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int32_base_atomics cl_khr_local_int32_extended_atomics cl_khr_byte_addressable_store cl_khr_depth_images cl_khr_3d_image_writes cl_intel_exec_by_local_thread cl_khr_spir cl_khr_fp64 cl_khr_image2d_from_buffer
Platform Extensions function suffix INTEL
Platform Name Intel(R) OpenCL
Number of devices 1
Device Name Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
Device Vendor Intel(R) Corporation
Device Vendor ID 0x8086
Device Version OpenCL 2.0 (Build 475)
Driver Version 1.2.0.475
Device OpenCL C Version OpenCL C 2.0
Device Type CPU
Device Profile FULL_PROFILE
Device Available Yes
Compiler Available Yes
Linker Available Yes
Max compute units 8
Max clock frequency 1700MHz
Device Partition (core)
Max number of sub-devices 8
Supported partition types by counts, equally, by names (Intel)
Supported affinity domains (n/a)
Max work item dimensions 3
Max work item sizes 8192x8192x8192
Max work group size 8192
Preferred work group size multiple (kernel) 128
Preferred / native vector sizes
char 1 / 32
short 1 / 16
int 1 / 8
long 1 / 4
half 0 / 0 (n/a)
float 1 / 8
double 1 / 4 (cl_khr_fp64)
Half-precision Floating-point support (n/a)
Single-precision Floating-point support (core)
Denormals Yes
Infinity and NANs Yes
Round to nearest Yes
Round to zero No
Round to infinity No
IEEE754-2008 fused multiply-add No
Support is emulated in software No
Correctly-rounded divide and sqrt operations No
Double-precision Floating-point support (cl_khr_fp64)
Denormals Yes
Infinity and NANs Yes
Round to nearest Yes
Round to zero Yes
Round to infinity Yes
IEEE754-2008 fused multiply-add Yes
Support is emulated in software No
Address bits 64, Little-Endian
Global memory size 33492631552 (31.19GiB)
Error Correction support No
Max memory allocation 8373157888 (7.798GiB)
Unified memory for Host and Device Yes
Shared Virtual Memory (SVM) capabilities (core)
Coarse-grained buffer sharing Yes
Fine-grained buffer sharing Yes
Fine-grained system sharing Yes
Atomics Yes
Minimum alignment for any data type 128 bytes
Alignment of base address 1024 bits (128 bytes)
Preferred alignment for atomics
SVM 64 bytes
Global 64 bytes
Local 0 bytes
Max size for global variable 65536 (64KiB)
Preferred total size of global vars 65536 (64KiB)
Global Memory cache type Read/Write
Global Memory cache size 262144 (256KiB)
Global Memory cache line size 64 bytes
Image support Yes
Max number of samplers per kernel 480
Max size for 1D images from buffer 523322368 pixels
Max 1D or 2D image array size 2048 images
Base address alignment for 2D image buffers 64 bytes
Pitch alignment for 2D image buffers 64 pixels
Max 2D image size 16384x16384 pixels
Max 3D image size 2048x2048x2048 pixels
Max number of read image args 480
Max number of write image args 480
Max number of read/write image args 480
Max number of pipe args 16
Max active pipe reservations 32767
Max pipe packet size 1024
Local memory type Global
Local memory size 32768 (32KiB)
Max number of constant args 480
Max constant buffer size 131072 (128KiB)
Max size of kernel argument 3840 (3.75KiB)
Queue properties (on host)
Out-of-order execution Yes
Profiling Yes
Local thread execution (Intel) Yes
Queue properties (on device)
Out-of-order execution Yes
Profiling Yes
Preferred size 4294967295 (4GiB)
Max size 4294967295 (4GiB)
Max queues on device 4294967295
Max events on device 4294967295
Prefer user sync for interop No
Profiling timer resolution 1ns
Execution capabilities
Run OpenCL kernels Yes
Run native kernels Yes
SPIR versions 1.2
printf() buffer size 1048576 (1024KiB)
Built-in kernels (n/a)
Device Extensions cl_khr_icd cl_khr_global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int32_base_atomics cl_khr_local_int32_extended_atomics cl_khr_byte_addressable_store cl_khr_depth_images cl_khr_3d_image_writes cl_intel_exec_by_local_thread cl_khr_spir cl_khr_fp64 cl_khr_image2d_from_buffer
