Re: [PATCH v3] crypto: talitos - fix ablkcipher for CONFIG_VMAP_STACK

[Christophe Leroy]

Le 04/01/2019 Ã 16:24, Horia Geanta a ÃcritÂ:
> On 1/4/2019 5:17 PM, Horia Geanta wrote:
> > On 12/21/2018 10:07 AM, Christophe Leroy wrote:
> > [snip]
> > > IV cannot be on stack when CONFIG_VMAP_STACK is selected because the stack
> > > cannot be DMA mapped anymore.
> > > This looks better, thanks.
> >
> > > This patch copies the IV into the extended descriptor when iv is not
> > > a valid linear address.
> > Though I am not sure the checks in place are enough.
> >
> > > Fixes: 4de9d0b547b9 ("crypto: talitos - Add ablkcipher algorithms")
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> > > ---
> > >   v3: Using struct edesc buffer.
> > >
> > >   v2: Using per-request context.
> > [snip]
> > > +	if (ivsize && !virt_addr_valid(iv))
> > > +		alloc_len += ivsize;
> > [snip]
> > >   
> > > +	if (ivsize && !virt_addr_valid(iv))
> > A more precise condition would be (!is_vmalloc_addr || is_vmalloc_addr(iv))
> Sorry for the typo, I meant:
> (!virt_addr_valid(iv) || is_vmalloc_addr(iv))

As far as I know, virt_addr_valid() means the address is in the linear 
memory space. So it cannot be a vmalloc_addr if it is a linear space 
addr, can it ?

At least, it is that way on powerpc which is the arch embedding the 
talitos crypto engine. virt_addr_valid() means we are under max_pfn, 
while VMALLOC_START is above max_pfn.

Christophe

> > It matches the checks in debug_dma_map_single() helper, though I am not sure
> > they are enough to rule out all exceptions of DMA API.