Widen the savename self-test and cover Content-Disposition end to end (#477)

* tests: widen the savename self-test and cover Content-Disposition end to end

-#test=savename grows key=value knobs (cdispo=, statuscode=, status=, adr=,
strip=, urlhack= and its negatives, n83=, type=) plus repeatable
prior=adr|fil|sav rows that register an already-crawled link, so the .test
can pin the still-downloading mime path, redirect delayed naming, dedup and
collision suffixing, 8-3 modes, --strip-query dedup and hostile fils
(traversal, control chars, oversized names) - the regression net for the
upcoming resolve_extension work.

A new cdispo/ endpoint in local-server.py and 32_local-cdispo.test give the
Content-Disposition branches their first end-to-end coverage, including a
traversal filename reduced to its last component.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

* review follow-ups: isolate the wire cdispo strip, add over-match negatives

The review found the e2e traversal row masked by two independent layers
(the wire parser and url_savename both strip path components), so a new
-#test=header self-test pins treathead's Content-Disposition parse alone.
Three negative rows keep dedup honest: a kept query key that differs, a
distinct URL under urlhack, and a same-basename-different-directory prior
must all produce a fresh name, not a false match. route_cdispo now reuses
send_raw via an extra_headers argument.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: Xavier Roche <roche@httrack.com>

---------

Signed-off-by: Xavier Roche <roche@httrack.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

src/htsname.c

@@ -167,8 +167,24 @@ static int wire_patches_ext(httrackp *opt, const char *wiremime,
   return 1;
 }
 
-// forme le nom du fichier à sauver (save) à partir de fil et adr
-// système intelligent, qui renomme en cas de besoin (exemple: deux INDEX.HTML et index.html)
+/* Wire-metadata name change: a Content-Disposition filename wins (returns 2),
+   else the declared type's ext when wire_patches_ext() allows (returns 1),
+   else 0. ext receives the new extension or replacement filename. */
+static int resolve_extension(httrackp *opt, const char *cdispo,
+                             const char *contenttype, const char *fil,
+                             char *ext, size_t ext_size) {
+  if (strnotempty(cdispo)) {
+    strlcpybuff(ext, cdispo, ext_size);
+    return 2;
+  }
+  if (wire_patches_ext(opt, contenttype, fil) &&
+      give_mimext(ext, ext_size, contenttype))
+    return 1;
+  return 0;
+}
+
+// Build the local save name (save) from adr/fil; renames on collision
+// (e.g. INDEX.HTML vs index.html).
 int url_savename(lien_adrfilsave *const afs,
                  lien_adrfil *const former,
                  const char *referer_adr, const char *referer_fil, 
@@ -405,45 +421,23 @@ int url_savename(lien_adrfilsave *const afs,
 
   // si option check_type activée
   if (is_html < 0 && opt->check_type && !ext_chg) {
-    int ishtest = 0;
-
     if (protocol != PROTOCOL_FILE
         && protocol != PROTOCOL_FTP
       ) {
       // tester type avec requète HEAD si on ne connait pas le type du fichier
       if (!((opt->check_type == 1) && (fil[strlen(fil) - 1] == '/')))   // slash doit être html?
         if (opt->savename_delayed == HTS_SAVENAME_DELAYED_HARD ||
-            (ishtest = ishtml(opt, fil)) <
-                0) { // unsure whether it's html or a file
+            ishtml(opt, fil) < 0) { // unsure whether it's html or a file
           // lire dans le cache
           htsblk r = cache_read_including_broken(opt, cache, adr, fil); // test uniquement
 
