39 lines
1.3 KiB
Diff
39 lines
1.3 KiB
Diff
# UNDF: UNDF-2026-000000081
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diff --git a/src/cmd/compile/internal/types2/infer.go b/src/cmd/compile/internal/types2/infer.go
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index eeefb117..cwe407fix 100644
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--- a/src/cmd/compile/internal/types2/infer.go
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+++ b/src/cmd/compile/internal/types2/infer.go
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@@ -543,14 +543,20 @@ func isParameterized(tparams []*TypeParam, typ Type) bool {
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- w := tpWalker{
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- tparams: tparams,
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- seen: make(map[Type]bool),
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- }
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+ // CWE-407 fix: pre-build a map for O(1) TypeParam membership check.
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+ // Previously tpWalker used a []*TypeParam slice and called slices.Index
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+ // (O(n)) at every *TypeParam node during the walk — O(n²) total for n
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+ // type parameters in a generic function.
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+ tset := make(map[*TypeParam]bool, len(tparams))
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+ for _, tp := range tparams {
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+ tset[tp] = true
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+ }
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+ w := tpWalker{
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+ tparams: tset,
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+ seen: make(map[Type]bool),
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+ }
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return w.isParameterized(typ)
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}
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type tpWalker struct {
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- tparams []*TypeParam
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+ tparams map[*TypeParam]bool // CWE-407: was []*TypeParam (O(n) contains)
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seen map[Type]bool
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}
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@@ -627,7 +633,7 @@ func (w *tpWalker) isParameterized(typ Type) (res bool) {
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case *TypeParam:
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- return slices.Index(w.tparams, t) >= 0
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+ return w.tparams[t] // CWE-407: O(1) map lookup, was O(n) slices.Index
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default:
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panic(fmt.Sprintf("unexpected %T", typ))
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