Doccomments, tidy, PCCS url

Author: ameba23

src/attestation.rs

@@ -1,17 +1,22 @@
+use std::time::SystemTimeError;
+
 use configfs_tsm::QuoteGenerationError;
 use dcap_qvl::{
     collateral::get_collateral_for_fmspc,
     quote::{Quote, Report},
 };
 use sha2::{Digest, Sha256};
+use tdx_quote::QuoteParseError;
 use thiserror::Error;
 use tokio_rustls::rustls::pki_types::CertificateDer;
 use x509_parser::prelude::*;
 
+/// For fetching collateral directly from intel, if no PCCS is specified
 const PCS_URL: &str = "https://api.trustedservices.intel.com";
 
+/// Defines how to generate a quote
 pub trait QuoteGenerator: Clone + Send + 'static {
-    /// Whether this is CVM attestation. This should always return true except for the [NoAttestation] case.
+    /// Whether this is CVM attestation. This should always return true except for the [NoQuoteGenerator] case.
     ///
     /// When false, allows TLS client to be configured without client authentication
     fn is_cvm(&self) -> bool;
@@ -24,8 +29,9 @@ pub trait QuoteGenerator: Clone + Send + 'static {
     ) -> Result<Vec<u8>, AttestationError>;
 }
 
+/// Defines how to verify a quote
 pub trait QuoteVerifier: Clone + Send + 'static {
-    /// Whether this is CVM attestation. This should always return true except for the [NoAttestation] case.
+    /// Whether this is CVM attestation. This should always return true except for the [NoQuoteVerifier] case.
     ///
     /// When false, allows TLS client to be configured without client authentication
     fn is_cvm(&self) -> bool;
@@ -39,6 +45,7 @@ pub trait QuoteVerifier: Clone + Send + 'static {
     ) -> impl Future<Output = Result<(), AttestationError>> + Send;
 }
 
+/// Quote generation using configfs_tsm
 #[derive(Clone)]
 pub struct DcapTdxQuoteGenerator;
 
@@ -120,10 +127,18 @@ impl CvmImageMeasurements {
         }
     }
 }
+
+/// Verify DCAP TDX quotes, allowing them if they have one of a given set of platform-specific and
+/// OS image specific measurements
 #[derive(Clone)]
 pub struct DcapTdxQuoteVerifier {
+    /// Platform specific allowed Measurements
+    /// Currently an option as this may be determined internally on a per-platform basis (Eg: GCP)
     pub accepted_platform_measurements: Option<Vec<PlatformMeasurements>>,
+    /// OS-image specific allows measurement - this is effectively a list of allowed OS images
     pub accepted_cvm_image_measurements: Vec<CvmImageMeasurements>,
+    /// URL of a PCCS (defaults to Intel PCS)
+    pub pccs_url: Option<String>,
 }
 