-          if (r.statuscode != -1) {     // pas d'erreur de lecture cache
-            char s[32];
-
-            s[0] = '\0';
+          if (r.statuscode != -1) { // cache entry read OK
             hts_log_print(opt, LOG_DEBUG, "Testing link type (from cache) %s%s",
                           adr_complete, fil_complete);
             if (!HTTP_IS_REDIRECT(r.statuscode)) {
-              if (strnotempty(r.cdispo)) {        /* filename given */
-                ext_chg = 2;      /* change filename */
-                strcpybuff(ext, r.cdispo);
-              } else if (wire_patches_ext(opt, r.contenttype, fil)) {
-                if (give_mimext(s, sizeof(s),
-                                r.contenttype)) { // recognized extension
-                  ext_chg = 1;
-                  strcpybuff(ext, s);
-                }
-              }
+              ext_chg = resolve_extension(opt, r.cdispo, r.contenttype, fil,
+                                          ext, sizeof(ext));
             }
-#ifdef DEFAULT_BIN_EXT
-            // no extension and potentially bogus
-            else if (ishtest == -2) {
-              ext_chg = 1;
-              strcpybuff(ext, DEFAULT_BIN_EXT + 1);
-            }
-#endif
-            //
           } else if (opt->savename_delayed != HTS_SAVENAME_DELAYED_HARD &&
                      is_userknowntype(opt, fil)) { /* PATCH BY BRIAN SCHRÖDER.
                               Lookup mimetype not only by extension,
@@ -467,22 +461,11 @@ int url_savename(lien_adrfilsave *const afs,
           // fail later
           else if (opt->savename_delayed != HTS_SAVENAME_DELAYED_NONE &&
                    !opt->state.stop) {
-            // Check if the file is ready in backing. We basically take the same logic as later.
-            // FIXME: we should cleanup and factorize this unholy mess
+            // Check if the file is ready in backing.
             if (headers != NULL && headers->status >= 0 && !is_redirect) {
-              if (strnotempty(headers->r.cdispo)) {        /* filename given */
-                ext_chg = 2;      /* change filename */
-                strcpybuff(ext, headers->r.cdispo);
-              } else if (wire_patches_ext(opt, headers->r.contenttype,
-                                          headers->url_fil)) {
-                char s[16];
-                if (give_mimext(
-                        s, sizeof(s),
-                        headers->r.contenttype)) { // recognized extension
-                  ext_chg = 1;
-                  strcpybuff(ext, s);
-                }
-              }
+              ext_chg = resolve_extension(opt, headers->r.cdispo,
+                                          headers->r.contenttype,
+                                          headers->url_fil, ext, sizeof(ext));
             }
             else if (mime_type != NULL) {
               ext[0] = '\0';
@@ -500,13 +483,6 @@ int url_savename(lien_adrfilsave *const afs,
                   if (!may_unknown2(opt, mime_type, fil)) {
                     ext_chg = 1;
                   }
-#ifdef DEFAULT_BIN_EXT
-                  // no extension and potentially bogus
-                  else if (ishtml(opt, fil) == -2) {
-                    ext_chg = 1;
-                    strcpybuff(ext, DEFAULT_BIN_EXT + 1);
-                  }
-#endif
                 } else {
                   ext_chg = 0;
                 }
@@ -696,30 +672,10 @@ int url_savename(lien_adrfilsave *const afs,
                     // libérer emplacement backing
                   }
 
-                  {             // pas d'erreur, changer type?
-                    char s[16];
-
-                    s[0] = '\0';
-                    if (strnotempty(back[b].r.cdispo)) {        /* filename given */
-                      ext_chg = 2;      /* change filename */
-                      strcpybuff(ext, back[b].r.cdispo);
-                    } else if (wire_patches_ext(opt, back[b].r.contenttype,
-                                                back[b].url_fil)) {
-                      if (give_mimext(
-                              s, sizeof(s),
-                              back[b].r.contenttype)) { // recognized extension
-                        ext_chg = 1;
-                        strcpybuff(ext, s);
-                      }
-                    }
-#ifdef DEFAULT_BIN_EXT
-                    // no extension and potentially bogus
-                    else if (ishtest == -2) {
-                      ext_chg = 1;
-                      strcpybuff(ext, DEFAULT_BIN_EXT + 1);
-                    }
-#endif
-                  }
+                  // no error: change the type?
+                  ext_chg = resolve_extension(
+                      opt, back[b].r.cdispo, back[b].r.contenttype,
+                      back[b].url_fil, ext, sizeof(ext));
                 }
                 // FIN Si non déplacé, forcer type?
 

src/htsselftest.c

@@ -1093,31 +1093,113 @@ static int st_resolve(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+/* Extra args are key=value: adr= cdispo= statuscode= status= strip= urlhack=
+   no-www= no-slash= no-query= n83= type=, plus repeatable prior=adr|fil|sav
+   registering an already-crawled link (dedup/collision paths). */
+/* Parse raw response-header lines and print the naming-relevant fields. */
+static int st_header(httrackp *opt, int argc, char **argv) {
+  htsblk r;
+  int i;
+
+  (void) opt;
+  if (argc < 1) {
+    fprintf(stderr, "header: needs at least one raw header line\n");
+    return 1;
+  }
+  memset(&r, 0, sizeof(r));
+  for (i = 0; i < argc; i++) {
+    char BIGSTK line[HTS_URLMAXSIZE * 2];
+
+    strcpybuff(line, argv[i]);
+    treathead(NULL, "www.example.com", "/", &r, line);
+  }
+  printf("contenttype=%s cdispo=%s\n", r.contenttype, r.cdispo);
+  return 0;
+}
+
 static int st_savename(httrackp *opt, int argc, char **argv) {
   lien_adrfilsave afs;
   cache_back cache;
   struct_back *sback;
   hash_struct hash;
   lien_back headers;
+  const char *adr = "www.example.com";
+  const char *cdispo = NULL;
+  int statuscode = HTTP_OK, status = 0;
+  int i;
 
