| SIG-LIST-TO-CERTS(1) | User Commands | SIG-LIST-TO-CERTS(1) |
sig-list-to-certs - tool for converting EFI signature lists back to openssl certificates
sig-list-to-certs <efi sig list file> <cert file base name>
Takes <efi sig list file> and converts it to a set of DER format openssl certificates in <cert file base name>.n (where n runs from 0 to the number of certificates in the file)
To see what certificates your UEFI system currently has, you can run the dmpstore command to print them to a file
dmpstore PK > PK.uc16
This file isn't readily readable on a standard unix system because it's in UC-16 format, so convert it to ordinary text
iconv -f utf-16 PK.uc16 > PK.txt
Now remove the header which says something like
Dump Variable pk
Variable NV+RT+BS 'Efi:PK' DataSize = 2DA
Leaving only the hex dump. This can then be converted to an EFI signature list by xxd
xxd -r PK.txt > PK.esl
and you can now extract openssl readable certificates from this
sig-list-to-certs PK.esl PK
Which will print some information like
X509 Header sls=730, header=0, sig=686
file PK.0: Guid 77fa9abd-0359-4d32-4d60-28f4e78f784b
Written 686 bytes
And finally, you can see the certificate in text format
openssl x509 -text -inform DER -in PK.0
Assuming it's an X509 certificate
| June 2022 | Usage: ./sig-list-to-certs <efi sig list file> <cert file base name> |