Fix three network-facing overflows in the FTP and Java parsers

get_ftp_line() copied a server reply byte-by-byte into a fixed char[1024]
with no index bound, so a hostile or MITM FTP server could smash the stack
with an over-long CRLF-less line. Bound the write and truncate.

The ftp:// userinfo parser copied "user:pass@" into user[256]/pass[256] with
two unbounded loops, overflowing from a long userinfo supplied by a hostile
ftp:// link. Extract the split into ftp_split_userpass(), which truncates
each field to fit.

The Java .class parser did calloc(header.count, sizeof(RESP_STRUCT)) on an
attacker-controlled u2 count, allocating ~68 MB per crafted class (DoS). Cap
the count to the file size (each constant-pool entry is at least one byte on
disk) via a new hts_count_fits() guard, and move the alloc/free to the
bounds-checked calloct/freet wrappers.

Self-tests: ftp-line drives get_ftp_line over a socketpair with a 4 KB reply,
ftp-userpass feeds an over-long userinfo, java exercises the count cap. The
first two abort under ASan on the pre-fix code.

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

debian/control

@@ -1,9 +1,8 @@
 Source: httrack
 Section: web
-Priority: optional
 Maintainer: Xavier Roche <roche@httrack.com>
 Standards-Version: 4.7.4
-Build-Depends: debhelper-compat (= 13), autoconf, autoconf-archive, automake, libtool, zlib1g-dev, libssl-dev
+Build-Depends: debhelper-compat (= 14), autoconf, autoconf-archive, automake, libtool, zlib1g-dev, libssl-dev
 Rules-Requires-Root: no
 Homepage: http://www.httrack.com
 Vcs-Git: https://github.com/xroche/httrack.git

debian/source/lintian-overrides

@@ -1,4 +1,6 @@
-httrack source: changelog-should-mention-nmu
+# Maintainer uploads sign the changelog as xavier@debian.org while the control
+# Maintainer is roche@httrack.com; lintian reads the address mismatch as an NMU.
+httrack source: no-nmu-in-changelog
 httrack source: source-nmu-has-incorrect-version-number
 
 # The bundled HTML pages are the genuine upstream documentation taken from

debian/upstream/metadata

@@ -0,0 +1,6 @@
+---
+Repository: https://github.com/xroche/httrack.git
+Repository-Browse: https://github.com/xroche/httrack
+Bug-Database: https://github.com/xroche/httrack/issues
+Bug-Submit: https://github.com/xroche/httrack/issues/new
+Contact: Xavier Roche <roche@httrack.com>

src/htscore.c

@@ -441,6 +441,72 @@ void hts_finish_makeindex(httrackp *opt, int *makeindex_done,
   *makeindex_done = 1;
 }
 
+/* Flush the parsed HTML output buffer to disk, skipping the rewrite when the
+ * on-disk MD5 is unchanged. */
+void hts_finish_html_file(httrackp *opt, cache_back *cache, htsblk *r,
+                          FILE **fp, const char *ht_buff, size_t ht_len,
+                          const char *adr, const char *fil, const char *save) {
+  char digest[32 + 2];
+  off_t fsize_old =
+      fsize(fconv(OPT_GET_BUFF(opt), OPT_GET_BUFF_SIZE(opt), save));
+  int ok = 0;
+
+  digest[0] = '\0';
+  domd5mem(ht_buff, ht_len, digest, 1);
+  if (fsize_old == (off_t) ht_len) {
+    int mlen = 0;
+    char *mbuff;
+
+    cache_readdata(cache, "//[HTML-MD5]//", save, &mbuff, &mlen);
+    if (mlen)
+      mbuff[mlen] = '\0';
+    if ((mlen == 32) && (strcmp(((mbuff != NULL) ? mbuff : ""), digest) == 0)) {
+      ok = 1;
+      hts_log_print(opt, LOG_DEBUG, "File not re-written (md5): %s", save);
+    }
+    freet(mbuff);
+  }
+  if (!ok) {
+    file_notify(opt, adr, fil, save, 1, 1, r->notmodified);
+    *fp = filecreate(&opt->state.strc, save);
+    if (*fp) {
+      if (ht_len > 0 && fwrite(ht_buff, 1, ht_len, *fp) != ht_len) {
+        int fcheck = check_fatal_io_errno();
+
+        if (fcheck)
+          opt->state.exit_xh = -1;
+        if (opt->log) {
+          hts_log_print(opt, LOG_ERROR | LOG_ERRNO,
+                        "Unable to write HTML file %s", save);
+          if (fcheck)
+            hts_log_print(opt, LOG_ERROR, "* * Fatal write error, giving up");
+        }
+      }
+      fclose(*fp);
+      *fp = NULL;
+      if (strnotempty(r->lastmodified))
+        set_filetime_rfc822(save, r->lastmodified);
+    } else {
+      int fcheck = check_fatal_io_errno();
+
+      if (fcheck) {
+        hts_log_print(opt, LOG_ERROR,
+                      "Mirror aborted: disk full or filesystem problems");
+        opt->state.exit_xh = -1;
+      }
+      hts_log_print(opt, LOG_ERROR | LOG_ERRNO, "Unable to save file %s", save);
+      if (fcheck)
+        hts_log_print(opt, LOG_ERROR, "* * Fatal write error, giving up");
+    }
+  } else {
+    file_notify(opt, adr, fil, save, 0, 0, r->notmodified);
+    filenote(&opt->state.strc, save, NULL);
+  }
+  if (cache->ndx)
+    cache_writedata(cache->ndx, cache->dat, "//[HTML-MD5]//", save, digest,
+                    (int) strlen(digest));
+}
+
 /* does it look like XML ? (SVG et al.) */
 static int look_like_xml(const char *s) {
   return strncmp(s, "<?xml", 5) == 0

src/htscore.h

@@ -370,6 +370,12 @@ void hts_finish_makeindex(httrackp *opt, int *makeindex_done,
                           const char *template_footer, const char *adr,
                           const char *fil);
 
+// Flush ht_buff[0..ht_len] to save on disk (skip if MD5 unchanged); *fp
+// closed+NULLed on write. Precondition: ht_len>0.
+void hts_finish_html_file(httrackp *opt, cache_back *cache, htsblk *r,
+                          FILE **fp, const char *ht_buff, size_t ht_len,
+                          const char *adr, const char *fil, const char *save);
+
 int filters_init(char ***ptrfilters, int maxfilter, int filterinc);
 
 int fspc(httrackp * opt, FILE * fp, const char *type);
@@ -478,4 +484,8 @@ void voidf(void);
 /* HTML marker comment marking where the top index is spliced. */
 #define HTS_TOPINDEX "TOP_INDEX_HTTRACK"
 
+/* Worst-case byte expansion HT_ADD_HTMLESCAPED* must reserve per escaper. */
+#define HTS_HTMLESCAPE_MAXEXP 5      /* escape_for_html_print: '&'->"&" */
+#define HTS_HTMLESCAPE_FULL_MAXEXP 6 /* _full: high byte->"&#xHH;" */
+
 #endif

src/htsftp.c

@@ -128,6 +128,31 @@ void launch_ftp(FTPDownloadStruct * params) {
   return 0; \
   }
 
