Add new fuzzer for the FTP listing parsers

* fuzz/Makefile.am: Add wget_ftpls_fuzzer
* fuzz/wget_ftpls_fuzzer.c: New fuzzer
* fuzz/wget_ftpls_fuzzer.dict: Fuzzer dictionary
* fuzz/wget_ftpls_fuzzer.in/starter: Starting corpus
* src/ftp-ls.c: Parsing function take FILE * as argument,
  new function ftp_parse_ls_fp()
* src/ftp.c: Remove static from freefileinfo()
* src/ftp.h: Add ftp_parse_ls_fp() and freefileinfo()

fuzz/Makefile.am

@@ -10,6 +10,7 @@ LDADD = ../lib/libgnu.a \
 
 WGET_TESTS = \
  wget_css_fuzzer$(EXEEXT) \
+ wget_ftpls_fuzzer$(EXEEXT) \
  wget_html_fuzzer$(EXEEXT) \
  wget_options_fuzzer$(EXEEXT)
 
@@ -34,6 +35,9 @@ endif
 wget_css_fuzzer_SOURCES = wget_css_fuzzer.c $(MAIN)
 wget_css_fuzzer_LDADD = ../src/libunittest.a $(LDADD)
 
+wget_ftpls_fuzzer_SOURCES = wget_ftpls_fuzzer.c $(MAIN)
+wget_ftpls_fuzzer_LDADD = ../src/libunittest.a $(LDADD)
+
 wget_html_fuzzer_SOURCES = wget_html_fuzzer.c $(MAIN)
 wget_html_fuzzer_LDADD = ../src/libunittest.a $(LDADD)
 

fuzz/wget_ftpls_fuzzer.c

@@ -0,0 +1,107 @@
+/*
+ * Copyright(c) 2017-2018 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Wget.
+ *
+ * GNU Wget is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GNU Wget is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Wget.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <dirent.h> // opendir, readdir
+#include <stdint.h> // uint8_t
+#include <stdio.h>  // fmemopen
+#include <string.h>  // strncmp
+#include <stdlib.h>  // free
+#include <fcntl.h>  // open flags
+#include <unistd.h>  // close
+#include <setjmp.h> // longjmp, setjmp
+
+#include "wget.h"
+#undef fopen_wgetrc
+
+#ifdef __cplusplus
+  extern "C" {
+#endif
+  #include "ftp.h"
+
+  // declarations for wget internal functions
+  int main_wget(int argc, const char **argv);
+  void cleanup(void);
+  FILE *fopen_wget(const char *pathname, const char *mode);
+  FILE *fopen_wgetrc(const char *pathname, const char *mode);
+  void exit_wget(int status);
+#ifdef __cplusplus
+  }
+#endif
+
+#include "fuzzer.h"
+
+FILE *fopen_wget(const char *pathname, const char *mode)
+{
+	return fopen("/dev/null", mode);
+}
+
+FILE *fopen_wgetrc(const char *pathname, const char *mode)
+{
+	return NULL;
+}
+
+#ifdef FUZZING
+void exit_wget(int status)
+{
+}
+#else
+void exit(int status)
+{
+}
+#endif
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+	FILE *fp, *bak;
+	struct fileinfo *fi;
+
+	if (size > 4096) // same as max_len = ... in .options file
+		return 0;
+
+	bak = stderr;
+	stderr = fopen("/dev/null", "w");
+
+	fp = fmemopen((void *) data, size, "r");
+	if (!fp) return 0;
+
+	fi = ftp_parse_ls_fp(fp, ST_UNIX);
+	freefileinfo(fi);
+	rewind(fp);
+
+	fi = ftp_parse_ls_fp(fp, ST_VMS);
+	freefileinfo(fi);
+	rewind(fp);
+
+	fi = ftp_parse_ls_fp(fp, ST_WINNT);
+	freefileinfo(fi);
+	rewind(fp);
+
+	fi = ftp_parse_ls_fp(fp, ST_MACOS);
+	freefileinfo(fi);
+
+	fclose(fp);
+
+	fclose(stderr);
+	stderr = bak;
+
+	return 0;
+}

fuzz/wget_ftpls_fuzzer.dict

@@ -0,0 +1,20 @@
+"Jan"
+"Feb"
+"Mar"
+"Apr"
+"May"
+"Jun"
+"Jul"
+"Aug"
+"Sep"
+"Oct"
+"Nov"
+"Dec"
+"total"
+"0644"
+"0755"
+" -> "
+".."
+"Total of "
+".DIR"
+".DIR;1"

fuzz/wget_ftpls_fuzzer.in/starter

@@ -0,0 +1 @@
+-rwxr--r--  1   owner   group 640   1970 01 01  test

src/ftp-ls.c

@@ -90,9 +90,8 @@ clean_line (char *line, int len)
    The time stamps are stored in a separate variable, time_t
    compatible (I hope).  The timezones are ignored.  */
 static struct fileinfo *
-ftp_parse_unix_ls (const char *file, int ignore_perms)
+ftp_parse_unix_ls (FILE *fp, int ignore_perms)
 {
-  FILE *fp;
   static const char *months[] = {
     "Jan", "Feb", "Mar", "Apr", "May", "Jun",
     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
@@ -107,12 +106,6 @@ ftp_parse_unix_ls (const char *file, int ignore_perms)
   char *line = NULL, *tok, *ptok;      /* tokenizer */
   struct fileinfo *dir, *l, cur;       /* list creation */
 
-  fp = fopen (file, "rb");
-  if (!fp)
-    {
-      logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
-      return NULL;
-    }
   dir = l = NULL;
 
