On Fri, 20 Aug 2021 at 10:31, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, Aug 09, 2021 at 07:40:27PM +0530, Shreyansh Chouhan wrote: > > xts_crypt() code doesn't call kernel_fpu_end() after calling > > kernel_fpu_begin() if walk.nbytes is 0. The correct behavior should be > > not calling kernel_fpu_begin() if walk.nbytes is 0. > > > > Reported-by: syzbot+20191dc583eff8602d2d@xxxxxxxxxxxxxxxxxxxxxxxxx > > Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@xxxxxxxxx> > > --- > > arch/x86/crypto/aesni-intel_glue.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c > > index 388643ca2177..ec6eac57c493 100644 > > --- a/arch/x86/crypto/aesni-intel_glue.c > > +++ b/arch/x86/crypto/aesni-intel_glue.c > > @@ -849,7 +849,7 @@ static int xts_crypt(struct skcipher_request *req, bool encrypt) > > return -EINVAL; > > > > err = skcipher_walk_virt(&walk, req, false); > > - if (err) > > + if (err || !walk.nbytes) > > return err; > > The err check is now redundant because when there is an error > nbytes is always zero. > In spite of that, I have a slight preference for this version, given that it makes it obvious that we bail on two separate conditions: - an error has occurred - no error has occurred but the resulting walk is empty Testing walk.nbytes only needlessly obfuscates the code, as we need to return 'err' in the end anyway.
