sec/wave-2: C-1 WASM allocator OOB + C-2 lazy WASI imports; remove wasm-unstable gate#168
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sec/wave-2: C-1 WASM allocator OOB + C-2 lazy WASI imports; remove wasm-unstable gate#168
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… wasm-unstable gate
C-1 (backend/wasm.rs, codegen/wasm.rs):
Rewrote emit_malloc_builtin / code-section malloc body to use memory.size +
memory.grow + unreachable trap on OOM. No -1 sentinel pointer escapes to user
code. Static heap_start derived from data_end_offset (C-1b); memory cap
(100-page static limit) removed in favor of dynamic growth.
C-2 (backend/wasm.rs, codegen/wasm.rs):
WASI imports (fd_write, proc_exit) are now lazy/conditional:
- backend/wasm.rs: needs_fd_write/needs_proc_exit flags; emit_println_builtin
lazily reserves the fd_write import; compile_module scans func_refs for IO
builtins and skips emit_println_builtin for pure modules.
- codegen/wasm.rs: needed_wasi_imports() scan added before Phase 2 import
section; only imports actually used are included.
A pure-function module now emits zero WASI imports.
Gate removal:
wasm-unstable feature renamed back to wasm (C-1/C-2 exit criterion met).
docs/WASM.md updated to remove instability notice.
CI workflow can now use --features wasm (original flag) unchanged.
Tests added (backend/wasm.rs unit + wasm_tests.rs integration):
- pure_module_emits_no_imports: C-2 regression
- alloc_grows_module_compiles: C-1 regression
- data_heap_no_alias: C-1b regression
- test_wasi_imports_lazy: C-2 regression
All 1101 tests pass.
Three issues flagged by Ops:
1. E2E test regression (test_e2e_wasm_validation):
Pure "validate" module no longer gets WASI imports after C-2 fix.
Remove the now-incorrect "Missing Import section" assertion.
2. Flaky agent security tests (load_*):
env::set_current_dir is process-global; three tests racy under parallel
execution. Serialize them with a module-level static Mutex (CWD_LOCK).
No new dependencies required.
3. Lint warnings in backend/wasm.rs and test files:
- Remove `mut` from `let mut imports` (unused)
- Remove unused imports: Literal, std::io::Write, CodegenBackend
from wasm_tests.rs and wasm_e2e_tests.rs
cargo clippy -p gradient-compiler --features wasm -- -D warnings: clean.
cargo test --workspace --features wasm: 1101 passed, 0 failed.
Closed
3 tasks
Three root causes in backend/wasm.rs after the C-2 lazy-imports refactor: 1. emit_malloc_builtin and compile_function added function bodies to the CodeSection but never called self.functions.function(type_idx), leaving the FunctionSection empty. WASM validators require a 1:1 correspondence between FunctionSection and CodeSection entries. 2. finish() used a hardcoded 2-type manual byte sequence that described only the old always-present WASI imports, not the actual functions emitted. 3. emit_println_builtin did not register its wrapper's type at all. Fix: replace type_section_bytes + manual LEB128 with a TypeSection field. Add a register_type() helper called from every function emitter. Each emit_*_builtin and compile_function now also calls self.functions.function() with the freshly registered type index. encode_leb128() is deleted (no longer used). Also: harden agent_security_tests CWD restoration with a CwdGuard Drop impl so a panicking test cannot leave the process in a temp directory. All 16 wasm + e2e tests pass; 7 security regression tests pass. Zero warnings under --features wasm. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
3 tasks
…le (GRA-92) Wave-1 (e93e6ab) renamed the feature flag to wasm-unstable in CI while the WASM backend was behind a safety gate. Wave-2 removes the gate and restores the flag to plain `wasm`, but that earlier CI commit was not on the wave-2 branch, so 3-way merge always let main's wasm-unstable win. This commit merges current main and explicitly flips wasm-unstable → wasm in all five CI steps, giving the PR branch an owned diff that survives the merge and ensures CI runs with a feature that actually exists. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
Wave 2 of the security remediation plan (GRA-79). Resolves the two CRITICAL WASM findings that blocked the
wasmfeature gate.backend/wasm.rs,codegen/wasm.rs) — Rewrote the WASM bump allocator to usememory.size+memory.grow+unreachabletrap on OOM. No-1sentinel pointer ever escapes into user code.heap_startis computed fromdata_end_offset(aligned) so the static-data region and heap cannot alias.backend/wasm.rs,codegen/wasm.rs) — WASI imports (fd_write,proc_exit) are now lazy/conditional. A pure-function module emits zero WASI imports. Both backends scan the module'sfunc_refsto determine which imports are actually needed.wasm-unstablerenamed back towasm(exit criterion met).docs/WASM.mdupdated. CI can use--features wasmwithout change.Notes for Ops (GRA-91)
With this PR merged, the CI
wasmjob inci.ymlshould work as-is (--features wasm) — no changes needed to the workflow file. GRA-91 can be closed once this PR merges to main.Test plan
cargo test --workspace --features wasm— all 1101 tests passpure_module_emits_no_imports— pure module has no import sectionalloc_grows_module_compiles— module with malloc has memory + global sectionsdata_heap_no_alias— string data starts at/above null guard; heap aftertest_wasi_imports_lazy— no imports without IO, imports with IOcargo build --workspace --features wasm— clean, no unexpected_cfg warnings🤖 Generated with Claude Code