   /* Line loop to end of file: */
@@ -413,14 +406,12 @@ ftp_parse_unix_ls (const char *file, int ignore_perms)
     }
 
   xfree (line);
-  fclose (fp);
   return dir;
 }
 
 static struct fileinfo *
-ftp_parse_winnt_ls (const char *file)
+ftp_parse_winnt_ls (FILE *fp)
 {
-  FILE *fp;
   int len;
   int year, month, day;         /* for time analysis */
   int hour, min;
@@ -431,12 +422,6 @@ ftp_parse_winnt_ls (const char *file)
   char *filename;
   struct fileinfo *dir, *l, cur; /* list creation */
 
-  fp = fopen (file, "rb");
-  if (!fp)
-    {
-      logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
-      return NULL;
-    }
   dir = l = NULL;
 
   /* Line loop to end of file: */
@@ -562,7 +547,6 @@ ftp_parse_winnt_ls (const char *file)
     }
 
   xfree (line);
-  fclose(fp);
   return dir;
 }
 
@@ -677,25 +661,18 @@ static void eat_carets( char *str)
 
 
 static struct fileinfo *
-ftp_parse_vms_ls (const char *file)
+ftp_parse_vms_ls (FILE *fp)
 {
-  FILE *fp;
   int dt, i, j, len;
   int perms;
   size_t bufsize = 0;
   time_t timenow;
   struct tm *timestruct;
-  char date_str[ 32];
+  char date_str[32];
 
   char *line = NULL, *tok; /* tokenizer */
   struct fileinfo *dir, *l, cur; /* list creation */
 
-  fp = fopen (file, "r");
-  if (!fp)
-    {
-      logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
-      return NULL;
-    }
   dir = l = NULL;
 
   /* Skip blank lines, Directory heading, and more blank lines. */
@@ -1003,7 +980,6 @@ ftp_parse_vms_ls (const char *file)
     }
 
   xfree (line);
-  fclose (fp);
   return dir;
 }
 
@@ -1016,39 +992,51 @@ ftp_parse_vms_ls (const char *file)
 
 struct fileinfo *
 ftp_parse_ls (const char *file, const enum stype system_type)
+{
+  FILE *fp;
+  struct fileinfo *fi;
+
+  fp = fopen (file, "rb");
+  if (!fp)
+    {
+      logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
+      return NULL;
+    }
+
+  fi = ftp_parse_ls_fp (fp, system_type);
+  fclose(fp);
+
+  return fi;
+}
+
+struct fileinfo *
+ftp_parse_ls_fp (FILE *fp, const enum stype system_type)
 {
   switch (system_type)
     {
     case ST_UNIX:
-      return ftp_parse_unix_ls (file, 0);
+      return ftp_parse_unix_ls (fp, 0);
     case ST_WINNT:
       {
         /* Detect whether the listing is simulating the UNIX format */
-        FILE *fp;
-        int   c;
-        fp = fopen (file, "rb");
-        if (!fp)
-        {
-          logprintf (LOG_NOTQUIET, "%s: %s\n", file, strerror (errno));
-          return NULL;
-        }
-        c = fgetc(fp);
-        fclose(fp);
+        int   c = fgetc(fp);
+        rewind(fp);
+
         /* If the first character of the file is '0'-'9', it's WINNT
            format. */
         if (c >= '0' && c <='9')
-          return ftp_parse_winnt_ls (file);
+          return ftp_parse_winnt_ls (fp);
         else
-          return ftp_parse_unix_ls (file, 1);
+          return ftp_parse_unix_ls (fp, 1);
       }
     case ST_VMS:
-      return ftp_parse_vms_ls (file);
+      return ftp_parse_vms_ls (fp);
     case ST_MACOS:
-      return ftp_parse_unix_ls (file, 1);
+      return ftp_parse_unix_ls (fp, 1);
     default:
       logprintf (LOG_NOTQUIET, _("\
 Unsupported listing type, trying Unix listing parser.\n"));
-      return ftp_parse_unix_ls (file, 0);
+      return ftp_parse_unix_ls (fp, 0);
     }
 }
 

src/ftp.c

@@ -2185,7 +2185,6 @@ static uerr_t ftp_retrieve_dirs (struct url *, struct url *,
                                  struct fileinfo *, ccon *);
 static uerr_t ftp_retrieve_glob (struct url *, struct url *, ccon *, int);
 static struct fileinfo *delelement (struct fileinfo *, struct fileinfo **);
-static void freefileinfo (struct fileinfo *f);
 
 /* Retrieve a list of files given in struct fileinfo linked list.  If
    a file is a symbolic link, do not retrieve it, but rather try to
@@ -2828,7 +2827,7 @@ delelement (struct fileinfo *f, struct fileinfo **start)
 }
 
 /* Free the fileinfo linked list of files.  */
-static void
+void
 freefileinfo (struct fileinfo *f)
 {
   while (f)

src/ftp.h

@@ -30,6 +30,9 @@ as that of the covered work.  */
 #ifndef FTP_H
 #define FTP_H
 
+#include <stdio.h>
+#include <stdbool.h>
+
 #include "host.h"
 #include "url.h"
 
@@ -167,6 +170,8 @@ enum wget_ftp_fstatus
 };
 
 struct fileinfo *ftp_parse_ls (const char *, const enum stype);
+struct fileinfo *ftp_parse_ls_fp (FILE *, const enum stype);
+void freefileinfo(struct fileinfo *);
 uerr_t ftp_loop (struct url *, struct url *, char **, int *, struct url *,
                  bool, bool);