/* unzip.c -- decompress files in gzip or pkzip format. Copyright (C) 1997-1999, 2009-2023 Free Software Foundation, Inc. Copyright (C) 1992-1993 Jean-loup Gailly This program 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, or (at your option) any later version. 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. */ /* * The code in this file is derived from the file funzip.c written * and put in the public domain by Mark Adler. */ /* This version can extract files in gzip or pkzip format. For the latter, only the first entry is extracted, and it has to be either deflated or stored. */ #include #include "tailor.h" #include "gzip.h" /* PKZIP header definitions */ #define LOCSIG 0x04034b50L /* four-byte lead-in (lsb first) */ #define LOCFLG 6 /* offset of bit flag */ #define CRPFLG 1 /* bit for encrypted entry */ #define EXTFLG 8 /* bit for extended local header */ #define LOCHOW 8 /* offset of compression method */ /* #define LOCTIM 10 UNUSED file mod time (for decryption) */ #define LOCCRC 14 /* offset of crc */ #define LOCSIZ 18 /* offset of compressed size */ #define LOCLEN 22 /* offset of uncompressed length */ #define LOCFIL 26 /* offset of file name field length */ #define LOCEXT 28 /* offset of extra field length */ #define LOCHDR 30 /* size of local header, including sig */ #define EXTHDR 16 /* size of extended local header, inc sig */ #define RAND_HEAD_LEN 12 /* length of encryption random header */ /* Globals */ ulg unzip_crc; /* CRC found by 'unzip'. */ static int decrypt; /* flag to turn on decryption */ static int pkzip = 0; /* set for a pkzip file */ static int ext_header = 0; /* set if extended local header */ /* =========================================================================== * Check zip file and advance inptr to the start of the compressed data. * Get ofname from the local header if necessary. * IN is the input file descriptor. */ int check_zipfile (int in) { uch *h = inbuf + inptr; /* first local header */ ifd = in; /* Check validity of local header, and skip name and extra fields */ inptr += LOCHDR + SH(h + LOCFIL) + SH(h + LOCEXT); if (inptr > insize || LG(h) != LOCSIG) { fprintf(stderr, "\n%s: %s: not a valid zip file\n", program_name, ifname); exit_code = ERROR; return ERROR; } method = h[LOCHOW]; if (method != STORED && method != DEFLATED) { fprintf(stderr, "\n%s: %s: first entry not deflated or stored -- use unzip\n", program_name, ifname); exit_code = ERROR; return ERROR; } /* If entry encrypted, decrypt and validate encryption header */ if ((decrypt = h[LOCFLG] & CRPFLG) != 0) { fprintf(stderr, "\n%s: %s: encrypted file -- use unzip\n", program_name, ifname); exit_code = ERROR; return ERROR; } /* Save flags for unzip() */ ext_header = (h[LOCFLG] & EXTFLG) != 0; pkzip = 1; /* Get ofname and timestamp from local header (to be done) */ return OK; } /* =========================================================================== * Unzip in to out. This routine works on both gzip and pkzip files. * * IN assertions: the buffer inbuf contains already the beginning of * the compressed data, from offsets inptr to insize-1 included. * The magic header has already been checked. The output buffer is cleared. * * 'in' and 'out' are the input and output file descriptors. */ int unzip (int in, int out) { ulg orig_crc = 0; /* original crc */ ulg orig_len = 0; /* original uncompressed length */ int n; uch buf[EXTHDR]; /* extended local header */ int err = OK; ifd = in; ofd = out; updcrc(NULL, 0); /* initialize crc */ if (pkzip && !ext_header) { /* crc and length at the end otherwise */ orig_crc = LG(inbuf + LOCCRC); orig_len = LG(inbuf + LOCLEN); } /* Decompress */ if (method == DEFLATED) { #ifdef IBM_Z_DFLTCC int res = dfltcc_inflate (); #else int res = inflate(); #endif if (res == 3) { xalloc_die (); } else if (res != 0) { gzip_error ("invalid compressed data--format violated"); } } else if (pkzip && method == STORED) { register ulg n = LG(inbuf + LOCLEN); if (n != LG(inbuf + LOCSIZ) - (decrypt ? RAND_HEAD_LEN : 0)) { fprintf(stderr, "len %lu, siz %lu\n", n, LG(inbuf + LOCSIZ)); gzip_error ("invalid compressed data--length mismatch"); } while (n--) { uch c = (uch)get_byte(); put_ubyte(c); } flush_window(); } else { gzip_error ("internal error, invalid method"); } /* Get the crc and original length */ if (!pkzip) { /* crc32 (see algorithm.doc) * uncompressed input size modulo 2^32 */ for (n = 0; n < 8; n++) { buf[n] = (uch)get_byte(); /* may cause an error if EOF */ } orig_crc = LG(buf); orig_len = LG(buf+4); } else if (ext_header) { /* If extended header, check it */ /* signature - 4bytes: 0x50 0x4b 0x07 0x08 * CRC-32 value * compressed size 4-bytes * uncompressed size 4-bytes */ for (n = 0; n < EXTHDR; n++) { buf[n] = (uch)get_byte(); /* may cause an error if EOF */ } orig_crc = LG(buf+4); orig_len = LG(buf+12); } /* Validate decompression */ if (orig_crc != updcrc(outbuf, 0)) { fprintf(stderr, "\n%s: %s: invalid compressed data--crc error\n", program_name, ifname); err = ERROR; } if (orig_len != (ulg)(bytes_out & 0xffffffff)) { fprintf(stderr, "\n%s: %s: invalid compressed data--length error\n", program_name, ifname); err = ERROR; } /* Check if there are more entries in a pkzip file */ if (pkzip && inptr + 4 < insize && LG(inbuf+inptr) == LOCSIG) { if (to_stdout) { WARN((stderr, "%s: %s has more than one entry--rest ignored\n", program_name, ifname)); } else { /* Don't destroy the input zip file */ fprintf(stderr, "%s: %s has more than one entry -- unchanged\n", program_name, ifname); err = ERROR; } } ext_header = pkzip = 0; /* for next file */ unzip_crc = orig_crc; if (err == OK) return OK; exit_code = ERROR; if (!test) abort_gzip(); return err; }