static AzureIoTResult_t prvVerifySHAMatch()

in ports/mbedTLS/azure_iot_jws_mbedtls.c [637:698]
50 lines of code
7 McCabe index (conditional complexity)

static AzureIoTResult_t prvVerifySHAMatch( prvJWSValidationContext_t * pxManifestContext,
                                           const uint8_t * pucManifest,
                                           uint32_t ulManifestLength )
{
    AzureIoTJSONReader_t xJSONReader;
    AzureIoTResult_t ulVerificationResult;
    az_result xCoreResult;

    ulVerificationResult = prvJWS_SHA256Calculate( pucManifest,
                                                   ulManifestLength,
                                                   pxManifestContext->ucManifestSHACalculation );

    if( ulVerificationResult != eAzureIoTSuccess )
    {
        AZLogError( ( "[JWS] SHA256 Calculation failed" ) );
        return ulVerificationResult;
    }

    AzureIoTJSONReader_Init( &xJSONReader, pxManifestContext->ucJWSPayload, pxManifestContext->outJWSPayloadLength );

    if( prvFindManifestSHA( &xJSONReader, &pxManifestContext->sha256Span ) != eAzureIoTSuccess )
    {
        AZLogError( ( "Error finding manifest signature SHA" ) );
        return eAzureIoTErrorFailed;
    }

    xCoreResult = az_base64_decode( az_span_create( pxManifestContext->ucParsedManifestSha, azureiotjwsSHA256_SIZE ),
                                    pxManifestContext->sha256Span,
                                    &pxManifestContext->outParsedManifestShaSize );

    if( az_result_failed( xCoreResult ) )
    {
        AZLogError( ( "[JWS] az_base64_decode failed: result 0x%08x", ( uint16_t ) xCoreResult ) );

        if( xCoreResult == AZ_ERROR_NOT_ENOUGH_SPACE )
        {
            AZLogError( ( "[JWS] Decode buffer was too small: %i bytes", azureiotjwsSHA256_SIZE ) );
        }

        return eAzureIoTErrorFailed;
    }

    if( pxManifestContext->outParsedManifestShaSize != azureiotjwsSHA256_SIZE )
    {
        AZLogError( ( "[JWS] Base64 decoded SHA256 is not the correct length | expected: %i | actual: %i", azureiotjwsSHA256_SIZE, ( int16_t ) pxManifestContext->outParsedManifestShaSize ) );
        return eAzureIoTErrorFailed;
    }

    int32_t lComparisonResult = memcmp( pxManifestContext->ucManifestSHACalculation, pxManifestContext->ucParsedManifestSha, azureiotjwsSHA256_SIZE );

    if( lComparisonResult != 0 )
    {
        AZLogError( ( "[JWS] Calculated manifest SHA does not match SHA in payload" ) );
        return eAzureIoTErrorFailed;
    }
    else
    {
        AZLogInfo( ( "[JWS] Calculated manifest SHA matches parsed SHA" ) );
    }

    return eAzureIoTSuccess;
}