   if (argc < 2) {
     fprintf(stderr, "savename: needs a fil and a content-type\n");
     return 1;
   }
+  /* knobs first: hash_init and the prior links depend on them */
+  for (i = 2; i < argc; i++) {
+    const char *const a = argv[i];
+
+    if (strncmp(a, "adr=", 4) == 0)
+      adr = a + 4;
+    else if (strncmp(a, "cdispo=", 7) == 0)
+      cdispo = a + 7;
+    else if (strncmp(a, "statuscode=", 11) == 0)
+      statuscode = atoi(a + 11);
+    else if (strncmp(a, "status=", 7) == 0)
+      status = atoi(a + 7);
+    else if (strncmp(a, "strip=", 6) == 0)
+      StringCopy(opt->strip_query, a + 6);
+    else if (strncmp(a, "urlhack=", 8) == 0)
+      opt->urlhack = atoi(a + 8) ? HTS_TRUE : HTS_FALSE;
+    else if (strncmp(a, "no-www=", 7) == 0)
+      opt->no_www_dedup = atoi(a + 7) ? HTS_TRUE : HTS_FALSE;
+    else if (strncmp(a, "no-slash=", 9) == 0)
+      opt->no_slash_dedup = atoi(a + 9) ? HTS_TRUE : HTS_FALSE;
+    else if (strncmp(a, "no-query=", 9) == 0)
+      opt->no_query_dedup = atoi(a + 9) ? HTS_TRUE : HTS_FALSE;
+    else if (strncmp(a, "n83=", 4) == 0)
+      opt->savename_83 = atoi(a + 4);
+    else if (strncmp(a, "type=", 5) == 0)
+      opt->savename_type = atoi(a + 5);
+    else if (strncmp(a, "prior=", 6) != 0) {
+      fprintf(stderr, "savename: unknown arg '%s'\n", a);
+      return 1;
+    }
+  }
   memset(&afs, 0, sizeof(afs));
-  strcpybuff(afs.af.adr, "www.example.com");
+  strcpybuff(afs.af.adr, adr);
   strcpybuff(afs.af.fil, argv[0]);
 
   memset(&cache, 0, sizeof(cache));
   cache.hashtable = (void *) coucal_new(0);
 
   sback = back_new(opt, opt->maxsoc * 32 + 1024);
+  /* same wiring as hts_mirror (htscore.c) */
   hash_init(opt, &hash, opt->urlhack);
+  hash.liens = (const lien_url *const *const *) &opt->liens;
+  opt->hash = &hash;
+  hts_record_init(opt);
+
+  for (i = 2; i < argc; i++) {
+    if (strncmp(argv[i], "prior=", 6) == 0) {
+      char *dup = strdupt(argv[i] + 6);
+      char *const p1 = strchr(dup, '|');
+      char *const p2 = p1 != NULL ? strchr(p1 + 1, '|') : NULL;
+
+      if (p2 == NULL) {
+        fprintf(stderr, "savename: prior needs adr|fil|sav\n");
+        return 1;
+      }
+      *p1 = *p2 = '\0';
+      if (!hts_record_link(opt, dup, p1 + 1, p2 + 1, "", "", NULL))
+        return 1;
+      freet(dup);
+    }
+  }
 
   memset(&headers, 0, sizeof(headers));
-  headers.status = 0;
-  headers.r.statuscode = HTTP_OK;
+  headers.status = status;
+  headers.r.statuscode = statuscode;
   strcpybuff(headers.r.contenttype, argv[1]);
+  if (cdispo != NULL)
+    strcpybuff(headers.r.cdispo, cdispo);
   strcpybuff(headers.url_fil, argv[0]);
 
