On 4/27/19 7:31 AM, Paolo Bonzini wrote:
I've done porting linux's pkcs7/x509 parsers and they work well with my UEFI secure boot patch, but I'm still looking for other options as well.
- openssl Most of existing components linked to UEFI secure boot, including EDK2, shim and grub, reply on this library. Why not for U-Boot? The size of U-Boot UEFI code in U-Boot is already quite big, and so the size of openssl won't be a big issue.
- mbedTLS which is maintained by ARM and used with Zephyr, I guess it should have small footprint. But it currently lacks pkcs7 parser.
Any thoughts?
Paolo, Laszlo, Ard, if you could write a new secure boot implementation today, which of the options above would you pick and why so? :)
Difficult question. Ideally you'd want a library where three aspects met:
- widely used (so that there is a diverse community that's interested in
vulnerabilities, and fixing them too)
- easy to cross-compile for your free-standing environment (optimally
the upstream project would support being cross-compiled and packaged stand-alone, for that free-standing environment)
- cares about API stability
OpenSSL is very widely used... ...and that's where we can stop in the list :)
It's also license-incompatible with U-Boot's GPLv2 I think. I guess grub can use it because GPLv3 and Apache v2 can be combined just fine. Reusing Linux's code seems like the best match.
Paolo
You could have a look at GnuTLS available at https://gitlab.com/gnutls/gnutls/ .
PKCS7 is supported, cf. https://www.gnutls.org/manual/html_node/PKCS-7-API.html
There seem to be four main contributors to GnuTLS adding two patches a day: https://github.com/gnutls/gnutls/graphs/contributors?from=2018-04-28&to=...
Best regards
Heinrich