1 files changed, 410 insertions, 0 deletions

diff --git a/src/plugins/zip_extractor.c b/src/plugins/zip_extractor.c
new file mode 100644
index 0000000..c7fef95
--- /dev/null
+++ b/src/plugins/zip_extractor.c
@@ -0,0 +1,410 @@
+/** 
+     zipextractor.c  version 0.0.2
+
+     Changes from 0.0.1 to 0.0.2 
+     -> Searches for central dir struct from end of file if this is a self-extracting executable
+
+
+     This file was based on mp3extractor.c  (0.1.2)
+
+     Currently, this only returns a list of the filenames within a zipfile
+     and any comments on each file or the whole file itself. File sizes, 
+     modification times, and crc's are currently ignored.
+
+     TODO: Break the comments up into small, atomically, searchable chunks (keywords)
+         - might need some knowledge of English?
+
+     It returns:
+
+     one      EXTRACTOR_MIMETYPE
+     multiple EXTRACTOR_FILENAME
+     multiple EXTRACTOR_COMMENT
+     
+     ... from a .ZIP file
+
+     TODO: EXTRACTOR_DATE, EXTRACTOR_DESCRIPTION, EXTRACTOR_KEYWORDS, others?
+
+     Does NOT test data integrity (CRCs etc.)
+
+     This version is not recursive (i.e. doesn't look inside zip 
+     files within zip files)
+     
+     TODO: Run extract on files inside of archive (?) (i.e. gif, mp3, etc.)
+     
+     The current .ZIP format description:
+     ftp://ftp.pkware.com/appnote.zip
+
+     No Copyright 2003 Julia Wolf
+
+ */  
+  
+/*
+ * This file is part of libextractor.
+ * (C) 2002, 2003, 2009 Vidyut Samanta and Christian Grothoff
+ *
+ * libextractor 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 2, or (at your
+ * option) any later version.
+ * 
+ * libextractor 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 libextractor; see the file COPYING.  If not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */ 
+  
+#include "platform.h"
+#include "extractor.h"
+  
+#define DEBUG_EXTRACT_ZIP 0
+  
+/* In a zipfile there are two kinds of comments. One is a big one for the
+   entire .zip, it's usually a BBS ad. The other is a small comment on each
+   individual file; most people don't use this.
+ */ 
+  
+/* TODO: zip_entry linked list is handeled kinda messily, should clean up (maybe) */ 
+  typedef struct
+{
+  char *filename;
+   char *comment;
+   void *next;
+ } zip_entry;
+
+/* mimetype = application/zip */ 
+int 
+EXTRACTOR_zip_extract (const unsigned char *data,
+                       size_t size,
+                       EXTRACTOR_MetaDataProcessor proc,
+                       void *proc_cls,
+                       const char *options)
+{
+  int ret;
+  void *tmp;
+  zip_entry * info;
+  zip_entry * start;
+  char *filecomment = NULL;
+  const unsigned char *pos;
+  unsigned int offset, stop;
+  unsigned int name_length, extra_length, comment_length;
+  unsigned int filecomment_length;
+  unsigned int entry_total, entry_count;
+
+  /* I think the smallest zipfile you can have is about 120 bytes */ 
+  if ((NULL == data) || (size < 100))
+    return 0;
+  if (! (('P' == data[0]) && ('K' == data[1]) && (0x03 == data[2])
+         && (0x04 == data[3])))
+    return 0;
+  
+    /* The filenames for each file in a zipfile are stored in two locations.
+     * There is one at the start of each entry, just before the compressed data,
+     * and another at the end in a 'central directory structure'.
+     *
+     * In order to catch self-extracting executables, we scan backwards from the end
+     * of the file looking for the central directory structure. The previous version
+     * of this went forewards through the local headers, but that only works for plain
+     * vanilla zip's and I don't feel like writing a special case for each of the dozen
+     * self-extracting executable stubs.
+     *
+     * This assumes that the zip file is considered to be non-corrupt/non-truncated.
+     * If it is truncated then it's not considered to be a zip and skipped.
