Re: [PATCH 23/30] crypto: sa2ul - fix stack overflow in sa_prepare_iopads

[T Pratham]

On 9/15/26 15:25, Manorit Chawdhry wrote:
[...]
>  
> -static int sa_export_shash(void *state, struct shash_desc *hash,
> -			   int digest_size, __be32 *out)
> +static int sa_export_shash(struct shash_desc *hash, int digest_size,
> +			   __be32 *out)
>  {
> -	struct sha1_state *sha1;
> -	struct sha256_state *sha256;
>  	u32 *result;
>  	int ret = 0;
> +	int state_size;
> +	u8 *sha;
> +
> +	state_size = crypto_shash_statesize(hash->tfm);
> +	if (state_size <= 0) {
> +		dev_err(sa_k3_dev, "%s: invalid state_size=%d\n", __func__,
> +			state_size);
> +		return -EINVAL;
> +	}
> +
> +	sha = kmalloc(state_size, GFP_KERNEL);
> +	if (!sha)
> +		return -ENOMEM;
>  
>  	/* Export the intermediate digest to program into SA2UL */
> -	ret = crypto_shash_export(hash, state);
> +	ret = crypto_shash_export(hash, sha);
>  	if (ret) {
>  		dev_err(sa_k3_dev, "%s: crypto_shash_export failed\n",
>  			__func__);
> +		kfree_sensitive(sha);
>  		return ret;
>  	}
>  
>  	switch (digest_size) {
>  	case SHA1_DIGEST_SIZE:
> -		sha1 = state;
> -		result = sha1->state;
> +		result = (u32 *)sha;
>  		break;
>  	case SHA256_DIGEST_SIZE:
> -		sha256 = state;
> -		result = sha256->state;
> +		result = (u32 *)sha;
>  		break;
>  	default:
>  		dev_err(sa_k3_dev, "%s: bad digest_size=%d\n", __func__,
>  			digest_size);
> +		kfree_sensitive(sha);
>  		return -EINVAL;
>  	}
>  
All the arms in this switch-case are now doing the exact same thing. If
digest_size is guaranteed to be supplied correct in this function, this
can be removed.

-- 
Regards
T Pratham <t-pratham@xxxxxx>