Route the too-large chunk through the invalid-chunk teardown

Review found the first cut hand-rolled the abort (statuscode/status/finished)
and then fell through into the shared chunk dispatch, which re-ran finalize and
stomped the message; it was only safe by accident. Set chunk_size = -1 instead
and let the existing chunk_size < 0 path tear the transfer down (deletehttp +
deleteaddr + STATUSCODE_INVALID), matching the sibling error handling. Verified
by hand with a lowered cap: the resource is rejected as "Invalid chunk", the
socket is closed, and no partial file is written.

Also fix the test's decoded-vs-raw discriminator: '^40$' never matched the
CRLF-framed size line, and '</body></html>' is split by HTTrack's mirror
comment. Assert no CR (framing decoded) and '</body>' (no truncation).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

src/htsback.c

@@ -3310,16 +3310,26 @@ void back_wait(struct_back * sback, httrackp * opt, cache_back * cache,
                         back[i].chunk_blocksize = -1;   /* ending */
                       back[i].r.totalsize += chunk_size;        // noter taille
                       if (back[i].r.adr != NULL || !back[i].r.is_write) {       // Not to disk
-                        back[i].r.adr =
-                          (char *) realloct(back[i].r.adr,
-                                            (size_t) back[i].r.totalsize + 1);
-                        if (!back[i].r.adr) {
-                          if (cache->log != NULL) {
-                            hts_log_print(opt, LOG_ERROR,
-                                          "not enough memory (" LLintP
-                                          ") for %s%s",
-                                          (LLint) back[i].r.totalsize,
-                                          back[i].url_adr, back[i].url_fil);
+                        // totalsize sums attacker-declared chunk sizes; past
+                        // 2GB the (size_t) cast below truncates on 32-bit and
+                        // under-allocates. Mark the chunk invalid so the shared
+                        // error path tears the transfer down.
+                        if (back[i].r.totalsize > INT32_MAX) {
+                          hts_log_print(opt, LOG_WARNING,
+                                        "Chunked resource too large for %s%s",
+                                        back[i].url_adr, back[i].url_fil);
+                          chunk_size = -1;
+                        } else {
+                          back[i].r.adr = (char *) realloct(
+                              back[i].r.adr, (size_t) back[i].r.totalsize + 1);
+                          if (!back[i].r.adr) {
+                            if (cache->log != NULL) {
+                              hts_log_print(opt, LOG_ERROR,
+                                            "not enough memory (" LLintP
+                                            ") for %s%s",
+                                            (LLint) back[i].r.totalsize,
+                                            back[i].url_adr, back[i].url_fil);
+                            }
                           }
                         }
                       }

tests/55_local-chunked.test

@@ -0,0 +1,18 @@
+#!/bin/bash
+# A well-formed Transfer-Encoding: chunked response mirrors intact: the chunk
+# automaton (htsback.c) joins the bodies and the 2GB in-RAM cap stays quiet.
+# The 76-char run spans a 64-byte chunk boundary (only contiguous once joined);
+# a CR anywhere would be leftover framing; '</body>' proves no truncation.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+bash "$top_srcdir/tests/local-crawl.sh" --errors 0 \
+    --found 'chunked/page.html' \
+    --file-matches 'chunked/page.html' \
+    'chunk-body chunk-body chunk-body chunk-body chunk-body chunk-body chunk-body' \
+    --file-matches 'chunked/page.html' '</body>' \
+    --file-not-matches 'chunked/page.html' $'\r' \
+    --log-not-found 'too large' \
+    httrack 'BASEURL/chunked/index.html'

tests/Makefile.am

@@ -131,6 +131,7 @@ TESTS = \
 	51_local-update-codec.test \
 	52_local-socks5.test \
 	53_local-proxytrack-cache-corrupt.test \
-	54_local-update-truncate-purge.test
+	54_local-update-truncate-purge.test \
+	55_local-chunked.test
 
 CLEANFILES = check-network_sh.cache

tests/local-server.py

@@ -1215,6 +1215,28 @@ class Handler(SimpleHTTPRequestHandler):
         if self.command != "HEAD":
             self.wfile.write(body)
 
+    def route_chunked_index(self):
+        self.send_html('\t<a href="page.html">chunked</a>\n')
+
+    def route_chunked_page(self):
+        # Transfer-Encoding: chunked over many small chunks: drives the engine's
+        # chunk automaton (htsback.c). The mirrored file must equal the joined
+        # chunk bodies, so the 2GB in-RAM cap doesn't fire on ordinary traffic.
+        blob = big_html("chunked", "<p>" + "chunk-body " * 300 + "</p>")
+        self.protocol_version = "HTTP/1.1"
+        self.send_response(200)
+        self.send_header("Content-Type", "text/html; charset=utf-8")
+        self.send_header("Transfer-Encoding", "chunked")
+        self.send_header("Connection", "close")
+        self.end_headers()
+        if self.command == "HEAD":
+            return
+        step = 64
+        for off in range(0, len(blob), step):
+            piece = blob[off : off + step]
+            self.wfile.write(b"%X\r\n" % len(piece) + piece + b"\r\n")
+        self.wfile.write(b"0\r\n\r\n")
+
     # Content-Disposition naming: the attachment filename replaces the
     # URL-derived name; path components in it are stripped (RFC 2616).
     CDISPO_NAMES = {
@@ -1554,6 +1576,8 @@ class Handler(SimpleHTTPRequestHandler):
         "/crange206mem/blob.bin": route_crange206mem,
         "/size/index.html": route_size_index,
         "/size/oversize.bin": route_size_oversize,
+        "/chunked/index.html": route_chunked_index,
+        "/chunked/page.html": route_chunked_page,
         "/errpage/index.html": route_errpage_index,
         "/errpage/good.html": route_errpage_good,
         "/errpage/missing.html": route_errpage_missing,