Re: [PATCH] crypto: drbg: check the return value of crypto_shash_init()

[Eric Biggers <ebiggers@kernel.org>]

On Thu, Feb 24, 2022 at 11:46:23PM -0800, Jia-Ju Bai wrote:
> Then function crypto_shash_init() in drbg_kcapi_hash() can fail, but
> there is no check of its return value. To fix this bug, its return value
> should be checked with new error handling code.
> 
> Fixes: 541af946fe13 ("crypto: drbg - SP800-90A Deterministic Random Bit Generator")
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>  crypto/drbg.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/crypto/drbg.c b/crypto/drbg.c
> index 177983b6ae38..51feb9538701 100644
> --- a/crypto/drbg.c
> +++ b/crypto/drbg.c
> @@ -1725,8 +1725,11 @@ static int drbg_kcapi_hash(struct drbg_state *drbg, unsigned char *outval,
>  {
>  	struct sdesc *sdesc = (struct sdesc *)drbg->priv_data;
>  	struct drbg_string *input = NULL;
> +	int ret = 0;
>  
> -	crypto_shash_init(&sdesc->shash);
> +	ret = crypto_shash_init(&sdesc->shash);
> +	if (ret)
> +		return ret;
>  	list_for_each_entry(input, in, list)
>  		crypto_shash_update(&sdesc->shash, input->buf, input->len);
>  	return crypto_shash_final(&sdesc->shash, outval);

What about the call to crypto_shash_update() right below it?

- Eric