int ssl3_get_client_certificate(SSL *s)
	{
	int i,ok,al,ret= -1;
	X509 *x=NULL;
	unsigned long l,nc,llen,n;
	const unsigned char *p,*q;
	unsigned char *d;
	STACK_OF(X509) *sk=NULL;

	n=s->method->ssl_get_message(s,
		SSL3_ST_SR_CERT_A,
		SSL3_ST_SR_CERT_B,
		-1,
		s->max_cert_list,
		&ok);

	if (!ok) return((int)n);

	if	(s->s3->tmp.message_type == SSL3_MT_CLIENT_KEY_EXCHANGE)
		{
		if (	(s->verify_mode & SSL_VERIFY_PEER) &&
			(s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
			al=SSL_AD_HANDSHAKE_FAILURE;
			goto f_err;
			}
		/* If tls asked for a client cert, the client must return a 0 list */
		if ((s->version > SSL3_VERSION) && s->s3->tmp.cert_request)
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST);
			al=SSL_AD_UNEXPECTED_MESSAGE;
			goto f_err;
			}
		s->s3->tmp.reuse_message=1;
		return(1);
		}

	if (s->s3->tmp.message_type != SSL3_MT_CERTIFICATE)
		{
		al=SSL_AD_UNEXPECTED_MESSAGE;
		SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_WRONG_MESSAGE_TYPE);
		goto f_err;
		}
	p=d=(unsigned char *)s->init_msg;

	if ((sk=sk_X509_new_null()) == NULL)
		{
		SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,ERR_R_MALLOC_FAILURE);
		goto err;
		}

	n2l3(p,llen);
	if (llen+3 != n)
		{
		al=SSL_AD_DECODE_ERROR;
		SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_LENGTH_MISMATCH);
		goto f_err;
		}
	for (nc=0; nc<llen; )
		{
		n2l3(p,l);
		if ((l+nc+3) > llen)
			{
			al=SSL_AD_DECODE_ERROR;
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_CERT_LENGTH_MISMATCH);
			goto f_err;
			}

		q=p;
		x=d2i_X509(NULL,&p,l);
		if (x == NULL)
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,ERR_R_ASN1_LIB);
			goto err;
			}
		if (p != (q+l))
			{
			al=SSL_AD_DECODE_ERROR;
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_CERT_LENGTH_MISMATCH);
			goto f_err;
			}
		if (!sk_X509_push(sk,x))
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,ERR_R_MALLOC_FAILURE);
			goto err;
			}
		x=NULL;
		nc+=l+3;
		}

	if (sk_X509_num(sk) <= 0)
		{
		/* TLS does not mind 0 certs returned */
		if (s->version == SSL3_VERSION)
			{
			al=SSL_AD_HANDSHAKE_FAILURE;
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_NO_CERTIFICATES_RETURNED);
			goto f_err;
			}
		/* Fail for TLS only if we required a certificate */
		else if ((s->verify_mode & SSL_VERIFY_PEER) &&
			 (s->verify_mode & SSL_VERIFY_FAIL_IF_NO_PEER_CERT))
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE);
			al=SSL_AD_HANDSHAKE_FAILURE;
			goto f_err;
			}
		/* No client certificate so digest cached records */
		if (s->s3->handshake_buffer && !ssl3_digest_cached_records(s))
			{
			al=SSL_AD_INTERNAL_ERROR;
			goto f_err;
			}
		}
	else
		{
		EVP_PKEY *pkey;
		i=ssl_verify_cert_chain(s,sk);
		if (i <= 0)
			{
			al=ssl_verify_alarm_type(s->verify_result);
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,SSL_R_CERTIFICATE_VERIFY_FAILED);
			goto f_err;
			}
		if (i > 1)
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, i);
			al = SSL_AD_HANDSHAKE_FAILURE;
			goto f_err;
			}
		pkey = X509_get_pubkey(sk_X509_value(sk, 0));
		if (pkey == NULL)
			{
			al=SSL3_AD_HANDSHAKE_FAILURE;
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
						SSL_R_UNKNOWN_CERTIFICATE_TYPE);
			goto f_err;
			}
		EVP_PKEY_free(pkey);
		}

	if (s->session->peer != NULL) /* This should not be needed */
		X509_free(s->session->peer);
	s->session->peer=sk_X509_shift(sk);
	s->session->verify_result = s->verify_result;

	/* With the current implementation, sess_cert will always be NULL
	 * when we arrive here. */
	if (s->session->sess_cert == NULL)
		{
		s->session->sess_cert = ssl_sess_cert_new();
		if (s->session->sess_cert == NULL)
			{
			SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE, ERR_R_MALLOC_FAILURE);
			goto err;
			}
		}
	if (s->session->sess_cert->cert_chain != NULL)
		sk_X509_pop_free(s->session->sess_cert->cert_chain, X509_free);
	s->session->sess_cert->cert_chain=sk;
	/* Inconsistency alert: cert_chain does *not* include the
	 * peer's own certificate, while we do include it in s3_clnt.c */

	sk=NULL;

	ret=1;
	if (0)
		{
f_err:
		ssl3_send_alert(s,SSL3_AL_FATAL,al);
		}
err:
	if (x != NULL) X509_free(x);
	if (sk != NULL) sk_X509_pop_free(sk,X509_free);
	return(ret);
	}

This weakness pertains to the use of cryptographic functions that are weak, misconfigured, or outdated, which undermines the intended protection of encrypted data and communications.