 impl QuoteVerifier for DcapTdxQuoteVerifier {
@@ -140,18 +155,22 @@ impl QuoteVerifier for DcapTdxQuoteVerifier {
         let quote_input = compute_report_input(cert_chain, exporter)?;
         let (platform_measurements, image_measurements) = if cfg!(not(test)) {
             let now = std::time::SystemTime::now()
-                .duration_since(std::time::UNIX_EPOCH)
-                .unwrap()
+                .duration_since(std::time::UNIX_EPOCH)?
                 .as_secs();
-            let quote = Quote::parse(&input).unwrap();
-            let ca = quote.ca().unwrap();
-            let fmspc = hex::encode_upper(quote.fmspc().unwrap());
-            let collateral = get_collateral_for_fmspc(PCS_URL, fmspc, ca, false)
-                .await
-                .unwrap();
-            let _verified_report = dcap_qvl::verify::verify(&input, &collateral, now).unwrap();
-
-            let quote = Quote::parse(&input).unwrap();
+            let quote = Quote::parse(&input)?;
+
+            let ca = quote.ca()?;
+            let fmspc = hex::encode_upper(quote.fmspc()?);
+            let collateral = get_collateral_for_fmspc(
+                &self.pccs_url.clone().unwrap_or(PCS_URL.to_string()),
+                fmspc,
+                ca,
+                false,
+            )
+            .await?;
+
+            let _verified_report = dcap_qvl::verify::verify(&input, &collateral, now)?;
+
             let measurements = (
                 PlatformMeasurements::from_dcap_qvl_quote(&quote)?,
                 CvmImageMeasurements::from_dcap_qvl_quote(&quote)?,
@@ -162,7 +181,7 @@ impl QuoteVerifier for DcapTdxQuoteVerifier {
             measurements
         } else {
             // In tests we use mock quotes which will fail to verify
-            let quote = tdx_quote::Quote::from_bytes(&input).unwrap();
+            let quote = tdx_quote::Quote::from_bytes(&input)?;
             if quote.report_input_data() != quote_input {
                 return Err(AttestationError::InputMismatch);
             }
@@ -176,15 +195,16 @@ impl QuoteVerifier for DcapTdxQuoteVerifier {
         if let Some(accepted_platform_measurements) = &self.accepted_platform_measurements
             && !accepted_platform_measurements.contains(&platform_measurements)
         {
-            panic!("Bad measurements");
+            return Err(AttestationError::UnacceptablePlatformMeasurements);
         }
 
         if !self
             .accepted_cvm_image_measurements
             .contains(&image_measurements)
         {
-            panic!("Bad measurements");
+            return Err(AttestationError::UnacceptableOsImageMeasurements);
         }
+
         Ok(())
     }
 }
@@ -304,4 +324,14 @@ pub enum AttestationError {
     QuoteGeneration(#[from] configfs_tsm::QuoteGenerationError),
     #[error("SGX quote given when TDX quote expected")]
     SgxNotSupported,
+    #[error("Platform measurements do not match any accepted values")]
+    UnacceptablePlatformMeasurements,
+    #[error("OS image measurements do not match any accepted values")]
+    UnacceptableOsImageMeasurements,
+    #[error("System Time: {0}")]
+    SystemTime(#[from] SystemTimeError),
+    #[error("DCAP quote verification: {0}")]
+    DcapQvl(#[from] anyhow::Error),
+    #[error("Quote parse: {0}")]
+    QuoteParse(#[from] QuoteParseError),
 }

src/lib.rs

@@ -536,6 +536,7 @@ mod tests {
                 rtmr2: [0u8; 48],
                 rtmr3: [0u8; 48],
             }],
+            pccs_url: None,
         };
 
         tokio::spawn(async move {
@@ -595,6 +596,7 @@ mod tests {
                 rtmr2: [0u8; 48],
                 rtmr3: [0u8; 48],
             }],
+            pccs_url: None,
         };
 
         let proxy_server = ProxyServer::new_with_tls_config(
@@ -672,6 +674,7 @@ mod tests {
                 rtmr2: [0u8; 48],
                 rtmr3: [0u8; 48],
             }],
+            pccs_url: None,
         };
 
         let proxy_client = ProxyClient::new_with_tls_config(
@@ -730,6 +733,7 @@ mod tests {
                 rtmr2: [0u8; 48],
                 rtmr3: [0u8; 48],
             }],
+            pccs_url: None,
         };
 
         let retrieved_chain =

src/main.rs

@@ -87,6 +87,7 @@ async fn main() -> anyhow::Result<()> {
                     rtmr2: [0u8; 48],
                     rtmr3: [0u8; 48],
                 }],
+                pccs_url: None,
             };
 
             let client = ProxyClient::new(
@@ -139,6 +140,7 @@ async fn main() -> anyhow::Result<()> {
                     rtmr2: [0u8; 48],
                     rtmr3: [0u8; 48],
                 }],
+                pccs_url: None,
             };
             let cert_chain = get_tls_cert(server, quote_verifier).await?;
             println!("{}", certs_to_pem_string(&cert_chain)?);