No longer error when runtime has custom sections mismatch (#607)

* No longer error when runtime has custom sections mismatch * Add regression test * Rustfmt * PR link
smol-dot · May 25, 2023 · e896cee · e896cee
1 parent 8f6e978
commit e896cee
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Showing 4 changed files with 61 additions and 4 deletions.
diff --git a/lib/src/executor/host.rs b/lib/src/executor/host.rs
@@ -206,7 +206,10 @@ use tiny_keccak::Hasher as _;
 
 pub mod runtime_version;
 
-pub use runtime_version::{CoreVersion, CoreVersionError, CoreVersionRef};
+pub use runtime_version::{
+    CoreVersion, CoreVersionApisFromSliceErr, CoreVersionError, CoreVersionRef,
+    FindEncodedEmbeddedRuntimeVersionApisError,
+};
 pub use trie::TrieEntryVersion;
 pub use vm::HeapPages;
 pub use zstd::Error as ModuleFormatError;
@@ -284,8 +287,31 @@ impl HostVmPrototype {
         // initialization. `Ok(None)` can also be returned, in which case the sections are
         // missing, and we will instead try to retrieve the version through a runtime call later
         // down this function.
-        let runtime_version = runtime_version::find_embedded_runtime_version(&module_bytes)
-            .map_err(NewErr::RuntimeVersion)?;
+        // In the case of `CustomSectionsPresenceMismatch`, indicating that one section is present
+        // but not the other, we must ignore the custom sections. This is necessary due to some
+        // historical accidents.
+        let runtime_version = match runtime_version::find_embedded_runtime_version(&module_bytes) {
+            Ok(Some(r)) => Some(r),
+            Ok(None) => None,
+            Err(
+                runtime_version::FindEmbeddedRuntimeVersionError::CustomSectionsPresenceMismatch,
+            ) => None,
+            Err(runtime_version::FindEmbeddedRuntimeVersionError::FindSections(err)) => {
+                return Err(NewErr::RuntimeVersion(
+                    FindEmbeddedRuntimeVersionError::FindSections(err),
+                ))
+            }
+            Err(runtime_version::FindEmbeddedRuntimeVersionError::RuntimeApisDecode(err)) => {
+                return Err(NewErr::RuntimeVersion(
+                    FindEmbeddedRuntimeVersionError::RuntimeApisDecode(err),
+                ))
+            }
+            Err(runtime_version::FindEmbeddedRuntimeVersionError::RuntimeVersionDecode) => {
+                return Err(NewErr::RuntimeVersion(
+                    FindEmbeddedRuntimeVersionError::RuntimeVersionDecode,
+                ))
+            }
+        };
 
         // Initialize the virtual machine.
         // Each symbol requested by the Wasm runtime will be put in `registered_functions`. Later,
@@ -3659,7 +3685,7 @@ pub enum NewErr {
     VirtualMachine(vm::NewErr),
     /// Error while finding the runtime-version-related sections in the Wasm blob.
     #[display(fmt = "Error in runtime spec Wasm sections: {_0}")]
-    RuntimeVersion(runtime_version::FindEmbeddedRuntimeVersionError),
+    RuntimeVersion(FindEmbeddedRuntimeVersionError),
     /// Error while calling `Core_version` to determine the runtime version.
     #[display(fmt = "Error while calling Core_version: {_0}")]
     CoreVersion(CoreVersionError),
@@ -3670,6 +3696,19 @@ pub enum NewErr {
     MemoryMaxSizeTooLow,
 }
 
+/// Error while determining .
+#[derive(Debug, derive_more::Display, Clone)]
+pub enum FindEmbeddedRuntimeVersionError {
+    /// Error while finding the custom section.
+    #[display(fmt = "{_0}")]
+    FindSections(FindEncodedEmbeddedRuntimeVersionApisError),
+    /// Error while decoding the runtime version.
+    RuntimeVersionDecode,
+    /// Error while decoding the runtime APIs.
+    #[display(fmt = "{_0}")]
+    RuntimeApisDecode(CoreVersionApisFromSliceErr),
+}
+
 /// Error that can happen when starting a VM.
 #[derive(Debug, Clone, derive_more::From, derive_more::Display)]
 pub enum StartErr {

diff --git a/lib/src/executor/host/tests/initialization.rs b/lib/src/executor/host/tests/initialization.rs
@@ -210,4 +210,21 @@ fn host_function_bad_signature() {
     }
 }
 
+#[test]
+fn rococo_genesis_works() {
+    // The Rococo genesis runtime has the particularity that it has a `runtime_apis` custom
+    // section but no `runtime_version` custom section.
+    let module_bytes = &include_bytes!("./rococo-genesis.wasm")[..];
+
+    for exec_hint in ExecHint::available_engines() {
+        assert!(HostVmPrototype::new(Config {
+            allow_unresolved_imports: true,
+            exec_hint,
+            heap_pages: HeapPages::new(1024),
+            module: &module_bytes,
+        })
+        .is_ok());
+    }
+}
+
 // TODO: add tests for the runtime version gathering after clarifying the errors in host.rs
diff --git a/lib/src/executor/host/tests/rococo-genesis.wasm b/lib/src/executor/host/tests/rococo-genesis.wasm
diff --git a/wasm-node/CHANGELOG.md b/wasm-node/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- When a runtime contains a `runtime_apis` custom section but no `runtime_version` custom section, or vice-versa, smoldot now falls back to calling `Core_version`. ([#607](https://github.com/smol-dot/smoldot/pull/607))
 - Fix panic when the checkpoint in the chain specification is invalid, which can normally only happen if the checkpoint was modified manually. ([#603](https://github.com/smol-dot/smoldot/pull/603))
 - Fix panic when the checkpoint in the chain specification contains zero or one Babe epochs, which can happen if the checkpoint was generated before any block was authored. ([#603](https://github.com/smol-dot/smoldot/pull/603))