On Tue, Jul 31, 2018 at 09:47:28AM +0100, Will Deacon wrote:
> On Tue, Jul 31, 2018 at 09:22:52AM +0200, Ard Biesheuvel wrote:
> > (+ Catalin, Will)
> >
> > On 27 July 2018 at 14:59, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:
> > > Calling pmull_gcm_encrypt_block() requires kernel_neon_begin() and
> > > kernel_neon_end() to be used since the routine touches the NEON
> > > register file. Add the missing calls.
> > >
> > > Also, since NEON register contents are not preserved outside of
> > > a kernel mode NEON region, pass the key schedule array again.
> > >
> > > Fixes: 7c50136a8aba ("crypto: arm64/aes-ghash - yield NEON after every ...")
> > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> > > ---
> > > arch/arm64/crypto/ghash-ce-glue.c | 8 ++++++--
> > > 1 file changed, 6 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/arch/arm64/crypto/ghash-ce-glue.c b/arch/arm64/crypto/ghash-ce-glue.c
> > > index 7cf0b1aa6ea8..8a10f1d7199a 100644
> > > --- a/arch/arm64/crypto/ghash-ce-glue.c
> > > +++ b/arch/arm64/crypto/ghash-ce-glue.c
> > > @@ -488,9 +488,13 @@ static int gcm_decrypt(struct aead_request *req)
> > > err = skcipher_walk_done(&walk,
> > > walk.nbytes % AES_BLOCK_SIZE);
> > > }
> > > - if (walk.nbytes)
> > > - pmull_gcm_encrypt_block(iv, iv, NULL,
> > > + if (walk.nbytes) {
> > > + kernel_neon_begin();
> > > + pmull_gcm_encrypt_block(iv, iv, ctx->aes_key.key_enc,
> > > num_rounds(&ctx->aes_key));
> > > + kernel_neon_end();
> > > + }
> > > +
> > > } else {
> > > __aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
> > > num_rounds(&ctx->aes_key));
> > > --
> > > 2.18.0
> > >
> >
> > This fixes a rather nasty bug in the AES-GCM code: failing to call
> > kernel_neon_begin()/_end() may clobber the NEON register state of
> > unrelated userland processes.
> >
> > Could we please get this queued before v4.18 is released? Thanks.
>
> I can take this via the arm64 tree if Herbert is ok with that.
Sure:
Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Thanks,
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
