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)
90 lines
3.4 KiB
Java
90 lines
3.4 KiB
Java
package unit;
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import java.util.*;
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/**
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* nmap-0002 — CWE-407: O(N²) port deduplication in merge_port_lists
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*
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* Models nmap.cc insert_port_into_merge_list():
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* Slow: for each port to insert, linear scan of already-merged list (O(N))
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* called N times → O(N²) total
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* Fast: unordered_set<uint16_t>: O(1) insert + dedup → O(N) total
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*
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* Trigger: nmap -PS<range> -PA<range> with large overlapping port lists.
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* Default lists are tiny (1-2 ports), but user can pass 1-65535 for both.
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*/
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public class NmapMergePortListsTest {
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// --- SLOW: linear scan dedup (defect) ---
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static long mergePortListsSlow(int[] list1, int[] list2) {
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long ops = 0;
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List<Integer> merged = new ArrayList<>(list1.length + list2.length);
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for (int p : list1) {
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boolean found = false;
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for (int m : merged) { ops++; if (m == p) { found = true; break; } }
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if (!found) merged.add(p);
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}
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for (int p : list2) {
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boolean found = false;
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for (int m : merged) { ops++; if (m == p) { found = true; break; } }
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if (!found) merged.add(p);
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}
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return ops;
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}
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// --- FAST: hash set dedup (fix) ---
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static long mergePortListsFast(int[] list1, int[] list2) {
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long ops = 0;
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Set<Integer> seen = new HashSet<>((list1.length + list2.length) * 2);
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for (int p : list1) { ops++; seen.add(p); }
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for (int p : list2) { ops++; seen.add(p); }
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return ops;
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}
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public static void main(String[] args) {
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System.out.println("nmap-0002 CWE-407: merge_port_lists O(N²) vs O(N)");
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System.out.println("===================================================");
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// Small test: two overlapping port lists
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int N = 500;
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int[] list1 = new int[N];
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int[] list2 = new int[N];
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for (int i = 0; i < N; i++) {
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list1[i] = i + 1; // ports 1..500
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list2[i] = i + 250; // ports 250..750 (overlap with list1)
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}
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long slowOps = mergePortListsSlow(list1, list2);
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long fastOps = mergePortListsFast(list1, list2);
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System.out.printf(" N=%d ports per list (250 overlap)%n", N);
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System.out.printf(" Slow (linear scan): %,d ops%n", slowOps);
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System.out.printf(" Fast (hash set): %,d ops%n", fastOps);
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System.out.printf(" Op ratio: %.0fx%n", (double) slowOps / fastOps);
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// Larger test
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int N2 = 2000;
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int[] big1 = new int[N2];
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int[] big2 = new int[N2];
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for (int i = 0; i < N2; i++) {
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big1[i] = i + 1;
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big2[i] = i + 1000; // 1000 overlap
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}
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long slowOps2 = mergePortListsSlow(big1, big2);
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long fastOps2 = mergePortListsFast(big1, big2);
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System.out.printf("%n N=%d ports per list (1000 overlap)%n", N2);
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System.out.printf(" Slow (linear scan): %,d ops%n", slowOps2);
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System.out.printf(" Fast (hash set): %,d ops%n", fastOps2);
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System.out.printf(" Op ratio: %.0fx%n", (double) slowOps2 / fastOps2);
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// Assert O(N²) vs O(N)
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assert slowOps > fastOps * (N / 2) :
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"Expected slow > fast*" + (N/2) + " but slow=" + slowOps + " fast=" + fastOps;
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assert slowOps2 > fastOps2 * (N2 / 4) :
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"Expected slow2 > fast2*" + (N2/4) + " but slow2=" + slowOps2 + " fast2=" + fastOps2;
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System.out.println("\nPASS");
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}
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}
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