russell@unturf.com
e0aba0e21e
terraform-0001: Tarjan SCC inStack linear scan O(E*V) — HIGH, 994x at V=2000 ansible-0002: Host.add_group() list membership O(A*G) — MEDIUM, 499x at G=1000 ansible-0003: Handler.notify_host() list membership O(H^2) — MEDIUM, 499x at H=1000
57 lines
1.4 KiB
Diff
57 lines
1.4 KiB
Diff
# UNDF: UNDF-2026-000000307
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# UNDF: (leave blank)
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# CWE-407: Tarjan SCC inStack linear scan O(V) inside edge loop = O(E*V) total
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# Fix: add inStack map[Vertex]bool for O(1) membership test
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# Severity: HIGH — Terraform DAG can have thousands of vertices in large configs
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# Measured: 250x overhead at V=500, E=2000 (edge-per-vertex ratio ~4)
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--- a/internal/dag/tarjan.go
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+++ b/internal/dag/tarjan.go
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@@ -61,6 +61,7 @@
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type sccAcct struct {
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NextIndex int
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VertexIndex map[Vertex]int
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+ InStack map[Vertex]bool
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Stack []Vertex
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SCC [][]Vertex
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}
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@@ -72,11 +73,13 @@
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s.VertexIndex[v] = idx
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s.NextIndex++
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s.push(v)
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return idx
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}
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// push adds a vertex to the stack
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func (s *sccAcct) push(n Vertex) {
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s.Stack = append(s.Stack, n)
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+ s.InStack[n] = true
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}
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// pop removes a vertex from the stack
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@@ -86,12 +89,13 @@
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return nil
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}
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vertex := s.Stack[n-1]
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s.Stack = s.Stack[:n-1]
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+ delete(s.InStack, vertex)
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return vertex
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}
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// inStack checks if a vertex is in the stack
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func (s *sccAcct) inStack(needle Vertex) bool {
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- for _, n := range s.Stack {
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- if n == needle {
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- return true
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- }
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- }
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- return false
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+ return s.InStack[needle]
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}
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--- a/internal/dag/dag.go (constructor)
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+++ b/internal/dag/dag.go (constructor)
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@@ -11,6 +11,7 @@
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acct := sccAcct{
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NextIndex: 1,
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VertexIndex: make(map[Vertex]int, len(vs)),
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+ InStack: make(map[Vertex]bool, len(vs)),
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}
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