On Tue, Jun 14, 2016 at 3:20 PM, Emese Revfy <re.emese@xxxxxxxxx> wrote: > This plugin mitigates the problem of the kernel having too little entropy during > and after boot for generating crypto keys. > > It creates a local variable in every marked function. The value of this variable is > modified by randomly chosen operations (add, xor and rol) and > random values (gcc generates them at compile time and the stack pointer at runtime). > It depends on the control flow (e.g., loops, conditions). > > Before the function returns the plugin writes this local variable > into the latent_entropy global variable. The value of this global variable is > added to the kernel entropy pool in do_one_initcall() and _do_fork(). > > Signed-off-by: Emese Revfy <re.emese@xxxxxxxxx> > [...] > diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile > index 2da380f..6c7e448 100644 > --- a/arch/powerpc/kernel/Makefile > +++ b/arch/powerpc/kernel/Makefile > @@ -16,10 +16,10 @@ endif > > ifdef CONFIG_FUNCTION_TRACER > # Do not trace early boot code > -CFLAGS_REMOVE_cputable.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) > -CFLAGS_REMOVE_prom_init.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) > -CFLAGS_REMOVE_btext.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) > -CFLAGS_REMOVE_prom.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) > +CFLAGS_REMOVE_cputable.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) $(DISABLE_LATENT_ENTROPY_PLUGIN) > +CFLAGS_REMOVE_prom_init.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) $(DISABLE_LATENT_ENTROPY_PLUGIN) > +CFLAGS_REMOVE_btext.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) $(DISABLE_LATENT_ENTROPY_PLUGIN) > +CFLAGS_REMOVE_prom.o = -mno-sched-epilog $(CC_FLAGS_FTRACE) $(DISABLE_LATENT_ENTROPY_PLUGIN) This doesn't look right to me: these are CFLAGS_REMOVE_* entries, and I think you want to _add_ the DISABLE_LATENT_ENTROPY_PLUGIN to the CFLAGS here. from scripts/Makefile.lib: _c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags)) -Kees -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>