Re: [PATCH] crypto: scatterwalk: propagate errors from failed call to skcipher_walk_first

[Eric Biggers]

On Fri, Nov 14, 2025 at 11:28:10AM -0800, Eric Biggers wrote:
> On Fri, Nov 14, 2025 at 12:26:19PM +0000, Colin Ian King wrote:
> > There are cases where skcipher_walk_first can fail and errors such as
> > -ENOMEM or -EDEADLK are being ignored in memcpy_sglist. Add error checks
> > and propagate the error down to callers.
> > 
> > This fixes silent data loss from callers to memcpy_sglist (since walk is
> > zero'd) or potential encryption on the wrong data.
> > 
> > Signed-off-by: Colin Ian King <coking@xxxxxxxxxx>
> 
> There's no need for copying between two scatterlists to be able to fail.
> memcpy_sglist() should just be implemented from first principles instead
> of misusing the skcipher_walk stuff.  I actually suggested this already
> (https://lore.kernel.org/linux-crypto/20250427010834.GB68006@quark/) but
> unfortunately it was disregarded.

Done at https://lore.kernel.org/linux-crypto/20251114225851.324143-2-ebiggers@xxxxxxxxxx/

- Eric