Re: [PATCH] nvme-auth: Uninitialized variable in nvme_auth_transform_key()

Hannes Reinecke
2022-07-22T06:23:24Z

On 7/18/22 13:10, Dan Carpenter wrote:
> A couple of the early error gotos call kfree_sensitive(transformed_key);
> before "transformed_key" has been initialized.
>
> Fixes: a476416bb57b ("nvme: implement In-Band authentication")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> I wrote this several times in different ways, and kept on doing it
> wrong so in the end I wrote it this way. It's a bigger diff, but I
> think it's the clearest way to write it.
>
> drivers/nvme/common/auth.c | 25 ++++++++++++++++---------
> 1 file changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c
> index bfb16fec0aed..1890193c7333 100644
> --- a/drivers/nvme/common/auth.c
> +++ b/drivers/nvme/common/auth.c
> @@ -278,26 +278,33 @@ u8 *nvme_auth_transform_key(struct nvme_dhchap_key *key, char *nqn)
> shash->tfm = key_tfm;
> ret = crypto_shash_setkey(key_tfm, key->key, key->len);
> if (ret < 0)
> - goto out_free_shash;
> + goto out_free_transformed_key;
> ret = crypto_shash_init(shash);
> if (ret < 0)
> - goto out_free_shash;
> + goto out_free_transformed_key;
> ret = crypto_shash_update(shash, nqn, strlen(nqn));
> if (ret < 0)
> - goto out_free_shash;
> + goto out_free_transformed_key;
> ret = crypto_shash_update(shash, "NVMe-over-Fabrics", 17);
> if (ret < 0)
> - goto out_free_shash;
> + goto out_free_transformed_key;
> ret = crypto_shash_final(shash, transformed_key);
> + if (ret < 0)
> + goto out_free_transformed_key;
> +
> + kfree(shash);
> + crypto_free_shash(key_tfm);
> +
> + return transformed_key;
> +
> +out_free_transformed_key:
> + kfree_sensitive(transformed_key);
> out_free_shash:
> kfree(shash);
> out_free_key:
> crypto_free_shash(key_tfm);
> - if (ret < 0) {
> - kfree_sensitive(transformed_key);
> - return ERR_PTR(ret);
> - }
> - return transformed_key;
> +
> + return ERR_PTR(ret);
> }
> EXPORT_SYMBOL_GPL(nvme_auth_transform_key);
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
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