/*

  *  Copyright (C) 2007-2008 Sourcefire, Inc.
  *
  *  Authors: Alberto Wu

  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2 as
  *  published by the Free Software Foundation.
  *
  *  This program 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 this program; if not, write to the Free Software
  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  *  MA 02110-1301, USA.
  */
 
 /* FIXME: get a clue about masked stuff */
 
 #if HAVE_CONFIG_H
 #include "clamav-config.h"
 #endif
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 #if HAVE_STRING_H
 #include <string.h>
 #endif
 #include <stdlib.h>
 #include <stdio.h>
 
 #include <zlib.h>
 #include "inflate64.h"
 #if HAVE_BZLIB_H
 #include <bzlib.h>
 #endif
 

 #include "explode.h"

 #include "others.h"
 #include "clamav.h"
 #include "scanners.h"
 #include "matcher.h"

 #include "fmap.h"

 
 #define UNZIP_PRIVATE
 #include "unzip.h"
 
 static int wrap_inflateinit2(void *a, int b) {
   return inflateInit2(a, b);
 }
 

 static int unz(uint8_t *src, uint32_t csize, uint32_t usize, uint16_t method, uint16_t flags, unsigned int *fu, cli_ctx *ctx, char *tmpd) {

   char name[1024], obuf[BUFSIZ];
   char *tempfile = name;
   int of, ret=CL_CLEAN;
   unsigned int res=1, written=0;
 
   if(tmpd) {

     snprintf(name, sizeof(name), "%s"PATHSEP"zip.%03u", tmpd, *fu);

     name[sizeof(name)-1]='\0';
   } else {

     if(!(tempfile = cli_gentemp(ctx->engine->tmpdir))) return CL_EMEM;

   }
   if((of = open(tempfile, O_RDWR|O_CREAT|O_TRUNC|O_BINARY, S_IRUSR|S_IWUSR))==-1) {
     cli_warnmsg("cli_unzip: failed to create temporary file %s\n", tempfile);
     if(!tmpd) free(tempfile);

     return CL_ECREAT;

   }
   switch (method) {
   case ALG_STORED:
     if(csize<usize) {
       unsigned int fake = *fu + 1;
       cli_dbgmsg("cli_unzip: attempting to inflate stored file with inconsistent size\n");

       if ((ret=unz(src, csize, usize, ALG_DEFLATE, 0, &fake, ctx, tmpd))==CL_CLEAN) {

 	(*fu)++;
 	res=fake-(*fu);
       }
       else break;
     }
     if(res==1) {

       if(ctx->engine->maxfilesize && csize > ctx->engine->maxfilesize) {

 	cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (long unsigned int) ctx->engine->maxfilesize);

 	csize = ctx->engine->maxfilesize;

       }

       if(cli_writen(of, src, csize)!=(int)csize) ret = CL_EWRITE;

       else res=0;
     }
     break;
 
   case ALG_DEFLATE:
   case ALG_DEFLATE64: {
     union {
       z_stream64 strm64;
       z_stream strm;
     } strm;
     typedef int (*unz_init_) (void *, int);
     typedef int (*unz_unz_) (void *, int);
     typedef int (*unz_end_) (void *);
     unz_init_ unz_init;
     unz_unz_ unz_unz;
     unz_end_ unz_end;
     int wbits;
     void **next_in;
     void **next_out;
     unsigned int *avail_in;
     unsigned int *avail_out;
 
     if(method == ALG_DEFLATE64) {
       unz_init = (unz_init_)inflate64Init2;
       unz_unz = (unz_unz_)inflate64;
       unz_end = (unz_end_)inflate64End;
       next_in = (void *)&strm.strm64.next_in;
       next_out = (void *)&strm.strm64.next_out;
       avail_in = &strm.strm64.avail_in;
       avail_out = &strm.strm64.avail_out;
       wbits=MAX_WBITS64;
     } else {
       unz_init = (unz_init_)wrap_inflateinit2;
       unz_unz = (unz_unz_)inflate;
       unz_end = (unz_end_)inflateEnd;
       next_in = (void *)&strm.strm.next_in;
       next_out = (void *)&strm.strm.next_out;
       avail_in = &strm.strm.avail_in;
       avail_out = &strm.strm.avail_out;
       wbits=MAX_WBITS;
     }
 
     memset(&strm, 0, sizeof(strm));
 
