static BaseType_t prvVerifySignature()

in components/crypto/source/iot_crypto.c [184:241]

• 38 lines of code
• 5 McCabe index (conditional complexity)

static BaseType_t prvVerifySignature( char * pcSignerCertificate,
                                      size_t xSignerCertificateLength,
                                      BaseType_t xHashAlgorithm,
                                      uint8_t * pucHash,
                                      size_t xHashLength,
                                      uint8_t * pucSignature,
                                      size_t xSignatureLength )
{
    BaseType_t xResult = pdTRUE;
    mbedtls_x509_crt xCertCtx;
    mbedtls_md_type_t xMbedHashAlg = MBEDTLS_MD_SHA256;


    memset( &xCertCtx, 0, sizeof( mbedtls_x509_crt ) );

    /*
     * Map the hash algorithm
     */
    if( cryptoHASH_ALGORITHM_SHA1 == xHashAlgorithm )
    {
        xMbedHashAlg = MBEDTLS_MD_SHA1;
    }

    /*
     * Decode and create a certificate context
     */
    mbedtls_x509_crt_init( &xCertCtx );

    if( 0 != mbedtls_x509_crt_parse(
            &xCertCtx, ( const unsigned char * ) pcSignerCertificate, xSignerCertificateLength ) )
    {
        xResult = pdFALSE;
    }

    /*
     * Verify the signature using the public key from the decoded certificate
     */
    if( pdTRUE == xResult )
    {
        if( 0 != mbedtls_pk_verify(
                &xCertCtx.pk,
                xMbedHashAlg,
                pucHash,
                xHashLength,
                pucSignature,
                xSignatureLength ) )
        {
            xResult = pdFALSE;
        }
    }

    /*
     * Clean-up
     */
    mbedtls_x509_crt_free( &xCertCtx );

    return xResult;
}