   url_savename(&afs, NULL, NULL, NULL, opt, sback, &cache, &hash, 0, 0,
@@ -1924,8 +2006,10 @@ static const struct selftest_entry {
      st_relative},
     {"resolve", "<link> <adr> <fil>", "resolve a link against an origin",
      st_resolve},
-    {"savename", "<fil> <content-type>", "local save-name for a URL",
-     st_savename},
+    {"header", "<raw-header-line> ...", "response header-line parsing",
+     st_header},
+    {"savename", "<fil> <content-type> [key=value ...]",
+     "local save-name for a URL", st_savename},
     {"cache", "<dir>", "cache read/write round-trip self-test", st_cache},
     {"cache-golden", "<dir> [regen]", "frozen cache-format read self-test",
      st_cache_golden},

tests/01_engine-header.test

@@ -0,0 +1,29 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# Response header-line parsing (treathead via -#test=header <raw-line> ...).
+# Isolates the wire layer from url_savename, which strips traversal on its own.
+
+hdr() {
+    local want="$1"
+    shift
+    out="$(httrack -O /dev/null -#test=header "$@" | grep '^contenttype=')"
+    test "$out" == "$want" || {
+        echo "FAIL: $* -> '$out' (want '$want')"
+        exit 1
+    }
+}
+
+hdr 'contenttype=application/pdf cdispo=' 'Content-Type: application/pdf'
+
+# filename= is honored quoted or bare.
+hdr 'contenttype= cdispo=report.pdf' \
+    'Content-Disposition: attachment; filename="report.pdf"'
+hdr 'contenttype= cdispo=report.pdf' \
+    'Content-Disposition: attachment; filename=report.pdf'
+
+# Path components in the filename are dropped on the wire (RFC 2616).
+hdr 'contenttype= cdispo=evil.pdf' \
+    'Content-Disposition: attachment; filename="../../evil.pdf"'

tests/01_engine-savename.test

@@ -3,13 +3,30 @@
 
 set -euo pipefail
 
-# Local save-name extension resolution (url_savename via -#test=savename <fil> <content-type>).
-# Asserts on the basename of "savename: <path>".
+# Local save-name resolution (url_savename via -#test=savename <fil> <content-type> [key=value ...]).
+# name() asserts on the basename, full() on the whole path; prior= registers an
+# already-crawled link whose sav is rooted under the -O path (/dev/null here).
+
+run() {
+    httrack -O /dev/null -#test=savename "$@" | sed -n 's/^savename: //p'
+}
 
 name() {
-    out="$(httrack -O /dev/null -#test=savename "$1" "$2" | sed -n 's/^savename: //p')"
-    test "${out##*/}" == "$3" || {
-        echo "FAIL: '$1' '$2' -> '$out' (want '$3')"
+    local fil="$1" ctype="$2" want="$3"
+    shift 3
+    out="$(run "$fil" "$ctype" "$@")"
+    test "${out##*/}" == "$want" || {
+        echo "FAIL: '$fil' '$ctype' $* -> '$out' (want '$want')"
+        exit 1
+    }
+}
+
+full() {
+    local fil="$1" ctype="$2" want="$3"
+    shift 3
+    out="$(run "$fil" "$ctype" "$@")"
+    test "$out" == "$want" || {
+        echo "FAIL: '$fil' '$ctype' $* -> '$out' (want '$want')"
         exit 1
     }
 }
@@ -39,3 +56,86 @@ name '/types/data.json' 'application/json' 'data.json'
 