+/* Bounded split of a hostile-URL "user[:pass]@" prefix (see htsftp.h). */
+void ftp_split_userpass(const char *src, const char *end, char *user,
+                        size_t user_size, char *pass, size_t pass_size) {
+  size_t n = 0;
+
+  while (src[n] != '\0' && src[n] != ':') {
+    if (n < user_size - 1)
+      user[n] = src[n];
+    n++;
+  }
+  user[n < user_size ? n : user_size - 1] = '\0';
+  pass[0] = '\0';
+  if (src[n] == ':') { // password follows the colon
+    const size_t base = n + 1;
+    size_t k = 0;
+
+    while (&src[base + k + 1] < end && src[base + k] != '\0') {
+      if (k < pass_size - 1)
+        pass[k] = src[base + k];
+      k++;
+    }
+    pass[k < pass_size ? k : pass_size - 1] = '\0';
+  }
+}
+
 // la véritable fonction une fois lancées les routines thread/fork
 int run_launch_ftp(FTPDownloadStruct * pStruct) {
   lien_back *back = pStruct->pBack;
@@ -173,24 +198,7 @@ int run_launch_ftp(FTPDownloadStruct * pStruct) {
   while(*real_adr == '/')
     real_adr++;                 // sauter /
   if ((adr = jump_identification(real_adr)) != real_adr) {      // user
-    int i = -1;
-
-    pass[0] = '\0';
-    do {
-      i++;
-      user[i] = real_adr[i];
-    } while((real_adr[i] != ':') && (real_adr[i]));
-    user[i] = '\0';
-    if (real_adr[i] == ':') {   // pass
-      int j = -1;
-
-      i++;                      // oui on saute aussi le :
-      do {
-        j++;
-        pass[j] = real_adr[i + j];
-      } while(((&real_adr[i + j + 1]) < adr) && (real_adr[i + j]));
-      pass[j] = '\0';
-    }
+    ftp_split_userpass(real_adr, adr, user, sizeof(user), pass, sizeof(pass));
   }
   // Calculer RETR <nom>
   {
@@ -984,8 +992,8 @@ int get_ftp_line(T_SOC soc, char *ptrline, size_t line_size, int timeout) {
       //case 0: break;    // pas encore --> erreur (on attend)!
     case 1:
       HTS_STAT.HTS_TOTAL_RECV += 1;     // compter flux entrant
-      if ((b != 10) && (b != 13))
-        data[i++] = b;
+      if ((b != 10) && (b != 13) && (i < (int) sizeof(data) - 1))
+        data[i++] = b; // truncate hostile over-long reply lines
       break;
     default:
       if (ptrline)

src/htsftp.h

@@ -70,6 +70,10 @@ int back_launch_ftp(FTPDownloadStruct * params);
 int run_launch_ftp(FTPDownloadStruct * params);
 int send_line(T_SOC soc, const char *data);
 int get_ftp_line(T_SOC soc, char *line, size_t line_size, int timeout);
+/* Split a "user[:pass]@" prefix (end = jump_identification result) into
+   bounded, NUL-terminated user/pass buffers, truncating to fit. */
+void ftp_split_userpass(const char *src, const char *end, char *user,
+                        size_t user_size, char *pass, size_t pass_size);
 T_SOC get_datasocket(char *to_send, size_t to_send_size);
 int stop_ftp(lien_back * back);
 char *linejmp(char *line);

src/htsjava.c

@@ -63,6 +63,9 @@ Please visit our Website: http://www.httrack.com
 /* This file */
 #include "htsjava.h"
 
+/* calloct/freet wrappers */
+#include "htssafe.h"
+
 static int reverse_endian(void) {
   int endian = 1;
 
@@ -204,7 +207,16 @@ static int hts_parse_java(t_hts_callbackarg * carg, httrackp * opt,
         return 0;
       }
 
-      tab = (RESP_STRUCT *) calloc(header.count, sizeof(RESP_STRUCT));
+      /* A constant-pool entry is >= 1 byte on disk; reject a count exceeding
+         the file size (hostile .class ~68 MB alloc DoS). */
+      if (!hts_count_fits(header.count, (LLint) fsize(file))) {
+        fclose(fpout);
+        sprintf(str->err_msg,
+                "Invalid constant pool count %u (file len " LLintP ")",
+                (unsigned) header.count, (LLint) fsize(file));
+        return 0;
+      }
+      tab = (RESP_STRUCT *) calloct(header.count, sizeof(RESP_STRUCT));
       if (!tab) {
         sprintf(str->err_msg, "Unable to alloc %d bytes",
                 (int) sizeof(RESP_STRUCT));
@@ -230,7 +242,7 @@ static int hts_parse_java(t_hts_callbackarg * carg, httrackp * opt,
           } else {              // ++ une erreur est survenue!
             if (strnotempty(str->err_msg) == 0)
               strcpy(str->err_msg, "Internal readtable error");
-            free(tab);
+            freet(tab);
             if (fpout) {
               fclose(fpout);
               fpout = NULL;
@@ -288,7 +300,7 @@ static int hts_parse_java(t_hts_callbackarg * carg, httrackp * opt,
 #if JAVADEBUG
       printf("end\n");
 #endif
-      free(tab);
+      freet(tab);
       if (fpout) {
         fclose(fpout);
         fpout = NULL;

src/htslib.c

@@ -4131,25 +4131,33 @@ DECLARE_APPEND_ESCAPE_VERSION(escape_uri)
 
 #undef DECLARE_APPEND_ESCAPE_VERSION
 
-// Same as above, but in-place
-#undef DECLARE_INPLACE_ESCAPE_VERSION
-#define DECLARE_INPLACE_ESCAPE_VERSION(NAME) \
-HTSEXT_API size_t inplace_ ##NAME(char *const dest, const size_t size) { \
-  char buffer[256]; \
-  const size_t len = strnlen(dest, size); \
-  const int in_buffer = len + 1 < sizeof(buffer); \
-  char *src = in_buffer ? buffer : malloct(len + 1); \
-  size_t ret; \
-  assertf(src != NULL); \
-  assertf(len < size); \
-  memcpy(src, dest, len + 1); \
-  ret = NAME(src, dest, size); \
-  if (!in_buffer) { \
-    freet(src); \
-  } \
-  return ret; \
+// In-place escaping: copy dest aside, then escape that copy back into dest.
+typedef size_t (*escape_fn_t)(const char *src, char *dest, size_t size);
+
+static size_t inplace_escape(char *const dest, const size_t size,
+                             escape_fn_t escape) {
+  char buffer[256];
+  const size_t len = strnlen(dest, size);
+  const int in_buffer = len + 1 < sizeof(buffer);
+  char *src = in_buffer ? buffer : malloct(len + 1);
+  size_t ret;
+  assertf(src != NULL);
+  assertf(len < size);
+  memcpy(src, dest, len + 1);
+  ret = escape(src, dest, size);
+  if (!in_buffer) {
+    freet(src);
+  }
+  return ret;
 }
 
+// Thin exported wrappers binding inplace_escape() to each escaper (ABI).
+#undef DECLARE_INPLACE_ESCAPE_VERSION
+#define DECLARE_INPLACE_ESCAPE_VERSION(NAME)                                   \
+  HTSEXT_API size_t inplace_##NAME(char *const dest, const size_t size) {      \
+    return inplace_escape(dest, size, NAME);                                   \
+  }
+
 DECLARE_INPLACE_ESCAPE_VERSION(escape_in_url)
 DECLARE_INPLACE_ESCAPE_VERSION(escape_spc_url)
 DECLARE_INPLACE_ESCAPE_VERSION(escape_uri_utf)

src/htsparse.c

@@ -77,13 +77,14 @@ Please visit our Website: http://www.httrack.com
 /** Append to the output buffer the string 'A'. **/
 #define HT_ADD(A) TypedArrayAppend(output_buffer, A, strlen(A))
 
