On Fri, Aug 26, 2016 at 01:21:50PM -0500, Eric Blake wrote:
> On 08/26/2016 07:47 AM, Daniel P. Berrange wrote:
> > The XTS cipher mode needs to be used with a cipher which has
> > a block size of 16 bytes. If a mis-matching block size is used,
> > the code will either corrupt memory beyond the IV array, or
> > not fully encrypt/decrypt the IV.
> >
> > This fixes a memory curruption crash when attempting to use
>
> s/curruption/corruption/
>
> > cast5-128 with xts, since the former has an 8 byte block size.
> >
> > A test case is added to ensure the cipher creation fails with
> > such an invalid combination.
> >
> > Signed-off-by: Daniel P. Berrange <berra...@redhat.com>
> > ---
> > crypto/cipher-gcrypt.c | 6 ++++++
> > crypto/cipher-nettle.c | 12 +++++++-----
> > tests/test-crypto-cipher.c | 44
> > ++++++++++++++++++++++++++++++++++++--------
> > 3 files changed, 49 insertions(+), 13 deletions(-)
>
> Are you aiming for a last-minute 2.7 fix, or should this just be 2.8
> material and cc qemu-stable?
This isn't critical for 2.7, as this is already invalid usage. IOW anyone
who hits the crash, simply shouldn't use this combination.
> Reviewed-by: Eric Blake <ebl...@redhat.com>
>
>
> > +++ b/tests/test-crypto-cipher.c
> > @@ -370,6 +370,17 @@ static QCryptoCipherTestData test_data[] = {
>
> > @@ -449,8 +468,16 @@ static void test_cipher(const void *opaque)
> > cipher = qcrypto_cipher_new(
> > data->alg, data->mode,
> > key, nkey,
> > - &error_abort);
> > - g_assert(cipher != NULL);
> > + &err);
> > + if (data->plaintext) {
> > + g_assert(err == NULL);
> > + g_assert(cipher != NULL);
> > + } else {
> > + g_assert(err != NULL);
> > + error_free(err);
>
> Could shorten these two lines as error_free_or_abort(&err), but that's
> cosmetic.
Will do.
Regards,
Daniel
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