     *next_in = src;
     *next_out = obuf;
     *avail_in = csize;
     *avail_out = sizeof(obuf);
     if (unz_init(&strm, -wbits)!=Z_OK) {
       cli_dbgmsg("cli_unzip: zinit failed\n");
       break;
     }
     while(1) {
       while((res = unz_unz(&strm, Z_NO_FLUSH))==Z_OK) {};
       if(*avail_out!=sizeof(obuf)) {
 	written+=sizeof(obuf)-(*avail_out);

 	if(ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {

 	  cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (long unsigned int) ctx->engine->maxfilesize);

 	  res = Z_STREAM_END;
 	  break;
 	}
 	if(cli_writen(of, obuf, sizeof(obuf)-(*avail_out)) != (int)(sizeof(obuf)-(*avail_out))) {
 	  cli_warnmsg("cli_unzip: falied to write %lu inflated bytes\n", sizeof(obuf)-(*avail_out));

 	  ret = CL_EWRITE;

 	  res = 100;
 	  break;

 	}
 	*next_out = obuf;
 	*avail_out = sizeof(obuf);
 	continue;
       }
       break;
     }
     unz_end(&strm);
     if (res == Z_STREAM_END) res=0;
     break;
   }
 
 
 #if HAVE_BZLIB_H

 #ifdef NOBZ2PREFIX

 #define BZ2_bzDecompress bzDecompress
 #define BZ2_bzDecompressEnd bzDecompressEnd
 #define BZ2_bzDecompressInit bzDecompressInit

 #endif
 

   case ALG_BZIP2: {
     bz_stream strm;
     memset(&strm, 0, sizeof(strm));
     strm.next_in = (char *)src;
     strm.next_out = obuf;
     strm.avail_in = csize;
     strm.avail_out = sizeof(obuf);
     if (BZ2_bzDecompressInit(&strm, 0, 0)!=BZ_OK) {
       cli_dbgmsg("cli_unzip: bzinit failed\n");
       break;
     }
     while((res = BZ2_bzDecompress(&strm))==BZ_OK || res==BZ_STREAM_END) {
       if(strm.avail_out!=sizeof(obuf)) {
 	written+=sizeof(obuf)-strm.avail_out;

 	if(ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {

 	  cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (unsigned long int) ctx->engine->maxfilesize);

 	  res = BZ_STREAM_END;

 	  break;
 	}
 	if(cli_writen(of, obuf, sizeof(obuf)-strm.avail_out) != (int)(sizeof(obuf)-strm.avail_out)) {
 	  cli_warnmsg("cli_unzip: falied to write %lu bunzipped bytes\n", sizeof(obuf)-strm.avail_out);

 	  ret = CL_EWRITE;

 	  res = 100;
 	  break;

 	}
 	strm.next_out = obuf;
 	strm.avail_out = sizeof(obuf);

 	if (res == BZ_OK) continue; /* after returning BZ_STREAM_END once, decompress returns an error */

       }
       break;
     }
     BZ2_bzDecompressEnd(&strm);

     if (res == BZ_STREAM_END) res=0;

     break;
   }
 #endif /* HAVE_BZLIB_H */
 

 
   case ALG_IMPLODE: {
     struct xplstate strm;

     strm.next_in = src;
     strm.next_out = (uint8_t *)obuf;

     strm.avail_in = csize;
     strm.avail_out = sizeof(obuf);
     if (explode_init(&strm, flags)!=EXPLODE_OK) {
       cli_dbgmsg("cli_unzip: explode_init() failed\n");
       break;
     }
     while((res = explode(&strm))==EXPLODE_OK) {
       if(strm.avail_out!=sizeof(obuf)) {
 	written+=sizeof(obuf)-strm.avail_out;

 	if(ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {

 	  cli_dbgmsg("cli_unzip: trimming output size to maxfilesize (%lu)\n", (unsigned long int) ctx->engine->maxfilesize);

 	  res = 0;
 	  break;
 	}
 	if(cli_writen(of, obuf, sizeof(obuf)-strm.avail_out) != (int)(sizeof(obuf)-strm.avail_out)) {
 	  cli_warnmsg("cli_unzip: falied to write %lu exploded bytes\n", sizeof(obuf)-strm.avail_out);

 	  ret = CL_EWRITE;

 	  res = 100;
 	  break;

