Re: [PATCH 06/21] nvme-auth: common: explicitly verify psk_len == hash_len

[Hannes Reinecke]

On 3/2/26 08:59, Eric Biggers wrote:
> nvme_auth_derive_tls_psk() is always called with psk_len == hash_len.
> And based on the comments above nvme_auth_generate_psk() and
> nvme_auth_derive_tls_psk(), this isn't an implementation choice but
> rather just the length the spec uses.  Add a check which makes this
> explicit, so that when cleaning up nvme_auth_derive_tls_psk() we don't
> have to retain support for arbitrary values of psk_len.
>
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> ---
>   drivers/nvme/common/auth.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
> index 2f83c9ddea5ec..9e33fc02cf51a 100644
> --- a/drivers/nvme/common/auth.c
> +++ b/drivers/nvme/common/auth.c
> @@ -786,10 +786,15 @@ int nvme_auth_derive_tls_psk(int hmac_id, const u8 *psk, size_t psk_len,
>   		pr_warn("%s: unsupported hash algorithm %s\n",
>   			__func__, hmac_name);
>   		return -EINVAL;
>   	}
>   
> +	if (psk_len != nvme_auth_hmac_hash_len(hmac_id)) {
> +		pr_warn("%s: unexpected psk_len %zu\n", __func__, psk_len);
> +		return -EINVAL;
> +	}
> +
>   	hmac_tfm = crypto_alloc_shash(hmac_name, 0, 0);
>   	if (IS_ERR(hmac_tfm))
>   		return PTR_ERR(hmac_tfm);
>   
>   	prk_len = crypto_shash_digestsize(hmac_tfm);

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
--
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@xxxxxxx                                +49 911 74053 688
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