-/** Append to the output buffer the string 'A', html-escaped. **/
-#define HT_ADD_HTMLESCAPED_ANY(A, FUNCTION) do { \
+/* clang-format off: an edit realigns all backslashes, churning the macro. */
+/* clang-format off */
+/** Append 'A' to the output buffer, html-escaped; FACTOR = max byte expansion. **/
+#define HT_ADD_HTMLESCAPED_ANY(A, FUNCTION, FACTOR) do { \
   if ((opt->getmode & 1) != 0 && ptr>0) { \
     const char *const str_ = (A); \
     size_t size_; \
-    /* & is the maximum expansion */ \
-    TypedArrayEnsureRoom(output_buffer, strlen(str_) * 5 + 1024); \
+    TypedArrayEnsureRoom(output_buffer, strlen(str_) * (FACTOR) + 1024); \
     size_ = FUNCTION(str_, &TypedArrayTail(output_buffer), \
                      TypedArrayRoom(output_buffer)); \
     TypedArraySize(output_buffer) += size_; \
@@ -91,164 +92,113 @@ Please visit our Website: http://www.httrack.com
 } while(0)
 
 /** Append to the output buffer the string 'A', html-escaped for &. **/
-#define HT_ADD_HTMLESCAPED(A) HT_ADD_HTMLESCAPED_ANY(A, escape_for_html_print)
+#define HT_ADD_HTMLESCAPED(A) \
+  HT_ADD_HTMLESCAPED_ANY(A, escape_for_html_print, HTS_HTMLESCAPE_MAXEXP)
 
 /**
- * Append to the output buffer the string 'A', html-escaped for & and 
+ * Append to the output buffer the string 'A', html-escaped for & and
  * high chars.
  **/
-#define HT_ADD_HTMLESCAPED_FULL(A) HT_ADD_HTMLESCAPED_ANY(A, escape_for_html_print_full)
+#define HT_ADD_HTMLESCAPED_FULL(A) \
+  HT_ADD_HTMLESCAPED_ANY(A, escape_for_html_print_full, HTS_HTMLESCAPE_FULL_MAXEXP)
+/* clang-format on */
 
 // does nothing
 #define XH_uninit do {} while(0)
 
-#define HT_ADD_END { \
-  int ok=0;\
-  if (TypedArraySize(output_buffer) != 0) { \
-    const size_t ht_len = TypedArraySize(output_buffer); \
-    const char *const ht_buff = TypedArrayElts(output_buffer); \
-    char digest[32+2];\
-    off_t fsize_old = fsize(fconv(OPT_GET_BUFF(opt),OPT_GET_BUFF_SIZE(opt),savename()));\
-    digest[0] = '\0';\
-    domd5mem(TypedArrayElts(output_buffer), ht_len, digest, 1);\
-    if (fsize_old == (off_t) ht_len) { \
-      int mlen = 0;\
-      char* mbuff;\
-      cache_readdata(cache,"//[HTML-MD5]//",savename(),&mbuff,&mlen);\
-      if (mlen) \
-        mbuff[mlen]='\0';\
-      if ((mlen == 32) && (strcmp(((mbuff!=NULL)?mbuff:""),digest)==0)) {\
-        ok=1;\
-        hts_log_print(opt, LOG_DEBUG, "File not re-written (md5): %s",savename());\
-      } else {\
-        ok=0;\
-      } \
-    }\
-    if (!ok) { \
-      file_notify(opt,urladr(), urlfil(), savename(), 1, 1, r->notmodified); \
-      fp=filecreate(&opt->state.strc, savename()); \
-      if (fp) { \
-        if (ht_len>0) {\
-        if (fwrite(ht_buff,1,ht_len,fp) != ht_len) { \
-          int fcheck;\
-          if ((fcheck=check_fatal_io_errno())) {\
-            opt->state.exit_xh=-1;\
-          }\
-          if (opt->log) {   \
-            hts_log_print(opt, LOG_ERROR | LOG_ERRNO, "Unable to write HTML file %s", savename());\
-            if (fcheck) {\
-              hts_log_print(opt, LOG_ERROR, "* * Fatal write error, giving up");\
-            }\
-          }\
-        }\
-        }\
-        fclose(fp); fp=NULL; \
-        if (strnotempty(r->lastmodified)) \
-        set_filetime_rfc822(savename(),r->lastmodified); \
-      } else {\
-        int fcheck;\
-        if ((fcheck=check_fatal_io_errno())) {\
-  				hts_log_print(opt, LOG_ERROR, "Mirror aborted: disk full or filesystem problems"); \
-          opt->state.exit_xh=-1;\
-        }\
-        hts_log_print(opt, LOG_ERROR | LOG_ERRNO, "Unable to save file %s", savename());\
-        if (fcheck) {\
-          hts_log_print(opt, LOG_ERROR, "* * Fatal write error, giving up");\
-        }\
-      }\
-    } else {\
-      file_notify(opt,urladr(), urlfil(), savename(), 0, 0, r->notmodified); \
-      filenote(&opt->state.strc, savename(),NULL); \
-    }\
-    if (cache->ndx)\
-      cache_writedata(cache->ndx,cache->dat,"//[HTML-MD5]//",savename(),digest,(int)strlen(digest));\
-  } \
-  TypedArrayFree(output_buffer); \
-}
 #define HT_ADD_FOP
 
+/* Mutable extended-context fields: one source of truth so the DEFINE/SET/SAVE
+   load and store lists can't drift apart. */
+/* clang-format off */
+#define ENGINE_MUTABLE_FIELDS(X) \
+  X(int, error, stre->error_) \
+  X(int, store_errpage, stre->store_errpage_) \
+  X(int, makeindex_done, stre->makeindex_done_) \
+  X(FILE *, makeindex_fp, stre->makeindex_fp_) \
+  X(int, makeindex_links, stre->makeindex_links_) \
+  X(LLint, stat_fragment, stre->stat_fragment_)
+
+#define ENGINE_FIELD_DECLARE(type, name, src) type name = *(src);
+#define ENGINE_FIELD_LOAD(type, name, src) name = *(src);
+#define ENGINE_FIELD_STORE(type, name, src) *(src) = name;
+
 #define ENGINE_DEFINE_CONTEXT() \
   ENGINE_DEFINE_CONTEXT_BASE(); \
-  /* */ \
   htsblk* const r HTS_UNUSED = stre->r_; \
   hash_struct* const hash HTS_UNUSED = stre->hash_; \
   char* const codebase HTS_UNUSED = stre->codebase; \
   char* const base HTS_UNUSED = stre->base; \
-  /* */ \
   const char * const template_header HTS_UNUSED = stre->template_header_; \
   const char * const template_body HTS_UNUSED = stre->template_body_; \
   const char * const template_footer HTS_UNUSED = stre->template_footer_; \
-  /* */ \
   HTS_UNUSED char* const makeindex_firstlink = stre->makeindex_firstlink_; \
-  /* */ \
-  /* */ \
-  int error = * stre->error_; \
-  int store_errpage = * stre->store_errpage_; \
-  /* */ \
-  int makeindex_done = *stre->makeindex_done_; \
-  FILE* makeindex_fp = *stre->makeindex_fp_; \
-  int makeindex_links = *stre->makeindex_links_; \
-  /* */ \
-  LLint stat_fragment = *stre->stat_fragment_; \
+  ENGINE_MUTABLE_FIELDS(ENGINE_FIELD_DECLARE) \
+  /* load-once (kept out of SET/SAVE): re-reading would reset the throttle */ \
   HTS_UNUSED TStamp makestat_time = stre->makestat_time; \
   HTS_UNUSED FILE* makestat_fp = stre->makestat_fp
 
