Re: [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var

[J Freyensee]

On 3/6/18 9:05 AM, J Freyensee wrote:
> > Â +#ifdef CONFIG_PROTECTABLE_MEMORY
> > +void lkdtm_WRITE_RO_PMALLOC(void)
> > +{
> > +ÂÂÂ struct gen_pool *pool;
> > +ÂÂÂ int *i;
> > +
> > +ÂÂÂ pool = pmalloc_create_pool("pool", 0);
> > +ÂÂÂ if (unlikely(!pool)) {
> > +ÂÂÂÂÂÂÂ pr_info("Failed preparing pool for pmalloc test.");
> > +ÂÂÂÂÂÂÂ return;
> > +ÂÂÂ }
> > +
> > +ÂÂÂ i = (int *)pmalloc(pool, sizeof(int), GFP_KERNEL);
> > +ÂÂÂ if (unlikely(!i)) {
> > +ÂÂÂÂÂÂÂ pr_info("Failed allocating memory for pmalloc test.");
> > +ÂÂÂÂÂÂÂ pmalloc_destroy_pool(pool);
> > +ÂÂÂÂÂÂÂ return;
> > +ÂÂÂ }
> > +
> > +ÂÂÂ *i = INT_MAX;
> > +ÂÂÂ pmalloc_protect_pool(pool);
> > +
> > +ÂÂÂ pr_info("attempting bad pmalloc write at %p\n", i);
> > +ÂÂÂ *i = 0;

Opps, disregard this, this is the last series of this patch series, not 
the most recent one :-(.



> Seems harmless, but I don't get why *i local variable needs to be set 
> to 0 at the end of this function.
>
>
> Otherwise,
>
> Reviewed-by: Jay Freyensee <why2jjj.linux@xxxxxxxxx>