Temporarily support missing raw cmd line in the evidence

oak_attestation_verification/src/verifier.rs

@@ -517,14 +517,27 @@ fn verify_kernel_layer(
     )
     .context("kernel failed verification")?;
 
-    verify_regex(
-        values.kernel_raw_cmd_line.as_str(),
-        reference_values
-            .kernel_cmd_line_regex
-            .as_ref()
-            .context("no kernel command line regex reference values")?,
-    )
-    .context("kernel command line failed verification")?;
+    if let Some(kernel_raw_cmd_line) = values.kernel_raw_cmd_line.as_ref() {
+        verify_regex(
+            kernel_raw_cmd_line.as_str(),
+            reference_values
+                .kernel_cmd_line_regex
+                .as_ref()
+                .context("no kernel command line regex reference values")?,
+        )
+        .context("kernel command line failed verification")?;
+    } else {
+        // Support missing kernel_cmd_line_regex but only if the corresponding reference
+        // value is set to skip. This is a temporary workaround until all clients are
+        // migrated.
+        anyhow::ensure!(
+            matches!(
+                reference_values.kernel_cmd_line_regex.as_ref().unwrap().r#type.as_ref(),
+                Some(regex_reference_value::Type::Skip(_))
+            ),
+            "No kernel_raw_cmd_line provided"
+        )
+    }
 
     verify_measurement_digest(
         values.init_ram_fs.as_ref().context("no initial RAM disk evidence value")?,
@@ -938,11 +951,9 @@ fn extract_kernel_values(claims: &ClaimsSet) -> anyhow::Result<KernelLayerData>
         Some(value_to_raw_digest(extract_value(values, SETUP_DATA_MEASUREMENT_ID)?)?);
     let kernel_cmd_line =
         Some(value_to_raw_digest(extract_value(values, KERNEL_COMMANDLINE_MEASUREMENT_ID)?)?);
-    let kernel_raw_cmd_line = String::from(
-        extract_value(values, KERNEL_COMMANDLINE_ID)?
-            .as_text()
-            .expect("kernel cmd line CWT value is not a text"),
-    );
+    let kernel_raw_cmd_line = extract_value(values, KERNEL_COMMANDLINE_ID)
+        .ok()
+        .map(|v| String::from(v.as_text().expect("kernel_raw_cmd_line found but is not a string")));
     let init_ram_fs = Some(value_to_raw_digest(extract_value(values, INITRD_MEASUREMENT_ID)?)?);
     let memory_map = Some(value_to_raw_digest(extract_value(values, MEMORY_MAP_MEASUREMENT_ID)?)?);
     let acpi = Some(value_to_raw_digest(extract_value(values, ACPI_MEASUREMENT_ID)?)?);