+     *
+     */ 
+    
+    /* From appnote.iz and appnote.txt (more or less)
+     *
+     *   (this is why you always need to put in the last floppy if you span disks)
+     *
+     *   0- 3  end of central dir signature    4 bytes  (0x06054b50) P K ^E ^F
+     *   4- 5  number of this disk             2 bytes
+     *   6- 7  number of the disk with the
+     *         start of the central directory  2 bytes
+     *   8- 9  total number of entries in
+     *         the central dir on this disk    2 bytes
+     *  10-11  total number of entries in
+     *         the central dir                 2 bytes
+     *  12-15  size of the central directory   4 bytes
+     *  16-19  offset of start of central
+     *         directory with respect to
+     *         the starting disk number        4 bytes
+     *  20-21  zipfile comment length          2 bytes
+     *  22-??  zipfile comment (variable size) max length 65536 bytes
+     */ 
+    
+    /*  the signature can't be more than 22 bytes from the end */ 
+  offset = size - 22;
+  pos = &data[offset];
+  stop = 0;
+  if (((signed int) size - 65556) > 0)
+    stop = size - 65556;
+  
+    /* not using int 0x06054b50 so that we don't have to deal with endianess issues.
+       break out if we go more than 64K backwards and havn't found it, or if we hit the
+       begining of the file. */ 
+    while ((!(('P' == pos[0]) && ('K' == pos[1]) && (0x05 == pos[2])
+              && (0x06 == pos[3]))) && (offset > stop))
+    pos = &data[offset--];
+  if (offset == stop)
+    {
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr,
+                 "Did not find end of central directory structure signature. offset: %i\n",
+                 offset);
+      
+#endif  /*  */
+        return 0;
+    }
+  
+    /* offset should now point to the start of the end-of-central directory structure */ 
+    /* and pos[0] should be pointing there too */ 
+    /* so slurp down filecomment while here... */ 
+    filecomment_length = pos[20] + (pos[21] << 8);
+  if (filecomment_length + offset + 22 > size)
+    {
+      return 0;             /* invalid zip file format! */
+    }
+  filecomment = NULL;
+  if (filecomment_length > 0)
+    {
+      filecomment = malloc (filecomment_length + 1);
+      memcpy (filecomment, &pos[22], filecomment_length);
+      filecomment[filecomment_length] = '\0';
+    }
+  if ((0 != pos[4]) && (0 != pos[5]))
+    {
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr,
+                 "WARNING: This seems to be the last disk in a multi-volume"
+                  " ZIP archive, and so this might not work.\n");
+      
+#endif  /*  */
+    }
+  if ((pos[8] != pos[10]) && (pos[9] != pos[11]))
+    {
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr,
+                 "WARNING: May not be able to find all the files in this" 
+                 " ZIP archive (no multi-volume support right now).\n");
+      
+#endif  /*  */
+    }
+  entry_total = pos[10] + (pos[11] << 8);
+  entry_count = 0;
+  
+    /* jump to start of central directory, ASSUMING that the starting disk that it's on is disk 0 */ 
+    /* starting disk would otherwise be pos[6]+pos[7]<<8 */ 
+    offset = pos[16] + (pos[17] << 8) + (pos[18] << 16) + (pos[19] << 24);     /* offset of cent-dir from start of disk 0 */
+  
+    /* stop   = pos[12] + (pos[13]<<8) + (pos[14]<<16) + (pos[15]<<24); *//* length of central dir */ 
+    if (offset + 46 > size)
+    {
+      
+        /* not a zip */ 
+      if (filecomment != NULL)
+        free (filecomment);
+      return 0;
+    }
+  pos = &data[offset];         /* jump */
+  
+    /* we should now be at the begining of the central directory structure */ 
+    
+    /* from appnote.txt and appnote.iz (mostly)
+     *
+     *   0- 3  central file header signature   4 bytes  (0x02014b50)
+     *   4- 5  version made by                 2 bytes
+     *   6- 7  version needed to extract       2 bytes
+     *   8- 9  general purpose bit flag        2 bytes
+     *  10-11  compression method              2 bytes
+     *  12-13  last mod file time              2 bytes
+     *  14-15  last mod file date              2 bytes
+     *  16-19  crc-32                          4 bytes
+     *  20-23  compressed size                 4 bytes
+     *  24-27  uncompressed size               4 bytes
+     *  28-29  filename length                 2 bytes
+     *  30-31  extra field length              2 bytes
+     *  32-33  file comment length             2 bytes
+     *  34-35  disk number start               2 bytes
+     *  36-37  internal file attributes        2 bytes
+     *  38-41  external file attributes        4 bytes
+     *  42-45  relative offset of local header 4 bytes
+     *
+     *  46-??  filename (variable size)
+     *   ?- ?  extra field (variable size)
+     *   ?- ?  file comment (variable size)
+     */ 
+    if (!(('P' == pos[0]) && ('K' == pos[1]) && (0x01 == pos[2])
+          && (0x02 == pos[3])))
+    {