NULL platform behavior
clGetPlatformInfo(NULL, CL_PLATFORM_NAME, ...) Intel(R) OpenCL
clGetDeviceIDs(NULL, CL_DEVICE_TYPE_ALL, ...) Success [INTEL]
clCreateContext(NULL, ...) [default] Success [INTEL]
clCreateContextFromType(NULL, CL_DEVICE_TYPE_DEFAULT) Success (1)
Platform Name Intel(R) OpenCL
Device Name Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
clCreateContextFromType(NULL, CL_DEVICE_TYPE_CPU) Success (1)
Platform Name Intel(R) OpenCL
Device Name Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
clCreateContextFromType(NULL, CL_DEVICE_TYPE_GPU) No devices found in platform
clCreateContextFromType(NULL, CL_DEVICE_TYPE_ACCELERATOR) No devices found in platform
clCreateContextFromType(NULL, CL_DEVICE_TYPE_CUSTOM) No devices found in platform
clCreateContextFromType(NULL, CL_DEVICE_TYPE_ALL) Success (1)
Platform Name Intel(R) OpenCL
Device Name Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
ICD loader properties
ICD loader Name OpenCL ICD Loader
ICD loader Vendor OCL Icd free software
ICD loader Version 2.3.2
ICD loader Profile OpenCL 3.0
❯ hashcat -I
hashcat (6.2.6) starting in backend information mode
OpenCL Info:
============
OpenCL Platform ID #1
Vendor..: Intel(R) Corporation
Name....: Intel(R) OpenCL
Version.: OpenCL 2.0 LINUX
Backend Device ID #1
Type...........: CPU
Vendor.ID......: 8
Vendor.........: Intel(R) Corporation
Name...........: Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
Version........: OpenCL 2.0 (Build 475)
Processor(s)...: 8
Clock..........: 1700
Memory.Total...: 31941 MB (limited to 3992 MB allocatable in one block)
Memory.Free....: 15938 MB
Local.Memory...: 32 KB
OpenCL.Version.: OpenCL C 2.0
Driver.Version.: 1.2.0.475
❯ lspci
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers (rev 08)
00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 620 (rev 07)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 08)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1 (rev f1)
00:1c.4 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #5 (rev f1)
00:1c.6 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #7 (rev f1)
00:1d.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #9 (rev f1)
00:1d.2 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #11 (rev f1)
00:1f.0 ISA bridge: Intel Corporation Sunrise Point LPC/eSPI Controller (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)
00:1f.4 SMBus: Intel Corporation Sunrise Point-LP SMBus (rev 21)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (4) I219-LM (rev 21)
03:00.0 Non-Volatile memory controller: Sandisk Corp PC SN520 x2 M.2 2242 NVMe SSD (rev 01)
04:00.0 Network controller: Intel Corporation Wireless 8265 / 8275 (rev 78)
40:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981/PM983
Additional context I have no issues with the same hashcat version 6.2.6 on the same hardware on arch linux.
Same problem:
❯ clinfo Number of platforms 1 Platform Name Intel(R) OpenCL Platform Vendor Intel(R) Corporation Platform Version OpenCL 1.2 LINUX Platform Profile FULL_PROFILE Platform Extensions cl_khr_icd cl_khr_global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_local_int32_base_atomics cl_khr_local_int32_extended_atomics cl_khr_byte_addressable_store cl_khr_depth_images cl_khr_3d_image_writes cl_intel_exec_by_local_thread cl_khr_spir cl_khr_fp64 Platform Extensions function suffix INTEL
Platform Name Intel(R) OpenCL Number of devices 1 Device Name Intel(R) Core(TM) i5-4570 CPU @ 3.20GHz Device Vendor Intel(R) Corporation Device Vendor ID 0x8086 Device Version OpenCL 1.2 (Build 475) Driver Version 1.2.0.475 Device OpenCL C Version OpenCL C 1.2 Device Type CPU Device Profile FULL_PROFILE Device Available Yes Compiler Available Yes Linker Available Yes Max compute units 4 Max clock frequency 3200MHz
We have updated hashcat to v7.0.0 and reworked lot's of stuff. Please retry with latest version and close the issue if solved.
