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Date: Fri, 17 Jul 2015 19:43:39 +0200
From: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20150717174339.GD4622@noname.redhat.com>
References: <1437062641-12684-1-git-send-email-rkrcmar@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v3 2/3] crypto: avoid undefined behavior in
 nettle calls
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To: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, qemu-devel@nongnu.org

Am 16.07.2015 um 18:04 hat Radim Kr=C4=8Dm=C3=A1=C5=99 geschrieben:
> Calling a function pointer that was cast from an incompatible function
> results in undefined behavior.  'void *' isn't compatible with 'struct
> XXX *', so we can't cast to nettle_cipher_func, but have to provide a
> wrapper.  (Conversion from 'void *' to 'struct XXX *' might require
> computation, which won't be done if we drop argument's true type and
> pointers can have different sizes so passing arguments on stack would
> bug.)
>=20
> Having two different prototypes based on nettle version doesn't make
> this solution any nicer.
>=20
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Radim Kr=C4=8Dm=C3=A1=C5=99 <rkrcmar@redhat.com>

git bisect says that it's this commit which broke qemu-iotests 134.

> +static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t leng=
th,
> +                         uint8_t *dst, const uint8_t *src)
> +{
> +    aes_encrypt(ctx, length, dst, src);
> +}

And this is why (decrypt -> encrypt). I'll send a fix.

Kevin