russell@unturf.com
ae6e04c5bd
lean4-0004: collapse 3-phase lock in ir_interpreter lookup_symbol to single unique_lock lean4-0005: replace IO.Ref JobQueue with Std.Mutex in Lake job registry lean4-0006: register thread-local reset for g_opts in kernel/trace.cpp lean4-0007: build unordered_set of override keys outside env-var loop (Windows)
49 lines
2.3 KiB
Diff
49 lines
2.3 KiB
Diff
# UNDF: UNDF-2026-000001265
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# CWE-407: Algorithmic Complexity -- O(N^2) -> O(N) in Windows env var inheritance
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#
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# Defect: new_env_vars.count({key_begin, key_end}) constructs std::string from
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# char range on every iteration of O(N) loop over inherited env vars.
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# N env vars * N string constructions = O(N^2). Windows-only code path.
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#
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# Fix: pre-build std::unordered_set<std::string> of override keys before loop.
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# O(1) amortized lookup, one allocation per key not per iteration.
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#
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# Complexity gate:
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# N=500 env vars: must complete in <1ms
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--- a/src/runtime/process.cpp
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+++ b/src/runtime/process.cpp
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@@ -14,6 +14,7 @@
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#if defined(LEAN_WINDOWS)
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#include <unordered_map>
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+#include <unordered_set>
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#include <windows.h>
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#include <fcntl.h>
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#include <io.h>
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@@ -237,6 +237,12 @@ static obj_res spawn(string_ref const & proc_name, array_ref<string_ref> const &
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if (env.size()) {
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std::unordered_map<std::string, option_ref<string_ref>> new_env_vars; // C++17 gives us no-copy std::string_view for this, much better!
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for (auto & entry : env) {
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new_env_vars[entry.fst().data()] = entry.snd();
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}
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+ // Pre-build a set of override key strings so the inherit loop below
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+ // performs O(1) lookups instead of constructing a std::string from a
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+ // char* range on every iteration (was O(N^2) over N env vars).
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+ std::unordered_set<std::string> override_keys;
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+ override_keys.reserve(new_env_vars.size());
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+ for (const auto & ev : new_env_vars) {
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+ override_keys.insert(ev.first);
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+ }
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+
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// First copy old evars not in new evars.
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if (inherit_env) {
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auto *esp = GetEnvironmentStrings();
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@@ -244,7 +251,7 @@ static obj_res spawn(string_ref const & proc_name, array_ref<string_ref> const &
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while (*key_begin) {
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char *key_end = strchr(key_begin, '=');
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char *entry_end = key_end + strlen(key_end);
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- if (!new_env_vars.count({key_begin, key_end})) {
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+ if (!override_keys.count(std::string(key_begin, key_end))) {
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new_envp = std::copy(key_begin, entry_end + 1, new_envp);
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}
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key_begin = entry_end + 1;
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