 #define ENGINE_SET_CONTEXT() \
   ENGINE_SET_CONTEXT_BASE(); \
-  /* */ \
-  error = * stre->error_; \
-  store_errpage = * stre->store_errpage_; \
-  /* */ \
-  makeindex_done = *stre->makeindex_done_; \
-  makeindex_fp = *stre->makeindex_fp_; \
-  makeindex_links = *stre->makeindex_links_; \
-  /* */ \
-  stat_fragment = *stre->stat_fragment_; \
-  makestat_time = stre->makestat_time; \
-  makestat_fp = stre->makestat_fp
+  ENGINE_MUTABLE_FIELDS(ENGINE_FIELD_LOAD)
 
 #define ENGINE_LOAD_CONTEXT() \
   ENGINE_DEFINE_CONTEXT()
 
 #define ENGINE_SAVE_CONTEXT() \
   ENGINE_SAVE_CONTEXT_BASE(); \
-  /* */ \
-  * stre->error_ = error; \
-  * stre->store_errpage_ = store_errpage; \
-  /* */ \
-  *stre->makeindex_done_ = makeindex_done; \
-  *stre->makeindex_fp_ = makeindex_fp; \
-  *stre->makeindex_links_ = makeindex_links; \
-  /* */ \
-  *stre->stat_fragment_ = stat_fragment
+  ENGINE_MUTABLE_FIELDS(ENGINE_FIELD_STORE)
+/* clang-format on */
 
-#define _FILTERS     (*opt->filters.filters)
-#define _FILTERS_PTR (opt->filters.filptr)
 #define _ROBOTS      ((robots_wizard*)opt->robotsptr)
 
-/* Apply current *adr character for the script automate */
-#define AUTOMATE_LOOKUP_CURRENT_ADR() do { \
-  if (inscript) { \
-  int new_state_pos; \
-  new_state_pos=inscript_state[inscript_state_pos][(unsigned char)*html]; \
-  if (new_state_pos < 0) { \
-  new_state_pos=inscript_state[inscript_state_pos][INSCRIPT_DEFAULT]; \
-  } \
-  assertf(new_state_pos >= 0); \
-  assertf(new_state_pos*sizeof(inscript_state[0]) < sizeof(inscript_state)); \
-  inscript_state_pos=new_state_pos; \
-  } \
-} while(0)
+/* JS-detection automaton states; INSCRIPT_DEFAULT is the synthetic "any other
+   char" column of the transition table. */
+typedef enum {
+  INSCRIPT_START = 0,
+  INSCRIPT_ANTISLASH,
+  INSCRIPT_INQUOTE,
+  INSCRIPT_INQUOTE2,
+  INSCRIPT_SLASH,
+  INSCRIPT_SLASHSLASH,
+  INSCRIPT_COMMENT,
+  INSCRIPT_COMMENT2,
+  INSCRIPT_ANTISLASH_IN_QUOTE,
+  INSCRIPT_ANTISLASH_IN_QUOTE2,
+  INSCRIPT_DEFAULT = 256
+} INSCRIPT;
 
-/* Increment current pointer to 'steps' characters, modifying automate if necessary */
-#define INCREMENT_CURRENT_ADR(steps) do { \
-  int steps__ = (int) ( steps ); \
-  while(steps__ > 0) { \
-  html++; \
-  AUTOMATE_LOOKUP_CURRENT_ADR(); \
-  steps__ --; \
-  } \
-} while(0)
+#define INSCRIPT_NSTATES 10 /* rows in the transition table */
+
+/* Live view of the parser's automaton locals, set up once so the helpers below
+   can drive it without capturing them by lexical scope. */
+typedef struct {
+  const int *inscript;             /* nonzero while inside a script body */
+  const signed char (*table)[257]; /* [INSCRIPT_NSTATES][257] transitions */
+  INSCRIPT *pos;                   /* current state */
+  const char **html;               /* parse cursor */
+} script_automate;
+
+/* Feed the current *html byte to the automaton. No-op outside a script body. */
+static void hts_automate_lookup(const script_automate *aut) {
+  if (*aut->inscript) {
+    int next = aut->table[*aut->pos][(unsigned char) **aut->html];
+    if (next < 0) {
+      next = aut->table[*aut->pos][INSCRIPT_DEFAULT];
+    }
+    assertf(next >= 0 && next < INSCRIPT_NSTATES);
+    *aut->pos = (INSCRIPT) next;
+  }
+}
+
+/* Advance the cursor by 'steps' bytes, feeding each to the automaton. */
+static void hts_automate_increment(const script_automate *aut, int steps) {
+  while (steps > 0) {
+    (*aut->html)++;
+    hts_automate_lookup(aut);
+    steps--;
+  }
+}
 
 /* Percent-encode the angle brackets of a string so it is safe to embed inside
    an HTML comment (the default footer) or any other HTML context. A URL holding
@@ -393,20 +343,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
       int incomment = 0;        // dans un <!--
       int inscript = 0;         // dans un scipt pour applets javascript)
       int inscript_locked = 0;  // in locked script (ie. js file)
-      signed char inscript_state[10][257];
-      typedef enum {
-        INSCRIPT_START = 0,
-        INSCRIPT_ANTISLASH,
-        INSCRIPT_INQUOTE,
-        INSCRIPT_INQUOTE2,
-        INSCRIPT_SLASH,
-        INSCRIPT_SLASHSLASH,
-        INSCRIPT_COMMENT,
-        INSCRIPT_COMMENT2,
-        INSCRIPT_ANTISLASH_IN_QUOTE,
-        INSCRIPT_ANTISLASH_IN_QUOTE2,
-        INSCRIPT_DEFAULT = 256
-      } INSCRIPT;
+      signed char inscript_state[INSCRIPT_NSTATES][257];
       INSCRIPT inscript_state_pos = INSCRIPT_START;
       const char *inscript_name = NULL;       // script tag name
       int inscript_tag = 0;     // on est dans un <body onLoad="... terminé par >
@@ -467,6 +404,8 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
       inscript_state[INSCRIPT_COMMENT2]['*'] = INSCRIPT_COMMENT2;
       inscript_state[INSCRIPT_ANTISLASH_IN_QUOTE][INSCRIPT_DEFAULT] = INSCRIPT_INQUOTE; /* #8: escape in '' */
       inscript_state[INSCRIPT_ANTISLASH_IN_QUOTE2][INSCRIPT_DEFAULT] = INSCRIPT_INQUOTE2;       /* #9: escape in "" */
+      const script_automate saut = {&inscript, inscript_state,
+                                    &inscript_state_pos, &html};
 
       /* Primary list or URLs */
       if (ptr == 0) {
@@ -905,7 +844,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
             }
 
             /* automate */
-            AUTOMATE_LOOKUP_CURRENT_ADR();
+            hts_automate_lookup(&saut);
 
             // Note:
             // Certaines pages ne respectent pas le html
@@ -1821,7 +1760,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
             }
             // sauter espaces
             // adr+=p;
-            INCREMENT_CURRENT_ADR(p);
+            hts_automate_increment(&saut, p);
             while((is_space(*html)
                    || (inscriptgen && html[0] == '\\' && is_space(html[1])
                    )
@@ -1836,7 +1775,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                 }
               // puis quitter
               // html++;    // sauter les espaces, "" et cie
-              INCREMENT_CURRENT_ADR(1);
+              hts_automate_increment(&saut, 1);
             }
 
             /* Stop at \n (LF) if primary links or link lists */
@@ -1851,7 +1790,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
               if (*html == '\\') {
                 if ((*(html + 1) == '\'') || (*(html + 1) == '"')) {      // \" ou \'
                   // html+=2;    // sauter
-                  INCREMENT_CURRENT_ADR(2);
+                  hts_automate_increment(&saut, 2);
                 }
               }
             }
@@ -1899,7 +1838,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
             if (srcset_p) {
               while(html < r->adr + r->size
                     && (is_realspace(*html) || *html == ','))
-                INCREMENT_CURRENT_ADR(1);
+                hts_automate_increment(&saut, 1);
             }
             eadr = html;
 