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr,
+                 "Did not find central directory structure signature. offset: %i\n",
+                 offset);
+      
+#endif
+        if (filecomment != NULL)
+          free (filecomment);
+        return 0;
+    }
+  start = NULL;
+  info = NULL;
+  
+  do
+    {                           /* while ( (0x01==pos[2])&&(0x02==pos[3]) ) */
+      entry_count++;           /* check to make sure we found everything at the end */
+      name_length = pos[28] + (pos[29] << 8);
+      extra_length = pos[30] + (pos[31] << 8);
+      comment_length = pos[32] + (pos[33] << 8);
+      if (name_length + extra_length + comment_length + offset + 46 > size)
+        {
+          
+            /* ok, invalid, abort! */ 
+            break;
+        }
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr, "Found filename length %i  Comment length: %i\n",
+                 name_length, comment_length);
+      
+#endif  /*  */
+        
+        /* yay, finally get filenames */ 
+        if (start == NULL)
+        {
+          start = malloc (sizeof (zip_entry));
+          start->next = NULL;
+          info = start;
+        }
+      else
+        {
+          info->next = malloc (sizeof (zip_entry));
+          info = info->next;
+          info->next = NULL;
+        }
+      info->filename = malloc (name_length + 1);
+      info->comment = malloc (comment_length + 1);
+      
+        /* (strings in zip files are not null terminated) */ 
+        memcpy (info->filename, &pos[46], name_length);
+      info->filename[name_length] = '\0';
+      memcpy (info->comment, &pos[46 + name_length + extra_length],
+               comment_length);
+      info->comment[comment_length] = '\0';
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr, "Found file %s, Comment: %s\n", info->filename,
+                 info->comment);
+      
+#endif
+        offset += 46 + name_length + extra_length + comment_length;
+      pos = &data[offset];
+      
+        /* check for next header entry (0x02014b50) or (0x06054b50) if at end */ 
+        if (('P' != pos[0]) && ('K' != pos[1]))
+        {
+          
+#if DEBUG_EXTRACT_ZIP
+            fprintf (stderr,
+                     "Did not find next header in central directory.\n");
+          
+#endif
+            info = start;
+          while (info != NULL)
+            {
+              start = info->next;
+              free (info->filename);
+              free (info->comment);
+              free (info);
+              info = start;
+            }
+          if (filecomment != NULL)
+            free (filecomment);
+          return 0;
+        }
+    }
+  while ((0x01 == pos[2]) && (0x02 == pos[3]));
+  
+    /* end list */ 
+    
+    /* TODO: should this return an error? indicates corrupt zipfile (or
+       disk missing in middle of multi-disk)? */ 
+    if (entry_count != entry_total)
+    {
+      
+#if DEBUG_EXTRACT_ZIP
+        fprintf (stderr,
+                 "WARNING: Did not find all of the zipfile entries that we should have.\n");
+      
+#endif  /*  */
+    }
+  
+  ret = proc (proc_cls,
+              "zip",
+              EXTRACTOR_METATYPE_MIMETYPE,
+              EXTRACTOR_METAFORMAT_UTF8,
+              "text/plain",
+              "application/zip",
+              strlen ("application/zip")+1);
+  if ( (filecomment != NULL) && (ret != 0) )
+    {
+      ret = proc (proc_cls,
+                  "zip",
+                  EXTRACTOR_METATYPE_MIMETYPE,
+                  EXTRACTOR_METAFORMAT_UTF8,
+                  "text/plain",
+                  filecomment,
+                  strlen (filecomment)+1);
+    }
+  free (filecomment);
+
+  
+  /* if we've gotten to here then there is at least one zip entry (see get_zipinfo call above) */ 
+  /* note: this free()'s the info list as it goes */ 
+  info = start;
+  while (NULL != info)
+    {
+      if (info->filename != NULL)
+        {
+          if ( (ret == 0) && (strlen (info->filename)) )
+            {
+              ret = proc (proc_cls,
+                          "zip",
+                          EXTRACTOR_METATYPE_FILENAME,
+                          EXTRACTOR_METAFORMAT_UTF8,
+                          "text/plain",
+                          info->filename,
+                          strlen (info->filename)+1);
+            }
+        }
+      if (info->comment != NULL)
+        {
+          if ( (ret == 0) && (strlen (info->comment) > 0) )
+            {
+              ret = proc (proc_cls,
+                          "zip",
+                          EXTRACTOR_METATYPE_FILENAME,
+                          EXTRACTOR_METAFORMAT_UTF8,
+                          "text/plain",
+                          info->comment,
+                          strlen (info->comment)+1);
+            }
+        }
+      free (info->filename);
+      free (info->comment);
+      tmp = info;
+      info = info->next;
+      free (tmp);
+    }
+  return ret;
+}
+
+