mirror of
https://github.com/ipxe/ipxe
synced 2026-04-04 03:00:20 +03:00
3475b693b7
PXE is a catch-all image format with no signature checks. If an unsupported image file is loaded, it will be treated as a PXE image. In most cases, the image will be too large to be loaded as a PXE image (which has to fit in base memory), so the error returned to the user will be that the segment could not fit within the memory region. Add an explicit check to pxe_image.c to reject images larger than base memory with ENOEXEC. Add ENOEXEC to the error string table.
118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/**
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* @file
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*
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* PXE image format
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*
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*/
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#include <pxe.h>
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#include <pxe_call.h>
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#include <gpxe/uaccess.h>
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#include <gpxe/image.h>
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#include <gpxe/segment.h>
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#include <gpxe/netdevice.h>
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#include <gpxe/features.h>
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FEATURE ( FEATURE_IMAGE, "PXE", DHCP_EB_FEATURE_PXE, 1 );
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struct image_type pxe_image_type __image_type ( PROBE_PXE );
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/**
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* Execute PXE image
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*
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* @v image PXE image
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* @ret rc Return status code
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*/
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static int pxe_exec ( struct image *image ) {
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struct net_device *netdev;
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int rc;
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/* Ensure that PXE stack is ready to use */
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pxe_init_structures();
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pxe_hook_int1a();
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/* Arbitrarily pick the first open network device to use for PXE */
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for_each_netdev ( netdev ) {
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pxe_set_netdev ( netdev );
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break;
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}
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/* Many things will break if pxe_netdev is NULL */
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if ( ! pxe_netdev ) {
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DBGC ( image, "IMAGE %p could not locate PXE net device\n",
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image );
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return -ENODEV;
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}
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/* Start PXE NBP */
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rc = pxe_start_nbp();
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/* Deactivate PXE */
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pxe_set_netdev ( NULL );
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pxe_unhook_int1a();
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return rc;
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}
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/**
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* Load PXE image into memory
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*
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* @v image PXE file
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* @ret rc Return status code
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*/
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int pxe_load ( struct image *image ) {
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userptr_t buffer = real_to_user ( 0, 0x7c00 );
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size_t filesz = image->len;
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size_t memsz = image->len;
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int rc;
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/* Images too large to fit in base memory cannot be PXE
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* images. We include this check to help prevent unrecognised
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* images from being marked as PXE images, since PXE images
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* have no signature we can check against.
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*/
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if ( filesz > ( 0xa0000 - 0x7c00 ) )
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return -ENOEXEC;
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/* There are no signature checks for PXE; we will accept anything */
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if ( ! image->type )
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image->type = &pxe_image_type;
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/* Verify and prepare segment */
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if ( ( rc = prep_segment ( buffer, filesz, memsz ) ) != 0 ) {
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DBGC ( image, "IMAGE %p could not prepare segment: %s\n",
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image, strerror ( rc ) );
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return rc;
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}
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/* Copy image to segment */
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memcpy_user ( buffer, 0, image->data, 0, filesz );
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return 0;
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}
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/** PXE image type */
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struct image_type pxe_image_type __image_type ( PROBE_PXE ) = {
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.name = "PXE",
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.load = pxe_load,
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.exec = pxe_exec,
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};
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