@@ -3359,7 +3298,7 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
 
             assertf(eadr - html >= 0);   // Should not go back
             if (eadr > html) {
-              INCREMENT_CURRENT_ADR(eadr - 1 - html);
+              hts_automate_increment(&saut, (int) (eadr - 1 - html));
             }
             // adr=eadr-1;  // ** sauter
 
@@ -3378,7 +3317,8 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
                   q++;          // skip whitespace and empty candidates
                 if (q < endp && *q != '\0' && *q != ',' && *q != quote
                     && *q != '<' && *q != '>' && (unsigned char) *q >= 32) {
-                  INCREMENT_CURRENT_ADR(q - html);   // keep the automate in sync
+                  hts_automate_increment(
+                      &saut, (int) (q - html)); // keep the automate in sync
                   ok = 1;
                   goto srcset_next;
                 }
@@ -3518,7 +3458,12 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
         }
 
         /* Flush and save to disk */
-        HT_ADD_END;             // achever
+        if (TypedArraySize(output_buffer) != 0) {
+          hts_finish_html_file(
+              opt, cache, r, &fp, TypedArrayElts(output_buffer),
+              TypedArraySize(output_buffer), urladr(), urlfil(), savename());
+        }
+        TypedArrayFree(output_buffer);
       }
       //
       //
@@ -3543,6 +3488,24 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre) {
   return 0;
 }
 
+/* Mirror the savename to tell whether a redirect saves to the same file (#159);
+ * contract in htsparse.h. */
+hts_boolean hts_redirect_same_savefile(httrackp *opt, const char *cur_adr,
+                                       const char *cur_fil,
+                                       const char *moved_adr,
+                                       const char *moved_fil) {
+  const int norm_slash = opt->urlhack && !opt->no_slash_dedup;
+  const int norm_query = opt->urlhack && !opt->no_query_dedup;
+  char BIGSTK n_fil[HTS_URLMAXSIZE * 2], pn_fil[HTS_URLMAXSIZE * 2];
+
+  if (strcasecmp(jump_identification_const(moved_adr),
+                 jump_identification_const(cur_adr)) != 0)
+    return HTS_FALSE;
+  fil_normalized_filtered_ex(moved_fil, n_fil, NULL, norm_slash, norm_query);
+  fil_normalized_filtered_ex(cur_fil, pn_fil, NULL, norm_slash, norm_query);
+  return strcasecmp(n_fil, pn_fil) == 0;
+}
+
 /*
 Check 301, 302, .. statuscodes (moved)
 */
@@ -3588,36 +3551,9 @@ int hts_mirror_check_moved(htsmoduleStruct * str,
         if ((reponse =
              ident_url_relatif(mov_url, urladr(), urlfil(), moved)) >= 0) {
           int set_prio_to = 0;  // pas de priotité fixéd par wizard
-
-          // check whether URLHack is harmless or not (per the effective
-          // sub-flags)
-          if (opt->urlhack && (!opt->no_www_dedup || !opt->no_slash_dedup ||
-                               !opt->no_query_dedup)) {
-            const int norm_host = !opt->no_www_dedup;
-            const int norm_slash = !opt->no_slash_dedup;
-            const int norm_query = !opt->no_query_dedup;
-            char BIGSTK n_adr[HTS_URLMAXSIZE * 2], n_fil[HTS_URLMAXSIZE * 2];
-            char BIGSTK pn_adr[HTS_URLMAXSIZE * 2], pn_fil[HTS_URLMAXSIZE * 2];
-
-            strlcpybuff(n_adr,
-                        norm_host ? jump_normalized_const(moved->adr)
-                                  : jump_identification_const(moved->adr),
-                        sizeof(n_adr));
-            strlcpybuff(pn_adr,
-                        norm_host ? jump_normalized_const(urladr())
-                                  : jump_identification_const(urladr()),
-                        sizeof(pn_adr));
-            fil_normalized_filtered_ex(moved->fil, n_fil, NULL, norm_slash,
-                                       norm_query);
-            fil_normalized_filtered_ex(urlfil(), pn_fil, NULL, norm_slash,
-                                       norm_query);
-            if (strcasecmp(n_adr, pn_adr) == 0
-                && strcasecmp(n_fil, pn_fil) == 0) {
-              hts_log_print(opt, LOG_WARNING,
-                            "Redirected link is identical because of 'URL Hack' option: %s%s and %s%s",
-                            urladr(), urlfil(), moved->adr, moved->fil);
-            }
-          }
+          // A same-file alias redirect must be followed, not stubbed (#159).
+          const hts_boolean same_savefile = hts_redirect_same_savefile(
+              opt, urladr(), urlfil(), moved->adr, moved->fil);
           //if (ident_url_absolute(mov_url,moved->adr,moved->fil)!=-1) {    // ok URL reconnue
           // c'est (en gros) la même URL..
           // si c'est un problème de casse dans le host c'est que le serveur est buggé
@@ -3645,7 +3581,17 @@ int hts_mirror_check_moved(htsmoduleStruct * str,
                 hts_log_print(opt, LOG_DEBUG, "moved link accepted: %s%s",
                               moved->adr, moved->fil);
               }
-            }                   /* sinon traité normalement */
+            } else if (same_savefile) {
+              // A stub would point at itself; follow the redirect instead.
+              if (hts_acceptlink(opt, ptr, moved->adr, moved->fil, NULL, NULL,
+                                 &set_prio_to, NULL) != 1) {
+                get_it = 1;
+                hts_log_print(opt, LOG_WARNING,
+                              "Redirect to a same-file alias, fetching real "
+                              "content: %s%s -> %s%s",
+                              urladr(), urlfil(), moved->adr, moved->fil);
+              }
+            } /* sinon traité normalement */
           }
 
           //if ((strfield2(moved->adr,urladr())!=0) && (strfield2(moved->fil,urlfil())!=0)) {  // identique à casse près
@@ -3668,7 +3614,11 @@ int hts_mirror_check_moved(htsmoduleStruct * str,
                    heap(heap(ptr)->precedent)->adr,
                    heap(heap(ptr)->precedent)->fil, opt,
                    sback, cache, hash, ptr, numero_passe, NULL) != -1) {
-                if (hash_read(hash, savedmoved.save, NULL, HASH_STRUCT_FILENAME) < 0) {   // n'existe pas déja
+                // Same-file alias: the reserved name is the invalidated source,
+                // so record anyway.
+                if (same_savefile ||
+                    hash_read(hash, savedmoved.save, NULL,
+                              HASH_STRUCT_FILENAME) < 0) { // n'existe pas déja
                   // enregistrer lien avec SAV IDENTIQUE
                   if (hts_record_link(opt, moved->adr, moved->fil, heap(ptr)->sav, "", "", NULL)) {
                     // mode test?
@@ -3692,7 +3642,6 @@ int hts_mirror_check_moved(htsmoduleStruct * str,
                                 "moving %s to an existing file %s",
                                 heap(ptr)->fil, urlfil());
                 }
-
               }
             }
 

src/htsparse.h

@@ -116,6 +116,19 @@ int htsparse(htsmoduleStruct * str, htsmoduleStructExtended * stre);
 int hts_mirror_check_moved(htsmoduleStruct * str,
                            htsmoduleStructExtended * stre);
 
+/*
+  Non-zero if a redirect (cur_adr,cur_fil)->(moved_adr,moved_fil) saves to the
+  same local file, so it must be followed rather than turned into a
+  self-pointing "moved" stub (#159). Mirrors the savename: scheme+userinfo
+  stripped, www kept (www dedup is the crawl layer's job), path
+  slash/query-normalized per the URL-hack flags. Not hash_url_equals: that keys
+  on the dedup hash, which folds www and never collapses http<->https.
+*/
+hts_boolean hts_redirect_same_savefile(httrackp *opt, const char *cur_adr,
+                                       const char *cur_fil,
+                                       const char *moved_adr,
+                                       const char *moved_fil);
+
 /*
   Process user intercations: pause, add link, delete link..
 */

src/htssafe.h

@@ -456,6 +456,13 @@ static HTS_INLINE HTS_UNUSED const char *htsbuff_str(const htsbuff *b) {
   return b->buf;
 }
 
+/** True if 'count' records of >= 1 byte each fit in 'available' bytes; guards
+    an attacker-controlled count driving a large allocation. */
+static HTS_INLINE HTS_UNUSED hts_boolean hts_count_fits(size_t count,
+                                                        LLint available) {
+  return (available >= 0 && (LLint) count <= available) ? HTS_TRUE : HTS_FALSE;
+}
+
 /* Thin aliases over the libc allocator/memcpy (historical "t" suffix); no
    added bounds checking. freet() also NULLs the freed pointer and tolerates
    NULL. memcpybuff() despite the name is a raw memcpy: the caller owns the

src/htsselftest.c

@@ -45,10 +45,12 @@ Please visit our Website: http://www.httrack.com
 #include "htscore.h"
 #include "htsdefines.h"
 #include "htslib.h"
+#include "htsparse.h"
 #include "htscache_selftest.h"
 #include "htsdns_selftest.h"
 #include "htscharset.h"
 #include "htsencoding.h"
+#include "htsftp.h"
 #include "htsmd5.h"
 #if HTS_USEZLIB
 #include "htszlib.h"
@@ -60,6 +62,10 @@ Please visit our Website: http://www.httrack.com
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#ifndef _WIN32
+#include <sys/socket.h>
+#include <unistd.h>
+#endif
 
 /* very minimalistic internal tests */
 static void basic_selftests(void) {
@@ -524,6 +530,41 @@ static int string_safety_selftests(void) {
       return 1;
   }
 
+  /* StringCatN/StringSetLength must eval SIZE once: (n_eval++, V) leaves
+     n_eval == 2 on a double-eval macro. */
+  {
+    String s = STRING_EMPTY;
+    int n_eval = 0;
+
+    StringCat(s, "hello");
+    StringCatN(s, "world", (n_eval++, 3)); /* strlen>SIZE so the clamp runs */
+    if (n_eval != 1 || strcmp(StringBuff(s), "hellowor") != 0) {
+      StringFree(s);
+      return 1;
+    }
+
+    n_eval = 0;
+    StringSetLength(s, (n_eval++, 5));
+    if (n_eval != 1 || StringLength(s) != 5) {
+      StringFree(s);
+      return 1;
+    }
+    StringFree(s);
+  }
+
+  /* StringSubRW still reads/writes after dropping its duplicate definition. */
+  {
+    String s = STRING_EMPTY;
+
+    StringCat(s, "abc");
+    StringSubRW(s, 1) = 'X';
+    if (StringSub(s, 1) != 'X' || strcmp(StringBuff(s), "aXc") != 0) {
+      StringFree(s);
+      return 1;
+    }
+    StringFree(s);
+  }
+
   return 0;
 }
 
@@ -1305,6 +1346,37 @@ static int st_urlhack(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+/* #159: hts_redirect_same_savefile decides whether a redirect is a same-file
+ * alias. */
+static int st_redirect_samefile(httrackp *opt, int argc, char **argv) {
+  (void) argc;
+  (void) argv;
+#define SAME(aa, fa, ab, fb) hts_redirect_same_savefile(opt, aa, fa, ab, fb)
+  /* scheme and userinfo collapse (the #159 case); a different path does not */
+  assertf(SAME("http://foo.com", "/a/b", "https://foo.com", "/a/b"));
+  assertf(SAME("http://user@foo.com", "/a", "http://foo.com", "/a"));
+  assertf(!SAME("http://foo.com", "/a", "http://foo.com", "/b"));
+  /* www stays distinct here; the crawl's dedup layer folds www, not this helper
+   */
+  opt->urlhack = HTS_TRUE;
+  opt->no_www_dedup = opt->no_slash_dedup = opt->no_query_dedup = HTS_FALSE;
+  assertf(!SAME("http://www.foo.com", "/a", "http://foo.com", "/a"));
+  /* slash/query fold only when the dedup flag is on */
+  assertf(SAME("https://foo.com", "/a//b", "http://foo.com", "/a/b"));
+  assertf(
+      SAME("https://foo.com", "/p?b=2&a=1", "http://foo.com", "/p?a=1&b=2"));
+  opt->no_slash_dedup = opt->no_query_dedup = HTS_TRUE;
+  assertf(!SAME("https://foo.com", "/a//b", "http://foo.com", "/a/b"));
+  assertf(
+      !SAME("https://foo.com", "/p?b=2&a=1", "http://foo.com", "/p?a=1&b=2"));
+  /* but a pure scheme alias still collapses regardless of dedup opt-outs */
+  assertf(SAME("http://foo.com", "/a/b", "https://foo.com", "/a/b"));
+  opt->no_slash_dedup = opt->no_query_dedup = HTS_FALSE;
+#undef SAME
+  printf("redirect-samefile self-test OK\n");
+  return 0;
+}
+
 // hts_finish_makeindex writes the footer, emits the refresh meta only when
 // makeindex_links==1, and clears *fp / sets *done. argv[0] is a writable dir.
 static int st_makeindex(httrackp *opt, int argc, char **argv) {
@@ -1354,6 +1426,85 @@ static int st_makeindex(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+/* Each inplace_escape_*() must equal escape_*() on a copy. */
+static int st_inplace_escape(httrackp *opt, int argc, char **argv) {
+  /* >255 bytes forces the helper's malloct path, not the stack buffer */
+  static char longstr[600];
+  static const char *const samples[] = {
+      "",          "abc",           "a b/c?d=e&f", "h\x8ello w\x94rld",
+      "a%b\"c<d>", "/path to/file", longstr};
+  static size_t (*const inplace[])(char *, size_t) = {
+      inplace_escape_in_url, inplace_escape_spc_url, inplace_escape_uri_utf,
+      inplace_escape_check_url, inplace_escape_uri};
+  static size_t (*const plain[])(const char *, char *, size_t) = {
+      escape_in_url, escape_spc_url, escape_uri_utf, escape_check_url,
+      escape_uri};
+  size_t i, f;
+
+  (void) opt;
+  (void) argc;
+  (void) argv;
+
+  memset(longstr, 'a', sizeof(longstr) - 1);
+  for (f = 0; f < sizeof(inplace) / sizeof(inplace[0]); f++) {
+    for (i = 0; i < sizeof(samples) / sizeof(samples[0]); i++) {
+      char ref[4096], work[4096];
+      size_t rret, iret;
+      rret = plain[f](samples[i], ref, sizeof(ref));
+      strcpybuff(work, samples[i]);
+      iret = inplace[f](work, sizeof(work));
+      assertf(iret == rret);
+      assertf(strcmp(work, ref) == 0);
+    }
+  }
+  printf("inplace-escape self-test OK\n");
+  return 0;
+}
+
+/* Pin HTS_HTMLESCAPE*_MAXEXP to each escaper's true max byte expansion. */
+static int st_escape_room(httrackp *opt, int argc, char **argv) {
+  /* N > 1023: where 6n outgrows the old 5n+1024 reservation */
+  enum { N = 2000 };
+
+  char *src = malloct(N + 1);
+  char *dst;
+  size_t room, got;
+  (void) opt;
+  (void) argc;
+  (void) argv;
+
+  /* _full worst case: a high byte expands to "&#xHH;" (6 bytes) */
+  memset(src, 0xE9, N);
+  src[N] = '\0';
+  room = (size_t) N * HTS_HTMLESCAPE_FULL_MAXEXP + 1024;
+  dst = malloct(room);
+  got = escape_for_html_print_full(src, dst, room);
+  assertf(got == (size_t) N * HTS_HTMLESCAPE_FULL_MAXEXP);
+  assertf(strlen(dst) == got);
+  freet(dst);
+
+  /* one factor short overflows (returns size), truncating the page: the bug */
+  room = (size_t) N * (HTS_HTMLESCAPE_FULL_MAXEXP - 1) + 1024;
+  dst = malloct(room);
+  got = escape_for_html_print_full(src, dst, room);
+  assertf(got == room);
+  freet(dst);
+
+  /* plain escaper worst case: '&' -> "&amp;" (5); high bytes stay verbatim */
+  memset(src, '&', N);
+  src[N] = '\0';
+  room = (size_t) N * HTS_HTMLESCAPE_MAXEXP + 1024;
+  dst = malloct(room);
+  got = escape_for_html_print(src, dst, room);
+  assertf(got == (size_t) N * HTS_HTMLESCAPE_MAXEXP);
+  assertf(strlen(dst) == got);
+  freet(dst);
+
+  freet(src);
+  printf("escape-room self-test OK\n");
+  return 0;
+}
+
 /* Default User-Agent: honest HTTrack token, no resurrected Windows 98. */
 static int st_useragent(httrackp *opt, int argc, char **argv) {
   const char *ua = StringBuff(opt->user_agent);
@@ -1623,6 +1774,75 @@ static int st_robots(httrackp *opt, int argc, char **argv) {
   return 0;
 }
 
