freebsd-dev/stand/i386/loader/chain.c
Simon J. Gerraty 91cd69ee2c veloader use vectx API for kernel and modules
The vectx API, computes the hash for verifying a file as it is read.
This avoids the overhead of reading files twice - once to verify, then
again to load.

For doing an install via loader, avoiding the need to rewind
large files is critical.

This API is only used for modules, kernel and mdimage as these are the
biggest files read by the loader.
The reduction in boot time depends on how expensive the I/O is
on any given platform.  On a fast VM we see 6% improvement.

For install via loader the first file to be verified is likely to be the
kernel, so some of the prep work (finding manifest etc) done by
verify_file() needs to be factored so it can be reused for
vectx_open().

For missing or unrecognized fingerprint entries, we fail
in vectx_open() unless verifying is disabled.

Otherwise fingerprint check happens in vectx_close() and
since this API is only used for files which must be verified
(VE_MUST) we panic if we get an incorrect hash.

Reviewed by:	imp,tsoome
MFC after:	1 week
Sponsored by:	Juniper Networks
Differential Revision:	https://reviews.freebsd.org//D23827
2020-03-09 16:02:54 +00:00

170 lines
4.4 KiB
C

/*-
* Copyright 2015 Toomas Soome <tsoome@me.com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Chain loader to load BIOS boot block either from MBR or PBR.
*
* Note the boot block location 0000:7c000 conflicts with loader, so we need to
* read in to temporary space and relocate on exec, when btx is stopped.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include <sys/param.h>
#include <sys/linker.h>
#include <sys/diskmbr.h>
#include "bootstrap.h"
#include "libi386/libi386.h"
#include "btxv86.h"
#ifdef LOADER_VERIEXEC_VECTX
#define VECTX_HANDLE(x) vctx
#else
#define VECTX_HANDLE(x) x
#endif
/*
* The MBR/VBR is located in first sector of disk/partition.
* Read 512B to temporary location and set up relocation. Then
* exec relocator.
*/
#define SECTOR_SIZE (512)
COMMAND_SET(chain, "chain", "chain load boot block from device", command_chain);
static int
command_chain(int argc, char *argv[])
{
int fd, len, size = SECTOR_SIZE;
struct stat st;
vm_offset_t mem = 0x100000;
struct i386_devdesc *rootdev;
#ifdef LOADER_VERIEXEC_VECTX
struct vectx *vctx;
int verror;
#endif
if (argc == 1) {
command_errmsg = "no device or file name specified";
return (CMD_ERROR);
}
if (argc != 2) {
command_errmsg = "invalid trailing arguments";
return (CMD_ERROR);
}
fd = open(argv[1], O_RDONLY);
if (fd == -1) {
command_errmsg = "open failed";
return (CMD_ERROR);
}
#ifdef LOADER_VERIEXEC_VECTX
vctx = vectx_open(fd, argv[1], 0L, NULL, &verror, __func__);
if (verror) {
sprintf(command_errbuf, "can't verify: %s", argv[1]);
close(fd);
free(vctx);
return (CMD_ERROR);
}
#else
#ifdef LOADER_VERIEXEC
if (verify_file(fd, argv[1], 0, VE_MUST, __func__) < 0) {
sprintf(command_errbuf, "can't verify: %s", argv[1]);
close(fd);
return (CMD_ERROR);
}
#endif
#endif
len = strlen(argv[1]);
if (argv[1][len-1] != ':') {
if (fstat(fd, &st) == -1) {
command_errmsg = "stat failed";
close(fd);
return (CMD_ERROR);
}
size = st.st_size;
} else if (strncmp(argv[1], "disk", 4) != 0) {
command_errmsg = "can only use disk device";
close(fd);
return (CMD_ERROR);
}
i386_getdev((void **)(&rootdev), argv[1], NULL);
if (rootdev == NULL) {
command_errmsg = "can't determine root device";
close(fd);
return (CMD_ERROR);
}
if (archsw.arch_readin(VECTX_HANDLE(fd), mem, size) != size) {
command_errmsg = "failed to read disk";
close(fd);
return (CMD_ERROR);
}
close(fd);
#ifdef LOADER_VERIEXEC_VECTX
verror = vectx_close(vctx, VE_MUST, __func__);
if (verror) {
free(vctx);
return (CMD_ERROR);
}
#endif
if (argv[1][len-1] == ':' &&
*((uint16_t *)PTOV(mem + DOSMAGICOFFSET)) != DOSMAGIC) {
command_errmsg = "wrong magic";
return (CMD_ERROR);
}
relocater_data[0].src = mem;
relocater_data[0].dest = 0x7C00;
relocater_data[0].size = size;
relocator_edx = bd_unit2bios(rootdev);
relocator_esi = relocater_size;
relocator_ds = 0;
relocator_es = 0;
relocator_fs = 0;
relocator_gs = 0;
relocator_ss = 0;
relocator_cs = 0;
relocator_sp = 0x7C00;
relocator_ip = 0x7C00;
relocator_a20_enabled = 0;
i386_copyin(relocater, 0x600, relocater_size);
dev_cleanup();
__exec((void *)0x600);
panic("exec returned");
return (CMD_ERROR); /* not reached */
}