Re: [PATCH] s390/crypto: fix scatterwalk_unmap() callers in AES-GCM

Heiko Carstens
2022-05-17T18:01:41Z

On Tue, May 17, 2022 at 04:30:47PM +0200, Jann Horn wrote:
> The argument of scatterwalk_unmap() is supposed to be the void* that was
> returned by the previous scatterwalk_map() call.
> The s390 AES-GCM implementation was instead passing the pointer to the
> struct scatter_walk.
>
> This doesn't actually break anything because scatterwalk_unmap() only uses
> its argument under CONFIG_HIGHMEM and ARCH_HAS_FLUSH_ON_KUNMAP.
>
> Note that I have not tested this patch in any way, not even compile-tested
> it.
>
> Fixes: bf7fa038707c ("s390/crypto: add s390 platform specific aes gcm support.")
> Signed-off-by: Jann Horn <jannh@google.com>
> ---
> IDK which tree this has to go through - s390 or crypto?
> maybe s390 is better, since they can actually test it?
>
> arch/s390/crypto/aes_s390.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

This can go via the s390 tree, however I'd like to have an ACK from
Harald, who wrote the original code.

> diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
> index 54c7536f2482..1023e9d43d44 100644
> --- a/arch/s390/crypto/aes_s390.c
> +++ b/arch/s390/crypto/aes_s390.c
> @@ -701,7 +701,7 @@ static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,
> unsigned int nbytes)
> {
> gw->walk_bytes_remain -= nbytes;
> - scatterwalk_unmap(&gw->walk);
> + scatterwalk_unmap(gw->walk_ptr);
> scatterwalk_advance(&gw->walk, nbytes);
> scatterwalk_done(&gw->walk, 0, gw->walk_bytes_remain);
> gw->walk_ptr = NULL;
> @@ -776,7 +776,7 @@ static int gcm_out_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)
> goto out;
> }
>
> - scatterwalk_unmap(&gw->walk);
> + scatterwalk_unmap(gw->walk_ptr);
> gw->walk_ptr = NULL;
>
> gw->ptr = gw->buf;
>
> base-commit: 42226c989789d8da4af1de0c31070c96726d990c
> --
> 2.36.0.550.gb090851708-goog
>