Some side note, your intel CPU runtime seems out of date. Latest runtime already supports OpenCL 3.0, so it's very likely the segfault is coming from the old runtime, not from hashcat.
Some log working:
atom@x870:~/hashcat$ ./hashcat -a 0 -m 18200 svc-alfresco.hash rockyou.txt -D 1 --backend-ignore-hip
hashcat (v7.0.0-59-g5f2216ef3) starting
OpenCL API (OpenCL 3.0 LINUX) - Platform #1 [Intel(R) Corporation]
==================================================================
* Device #01: AMD Ryzen 9 9900X 12-Core Processor, 15581/31163 MB (7790 MB allocatable), 24MCU
...
[email protected]:72b67b5955b338756f7b547081ede581$d9e112aebab2e9dd2360b0746e9b718c1114e3e1e86aac9a24d809a226d67ee7636d2fc0ed83dd6afd0159a817438dce603baf18aece570c6820f9733c48f54ce0b9841d5b8cfab879e8581892e9ad61e055ca28fefd6aa81cf4cd443183f0d3b8020c68cce1b714932575d634f11d8329314b5eb20da93b15c9ed9c75f21a4b597ed8ae2ed75c5b4980918e046b4d0ec923fb02919f2ec3146ea4bc1af59fbbdc5c8fc0c3a8df64930c1ff48c58f6804268791610aba3355dd44127a0897666479ec7dbd0bfbc721ab1aa2dd09df12adf28b748c3969cbcfd1d7f72172d93112dec81ecf81d:s3rvice
Session..........: hashcat
Status...........: Cracked
...
Started: Tue Aug 5 10:08:11 2025
Stopped: Tue Aug 5 10:08:24 2025
I still get the same issues.
I feel like this is an OpenCL issue with my hardware.
* Device #1: Outdated or broken Intel OpenCL runtime '1.2.0.475' detected!
Initializing backend runtime for device #1. Please be patient...Stack dump:
0. Running pass 'Intel OpenCL Vectorizer' on module 'main'.
1. Running pass 'Intel OpenCL VectorizerCore' on function '@__Vectorized_.gpu_utf8_to_utf16'
2. Running pass 'Predicator' on function '@__Vectorized_.gpu_utf8_to_utf16'
Segmentation fault hashcat -a 0 -m 18200 svc-alfresco.hash /usr/share/wordlists/rockyou.txt -D 1 --backend-ignore-hip --force
Yes, it's not hashcat that crashes, but the runtime. It's not a hardware issue, but the opencl runtime is ways too old.
I have intel-compute-runtime installed. That package is on version 25.22.33944.8
=> https://github.com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/by-name/in/intel-compute-runtime/package.nix
I have
intel-compute-runtimeinstalled. That package is on version25.22.33944.8=> https://github.com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/by-name/in/intel-compute-runtime/package.nix
Is old, check here: https://github.com/intel/compute-runtime
I was able to fix my issues with hashcat by replacing intel-compute-runtime with intel-compute-runtime-legacy1.