oak_attestation_verification/testdata/rk_evidence_20240312.textproto

@@ -0,0 +1,20 @@
+# proto-file: proto/attestation/evidence.proto
+# proto-message: oak.attestaton.v1.Evidence
+#
+# Valid real-world evidence for a Restricted Kernel chain, used for testing.
+# Generated on 2024-03-12. `oc_evidence.binarypb` is the same instance in
+# serialized binary format. ECA: Embedded Certification Authority
+#
+# The stage0 binary is measured in the attestation report.
+root_layer {
+  platform: AMD_SEV_SNP
+  remote_attestation_report: "\002\000\000\000\000\000\000\000\000\000\003\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\001\000\000\000\003\000\000\000\000\000\024\321\001\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000w2\252D\223\000Db\2172\355\260\235\024\250\335\376\036\200\002\346\036x\347a\230\255\005}\005x#\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\366\337 T\243\207\363\370)\221A\226\010mY\222dk|\275\203Bp\304\333 \\\323hy\227~\340`\026\301\346\\\236\304S\3434\2415>\223:\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\3111\312\374\2427ynn\373\n\264W\226\014=\323P\304\216\230\007\256\306g%\316^my>\343\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\377\003\000\000\000\000\000\024\321\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\013\272\370\027|i\366~39}\203*\3533\270-d\256\351S\246#\001\351\017r\000r\232\313\351\222G\'wbZ*B\'\2553\322\336\303\366\024\215aAa\033\264\237d\315m\317\227Z>\267\300\003\000\000\000\000\000\024\321\0207\001\000\0207\001\000\003\000\000\000\000\000\024\321\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\310\274\324\320<\030\t+\017\2040\361\344\020\376\376\374\323\\\347\231\241\270\226\354U}\255\0062E\333\255\202eC\370\035{\02321\321<\314\266\020Z\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\232\355A\263Lm\2007m\237\0265Wu\322\277\371\305\343\204\302\007R\001eLq\305\344Ue\336\013FT\317<\263\373!\203\313\"}\311\301\252\235\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"
+  eca_public_key: "\247\001\002\002T\256jOA}\026Vj\025\024\341\306\323\036K\3671\201\032\336\003&\004\201\002 \001!X \361v\376\347?\377\233\211\240\326Za\0369\335\202\r\005d\267\016\331\365\221\\\007w\0261$\264^\"X \314\345!\266e[\365\377R\034\036S\245 ^\353\322{\377]\212\367X\367\034;V\203y>\344\317"
+}
+layers {
+  eca_certificate: "\204C\241\001&\241\004RAsymmetricECDSA256Y\001\340\245\001x(ae6a4f417d16566a1514e1c6d31e4bf731811ade\002x(25c27a19fda31d66242035a30892ead3746e6920:\000GDWXf\247\001\002\002T%\302z\031\375\243\035f$ 5\243\010\222\352\323tni \003&\004\201\002 \001!X N\330n\007\260Wi\347Q\337\300.\336\264\234\216hL\213z\235\342E\0358\000\312\0378k)\'\"X \344\302\006i\255\257:|L\370\2555\326\307d_\261VSO6\315}z\336\312hc\\bT\210:\000GDXB \000:\000GDZ\246:\000GD`\241:\000GDkX \314\216\243\312j\305\340\247s\342[\037\017}\365j\356\340wB\033R\206\375\345BOc\005\007\373N:\000GDa\241:\000GDkX +\230Xm\231\005\246\005\302\225\327|a\350\317\322\002z\345\270\240N\357\251\001\2046\366\255\021B\227:\000GDb\241:\000GDkX L\320 \202\r\246c\006?A\205\312\024\247\350\003\315|\234\241H<d\3506\333\204\006\004\266\372\301:\000GDc\241:\000GDkX \000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000:\000GDd\241:\000GDkX \001u>\274BEU\250\r5\255\252!\365\310\305\360\tH.\213\\\305\332\360I\274\033\277\376\274{:\000GDe\241:\000GDkX d\365U2r\207\242\024\024vh\036NM\330\r_u\253\234\'om\270\357\374U#m\272\231SX@d\016\\\353\314\230\267A\231\017\232\267\241A\037\322e\333\325\3222\210\322\244\360\322\212L\220\212\030\0073\265\211\032\356=\354\215\226\201e\247\334\230\334C}\014l\317H\336]b2\277YJ\004\217\036\357"
+}
+application_keys {
+  encryption_public_key_certificate: "\204C\241\001&\241\004RAsymmetricECDSA256X\351\245\001x(25c27a19fda31d66242035a30892ead3746e6920\002x(ba848bf3163adcebaa6a86e85593e64112bec8f7:\000GDWXD\246\001\001\002T\272\204\213\363\026:\334\353\252j\206\350U\223\346A\022\276\310\367\0038\036\004\201\005 \004!X \361u\235\355Wh\224\375\250\342\213~H\241>\240s\346Ns\250\351\247\346\256Z=\300U\323)\016:\000GDXB \000:\000GD[\242:\000GDf\241:\000GDkX \225\377$\246\2763\321\225\302\237O\342\256\342r\025\'\371X\244$T\247\3042$^\305\354\214T\235:\000GDi\241:\000GDk@X@d\365\367\267\333b\327yE\352\003\276\263>\r\031b\346\344`\242^\317\204B\313\256\371\303\263\020\034R\327`\356\007\311\200\324\375<\316\366\036\265 E\274\010$\'\256M-\277\016\362\013=Kf\023\342"
+  signing_public_key_certificate: "\204C\241\001&\241\004RAsymmetricECDSA256Y\001\013\245\001x(25c27a19fda31d66242035a30892ead3746e6920\002x(38d213454f2a0f4668c7816c35ac857c7f85a0e6:\000GDWXf\247\001\002\002T8\322\023EO*\017Fh\307\201l5\254\205|\177\205\240\346\003&\004\201\002 \001!X \215\315\337\177~\331}\254.\307`@#\020%G9=\361t\375v\202<\266\236\351\210QW\357\311\"X 8z\255\376\263Vd\320#>\027\177\237\335\377\315<\237\345\227\273\242\000\002&I\312G\2174n\004:\000GDXB \000:\000GD[\242:\000GDf\241:\000GDkX \225\377$\246\2763\321\225\302\237O\342\256\342r\025\'\371X\244$T\247\3042$^\305\354\214T\235:\000GDi\241:\000GDk@X@\215\323\254\332\321Z\177A\344\315Rr(\212\253E\0050-\367=\231\036\237\357\007*b\254\340\317O)\213\370]P\344\3261\356\311\333\007\264\201B\360!\276:\275>\027\007\254\027$\316\314\263\032\247$"
+}

