On 07/13/15 at 10:13am, Dave Young wrote: > Previously Theodore Ts'o brought up an issue about kexec_load syscall bypassing > signature verification: > https://lkml.org/lkml/2015/6/14/280 > > Because we have two kexec load syscall, one kexec_load, another kexec_file_load, > the latter one was introduced by Vivek Goyal, it is mainly for supporting UEFI > secure boot. kexec_file_load verifies kernel signature, but even if with > CONFIG_KEXEC_VERIFY_SIG=y and CONFIG_KEXEC_FILE=y, kexec-tools still can use > old syscall and bypass signature verification. > > KEXEC_FILE can also be used without UEFI, so kexec can always verify kernel > signature for security purpose. > > The suggestion in above thread is add a new Kconfig option for kexec common > code, here I use KEXEC_CORE, KEXEC and KEXEC_FILE select KEXEC_CORE so one can > compile only KEXEC_FILE without old kexec_load syscall. > > There's checkpatch warnings and errors, I would like to send furthuer cleanup > patches after this series. Please let me know if you have other suggestions. > checkpatch errors are for cases such as assign a value to static variables. > > PATCH 3/3 can be sort out from the series if people do not like. It is a > cleanup for a macro. Since it is not related to the Kconfig cleanup thus I will drop it in next update, will send out as a standalone patch later. Also there's a kexec-tools patch needed for testing KEXEC_FILE only, I forgot to mention, will take it in cover letter when I repost: --- kexec/crashdump-elf.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- kexec-tools.orig/kexec/crashdump-elf.c +++ kexec-tools/kexec/crashdump-elf.c @@ -145,11 +145,12 @@ int FUNC(struct kexec_info *info, count_cpu = nr_cpus; for (i = 0; count_cpu > 0; i++) { - if (get_note_info(i, ¬es_addr, ¬es_len) < 0) { - /* This cpu is not present. Skip it. */ - continue; - } + int ret; + + ret = get_note_info(i, ¬es_addr, ¬es_len); count_cpu--; + if (ret < 0) /* This cpu is not present. Skip it. */ + continue; phdr = (PHDR *) bufp; bufp += sizeof(PHDR); Thanks Dave
