On 2024/8/2 19:47, Russell King (Oracle) wrote: > On Mon, Jul 22, 2024 at 10:53:10AM +0800, Jinjie Ruan wrote: >> Gentle ping. >> >> On 2024/6/24 10:36, Jinjie Ruan 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> > > Is this a feature that you have a use case for? Yes, We have ARM32 products internally, and there is a need for security hardening. >