+/* get_ftp_line must bound a hostile, CRLF-less reply into its internal
+   1024-byte buffer; ASan turns the pre-fix overflow into an abort here. */
+#ifndef _WIN32
+static int st_ftpline(httrackp *opt, int argc, char **argv) {
+  int sv[2];
+  char line[2048];
+  char flood[4096];
+
+  (void) opt;
+  (void) argc;
+  (void) argv;
+  memset(flood, 'x', sizeof(flood));
+  assertf(socketpair(AF_UNIX, SOCK_STREAM, 0, sv) == 0);
+  assertf(write(sv[1], "220 ", 4) == 4); // valid 3-digit code
+  assertf(write(sv[1], flood, sizeof(flood)) == (ssize_t) sizeof(flood));
+  assertf(write(sv[1], "\r\n", 2) == 2); // end the line so we return
+  close(sv[1]);
+  line[0] = '\0';
+  get_ftp_line(sv[0], line, sizeof(line), 5);
+  close(sv[0]);
+  printf("ftp-line self-test OK (bounded %d-byte reply)\n",
+         (int) sizeof(flood));
+  return 0;
+}
+#endif
+
+/* ftp_split_userpass: well-formed split, plus a hostile over-long userinfo
+   that pre-fix overran user[256]/pass[256]. */
+static int st_ftpuser(httrackp *opt, int argc, char **argv) {
+  char user[256], pass[256];
+  char in[1200];
+
+  (void) opt;
+  (void) argc;
+  (void) argv;
+  {
+    const char ok[] = "bob:secret@host/f"; // '@' at index 10
+
+    ftp_split_userpass(ok, ok + 11, user, sizeof(user), pass, sizeof(pass));
+    assertf(strcmp(user, "bob") == 0);
+    assertf(strcmp(pass, "secret") == 0);
+  }
+  memset(in, 'u', 400);
+  in[400] = ':';
+  memset(in + 401, 'p', 400);
+  in[801] = '@';
+  in[802] = '\0';
+  ftp_split_userpass(in, in + 802, user, sizeof(user), pass, sizeof(pass));
+  assertf(strlen(user) == sizeof(user) - 1);
+  assertf(strlen(pass) == sizeof(pass) - 1);
+  printf("ftp-userpass self-test OK\n");
+  return 0;
+}
+
+/* hts_count_fits caps the .class constant-pool entry count to the file size,
+   rejecting the ~68 MB-per-file calloc DoS. */
+static int st_java(httrackp *opt, int argc, char **argv) {
+  (void) opt;
+  (void) argc;
+  (void) argv;
+  assertf(hts_count_fits(10, 1000) == HTS_TRUE);
+  assertf(hts_count_fits(0, 10) == HTS_TRUE);
+  assertf(hts_count_fits(65535, 10) == HTS_FALSE);
+  assertf(hts_count_fits(1, 0) == HTS_FALSE);
+  assertf(hts_count_fits(1, -1) == HTS_FALSE);
+  printf("java constant-pool cap self-test OK\n");
+  return 0;
+}
+
 /* ------------------------------------------------------------ */
 /* Registry: name -> handler, with a usage hint and a one-line description. */
 /* ------------------------------------------------------------ */
@@ -1643,6 +1863,8 @@ static const struct selftest_entry {
      st_stripquery},
     {"urlhack", "", "-%u url-hack sub-flag (www/slash/query) self-test",
      st_urlhack},
+    {"redirect-samefile", "", "same-file redirect detection self-test (#159)",
+     st_redirect_samefile},
     {"mime", "<filename>", "MIME type for a filename", st_mime},
     {"charset", "<charset> <string>",
      "convert a string to UTF-8 from a charset", st_charset},
@@ -1672,11 +1894,21 @@ static const struct selftest_entry {
     {"useragent", "", "default User-Agent self-test", st_useragent},
     {"makeindex", "[dir]", "hts_finish_makeindex footer/refresh self-test",
      st_makeindex},
+    {"inplace-escape", "", "inplace_escape_* vs escape_* equivalence self-test",
+     st_inplace_escape},
+    {"escape-room", "", "HT_ADD_HTMLESCAPED* reservation-factor self-test",
+     st_escape_room},
     {"status", "", "HTTP status code -> reason phrase self-test", st_status},
     {"acceptencoding", "[dir]",
      "Accept-Encoding advertises gzip+deflate, both decode", st_acceptencoding},
     {"robots", "", "robots.txt RFC 9309 Allow/Disallow precedence self-test",
      st_robots},
+#ifndef _WIN32
+    {"ftp-line", "", "get_ftp_line bounds a hostile FTP reply line",
+     st_ftpline},
+#endif
+    {"ftp-userpass", "", "ftp_split_userpass bounds URL userinfo", st_ftpuser},
+    {"java", "", "java .class constant-pool count cap self-test", st_java},
 };
 
 static void list_selftests(void) {

src/htsstrings.h

@@ -121,9 +121,6 @@ struct String {
 /** Byte at POS (read/write). No bounds check; POS must be < StringLength. **/
 #define StringSubRW(BLK, POS) (StringBuffRW(BLK)[POS])
 
-/** Subcharacter (read/write) **/
-#define StringSubRW(BLK, POS) (StringBuffRW(BLK)[POS])
-
 /** Byte POS positions from the end (read). POS==1 is the last byte. **/
 #define StringRight(BLK, POS) (StringBuff(BLK)[StringLength(BLK) - POS])
 