oak_attestation_verification/tests/verifier_tests.rs

@@ -47,6 +47,7 @@ const ENDORSER_PUBLIC_KEY_PATH: &str = "testdata/oak-development.pem";
 const REKOR_PUBLIC_KEY_PATH: &str = "testdata/rekor_public_key.pem";
 const CONTAINERS_EVIDENCE_PATH: &str = "testdata/oc_evidence.binarypb";
 const RK_EVIDENCE_PATH: &str = "testdata/rk_evidence.binarypb";
+const RK_OBSOLETE_EVIDENCE_PATH: &str = "testdata/rk_evidence_20240312.binarypb";
 const FAKE_EVIDENCE_PATH: &str = "testdata/fake_evidence.binarypb";
 
 // Pretend the tests run at this time: 1 Nov 2023, 9:00 UTC
@@ -65,6 +66,13 @@ fn create_rk_evidence() -> Evidence {
     Evidence::decode(serialized.as_slice()).expect("could not decode evidence")
 }
 
+// Creates a valid AMD SEV-SNP evidence instance for a restricted kernel
+// application but with obsolete DICE data that is still used by some clients.
+fn create_rk_obsolete_evidence() -> Evidence {
+    let serialized = fs::read(RK_OBSOLETE_EVIDENCE_PATH).expect("could not read evidence");
+    Evidence::decode(serialized.as_slice()).expect("could not decode evidence")
+}
+
 // Creates a valid fake evidence instance.
 fn create_fake_evidence() -> Evidence {
     let serialized = fs::read(FAKE_EVIDENCE_PATH).expect("could not read fake evidence");
@@ -536,3 +544,44 @@ fn verify_succeeds_with_matching_command_line_reference_value_set() {
     assert!(r.is_ok());
     assert!(p.status() == Status::Success);
 }
+
+#[test]
+fn verify_fails_with_command_line_reference_value_set_and_obsolete_evidence() {
+    let evidence = create_rk_obsolete_evidence();
+    let endorsements = create_rk_endorsements();
+    let reference_values = create_rk_reference_values();
+
+    let r = verify(NOW_UTC_MILLIS, &evidence, &endorsements, &reference_values);
+    let p = to_attestation_results(&r);
+
+    eprintln!("======================================");
+    eprintln!("code={} reason={}", p.status as i32, p.reason);
+    eprintln!("======================================");
+    assert!(r.is_err());
+    assert!(p.status() == Status::GenericFailure);
+}
+
+#[test]
+fn verify_succeeds_with_skip_command_line_reference_value_set_and_obsolete_evidence() {
+    let evidence = create_rk_obsolete_evidence();
+    let endorsements = create_rk_endorsements();
+    let mut reference_values = create_rk_reference_values();
+    match reference_values.r#type.as_mut() {
+        Some(reference_values::Type::OakRestrictedKernel(rfs)) => {
+            rfs.kernel_layer.as_mut().unwrap().kernel_cmd_line_regex = Some(RegexReferenceValue {
+                r#type: Some(regex_reference_value::Type::Skip(SkipVerification {})),
+            });
+        }
+        Some(_) => {}
+        None => {}
+    };
+
+    let r = verify(NOW_UTC_MILLIS, &evidence, &endorsements, &reference_values);
+    let p = to_attestation_results(&r);
+
+    eprintln!("======================================");
+    eprintln!("code={} reason={}", p.status as i32, p.reason);
+    eprintln!("======================================");
+    assert!(r.is_ok());
+    assert!(p.status() == Status::Success);
+}

proto/attestation/verification.proto

@@ -145,8 +145,12 @@ message KernelLayerData {
   // during startup.
   RawDigest kernel_cmd_line = 2 [deprecated = true];
 
-  // Command-line that was passed to the kernel during startup.
-  string kernel_raw_cmd_line = 7;
+  // Command-line that was passed to the kernel during startup. If absent,
+  // verification will only succeed with the corresponding reference value set
+  // to skip (for compatibility with the legacy version of the evidence
+  // producing code). Empty value corresponds to the kernel being run with an
+  // empty command line.
+  optional string kernel_raw_cmd_line = 7;
 
   // Measured digests of the initial RAM disk.
   RawDigest init_ram_fs = 4;