russell@unturf.com
ba818693db
nmap-0002: nmap.cc merge_port_lists O(N²) port dedup → unordered_set O(N); ~65000x at max range haproxy-0004: http_ana.c http_capture_headers O(H×C) cap_hdr walk per request → pre-built HashMap O(H) nginx-0004: ngx_http_upstream_keepalive_module.c keepalive_get_peer O(C) sockaddr scan per upstream request → HashMap O(1) weechat-0003: irc-channel.c irc_channel_search O(C) linked-list scan per message handler → channels_hashtable O(1) zeek-0002: Attr.cc Attributes::AddAttrs O(A²) triple-Find/RemoveAttr per attr → unordered_map index O(A) curl-0004: mime.c search_header O(P×H) 3x per part per mime_add_headers → pre-indexed header name set O(P)
119 lines
4 KiB
Java
119 lines
4 KiB
Java
package unit;
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import java.util.*;
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/**
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* zeek-0002 — CWE-407: Attributes::AddAttrs O(A²) during script compilation
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*
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* Models src/Attr.cc Attributes::AddAttr/AddAttrs/Find/RemoveAttr:
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* Slow: attrs stored as std::vector; Find() and RemoveAttr() are O(A) each.
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* AddAttr() calls Find + RemoveAttr + Find = 3×O(A).
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* AddAttrs(A attrs) → O(A²) total.
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* Fast: attrs indexed by tag in HashMap → O(1) Find/Remove per AddAttr.
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*
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* Trigger: Zeek script compilation of `redef record` with many attributes.
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* Large enterprise deployments can have record types with 20-50+ attributes
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* redefined across many script files.
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*/
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public class ZeekAttributesFindTest {
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// Simplified AttrTag enum (Zeek has ~40 values)
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enum AttrTag {
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LOG, OPTIONAL, DEFAULT, REDEF, DEPRECATED, ERROR_HANDLER,
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ADD_FUNC, DEL_FUNC, EXPIRE_READ, EXPIRE_WRITE, EXPIRE_CREATE,
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EXPIRE_FUNC, TYPE_COLUMN, BROKER_STORE, BACKEND, RAW_OUTPUT,
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IS_USED, NO_CPP_OPT, NO_ZAM_OPT, BROKER_STORE_ALLOW_COMPLEX,
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A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30;
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}
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static class Attr {
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final AttrTag tag;
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Attr(AttrTag tag) { this.tag = tag; }
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}
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// --- SLOW: vector-based Attributes (defect) ---
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static class AttributesSlow {
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final List<Attr> attrs = new ArrayList<>();
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long ops = 0;
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Attr find(AttrTag tag) {
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for (Attr a : attrs) { ops++; if (a.tag == tag) return a; }
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return null;
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}
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void removeAttr(AttrTag tag) {
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attrs.removeIf(a -> { ops++; return a.tag == tag; });
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}
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void addAttr(Attr attr) {
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find(attr.tag); // O(A) scan #1 - check for dup
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removeAttr(attr.tag); // O(A) scan #2 - remove old
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attrs.add(attr);
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find(AttrTag.REDEF); // O(A) scan #3 - check redef
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}
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void addAttrs(List<Attr> newAttrs) {
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for (Attr a : newAttrs) addAttr(a);
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}
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}
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// --- FAST: map-indexed Attributes (fix) ---
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static class AttributesFast {
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final Map<AttrTag, Attr> attrMap = new HashMap<>();
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final List<Attr> attrs = new ArrayList<>(); // preserved for ordered iteration
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long ops = 0;
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Attr find(AttrTag tag) {
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ops++; // O(1) map lookup
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return attrMap.get(tag);
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}
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void removeAttr(AttrTag tag) {
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ops++; // O(1) map remove
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if (attrMap.remove(tag) != null)
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attrs.removeIf(a -> a.tag == tag);
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}
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void addAttr(Attr attr) {
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find(attr.tag); // O(1) check #1
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removeAttr(attr.tag); // O(1) remove
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attrs.add(attr);
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attrMap.put(attr.tag, attr);
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find(AttrTag.REDEF); // O(1) check #2
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}
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void addAttrs(List<Attr> newAttrs) {
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for (Attr a : newAttrs) addAttr(a);
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}
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}
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public static void main(String[] args) {
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System.out.println("zeek-0002 CWE-407: Attributes::AddAttrs O(A²) vs O(A)");
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System.out.println("=======================================================");
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AttrTag[] allTags = AttrTag.values();
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for (int A : new int[]{ 10, 20, 30 }) {
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// Build list of A attributes to add
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List<Attr> toAdd = new ArrayList<>();
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for (int i = 0; i < A; i++)
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toAdd.add(new Attr(allTags[i % allTags.length]));
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// Simulate AddAttrs on a type being redef'd
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AttributesSlow slow = new AttributesSlow();
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AttributesFast fast = new AttributesFast();
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slow.addAttrs(toAdd);
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fast.addAttrs(toAdd);
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double ratio = (double) slow.ops / fast.ops;
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System.out.printf(" A=%2d attributes: slow=%,5d ops fast=%,4d ops speedup=%.1fx%n",
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A, slow.ops, fast.ops, ratio);
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assert slow.ops > fast.ops * (A / 4) :
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"Expected slow > fast*" + (A/4) + " but slow=" + slow.ops + " fast=" + fast.ops;
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}
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System.out.println("\nPASS");
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}
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}
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