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4c5f00f879
Windows text editors such as Notepad tend to use CRLF line endings, which breaks gPXE's signature detection for script images. Since scripts are usually very small, they end up falling back to being detected as valid PXE executable images (since there are no signature checks for PXE executables). Executing text files as x86 machine code tends not to work well. Fix by allowing for any isspace() character to terminate the "#!gpxe" signature, and by ensuring that CR characters get stripped during command line parsing. Suggested-by: Shao Miller <Shao.Miller@yrdsb.edu.on.ca>
127 lines
3.0 KiB
C
127 lines
3.0 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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FILE_LICENCE ( GPL2_OR_LATER );
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/**
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* @file
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*
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* gPXE scripts
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*
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*/
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#include <string.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <errno.h>
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#include <gpxe/image.h>
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struct image_type script_image_type __image_type ( PROBE_NORMAL );
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/**
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* Execute script
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*
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* @v image Script
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* @ret rc Return status code
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*/
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static int script_exec ( struct image *image ) {
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size_t offset = 0;
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off_t eol;
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size_t len;
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int rc;
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/* Temporarily de-register image, so that a "boot" command
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* doesn't throw us into an execution loop.
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*/
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unregister_image ( image );
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while ( offset < image->len ) {
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/* Find length of next line, excluding any terminating '\n' */
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eol = memchr_user ( image->data, offset, '\n',
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( image->len - offset ) );
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if ( eol < 0 )
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eol = image->len;
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len = ( eol - offset );
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/* Copy line, terminate with NUL, and execute command */
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{
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char cmdbuf[ len + 1 ];
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copy_from_user ( cmdbuf, image->data, offset, len );
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cmdbuf[len] = '\0';
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DBG ( "$ %s\n", cmdbuf );
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if ( ( rc = system ( cmdbuf ) ) != 0 ) {
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DBG ( "Command \"%s\" failed: %s\n",
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cmdbuf, strerror ( rc ) );
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goto done;
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}
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}
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/* Move to next line */
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offset += ( len + 1 );
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}
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rc = 0;
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done:
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/* Re-register image and return */
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register_image ( image );
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return rc;
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}
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/**
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* Load script into memory
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*
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* @v image Script
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* @ret rc Return status code
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*/
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static int script_load ( struct image *image ) {
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static const char magic[] = "#!gpxe";
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char test[ sizeof ( magic ) - 1 /* NUL */ + 1 /* terminating space */];
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/* Sanity check */
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if ( image->len < sizeof ( test ) ) {
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DBG ( "Too short to be a script\n" );
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return -ENOEXEC;
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}
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/* Check for magic signature */
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copy_from_user ( test, image->data, 0, sizeof ( test ) );
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if ( ( memcmp ( test, magic, ( sizeof ( test ) - 1 ) ) != 0 ) ||
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! isspace ( test[ sizeof ( test ) - 1 ] ) ) {
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DBG ( "Invalid magic signature\n" );
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return -ENOEXEC;
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}
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/* This is a script */
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image->type = &script_image_type;
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/* We don't actually load it anywhere; we will pick the lines
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* out of the image as we need them.
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*/
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return 0;
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}
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/** Script image type */
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struct image_type script_image_type __image_type ( PROBE_NORMAL ) = {
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.name = "script",
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.load = script_load,
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.exec = script_exec,
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};
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