Re: [PATCH 1/1] mesh: Handle invalid public keys

["Gix, Brian" <brian.gix@intel.com>]

Applied
On Wed, 2020-03-25 at 00:57 +0530, Prathyusha Nelluri wrote:
> From: Prathyusha N <prathyusha.n@samsung.com>
> 
> Check for invalid public keys received and send provision failed.
> ---
>  mesh/prov-acceptor.c | 38 ++++++++++++++++++++++++++------------
>  1 file changed, 26 insertions(+), 12 deletions(-)
> 
> diff --git a/mesh/prov-acceptor.c b/mesh/prov-acceptor.c
> index 03972c227..d395bc5f2 100644
> --- a/mesh/prov-acceptor.c
> +++ b/mesh/prov-acceptor.c
> @@ -180,7 +180,7 @@ static void swap_u256_bytes(uint8_t *u256)
>  	}
>  }
>  
> -static void prov_calc_secret(const uint8_t *pub, const uint8_t *priv,
> +static bool prov_calc_secret(const uint8_t *pub, const uint8_t *priv,
>  							uint8_t *secret)
>  {
>  	uint8_t tmp[64];
> @@ -190,22 +190,27 @@ static void prov_calc_secret(const uint8_t *pub, const uint8_t *priv,
>  	swap_u256_bytes(tmp);
>  	swap_u256_bytes(tmp + 32);
>  
> -	ecdh_shared_secret(tmp, priv, secret);
> +	if (!ecdh_shared_secret(tmp, priv, secret))
> +		return false;
>  
>  	/* Convert to Mesh byte order */
>  	swap_u256_bytes(secret);
> +	return true;
>  }
>  
> -static void acp_credentials(struct mesh_prov_acceptor *prov)
> +static bool acp_credentials(struct mesh_prov_acceptor *prov)
>  {
> -	prov_calc_secret(prov->conf_inputs.prv_pub_key,
> -			prov->private_key, prov->secret);
> +	if (!prov_calc_secret(prov->conf_inputs.prv_pub_key,
> +			prov->private_key, prov->secret))
> +		return false;
>  
> -	mesh_crypto_s1(&prov->conf_inputs,
> -			sizeof(prov->conf_inputs), prov->salt);
> +	if (!mesh_crypto_s1(&prov->conf_inputs,
> +			sizeof(prov->conf_inputs), prov->salt))
> +		return false;
>  
> -	mesh_crypto_prov_conf_key(prov->secret, prov->salt,
> -			prov->calc_key);
> +	if (!mesh_crypto_prov_conf_key(prov->secret, prov->salt,
> +			prov->calc_key))
> +		return false;
>  
>  	l_getrandom(prov->rand_auth_workspace, 16);
>  
> @@ -218,6 +223,7 @@ static void acp_credentials(struct mesh_prov_acceptor *prov)
>  	print_packet("LocalRandom", prov->rand_auth_workspace, 16);
>  	print_packet("ConfirmationSalt", prov->salt, 16);
>  	print_packet("ConfirmationKey", prov->calc_key, 16);
> +	return true;
>  }
>  
>  static uint32_t digit_mod(uint8_t power)
> @@ -298,8 +304,13 @@ static void priv_key_cb(void *user_data, int err, uint8_t *key, uint32_t len)
>  	swap_u256_bytes(prov->conf_inputs.dev_pub_key + 32);
>  
>  	prov->material |= MAT_LOCAL_PRIVATE;
> -	if ((prov->material & MAT_SECRET) == MAT_SECRET)
> -		acp_credentials(prov);
> +	if ((prov->material & MAT_SECRET) == MAT_SECRET) {
> +		if (!acp_credentials(prov)) {
> +			msg.opcode = PROV_FAILED;
> +			msg.reason = PROV_ERR_UNEXPECTED_ERR;
> +			prov->trans_tx(prov->trans_data, &msg, sizeof(msg));
> +		}
> +	}
>  }
>  
>  static void send_caps(struct mesh_prov_acceptor *prov)
> @@ -423,7 +434,10 @@ static void acp_prov_rx(void *user_data, const uint8_t *data, uint16_t len)
>  		if ((prov->material & MAT_SECRET) != MAT_SECRET)
>  			return;
>  
> -		acp_credentials(prov);
> +		if (!acp_credentials(prov)) {
> +			fail.reason = PROV_ERR_UNEXPECTED_ERR;
> +			goto failure;
> +		}
>  
>  		if (!prov->conf_inputs.start.pub_key)
>  			send_pub_key(prov);