 	}

 	strm.next_out = (uint8_t *)obuf;

 	strm.avail_out = sizeof(obuf);
 	continue;
       }
       break;
     }
     break;
   }
 
 

   case ALG_LZMA:
     /* easy but there's not a single sample in the zoo */
 
 #if !HAVE_BZLIB_H
   case ALG_BZIP2:
 #endif
   case ALG_SHRUNK:
   case ALG_REDUCE1:
   case ALG_REDUCE2:
   case ALG_REDUCE3:
   case ALG_REDUCE4:
   case ALG_TOKENZD:
   case ALG_OLDTERSE:
   case ALG_RSVD1:
   case ALG_RSVD2:
   case ALG_RSVD3:
   case ALG_RSVD4:
   case ALG_RSVD5:
   case ALG_NEWTERSE:
   case ALG_LZ77:
   case ALG_WAVPACK:
   case ALG_PPMD:
     cli_dbgmsg("cli_unzip: unsupported method (%d)\n", method);
     break;
   default:
     cli_dbgmsg("cli_unzip: unknown method (%d)\n", method);
     break;
   }
 
   if(!res) {
     (*fu)++;
     cli_dbgmsg("cli_unzip: extracted to %s\n", tempfile);
     lseek(of, 0, SEEK_SET);
     ret = cli_magic_scandesc(of, ctx);
     close(of);

     if(!ctx->engine->keeptmp)

       if(cli_unlink(tempfile)) ret = CL_EUNLINK;

     if(!tmpd) free(tempfile);
     return ret;
   }
 
   close(of);

   if(!ctx->engine->keeptmp)

     if(cli_unlink(tempfile)) ret = CL_EUNLINK;

   if(!tmpd) free(tempfile);
   cli_dbgmsg("cli_unzip: extraction failed\n");
   return ret;
 }
 

 static unsigned int lhdr(fmap_t *map, uint32_t loff,uint32_t zsize, unsigned int *fu, unsigned int fc, uint8_t *ch, int *ret, cli_ctx *ctx, char *tmpd, int detect_encrypted) {

   uint8_t *lh, *zip;

   char name[256];

   uint32_t csize, usize;

   if(!(lh = fmap_need_off(map, loff, SIZEOF_LH))) {
       cli_dbgmsg("cli_unzip: lh - out of file\n");
       return 0;

   }
   if(LH_magic != 0x04034b50) {
     if (!ch) cli_dbgmsg("cli_unzip: lh - wrkcomplete\n");
     else cli_dbgmsg("cli_unzip: lh - bad magic\n");

     fmap_unneed_off(map, loff, SIZEOF_LH);

     return 0;
   }
 

   zip = lh + SIZEOF_LH;

   zsize-=SIZEOF_LH;
 
   if(zsize<=LH_flen) {
     cli_dbgmsg("cli_unzip: lh - fname out of file\n");

     fmap_unneed_off(map, loff, SIZEOF_LH);

     return 0;
   }

   if(ctx->engine->cdb || cli_debug_flag) {

       uint32_t nsize = (LH_flen>=sizeof(name))?sizeof(name)-1:LH_flen;
       char *src;
       if(nsize && (src = fmap_need_ptr_once(map, zip, nsize))) {
 	  memcpy(name, zip, nsize);
 	  name[nsize]='\0';
       } else
 	  name[0] = '\0';

   }
   zip+=LH_flen;
   zsize-=LH_flen;
 

   cli_dbgmsg("cli_unzip: lh - ZMDNAME:%d:%s:%u:%u:%x:%u:%u:%u\n", ((LH_flags & F_ENCR)!=0), name, LH_usize, LH_csize, LH_crc32, LH_method, fc, ctx->recursion);

   /* ZMDfmt virname:encrypted(0-1):filename(exact|*):usize(exact|*):csize(exact|*):crc32(exact|*):method(exact|*):fileno(exact|*):maxdepth(exact|*) */
 

   if(cli_matchmeta(ctx, name, LH_csize, LH_usize, (LH_flags & F_ENCR)!=0, fc, LH_crc32, NULL) == CL_VIRUS) {

     *ret = CL_VIRUS;

     return 0;
   }
 
   if(LH_flags & F_MSKED) {
     cli_dbgmsg("cli_unzip: lh - header has got unusable masked data\n");
     /* FIXME: need to find/craft a sample */

     fmap_unneed_off(map, loff, SIZEOF_LH);

     return 0;
   }
 

   if(detect_encrypted && (LH_flags & F_ENCR) && DETECT_ENCRYPTED) {

     cli_dbgmsg("cli_unzip: Encrypted files found in archive.\n");

     cli_append_virus(ctx, "Heuristics.Encrypted.Zip");

