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Message-ID: <0e3bfc37-53d6-422d-adb0-3ee23bbb0a8a@linux.ibm.com>
Date: Tue, 28 May 2024 07:18:59 -0400
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] crypto: ecdsa: Fix the public key format description
To: Jarkko Sakkinen <jarkko@kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>
Cc: linux-crypto@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        linux-kernel@vger.kernel.org
References: <20240527202840.4818-1-jarkko@kernel.org>
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From: Stefan Berger <stefanb@linux.ibm.com>
In-Reply-To: <20240527202840.4818-1-jarkko@kernel.org>
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On 5/27/24 16:28, Jarkko Sakkinen wrote:
> Public key blob is not just x and y concatenated. It follows RFC5480
> section 2.2. Address this by re-documenting the function with the
> correct description of the format.
> 
> Link: https://datatracker.ietf.org/doc/html/rfc5480
> Fixes: 4e6602916bc6 ("crypto: ecdsa - Add support for ECDSA signature verification")
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>

> ---
> It is a bug fix that does not really need a stable backport. Still
> categorizes as a bug because by following the existing documentation
> you end up with an error code.
>   crypto/ecdsa.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/crypto/ecdsa.c b/crypto/ecdsa.c
> index 258fffbf623d..55114146ff84 100644
> --- a/crypto/ecdsa.c
> +++ b/crypto/ecdsa.c
> @@ -215,9 +215,8 @@ static int ecdsa_ecc_ctx_reset(struct ecc_ctx *ctx)
>   }
>   
>   /*
> - * Set the public key given the raw uncompressed key data from an X509
> - * certificate. The key data contain the concatenated X and Y coordinates of
> - * the public key.
> + * Set the public ECC key as defined by RFC5480 section 2.2 "Subject Public
> + * Key". Only the uncompressed format is supported.
>    */
>   static int ecdsa_set_pub_key(struct crypto_akcipher *tfm, const void *key, unsigned int keylen)
>   {