From: Will Deacon <will@kernel.org>
To: Torsten Duwe <duwe@lst.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
Russell King <linux@armlinux.org.uk>,
linux-crypto@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, ardb@kernel.org
Subject: Re: [Patch][Fix] crypto: arm{,64} neon: memzero_explicit aes-cbc key
Date: Tue, 17 Mar 2020 22:17:43 +0000 [thread overview]
Message-ID: <20200317221743.GD20788@willie-the-truck> (raw)
In-Reply-To: <20200313110258.94A0668C4E@verein.lst.de>
[+Ard]
On Fri, Mar 13, 2020 at 12:02:58PM +0100, Torsten Duwe wrote:
> From: Torsten Duwe <duwe@suse.de>
>
> At function exit, do not leave the expanded key in the rk struct
> which got allocated on the stack.
>
> Signed-off-by: Torsten Duwe <duwe@suse.de>
> ---
> Another small fix from our FIPS evaluation. I hope you don't mind I merged
> arm32 and arm64 into one patch -- this is really simple.
> --- a/arch/arm/crypto/aes-neonbs-glue.c
> +++ b/arch/arm/crypto/aes-neonbs-glue.c
> @@ -138,6 +138,7 @@ static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
> kernel_neon_begin();
> aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
> kernel_neon_end();
> + memzero_explicit(&rk, sizeof(rk));
>
> return crypto_cipher_setkey(ctx->enc_tfm, in_key, key_len);
> }
> diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
> index e3e27349a9fe..c0b980503643 100644
> --- a/arch/arm64/crypto/aes-neonbs-glue.c
> +++ b/arch/arm64/crypto/aes-neonbs-glue.c
> @@ -151,6 +151,7 @@ static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
> kernel_neon_begin();
> aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
> kernel_neon_end();
> + memzero_explicit(&rk, sizeof(rk));
>
> return 0;
> }
I'm certainly not a crypto person, but this looks sensible to me and I
couldn't find any other similar stack variable usage under
arch/arm64/crypto/ at a quick glance.
Acked-by: Will Deacon <will@kernel.org>
Will
next prev parent reply other threads:[~2020-03-17 22:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 11:02 [Patch][Fix] crypto: arm{,64} neon: memzero_explicit aes-cbc key Torsten Duwe
2020-03-17 22:17 ` Will Deacon [this message]
2020-03-18 20:13 ` Ard Biesheuvel
2020-03-19 8:15 ` Will Deacon
2020-03-20 3:51 ` Herbert Xu
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