     *ret = CL_VIRUS;

     fmap_unneed_off(map, loff, SIZEOF_LH);

     return 0;
   }
  

   if(LH_flags & F_USEDD) {
     cli_dbgmsg("cli_unzip: lh - has data desc\n");

     if(!ch) {

 	fmap_unneed_off(map, loff, SIZEOF_LH);

 	return 0;
     }

     else { usize = CH_usize; csize = CH_csize; }
   } else { usize = LH_usize; csize = LH_csize; }

 
   if(zsize<=LH_elen) {
     cli_dbgmsg("cli_unzip: lh - extra out of file\n");

     fmap_unneed_off(map, loff, SIZEOF_LH);

     return 0;
   }
   zip+=LH_elen;
   zsize-=LH_elen;
 
   if (!csize) { /* FIXME: what's used for method0 files? csize or usize? Nothing in the specs, needs testing */

       cli_dbgmsg("cli_unzip: lh - skipping empty file\n");

   } else {

       if(zsize<csize) {
 	  cli_dbgmsg("cli_unzip: lh - stream out of file\n");

 	  fmap_unneed_off(map, loff, SIZEOF_LH);

 	  return 0;
       }
       if(LH_flags & F_ENCR) {
 	  cli_dbgmsg("cli_unzip: lh - skipping encrypted file\n");
       } else {
 	  if(fmap_need_ptr_once(map, zip, csize))
 	      *ret = unz(zip, csize, usize, LH_method, LH_flags, fu, ctx, tmpd);
       }
       zip+=csize;
       zsize-=csize;

   }
 

   fmap_unneed_off(map, loff, SIZEOF_LH); /* unneed now. block is guaranteed to exists till the next need */

   if(LH_flags & F_USEDD) {

       if(zsize<12) {
 	  cli_dbgmsg("cli_unzip: lh - data desc out of file\n");
 	  return 0;

       }

       zsize-=12;
       if(fmap_need_ptr_once(map, zip, 4)) {
 	  if(cli_readint32(zip)==0x08074b50) {
 	      if(zsize<4) {
 		  cli_dbgmsg("cli_unzip: lh - data desc out of file\n");
 		  return 0;
 	      }
 	      zip+=4;
 	  }
       }
       zip+=12;

   }
   return zip-lh;
 }
 
 

 static unsigned int chdr(fmap_t *map, uint32_t coff, uint32_t zsize, unsigned int *fu, unsigned int fc, int *ret, cli_ctx *ctx, char *tmpd) {

   char name[256];
   int last = 0;

   uint8_t *ch;

   if(!(ch = fmap_need_off(map, coff, SIZEOF_CH)) || CH_magic != 0x02014b50) {
       if(ch) fmap_unneed_ptr(map, ch, SIZEOF_CH);
       cli_dbgmsg("cli_unzip: ch - wrkcomplete\n");
       return 0;

   }
   coff+=SIZEOF_CH;
 
   cli_dbgmsg("cli_unzip: ch - flags %x - method %x - csize %x - usize %x - flen %x - elen %x - clen %x - disk %x - off %x\n", CH_flags, CH_method, CH_csize, CH_usize, CH_flen, CH_elen, CH_clen, CH_dsk, CH_off);
 
   if(zsize-coff<=CH_flen) {
     cli_dbgmsg("cli_unzip: ch - fname out of file\n");
     last=1;
   }
   if(cli_debug_flag && !last) {

       unsigned int size = (CH_flen>=sizeof(name))?sizeof(name)-1:CH_flen;
       char *src = fmap_need_off_once(map, coff, size);
       if(src) {
 	  memcpy(name, src, size);
 	  name[size]='\0';
 	  cli_dbgmsg("cli_unzip: ch - fname: %s\n", name);
       }

   }
   coff+=CH_flen;
 
   if(zsize-coff<=CH_elen && !last) {
     cli_dbgmsg("cli_unzip: ch - extra out of file\n");
     last=1;
   }
   coff+=CH_elen;
 
   if(zsize-coff<CH_clen && !last) {
     cli_dbgmsg("cli_unzip: ch - comment out of file\n");
     last = 1;
   }
   coff+=CH_clen;
 
   if(CH_off<zsize-SIZEOF_LH) {

       lhdr(map, CH_off, zsize-CH_off, fu, fc, ch, ret, ctx, tmpd, 1);

