couldn't mount to /sysroot after compile kernel with KSPP options. about kernel-hardening-checker

[a13xp0p0v]

Hello @bryn1u ,

I don't know the reason of such behavior on Centos.
Distros can have various issues because of the kernel hardening options, for example systemd on Ubuntu-18 has troubles with kernel modules unloading because of CONFIG_STATIC_USERMODEHELPER.

It would be great if you find the reason and share the result.
I would recommend you to use binary search to do it faster.

[bryn1u]

Hey,

I checked many options and recompiled kernel many times to find some answers, but it looks like everything works like a charm. I was doing everything based on Centos 7 with devtoolset-7 enabled to get never version of gcc like 7.2. With CONFIG_SECURITY_LOADPIN enabled im not able to load any module and getting "operation not permitted". Im guessing it's supposed to be like that.
@a13xp0p0v
Don't you know if ubuntu developers will enable KSPP options to the ubuntu kernel ? Or only manual compilation is available to get more security features ?
Thanks !

[a13xp0p0v]

With CONFIG_SECURITY_LOADPIN enabled im not able to load any module and getting "operation not permitted". Im guessing it's supposed to be like that.

Thanks for information!

That's the description of CONFIG_SECURITY_LOADPIN:
Any files read through the kernel file reading interface (kernel modules, firmware, kexec images, security policy) can be pinned to the first filesystem used for loading. When enabled, any files that come from other filesystems will be rejected.

I guess in your case the first modules are loaded from the ramdisk, and later loading from root filesystem fails.

Don't you know if ubuntu developers will enable KSPP options to the ubuntu kernel ? Or only manual compilation is available to get more security features ?

It's slow but steady process. More and more kernel hardening options are enabled by distros.

[bryn1u]

Hello
I have a weir problem. After successfully compiled kernel i can't use iptables:

[root@localhost ~]# iptables -L
iptables v1.4.21: can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

What am i doing wrong ?

Kernel KSSP options:

option name                            | desired val | decision |       reason       ||        check result        
  ===================================================================================================================
  CONFIG_BUG                             |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_PAGE_TABLE_ISOLATION            |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_RETPOLINE                       |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_X86_64                          |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_X86_SMAP                        |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_X86_INTEL_UMIP                  |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_STRICT_KERNEL_RWX               |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_DEBUG_WX                        |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_RANDOMIZE_BASE                  |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_RANDOMIZE_MEMORY                |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_STACKPROTECTOR_STRONG           |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_VMAP_STACK                      |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_THREAD_INFO_IN_TASK             |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_SCHED_STACK_END_CHECK           |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_SLUB_DEBUG                      |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_SLAB_FREELIST_HARDENED          |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_SLAB_FREELIST_RANDOM            |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_HARDENED_USERCOPY               |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_FORTIFY_SOURCE                  |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_LOCK_DOWN_KERNEL                |      y      | ubuntu18 |  self_protection   ||      FAIL: not found       
  CONFIG_STRICT_MODULE_RWX               |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_MODULE_SIG                      |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_MODULE_SIG_ALL                  |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_MODULE_SIG_SHA512               |      y      | ubuntu18 |  self_protection   ||     FAIL: "is not set"     
  CONFIG_SYN_COOKIES                     |      y      | ubuntu18 |  self_protection   ||             OK             
  CONFIG_DEFAULT_MMAP_MIN_ADDR           |    65536    | ubuntu18 |  self_protection   ||             OK             
  CONFIG_BUG_ON_DATA_CORRUPTION          |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_PAGE_POISONING                  |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_GCC_PLUGINS                     |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_GCC_PLUGIN_RANDSTRUCT           |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_GCC_PLUGIN_STRUCTLEAK           |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_GCC_PLUGIN_LATENT_ENTROPY       |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_REFCOUNT_FULL                   |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_DEBUG_LIST                      |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_DEBUG_SG                        |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_DEBUG_CREDENTIALS               |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_DEBUG_NOTIFIERS                 |      y      |   kspp   |  self_protection   ||             OK             
  CONFIG_MODULE_SIG_FORCE                |      y      |   kspp   |  self_protection   ||     FAIL: "is not set"     
  CONFIG_HARDENED_USERCOPY_FALLBACK      | is not set  |   kspp   |  self_protection   ||         FAIL: "y"          
  CONFIG_GCC_PLUGIN_STACKLEAK            |      y      |    my    |  self_protection   ||      FAIL: not found       
  CONFIG_SLUB_DEBUG_ON                   |      y      |    my    |  self_protection   ||             OK             
  CONFIG_SECURITY_DMESG_RESTRICT         |      y      |    my    |  self_protection   ||             OK             
  CONFIG_STATIC_USERMODEHELPER           |      y      |    my    |  self_protection   ||             OK             
  CONFIG_SECURITY_LOADPIN                |      y      |    my    |  self_protection   ||     FAIL: "is not set"     
  CONFIG_PAGE_POISONING_NO_SANITY        | is not set  |    my    |  self_protection   ||             OK             
  CONFIG_PAGE_POISONING_ZERO             | is not set  |    my    |  self_protection   ||             OK             
  CONFIG_SLAB_MERGE_DEFAULT              | is not set  |    my    |  self_protection   ||             OK             
  CONFIG_SECURITY                        |      y      | ubuntu18 |  security_policy   ||             OK             
  CONFIG_SECURITY_YAMA                   |      y      | ubuntu18 |  security_policy   ||             OK             
  CONFIG_SECURITY_SELINUX_DISABLE        | is not set  | ubuntu18 |  security_policy   ||             OK             
  CONFIG_SECCOMP                         |      y      | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_SECCOMP_FILTER                  |      y      | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_STRICT_DEVMEM                   |      y      | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_ACPI_CUSTOM_METHOD              | is not set  | ubuntu18 | cut_attack_surface ||         FAIL: "m"          
  CONFIG_COMPAT_BRK                      | is not set  | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_DEVKMEM                         | is not set  | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_COMPAT_VDSO                     | is not set  | ubuntu18 | cut_attack_surface ||       OK: not found        
  CONFIG_X86_PTDUMP                      | is not set  | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_ZSMALLOC_STAT                   | is not set  | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_PAGE_OWNER                      | is not set  | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_DEBUG_KMEMLEAK                  | is not set  | ubuntu18 | cut_attack_surface ||             OK             
  CONFIG_BINFMT_AOUT                     | is not set  | ubuntu18 | cut_attack_surface ||       OK: not found        
  CONFIG_MMIOTRACE_TEST                  | is not set  | ubuntu18 | cut_attack_surface ||       OK: not found        
  CONFIG_IO_STRICT_DEVMEM                |      y      |   kspp   | cut_attack_surface ||             OK             
  CONFIG_LEGACY_VSYSCALL_NONE            |      y      |   kspp   | cut_attack_surface ||             OK             
  CONFIG_BINFMT_MISC                     | is not set  |   kspp   | cut_attack_surface ||         FAIL: "m"          
  CONFIG_INET_DIAG                       | is not set  |   kspp   | cut_attack_surface ||         FAIL: "m"          
  CONFIG_KEXEC                           | is not set  |   kspp   | cut_attack_surface ||             OK             
  CONFIG_PROC_KCORE                      | is not set  |   kspp   | cut_attack_surface ||             OK             
  CONFIG_LEGACY_PTYS                     | is not set  |   kspp   | cut_attack_surface ||             OK             
  CONFIG_IA32_EMULATION                  | is not set  |   kspp   | cut_attack_surface ||             OK             
  CONFIG_X86_X32                         | is not set  |   kspp   | cut_attack_surface ||             OK             
  CONFIG_MODIFY_LDT_SYSCALL              | is not set  |   kspp   | cut_attack_surface ||         FAIL: "y"          
  CONFIG_HIBERNATION                     | is not set  |   kspp   | cut_attack_surface ||             OK             
  CONFIG_KPROBES                         | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_UPROBES                         | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_GENERIC_TRACER                  | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_PROC_VMCORE                     | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_PROC_PAGE_MONITOR               | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_USELIB                          | is not set  |grsecurity| cut_attack_surface ||             OK             
  CONFIG_CHECKPOINT_RESTORE              | is not set  |grsecurity| cut_attack_surface ||             OK             
  CONFIG_USERFAULTFD                     | is not set  |grsecurity| cut_attack_surface ||             OK             
  CONFIG_HWPOISON_INJECT                 | is not set  |grsecurity| cut_attack_surface ||             OK             
  CONFIG_MEM_SOFT_DIRTY                  | is not set  |grsecurity| cut_attack_surface ||       OK: not found        
  CONFIG_DEVPORT                         | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_DEBUG_FS                        | is not set  |grsecurity| cut_attack_surface ||         FAIL: "y"          
  CONFIG_NOTIFIER_ERROR_INJECTION        | is not set  |grsecurity| cut_attack_surface ||             OK             
  CONFIG_ACPI_TABLE_UPGRADE              | is not set  | lockdown | cut_attack_surface ||         FAIL: "y"          
  CONFIG_ACPI_APEI_EINJ                  | is not set  | lockdown | cut_attack_surface ||         FAIL: "m"          
  CONFIG_PROFILING                       | is not set  | lockdown | cut_attack_surface ||         FAIL: "y"          
  CONFIG_BPF_SYSCALL                     | is not set  | lockdown | cut_attack_surface ||         FAIL: "y"          
  CONFIG_MMIOTRACE                       | is not set  |    my    | cut_attack_surface ||             OK             
  CONFIG_KEXEC_FILE                      | is not set  |    my    | cut_attack_surface ||         FAIL: "y"          
  CONFIG_LIVEPATCH                       | is not set  |    my    | cut_attack_surface ||         FAIL: "y"          
  CONFIG_USER_NS                         | is not set  |    my    | cut_attack_surface ||         FAIL: "y"          
  CONFIG_IP_DCCP                         | is not set  |    my    | cut_attack_surface ||         FAIL: "m"          
  CONFIG_IP_SCTP                         | is not set  |    my    | cut_attack_surface ||         FAIL: "m"          
  CONFIG_FTRACE                          | is not set  |    my    | cut_attack_surface ||         FAIL: "y"          
  CONFIG_BPF_JIT                         | is not set  |    my    | cut_attack_surface ||         FAIL: "y"          
  CONFIG_ARCH_MMAP_RND_BITS              |     32      |    my    |userspace_protection||         FAIL: "28"         

[-] config check is NOT PASSED: 29 errors

[a13xp0p0v]

Hello @bryn1u ,
The error message which you posted makes me think that your issue is about kernel modules loading.
I would recommend you to look at the kernel log for more information and bisect again to find the reason.