Intel Graphics Compute Runtime oneAPI Level Zero and OpenCL with support for Gen8, Gen9 and Gen11 GPUs
See my commit here: https://github.com/Red-Flake/red-flake-nix/commit/e3c713fc6fb20738df0dbd1f6ca7ffdd3a6a4270
On NixOS i created an option to enable this for intel legacy GPUs:
self: super: {
# replace intel-compute-runtime with intel-compute-runtime-legacy1 for legacy Gen8, Gen9 and Gen11 Intel GPUs
intel-compute-runtime = super.intel-compute-runtime-legacy1;
# create symlink for intel-opencl/libigdrcl_legacy1.so
super.systemd.tmpfiles.rules =
let
createLink = src: dest: "L+ ${dest} - - - - ${src}";
in
[
(createLink "${super.pkgs.intel-compute-runtime-legacy1}/lib/intel-opencl/libigdrcl_legacy1.so" "/usr/lib/x86_64-linux-gnu/intel-opencl/libigdrcl_legacy1.so")
];
}
clinfo now gives me the correct info:
❯ clinfo
Number of platforms 1
Platform Name Intel(R) OpenCL Graphics
Platform Vendor Intel(R) Corporation
Platform Version OpenCL 3.0
Platform Profile FULL_PROFILE
Platform Extensions cl_khr_byte_addressable_store cl_khr_device_uuid cl_khr_fp16 cl_khr_global_int32_base_atomics cl_khr_global_int32_extended_atomics cl_khr_icd cl_khr_local_int32_base_atomics cl_khr_local_int32_extended_atomics cl_intel_command_queue_families cl_intel_subgroups cl_intel_required_subgroup_size cl_intel_subgroups_short cl_khr_spir cl_intel_accelerator cl_intel_driver_diagnostics cl_khr_priority_hints cl_khr_throttle_hints cl_khr_create_command_queue cl_intel_subgroups_char cl_intel_subgroups_long cl_khr_il_program cl_intel_mem_force_host_memory cl_khr_subgroup_extended_types cl_khr_subgroup_non_uniform_vote cl_khr_subgroup_ballot cl_khr_subgroup_non_uniform_arithmetic cl_khr_subgroup_shuffle cl_khr_subgroup_shuffle_relative cl_khr_subgroup_clustered_reduce cl_intel_device_attribute_query cl_khr_extended_bit_ops cl_khr_suggested_local_work_size cl_intel_split_work_group_barrier cl_khr_fp64 cl_khr_subgroups cl_intel_spirv_media_block_io cl_intel_spirv_subgroups cl_khr_spirv_linkonce_odr cl_khr_spirv_no_integer_wrap_decoration cl_intel_unified_shared_memory cl_khr_mipmap_image cl_khr_mipmap_image_writes cl_ext_float_atomics cl_khr_external_memory cl_intel_planar_yuv cl_intel_packed_yuv cl_intel_motion_estimation cl_intel_device_side_avc_motion_estimation cl_intel_spirv_device_side_avc_motion_estimation cl_intel_advanced_motion_estimation cl_khr_int64_base_atomics cl_khr_int64_extended_atomics cl_khr_image2d_from_buffer cl_khr_depth_images cl_khr_3d_image_writes cl_intel_media_block_io cl_khr_gl_sharing cl_khr_gl_depth_images cl_khr_gl_event cl_khr_gl_msaa_sharing cl_intel_va_api_media_sharing cl_intel_sharing_format_query cl_khr_pci_bus_info
Platform Extensions with Version cl_khr_byte_addressable_store 0x400000 (1.0.0)
cl_khr_device_uuid 0x400000 (1.0.0)
cl_khr_fp16 0x400000 (1.0.0)
.........................................SNIP................................................
And now hashcat works as expected on my machine:
❯ hashcat --benchmark
hashcat (7.0.0) starting in benchmark mode
Benchmarking uses hand-optimized kernel code by default.
You can use it in your cracking session by setting the -O option.
Note: Using optimized kernel code limits the maximum supported password length.
To disable the optimized kernel code in benchmark mode, use the -w option.
OpenCL API (OpenCL 3.0 ) - Platform #1 [Intel(R) Corporation]
=============================================================
* Device #01: Intel(R) UHD Graphics 620, 14782/29564 MB (2047 MB allocatable), 8MCU
Benchmark relevant options:
===========================
* --backend-devices-virtmulti=1
* --backend-devices-virthost=1
* --optimized-kernel-enable
-------------------
* Hash-Mode 0 (MD5)
-------------------
Speed.#01........: 494.1 MH/s (83.72ms) @ Accel:21 Loops:1024 Thr:256 Vec:1
----------------------
* Hash-Mode 100 (SHA1)
----------------------
Speed.#01........: 96366.5 kH/s (104.17ms) @ Accel:8 Loops:1024 Thr:256 Vec:1
.........................................SNIP................................................