nmap-0002 + haproxy-0004 + nginx-0004 + weechat-0003 + zeek-0002 + curl-0004: 6 new CWE-407 defects in network tools; count 693→699

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)

defects/haproxy/patch/haproxy-0004-http-capture-headers-O-HxC.md

@@ -0,0 +1,95 @@
+# haproxy-0004 — http_capture_headers O(H×C) per-request header capture scan
+
+## Ecosystem
+haproxy (C)
+
+## Severity
+MEDIUM — hot path: called for every HTTP request and response with `capture request header` or `capture response header` directives configured
+
+## Location
+`src/http_ana.c`
+- Function: `http_capture_headers` (~line 5096)
+- Inner loop: `for (h = cap_hdr; h; h = h->next)` at line 5113
+
+## Description
+
+`http_capture_headers` is called on every HTTP request and response when
+header capture is configured. It iterates over all H headers in the HTX
+message, and for each header performs a linear O(C) walk of the `cap_hdr`
+linked list to check for a name match:
+
+```c
+static void http_capture_headers(struct htx *htx, char **cap, struct cap_hdr *cap_hdr)
+{
+    for (pos = htx_get_first(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+        // ... get header name n ...
+        for (h = cap_hdr; h; h = h->next) {         // O(C) per header
+            if (h->namelen && (h->namelen == n.len) &&
+                (strncasecmp(n.ptr, h->name, h->namelen) == 0)) {
+                // capture value
+            }
+        }
+    }
+}
+```
+
+Total cost per request: O(H × C) where:
+- H = number of headers in the request/response (typically 10-50, up to 100+)
+- C = number of configured capture headers (can be dozens with complex configs)
+
+Since this runs on every HTTP request+response, it compounds:
+- Large H (100 headers) × large C (50 capture directives) = 5000 strncasecmp calls per request
+
+## Fix
+
+Build a hash map from `cap_hdr` name → `cap_hdr *` at config parse time. On each
+request, look up each header name in O(1):
+
+```c
+--- a/include/haproxy/proxy-t.h
++++ b/include/haproxy/proxy-t.h
+@@ -437,6 +437,8 @@
+    struct cap_hdr *req_cap;    /* chained list of request headers to be captured */
+    struct cap_hdr *rsp_cap;    /* chained list of response headers to be captured */
++   struct eb_root req_cap_tree;  /* name→cap_hdr for O(log C) lookup */
++   struct eb_root rsp_cap_tree;  /* name→cap_hdr for O(log C) lookup */
+
+--- a/src/http_ana.c
++++ b/src/http_ana.c
+@@ -5096,15 +5096,14 @@
+ static void http_capture_headers(struct htx *htx, char **cap, struct cap_hdr *cap_hdr)
+ {
+-   struct cap_hdr *h;
+    int32_t pos;
+
+    for (pos = htx_get_first(htx); pos != -1; pos = htx_get_next(htx, pos)) {
+        struct htx_blk *blk = htx_get_blk(htx, pos);
+        if (htx_get_blk_type(blk) == HTX_BLK_EOH) break;
+        if (htx_get_blk_type(blk) != HTX_BLK_HDR) continue;
+
+        struct ist n = htx_get_blk_name(htx, blk);
+
+-       for (h = cap_hdr; h; h = h->next) {          // O(C) walk eliminated
++       struct cap_hdr *h = cap_hdr_lookup(cap_hdr, n); // O(1) hash lookup
++       if (h) {
+            if (h->namelen && /* ... match ... */) {
+                // capture value
+            }
+        }
+    }
+}
+```
+
+## Complexity
+
+| Variant | Cost |
+|---------|------|
+| Before  | O(H × C) per request+response pair |
+| After   | O(H) per request+response pair — O(1) hash lookup per header |
+| Speedup | C× (number of capture headers) |
+
+## Notes
+- With C=1 (one capture directive) this is trivially already O(H); the defect
+  matters when C grows with complex proxy configurations
+- The cap_hdr list is immutable after config parse, making it safe to index
+- HAProxy already uses various tree structures (ceb-trees) for similar purposes