 # Agreeing type must not rewrite the extension's casing (no strip-and-reappend).
 name '/x.JPG' 'image/jpeg' 'x.JPG'
+
+# A Content-Disposition filename replaces the URL name outright.
+name '/x.php' 'application/pdf' 'report.pdf' cdispo=report.pdf
+name '/download' 'text/html' 'setup.exe' cdispo=setup.exe
+
+# Reserved characters in a hostile Content-Disposition name are sanitized.
+name '/x.php' 'application/pdf' 'set_up.exe' 'cdispo=set:up.exe'
+
+# The md5-of-query suffix lands inside a Content-Disposition name too.
+name '/x.php?id=1' 'application/pdf' 'report681a.pdf' cdispo=report.pdf
+
+# Still-downloading path (status=-1): mime drives the ext, cdispo is ignored
+# there (the deliberately unfolded 4th resolve_extension variant).
+name '/x.pdf' 'text/html' 'x.html' status=-1
+name '/x.html' 'text/html' 'x.html' status=-1
+name '/x.php' 'application/pdf' 'x.pdf' status=-1 cdispo=report.pdf
+
+# A redirect answer resolves nothing: delayed placeholder name.
+name '/x.php' 'text/html' 'x.0.delayed' statuscode=301
+
+# Root and query-only URLs get index + the md5-of-query suffix.
+name '/' 'text/html' 'index.html'
+name '/?a=1' 'text/html' 'index3872.html'
+
+# Same URL crawled before: reuse its sav verbatim (case preserved).
+full '/X.PHP' 'text/html' 'www.example.com/CASE.HTML' \
+    'prior=www.example.com|/X.PHP|www.example.com/CASE.HTML'
+
+# Another URL owns the name: collision suffix -2, then -3, case-insensitively.
+name '/x.php' 'text/html' 'x-2.html' \
+    'prior=www.example.com|/other.html|/dev/null/www.example.com/x.html'
+name '/x.php' 'text/html' 'x-3.html' \
+    'prior=www.example.com|/o1.html|/dev/null/www.example.com/x.html' \
+    'prior=www.example.com|/o2.html|/dev/null/www.example.com/x-2.html'
+name '/INDEX.HTML' 'text/html' 'INDEX-2.HTML' \
+    'prior=www.example.com|/index.html|/dev/null/www.example.com/index.html'
+
+# Same basename in another directory is NOT a collision.
+name '/x.php' 'text/html' 'x.html' \
+    'prior=www.example.com|/sub/x.html|/dev/null/www.example.com/sub/x.html'
+
+# 8-3 modes: DOS truncates every component to 8+3, ISO9660 level 2 to 31.
+full '/directory-long/verylongfilename.html' 'text/html' \
+    '/dev/null/EXAMPLE/DIRECTOR/VERYLONG.HTM' n83=1
+full '/directory-long/verylongfilename.html' 'text/html' \
+    '/dev/null/EXAMPLE_C/DIRECTORY_LONG/VERYLONGFILENAME.HTM' n83=2
+name '/verylongfilename.php' 'text/html' 'VERYLO-2.HTM' n83=1 \
+    'prior=www.example.com|/other.html|/dev/null/EXAMPLE/VERYLONG.HTM'
+
+# urlhack dedup (#271): // collapse and www-strip map to the prior link's sav;
+# the per-feature negatives opt out and take a fresh name.
+full '/a//b.php' 'text/html' '/dev/null/www.example.com/a/PRIOR.html' \
+    'prior=www.example.com|/a/b.php|/dev/null/www.example.com/a/PRIOR.html'
+full '/a//b.php' 'text/html' '/dev/null/www.example.com/a/b.html' no-slash=1 \
+    'prior=www.example.com|/a/b.php|/dev/null/www.example.com/a/PRIOR.html'
+full '/w.php' 'text/html' '/dev/null/www.example.com/W-PRIOR.html' adr=example.com \
+    'prior=www.example.com|/w.php|/dev/null/www.example.com/W-PRIOR.html'
+full '/w.php' 'text/html' '/dev/null/example.com/w.html' adr=example.com no-www=1 \
+    'prior=www.example.com|/w.php|/dev/null/www.example.com/W-PRIOR.html'
+
+# Distinct URLs must stay distinct under urlhack (no over-normalization).
+full '/a//b.php' 'text/html' '/dev/null/www.example.com/a/b.html' \
+    'prior=www.example.com|/a/c.php|/dev/null/www.example.com/a/C-PRIOR.html'
+
+# --strip-query (#112): stripped key dedups onto the prior sav; without the
+# option the same URLs stay distinct.
+full '/page.php?id=3&sid=42' 'text/html' '/dev/null/www.example.com/PAGE-PRIOR.html' \
+    strip=sid 'prior=www.example.com|/page.php?id=3|/dev/null/www.example.com/PAGE-PRIOR.html'
+full '/page.php?id=3&sid=42' 'text/html' '/dev/null/www.example.com/page475b.html' \
+    'prior=www.example.com|/page.php?id=3|/dev/null/www.example.com/PAGE-PRIOR.html'
+
+# A kept key that differs must still block the dedup (no over-stripping).
+full '/page.php?id=3&sid=42' 'text/html' '/dev/null/www.example.com/page475b.html' \
+    strip=sid 'prior=www.example.com|/page.php?id=4|/dev/null/www.example.com/PAGE-PRIOR.html'
+
+# Hostile fils stay rooted under the mirror: ../ (raw or %2e-encoded) drops out,
+# control characters become spaces, oversized names cap at 210 chars (the cap
+# can chop the extension off entirely).
+full '/../../etc/passwd' 'text/html' '/dev/null/www.example.com///etc/passwd.html'
+full '/%2e%2e/%2e%2e/etc/passwd' 'text/html' '/dev/null/www.example.com///etc/passwd.html'
+full '/x.php' 'application/pdf' '/dev/null/www.example.com///evil.exe' 'cdispo=../../evil.exe'
+name $'/evil\rname\t.php' 'text/html' 'evil name .html'
+name "/$(printf 'a%.0s' {1..300}).php" 'text/html' "$(printf 'a%.0s' {1..210})"

