linux-kernel - Re: [PATCH] crypto: add missing kernel_fpu

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Message-ID: <20210806082320.GA12731@gondor.apana.org.au>
Date:   Fri, 6 Aug 2021 16:23:20 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     Shreyansh Chouhan <chouhan.shreyansh630@...il.com>,
        Ard Biesheuvel <ardb@...nel.org>
Cc:     davem@...emloft.net, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, x86@...nel.org, hpa@...or.com,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzbot+20191dc583eff8602d2d@...kaller.appspotmail.com
Subject: Re: [PATCH] crypto: add missing kernel_fpu_end() call

On Fri, Jul 30, 2021 at 07:11:55PM +0530, Shreyansh Chouhan wrote:
> xts_crypt() code doesn't call kernel_fpu_end() after calling
> kernel_fpu_begin() if walk.nbytes is 0. Add a call to kernel_fpu_end()
> for this case.
> 
> Reported-by: syzbot+20191dc583eff8602d2d@...kaller.appspotmail.com
> Signed-off-by: Shreyansh Chouhan <chouhan.shreyansh630@...il.com>
> ---
>  arch/x86/crypto/aesni-intel_glue.c | 3 +++
>  1 file changed, 3 insertions(+)

Ard?

> diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
> index 2144e54a6c89..bd55a0cd7bde 100644
> --- a/arch/x86/crypto/aesni-intel_glue.c
> +++ b/arch/x86/crypto/aesni-intel_glue.c
> @@ -894,6 +894,9 @@ static int xts_crypt(struct skcipher_request *req, bool encrypt)
>  			kernel_fpu_begin();
>  	}
>  
> +	if (walk.nbytes == 0)
> +		kernel_fpu_end();
> +
>  	if (unlikely(tail > 0 && !err)) {
>  		struct scatterlist sg_src[2], sg_dst[2];
>  		struct scatterlist *src, *dst;
> -- 
> 2.31.1

-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt