Project Description

Currently kernel module signature be attached in the end of kernel module (ko file). Scott Bahling has raised that there have some benefits that kernel allows to load module with a separate signature file.

Current module signature is PKCS#7 format, I thought that it's not hard to do that. But we will need a new system call for this.

Goal for this Hackweek

Implement a proof of concept in hackweek 20.

Resources

Base on the latest kernel mainline.

Looking for hackers with the skills:

kernel

This project is part of:

Hack Week 20

Activity

  • over 4 years ago: pperego liked this project.
  • over 4 years ago: mkubecek liked this project.
  • over 4 years ago: fanyadan liked this project.
  • over 4 years ago: joeyli added keyword "kernel" to this project.
  • over 4 years ago: joeyli originated this project.

  • Comments

    • joeyli
      over 4 years ago by joeyli | Reply

      Result: HEAD:users/jlee/stable/modsign-separate on kerncvs.suse.de

      TODO: - Support multi .ko.p7s file. - Search fingerprint in trusted keyring, platform keyring - Modify sign-file ? - Combine with current modverifysig() - coexist with embedded signature

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    Project Description

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    Goal for the Hackweeks

    1. Investigate if this is possible and the implications it would have (done in HW21)
    2. Hack up a PoC (done in HW22 and HW23)
    3. Prepare RFC series (giving it's only one week, we are entering wishful thinking territory here).

    update HW23

    • I was able to include the crash kernel into the kernel Image.
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      1. My initramfs in the porduction kernel does not have a new enough kexec version, that's not a blocker but where the week ended
      2. As the crash kernel is part of init.data it will be already stale once I can call kexec_file_load() from user-space.

    The solution is probably to rewrite the POC so that the invocation can be done from init.text (that's my theory) but I'm not sure if I can reuse the kexec infrastructure in the kernel from there, which I rely on heavily.

    update HW24

    • Day1
      • rebased on v6.12 with no problems others then me breaking the config
      • setting up a new compilation and qemu/virtme env
      • getting desperate as nothing works that used to work
    • Day 2
      • getting to call the invocation of loading the early kernel from __init after kcsan_init()
    • Day 3

      • fix problem of memdup not being able to alloc so much memory... use 64K page sizes for now
      • code refactoring
      • I'm now able to load the crash kernel
      • When using virtme I can boot into the crash kernel, also it doesn't boot completely (major milestone!), crash in elfcorehdr_read_notes()
    • Day 4

      • crash systems crashes (no pun intended) in copy_old_mempage() link; will need to understand elfcorehdr...
      • call path vmcore_init() -> parse_crash_elf_headers() -> elfcorehdr_read() -> read_from_oldmem() -> copy_oldmem_page() -> copy_to_iter()
    • Day 5

      • hacking arch/arm64/kernel/crash_dump.c:copy_old_mempage() to see if crash system really starts. It does.
      • fun fact: retested with more reserved memory and with UEFI FW, host kernel crashes in init but directly starts the crash kernel, so it works (somehow) \o/
    • TODOs

      • fix elfcorehdr so that we actually can make use of all this...
      • test where in the boot __init() chain we can/should call kexec_early_dump()