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/*
* Copyright (C) 2021 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 2 of the
* License, or 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.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/deflate.h>
#include <ipxe/uaccess.h>
#include <ipxe/image.h>
#include <ipxe/zlib.h>
#include <ipxe/gzip.h>
/** @file
*
* gzip compressed images
*
*/
/**
* Extract gzip image
*
* @v image Image
* @v extracted Extracted image
* @ret rc Return status code
*/
static int gzip_extract ( struct image *image, struct image *extracted ) {
struct gzip_header header;
struct gzip_extra_header extra;
struct gzip_crc_header crc;
struct gzip_footer footer;
struct deflate_chunk in;
unsigned int strings;
size_t offset;
size_t len;
off_t nul;
int rc;
/* Sanity check */
assert ( image->len >= ( sizeof ( header ) + sizeof ( footer ) ) );
/* Extract footer */
len = ( image->len - sizeof ( footer ) );
copy_from_user ( &footer, image->data, len, sizeof ( footer ) );
/* Extract fixed header */
copy_from_user ( &header, image->data, 0, sizeof ( header ) );
offset = sizeof ( header );
assert ( offset <= ( image->len - sizeof ( footer ) ) );
/* Skip extra header, if present */
if ( header.flags & GZIP_FL_EXTRA ) {
copy_from_user ( &extra, image->data, offset,
sizeof ( extra ) );
offset += sizeof ( extra );
offset += le16_to_cpu ( extra.len );
if ( offset > len ) {
DBGC ( image, "GZIP %p overlength extra header\n",
image );
return -EINVAL;
}
}
assert ( offset <= ( image->len - sizeof ( footer ) ) );
/* Skip name and/or comment, if present */
strings = 0;
if ( header.flags & GZIP_FL_NAME )
strings++;
if ( header.flags & GZIP_FL_COMMENT )
strings++;
while ( strings-- ) {
nul = memchr_user ( image->data, offset, 0, ( len - offset ) );
if ( nul < 0 ) {
DBGC ( image, "GZIP %p overlength name/comment\n",
image );
return -EINVAL;
}
offset = ( nul + 1 /* NUL */ );
}
assert ( offset <= ( image->len - sizeof ( footer ) ) );
/* Skip CRC, if present */
if ( header.flags & GZIP_FL_HCRC ) {
offset += sizeof ( crc );
if ( offset > len ) {
DBGC ( image, "GZIP %p overlength CRC header\n",
image );
return -EINVAL;
}
}
/* Initialise input chunk */
deflate_chunk_init ( &in, userptr_add ( image->data, offset ), 0, len );
/* Presize extracted image */
if ( ( rc = image_set_len ( extracted,
le32_to_cpu ( footer.len ) ) ) != 0 ) {
DBGC ( image, "GZIP %p could not presize: %s\n",
image, strerror ( rc ) );
return rc;
}
/* Decompress image (expanding if necessary) */
if ( ( rc = zlib_deflate ( DEFLATE_RAW, &in, extracted ) ) != 0 ) {
DBGC ( image, "GZIP %p could not decompress: %s\n",
image, strerror ( rc ) );
return rc;
}
return 0;
}
/**
* Probe gzip image
*
* @v image gzip image
* @ret rc Return status code
*/
static int gzip_probe ( struct image *image ) {
struct gzip_header header;
struct gzip_footer footer;
/* Sanity check */
if ( image->len < ( sizeof ( header ) + sizeof ( footer ) ) ) {
DBGC ( image, "GZIP %p image too short\n", image );
return -ENOEXEC;
}
/* Check magic header */
copy_from_user ( &header.magic, image->data, 0,
sizeof ( header.magic ) );
if ( header.magic != cpu_to_be16 ( GZIP_MAGIC ) ) {
DBGC ( image, "GZIP %p invalid magic\n", image );
return -ENOEXEC;
}
return 0;
}
/** gzip image type */
struct image_type gzip_image_type __image_type ( PROBE_NORMAL ) = {
.name = "gzip",
.probe = gzip_probe,
.extract = gzip_extract,
.exec = image_extract_exec,
};
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