On 2024/6/24 15:30, Linus Walleij wrote: > On Mon, Jun 24, 2024 at 4:33 AM Jinjie Ruan <ruanjinjie@xxxxxxxxxx> wrote: > >> Add the STACKLEAK gcc plugin to arm32 by adding the helper used by >> stackleak common code: on_thread_stack(). It initialize the stack with the >> poison value before returning from system calls which improves the kernel >> security. Additionally, this disables the plugin in EFI stub code and >> decompress code, which are out of scope for the protection. >> >> Before the test on Qemu versatilepb board: >> # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT >> lkdtm: Performing direct entry STACKLEAK_ERASING >> lkdtm: XFAIL: stackleak is not supported on this arch (HAVE_ARCH_STACKLEAK=n) >> >> After: >> # echo STACKLEAK_ERASING > /sys/kernel/debug/provoke-crash/DIRECT >> lkdtm: Performing direct entry STACKLEAK_ERASING >> lkdtm: stackleak stack usage: >> high offset: 80 bytes >> current: 280 bytes >> lowest: 696 bytes >> tracked: 696 bytes >> untracked: 192 bytes >> poisoned: 7220 bytes >> low offset: 4 bytes >> lkdtm: OK: the rest of the thread stack is properly erased >> >> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx> >> Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx> > > Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > > I was digging around to see if this would interfere with BPF > trampolines, but the > BPF code seems so generic that I assume it already takes stackleak into account. > Thank you very much, as Kees said, can this patch go via rmk's patch tracker now? > Yours, > Linus Walleij
