On Fri, Jun 30, 2017 at 11:27 AM, Kees Cook <[email protected]> wrote: > On Fri, Jun 30, 2017 at 9:03 AM, Arnd Bergmann <[email protected]> wrote: >> With the new task struct randomization, we can run into a build >> failure for certain random seeds: >> >> arch/arm/kernel/entry-armv.S: Assembler messages: >> arch/arm/kernel/entry-armv.S:803: Error: bad immediate value for offset >> (4096) >> >> Only two constants in asm-offset.h are affected, and I'm changing >> both of them here to work correctly in all configurations. >> >> One more macro has the problem, but is currently unused, so this >> removes it instead of adding complexity. >> >> Suggested-by: Ard Biesheuvel <[email protected]> >> Fixes: c33d8b12fbbd ("task_struct: Allow randomized layout") >> Signed-off-by: Arnd Bergmann <[email protected]> > > Looks great, thanks! > > Reviewed-by: Kees Cook <[email protected]> > > Russell, if you're happy with it can you Ack this? I'd like to carry > the change in the randstruct tree (so all the dependencies are in the > same tree).
I've also forced stack_canary into the end of task_struct and inflated the size of the struct (to match randomization inflation due to intentionally poor bitfield packing), verified the resulting .o files have the adjustment and boot tested both cases. Tested-by: Kees Cook <[email protected]> -Kees -- Kees Cook Pixel Security
