What do you need from ELF? ebiederm at xmission.com wrote: >Vivek Goyal <vgoyal at redhat.com> writes: > >> Current proposed secureboot implementation disables kexec/kdump >because >> it can allow unsigned kernel to run on a secureboot platform. Intial >> idea was to sign /sbin/kexec binary and let that binary do the kernel >> signature verification. I had posted RFC patches for this apparoach >> here. >> >> https://lkml.org/lkml/2013/9/10/560 >> >> Later we had discussion at Plumbers and most of the people thought >> that signing and trusting /sbin/kexec is becoming complex. So a >> better idea might be let kernel do the signature verification of >> new kernel being loaded. This calls for implementing a new system >call >> and moving lot of user space code in kernel. >> >> kexec_load() system call allows loading a kexec/kdump kernel and jump >> to that kernel at right time. Though a lot of processing is done in >> user space which prepares a list of segments/buffers to be loaded and >> kexec_load() works on that list of segments. It does not know what's >> contained in those segments. >> >> Now a new system call kexec_file_load() is implemented which takes >> kernel fd and initrd fd as parameters. Now kernel should be able >> to verify signature of newly loaded kernel. >> >> This is an early RFC patchset. I have not done signature handling >> part yet. This is more of a minimal patch to show how new system >> call and functionality will look like. Right now it can only handle >> bzImage with 64bit entry point on x86_64. No EFI, no x86_32 or any >> other architecture. Rest of the things can be added slowly as need >> arises. In first iteration, I have tried to address most common use >case >> for us. >> >> Any feedback is welcome. > >Before you are done we need an ELF loader. bzImage really is very >uninteresting. To the point I am not at all convinced that an in >kernel >loader should support it. > >There is also a huge missing piece of this in that your purgatory is >not >checking a hash of the loaded image before jumping too it. Without >that >this is a huge regression at least for the kexec on panic case. We >absolutely need to check that the kernel sitting around in memory has >not been corrupted before we let it run very far. > >Eric -- Sent from my mobile phone. Please pardon brevity and lack of formatting.
