On Wed, 2018-04-11 at 14:00 -0500, Eric W. Biederman wrote: > David Howells <dhowells@xxxxxxxxxx> writes: > > > From: Matthew Garrett <mjg59@xxxxxxxxxxxxx> > > > > The kexec_load() syscall permits the loading and execution of arbitrary > > code in ring 0, which is something that lock-down is meant to prevent. It > > makes sense to disable kexec_load() in this situation. > > > > This does not affect kexec_file_load() syscall which can check for a > > signature on the image to be booted. > > Maybing I am missing it but I am not seeing anything that would require > kexec_file_load be configured such that it checks the loaded kernel. > > Without that I don't see the point of disabling kexec_load. > > Nacked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> The IMA "secure boot" policy requires the kexec image to be signed. This call to kernel_is_locked_down() could be replaced with a call to security_kernel_read_file(NULL, READING_KEXEC_IMAGE). It would be similar to the existing init_module syscall calling security_kernel_read_file(). Mimi -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