tests/32_local-cdispo.test

@@ -0,0 +1,17 @@
+#!/bin/bash
+#
+# Content-Disposition names the saved file: the attachment filename replaces
+# the URL-derived name, and a traversal filename is reduced to its last
+# component, inside the mirror.
+
+set -euo pipefail
+
+: "${top_srcdir:=..}"
+
+bash "$top_srcdir/tests/local-crawl.sh" --errors 0 \
+    --found 'cdispo/report.pdf' \
+    --file-matches 'cdispo/report.pdf' '%PDF' \
+    --not-found 'cdispo/fetch.pdf' \
+    --found 'cdispo/evil.pdf' \
+    --not-found 'evil.pdf' \
+    httrack 'BASEURL/cdispo/index.html'

tests/Makefile.am

@@ -38,6 +38,7 @@ TESTS = \
 	01_engine-ftp-line.test \
 	01_engine-ftp-userpass.test \
 	01_engine-hashtable.test \
+	01_engine-header.test \
 	01_engine-idna.test \
 	01_engine-escape-room.test \
 	01_engine-inplace-escape.test \
@@ -91,6 +92,7 @@ TESTS = \
 	28_local-pause.test \
 	29_local-redirect-fragment.test \
 	30_local-fragment-link.test \
-	31_local-javaclass.test
+	31_local-javaclass.test \
+	32_local-cdispo.test
 
 CLEANFILES = check-network_sh.cache

tests/local-server.py

@@ -134,12 +134,14 @@ class Handler(SimpleHTTPRequestHandler):
 
     # --- type/extension matrix (issue #267 family) -------------------------
 
-    def send_raw(self, body, content_type):
+    def send_raw(self, body, content_type, extra_headers=()):
         """Send a raw body with an explicit Content-Type, or none at all when
         content_type is None (to observe httrack's typeless-file naming)."""
         self.send_response(200)
         if content_type is not None:
             self.send_header("Content-Type", content_type)
+        for name, value in extra_headers:
+            self.send_header(name, value)
         self.send_header("Content-Length", str(len(body)))
         self.end_headers()
         if self.command != "HEAD":
@@ -354,6 +356,27 @@ class Handler(SimpleHTTPRequestHandler):
         if self.command != "HEAD":
             self.wfile.write(body)
 
+    # Content-Disposition naming: the attachment filename replaces the
+    # URL-derived name; path components in it are stripped (RFC 2616).
+    CDISPO_NAMES = {
+        "/cdispo/fetch.php": "report.pdf",
+        "/cdispo/evil.php": "../../evil.pdf",
+    }
+
+    def route_cdispo_index(self):
+        self.send_html(
+            '\t<a href="fetch.php">report</a>\n' '\t<a href="evil.php">evil</a>\n'
+        )
+
+    def route_cdispo(self):
+        filename = self.CDISPO_NAMES[urlsplit(self.path).path]
+        cdispo = 'attachment; filename="%s"' % filename
+        self.send_raw(
+            self.FAKE_PDF,
+            "application/pdf",
+            extra_headers=[("Content-Disposition", cdispo)],
+        )
+
     # 302 whose Location carries a #fragment (#204): the fragment is a UA anchor
     # that must be dropped before the target is fetched. A leaked '#' reaches the
     # strict-server guard below and 400s.
@@ -406,6 +429,9 @@ class Handler(SimpleHTTPRequestHandler):
         "/mimex/index.html": route_mimex_index,
         "/mimex/blob.pdf": route_mimex_blob,
         "/mimex/real.html": route_mimex_real,
+        "/cdispo/index.html": route_cdispo_index,
+        "/cdispo/fetch.php": route_cdispo,
+        "/cdispo/evil.php": route_cdispo,
         "/redir/index.html": route_redir_index,
         "/redir/go.php": route_redir_go,
         "/redir/target.html": route_redir_target,