@@ -191,8 +188,9 @@ HTS_STATIC char *StringBuffN_(String *blk, int size) {
     asserts SIZE fits the existing content; does not (re)allocate. **/
 #define StringSetLength(BLK, SIZE)                                             \
   do {                                                                         \
-    if (SIZE >= 0) {                                                           \
-      (BLK).length_ = SIZE;                                                    \
+    const int len__ = (SIZE); /* signed: negative means strlen(buffer_) */     \
+    if (len__ >= 0) {                                                          \
+      (BLK).length_ = len__;                                                   \
     } else {                                                                   \
       (BLK).length_ = strlen((BLK).buffer_);                                   \
     }                                                                          \
@@ -308,10 +306,11 @@ HTS_STATIC void StringAttach(String *blk, char **str) {
 #define StringCatN(BLK, STR, SIZE)                                             \
   do {                                                                         \
     const char *str__ = (STR);                                                 \
+    const size_t usize__ = (SIZE);                                             \
     if (str__ != NULL) {                                                       \
       size_t size__ = strlen(str__);                                           \
-      if (size__ > (SIZE)) {                                                   \
-        size__ = (SIZE);                                                       \
+      if (size__ > usize__) {                                                  \
+        size__ = usize__;                                                      \
       }                                                                        \
       StringMemcat(BLK, str__, size__);                                        \
     }                                                                          \

tests/01_engine-escape-room.test

@@ -0,0 +1,7 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# HT_ADD_HTMLESCAPED* must reserve the escaper's worst case (6 for _full).
+httrack -O /dev/null -#test=escape-room run | grep -q "escape-room self-test OK"

tests/01_engine-ftp-line.test

@@ -0,0 +1,7 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# get_ftp_line bounds a hostile CRLF-less FTP reply into its 1024-byte buffer.
+httrack -O /dev/null -#test=ftp-line run | grep -q "ftp-line self-test OK"

tests/01_engine-ftp-userpass.test

@@ -0,0 +1,7 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# ftp_split_userpass bounds an over-long user:pass@ from a hostile ftp:// URL.
+httrack -O /dev/null -#test=ftp-userpass run | grep -q "ftp-userpass self-test OK"

tests/01_engine-inplace-escape.test

@@ -0,0 +1,7 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# inplace_escape_*() must match escape_*() on a copy: guards the shared helper.
+httrack -O /dev/null -#test=inplace-escape run | grep -q "inplace-escape self-test OK"

tests/01_engine-java.test

@@ -0,0 +1,7 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# .class constant-pool count is capped to the file size (calloc DoS).
+httrack -O /dev/null -#test=java run | grep -q "java constant-pool cap self-test OK"

tests/01_engine-redirect.test

@@ -0,0 +1,9 @@
+#!/bin/bash
+#
+
+set -euo pipefail
+
+# #159: a redirect to a same-file alias (http<->https, user@host, ..) must be
+# followed through, not turned into a self-pointing "moved" stub. The decision
+# helper is exercised by the engine self-test.
+httrack -O /dev/null -#test=redirect-samefile run | grep -q "redirect-samefile self-test OK"

tests/30_local-fragment-link.test

@@ -0,0 +1,13 @@
+#!/bin/bash
+# Issue #279: an anchored link (target.html#sec, quoted or bare) fetches the
+# target with the fragment dropped (strict server 400s on a '#' in the request)
+# but keeps it in the rewritten local link so the anchor still works.
+set -e
+
+: "${top_srcdir:=..}"
+
+bash "$top_srcdir/tests/local-crawl.sh" --errors 0 \
+    --found 'fraglink/target.html' \
+    --file-matches 'fraglink/index.html' 'href=target\.html#sec' \
+    --file-matches 'fraglink/index.html' 'href="target\.html#sec2"' \
+    httrack 'BASEURL/fraglink/index.html'

tests/Makefile.am

@@ -6,6 +6,7 @@ EXTRA_DIST = $(TESTS) crawl-test.sh run-all-tests.sh check-network.sh \
 	local-crawl.sh local-server.py server.crt server.key \
 	server-root/simple/basic.html server-root/simple/link.html \
 	server-root/stripquery/index.html server-root/stripquery/a.html \
+	server-root/fraglink/index.html server-root/fraglink/target.html \
 	fixtures/cache-golden/hts-cache/new.zip
 
 TESTS_ENVIRONMENT =
@@ -34,13 +35,19 @@ TESTS = \
 	01_engine-entities.test \
 	01_engine-filelist.test \
 	01_engine-filter.test \
+	01_engine-ftp-line.test \
+	01_engine-ftp-userpass.test \
 	01_engine-hashtable.test \
 	01_engine-idna.test \
+	01_engine-escape-room.test \
+	01_engine-inplace-escape.test \
+	01_engine-java.test \
 	01_engine-makeindex.test \
 	01_engine-mime.test \
 	01_engine-parse.test \
 	01_engine-pause.test \
 	01_engine-rcfile.test \
+	01_engine-redirect.test \
 	01_engine-relative.test \
 	01_engine-robots.test \
 	01_engine-savename.test \
@@ -81,6 +88,7 @@ TESTS = \
 	26_local-strip-query.test \
 	27_local-cookies-file.test \
 	28_local-pause.test \
-	29_local-redirect-fragment.test
+	29_local-redirect-fragment.test \
+	30_local-fragment-link.test
 
 CLEANFILES = check-network_sh.cache

tests/local-crawl.sh

@@ -15,8 +15,11 @@
 #   bash local-crawl.sh [--tls] [--root DIR] [--cookie NAME=VALUE ...] \
 #       --errors N --files N --found PATH ... --directory PATH ... \
 #       --log-found REGEX ... --log-not-found REGEX ... \
+#       --file-matches PATH REGEX ... --file-not-matches PATH REGEX ... \
 #       httrack BASEURL/some/path [httrack-args...]
 # --log-found/--log-not-found grep (ERE) the crawl's hts-log.txt.
+# --file-matches/--file-not-matches grep (ERE) a mirrored file (PATH under the
+# host root), to assert rewritten link/content survived the crawl.
 # --cookie writes a Netscape cookies.txt (scoped to the discovered host:port,
 # which the ephemeral port forces into the cookie domain) and passes it to
 # httrack via --cookies-file, to exercise preloaded cookies.
@@ -121,6 +124,10 @@ while test "$pos" -lt "$nargs"; do
         audit+=("${args[$pos]}" "${args[$((pos + 1))]}")
         pos=$((pos + 1))
         ;;
+    --file-matches | --file-not-matches)
+        audit+=("${args[$pos]}" "${args[$((pos + 1))]}" "${args[$((pos + 2))]}")
+        pos=$((pos + 2))
+        ;;
     httrack)
         pos=$((pos + 1))
         break
@@ -294,6 +301,24 @@ while test "$i" -lt "${#audit[@]}"; do
             exit 1
         else result "OK"; fi
         ;;
+    --file-matches)
+        path="${audit[$((i + 1))]}"
+        i=$((i + 2))
+        info "checking ${path} matches ${audit[$i]}"
+        if grep -aqE "${audit[$i]}" "${hostroot}/${path}"; then result "OK"; else
+            result "no match"
+            exit 1
+        fi
+        ;;
+    --file-not-matches)
+        path="${audit[$((i + 1))]}"
+        i=$((i + 2))
+        info "checking ${path} lacks ${audit[$i]}"
+        if grep -aqE "${audit[$i]}" "${hostroot}/${path}"; then
+            result "matched"
+            exit 1
+        else result "OK"; fi
+        ;;
     esac
     i=$((i + 1))
 done

tests/server-root/fraglink/index.html

@@ -0,0 +1,4 @@
+<html><body>
+<a href=target.html#sec>unquoted fragment link</a>
+<a href="target.html#sec2">quoted fragment link</a>
+</body></html>

tests/server-root/fraglink/target.html

@@ -0,0 +1 @@
+<html><body><a name="sec"></a><a name="sec2"></a>target</body></html>