Add libFuzzer harnesses for the HTTP header and cache-index parsers

P3-5 fuzz Tier-2. Two more harnesses over hostile-input parsers that read
structured bytes into fixed buffers: fuzz-header drives treatfirstline plus
treathead on each response-header line (the Content-Type/-Encoding path hardened
in #506, and the cookie/Location/Content-Range fields); fuzz-cachendx drives the
hts-cache/*.ndx length-prefixed scan that cache_readex_new loads on --update.

fuzz-cachendx found the over-advance fixed in the parent commit; its seed corpus
carries the two crash reproducers as replay regressions. The cache harness stops
at the scan rather than the trailing coucal insert, whose murmur hash trips a
separate pointer-overflow the .ndx parser does not own.

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

.github/workflows/codeql.yml

@@ -43,12 +43,6 @@ jobs:
           languages: c-cpp
           build-mode: manual
           queries: security-extended
-          # fopen's umask-controlled 0666 is intended for mirror/cache/log
-          # output; the one credential file (cookies.txt) is kept 0600 on Unix.
-          config: |
-            query-filters:
-              - exclude:
-                  id: cpp/world-writable-file-creation
 
       # Manual build: CodeQL traces the compiler, so build exactly what ships.
       - name: Build

fuzz/fuzz-cachendx.c

@@ -1,7 +1,7 @@
 /* ------------------------------------------------------------ */
 /*
 HTTrack Website Copier, Offline Browser for Windows and Unix
-Copyright (C) 2026 Xavier Roche and other contributors
+Copyright (C) 1998 Xavier Roche and other contributors
 
 SPDX-License-Identifier: GPL-3.0-or-later
 

fuzz/fuzz-header.c

@@ -1,7 +1,7 @@
 /* ------------------------------------------------------------ */
 /*
 HTTrack Website Copier, Offline Browser for Windows and Unix
-Copyright (C) 2026 Xavier Roche and other contributors
+Copyright (C) 1998 Xavier Roche and other contributors
 
 SPDX-License-Identifier: GPL-3.0-or-later
 

src/htsbauth.c

@@ -307,25 +307,14 @@ int cookie_load(t_cookie * cookie, const char *fpath, const char *name) {
   return -1;
 }
 
-/* Write cookies.txt; returns 0 on success. The jar holds live session
-   cookies, so keep it owner-only on Unix (Windows inherits folder ACLs). */
+// écrire cookies.txt
+// !=0 : erreur
 int cookie_save(t_cookie * cookie, const char *name) {
   char catbuff[CATBUFF_SIZE];
 
   if (strnotempty(cookie->data)) {
     char BIGSTK line[8192];
-#ifdef _WIN32
     FILE *fp = fopen(fconv(catbuff, sizeof(catbuff), name), "wb");
-#else
-    const int fd = open(fconv(catbuff, sizeof(catbuff), name),
-                        O_WRONLY | O_CREAT | O_TRUNC, HTS_PROTECT_FILE);
-    FILE *fp = fd != -1 ? fdopen(fd, "wb") : NULL;
-
-    if (fd != -1 && fp == NULL)
-      close(fd);    /* fdopen failed: don't leak the descriptor */
-    if (fp != NULL) /* O_CREAT's mode skips pre-existing jars: tighten those */
-      (void) fchmod(fd, HTS_PROTECT_FILE);
-#endif
 
     if (fp) {
       char *a = cookie->data;

src/htsglobal.h

@@ -422,10 +422,9 @@ typedef int T_SOC;
 #endif
 
 /* Permission bits for created folders and files (mkdir and chmod).
-   PROTECT_FOLDER/FILE are owner-only. With HTS_ACCESS set (the default) the
-   ACCESS_ modes also grant group/other read; otherwise they stay owner-only. */
+   PROTECT_FOLDER is owner-only. With HTS_ACCESS set (the default) the ACCESS_
+   modes also grant group/other read; otherwise they stay owner-only. */
 #define HTS_PROTECT_FOLDER (S_IRUSR | S_IWUSR | S_IXUSR)
-#define HTS_PROTECT_FILE (S_IRUSR | S_IWUSR)
 
 #if HTS_ACCESS
 #define HTS_ACCESS_FILE (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)

src/htsselftest.c

@@ -1551,26 +1551,6 @@ static int st_cookies(httrackp *opt, int argc, char **argv) {
     err = 1;
   if (strstr(hdr, "junk") != NULL) // wrong-domain cookie leaked
     err = 1;
-#ifndef _WIN32
-  /* the jar holds live session cookies: cookie_save must keep it 0600 */
-  {
-    const char *jar = "st-cookies-jar.txt";
-    struct stat st;
-
-    (void) UNLINK(jar);
-    assertf(cookie_save(&cookie, jar) == 0);
-    assertf(stat(jar, &st) == 0);
-    assertf((st.st_mode & 07777) == HTS_PROTECT_FILE);
-    assertf(st.st_size > 0); /* mode-only checks would pass an empty jar */
-    /* a pre-existing world-readable jar must be tightened, not kept */
-    assertf(chmod(jar, 0644) == 0);
-    assertf(cookie_save(&cookie, jar) == 0);
-    assertf(stat(jar, &st) == 0);
-    assertf((st.st_mode & 07777) == HTS_PROTECT_FILE);
-    assertf(st.st_size > 0);
-    (void) UNLINK(jar);
-  }
-#endif
   printf("cookie-header: %s\n", err ? "FAIL" : "OK");
   if (err)
     printf("  got: %s\n", hdr);