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    SubjectRe: [GIT PULL] Load keys from signed PE binaries
    On Thu, 21 Feb 2013, David Howells wrote:

    > The way we have come up with to get around this is to embed an X.509
    > certificate containing the key in a section called ".keylist" in an EFI PE
    > binary and then get the binary signed by Microsoft. The key can then be passed
    > to the kernel by passing the signed binary:
    >
    > keyctl padd asymmetric "" {ID of .system_keyring} <pekey.efi.signed

    Please let me take this back to square one for a very short moment.


    I completely fail to understand how your security model is dealing with
    this scenario:

    - Mr. Evil Blackhat creates EFI PE binary from "int main() { return 42; }"
    (psuedo)code
    - Mr. Evil Blackhat puts his own key into .keylist section of this binary
    - Mr. Evil Blackhat goes through the $99 process of having this binary
    signed by Microsoft. They don't have a slightest reason not to sign it,
    as the binary obviously can't be used to run backdoored Windows
    - Mr. Evil Blackhat then uses keyctl to process this signed binary
    - Mr. Evil Blackhat modprobes i_own_your_ring0.ko which is signed by
    his key, and he instantly has his code running in your SecureBoot
    environment


    Let me formulate my point more clearly -- Microsoft very likely going to
    sign hello world EFI PE binary, no matter the contents of .keylist
    section, as they don't give a damn about this section, as it has zero
    semantic value to them, right?

    They sign the binary. By signing the binary, they are *NOT* establishing
    cryptographic chain of trust to the key stored in .keylist, but your
    patchset seems to imply so.

    What am I missing?

    Thanks,

    --
    Jiri Kosina
    SUSE Labs



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