   } else cli_dbgmsg("cli_unzip: ch - local hdr out of file\n");

   fmap_unneed_ptr(map, ch, SIZEOF_CH);

   return last?0:coff;
 }
 
 

 int cli_unzip(cli_ctx *ctx) {

   unsigned int fc=0, fu=0;
   int ret=CL_CLEAN;
   uint32_t fsize, lhoff = 0, coff = 0;

   fmap_t *map = *ctx->fmap;

   char *tmpd, *ptr;

 
   cli_dbgmsg("in cli_unzip\n");

   fsize = (uint32_t)map->len;
   if(sizeof(off_t)!=sizeof(uint32_t) && (off_t)fsize!=map->len) {

     cli_dbgmsg("cli_unzip: file too big\n");
     return CL_CLEAN;
   }
   if (fsize < SIZEOF_CH) {
     cli_dbgmsg("cli_unzip: file too short\n");
     return CL_CLEAN;
   }

   if (!(tmpd = cli_gentemp(ctx->engine->tmpdir))) {

     return CL_ETMPDIR;

   }

   if (mkdir(tmpd, 0700)) {
     cli_dbgmsg("cli_unzip: Can't create temporary directory %s\n", tmpd);
     free(tmpd);
     return CL_ETMPDIR;
   }
 
   for(coff=fsize-22 ; coff>0 ; coff--) { /* sizeof(EOC)==22 */

       if(!(ptr = fmap_need_off_once(map, coff, 20)))
 	  continue;
       if(cli_readint32(ptr)==0x06054b50) {
 	  uint32_t chptr = cli_readint32(&ptr[16]);
 	  if(!CLI_ISCONTAINED(0, fsize, chptr, SIZEOF_CH)) continue;
 	  coff=chptr;
 	  break;
       }

   }
 
   if(coff) {

       cli_dbgmsg("cli_unzip: central @%x\n", coff);

       while(ret==CL_CLEAN && (coff=chdr(map, coff, fsize, &fu, fc+1, &ret, ctx, tmpd))) {

 	  fc++;
 	  if (ctx->engine->maxfiles && fu>=ctx->engine->maxfiles) {
 	      cli_dbgmsg("cli_unzip: Files limit reached (max: %u)\n", ctx->engine->maxfiles);
 	      ret=CL_EMAXFILES;
 	  }

       }
   } else cli_dbgmsg("cli_unzip: central not found, using localhdrs\n");
   if(fu<=(fc/4)) { /* FIXME: make up a sane ratio or remove the whole logic */
     fc = 0;

     while (ret==CL_CLEAN && lhoff<fsize && (coff=lhdr(map, lhoff, fsize-lhoff, &fu, fc+1, NULL, &ret, ctx, tmpd, 1))) {

       fc++;
       lhoff+=coff;

       if (ctx->engine->maxfiles && fu>=ctx->engine->maxfiles) {
 	cli_dbgmsg("cli_unzip: Files limit reached (max: %u)\n", ctx->engine->maxfiles);

 	ret=CL_EMAXFILES;
       }
     }
   }
 

   if (!ctx->engine->keeptmp) cli_rmdirs(tmpd);

   free(tmpd);
 
   return ret;
 }
 

 int cli_unzip_single(cli_ctx *ctx, off_t lhoffl) {

   int ret=CL_CLEAN;
   unsigned int fu=0;
   uint32_t fsize;

   fmap_t *map = *ctx->fmap;

 
   cli_dbgmsg("in cli_unzip_single\n");

   fsize = (uint32_t)(map->len - lhoffl);
   if (lhoffl<0 || lhoffl>map->len || (sizeof(off_t)!=sizeof(uint32_t) && (off_t)fsize!=map->len - lhoffl)) {

     cli_dbgmsg("cli_unzip: bad offset\n");
     return CL_CLEAN;
   }
   if (fsize < SIZEOF_LH) {
     cli_dbgmsg("cli_unzip: file too short\n");
     return CL_CLEAN;
   }
 

   lhdr(map, lhoffl, fsize, &fu, 0, NULL, &ret, ctx, NULL, 0);

 
   return ret;
 }