freebsd-dev/sys/boot/i386/libi386/bootinfo32.c
Allan Jude ec5c0e5be9 Implement boot-time encryption key passing (keybuf)
This patch adds a general mechanism for providing encryption keys to the
kernel from the boot loader. This is intended to enable GELI support at
boot time, providing a better mechanism for passing keys to the kernel
than environment variables. It is designed to be extensible to other
applications, and can easily handle multiple encrypted volumes with
different keys.

This mechanism is currently used by the pending GELI EFI work.
Additionally, this mechanism can potentially be used to interface with
GRUB, opening up options for coreboot+GRUB configurations with completely
encrypted disks.

Another benefit over the existing system is that it does not require
re-deriving the user key from the password at each boot stage.

Most of this patch was written by Eric McCorkle. It was extended by
Allan Jude with a number of minor enhancements and extending the keybuf
feature into boot2.

GELI user keys are now derived once, in boot2, then passed to the loader,
which reuses the key, then passes it to the kernel, where the GELI module
destroys the keybuf after decrypting the volumes.

Submitted by:	Eric McCorkle <eric@metricspace.net> (Original Version)
Reviewed by:	oshogbo (earlier version), cem (earlier version)
MFC after:	3 weeks
Relnotes:	yes
Sponsored by:	ScaleEngine Inc.
Differential Revision:	https://reviews.freebsd.org/D9575
2017-04-01 05:05:22 +00:00

292 lines
9.0 KiB
C

/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include <sys/param.h>
#include <sys/reboot.h>
#include <sys/linker.h>
#include <machine/bootinfo.h>
#include <machine/metadata.h>
#include "bootstrap.h"
#include "libi386.h"
#include "btxv86.h"
#ifdef LOADER_GELI_SUPPORT
#include "geliboot.h"
static const size_t keybuf_size = sizeof(struct keybuf) +
(GELI_MAX_KEYS * sizeof(struct keybuf_ent));
#endif
static struct bootinfo bi;
/*
* Copy module-related data into the load area, where it can be
* used as a directory for loaded modules.
*
* Module data is presented in a self-describing format. Each datum
* is preceded by a 32-bit identifier and a 32-bit size field.
*
* Currently, the following data are saved:
*
* MOD_NAME (variable) module name (string)
* MOD_TYPE (variable) module type (string)
* MOD_ARGS (variable) module parameters (string)
* MOD_ADDR sizeof(vm_offset_t) module load address
* MOD_SIZE sizeof(size_t) module size
* MOD_METADATA (variable) type-specific metadata
*/
#define COPY32(v, a, c) { \
u_int32_t x = (v); \
if (c) \
i386_copyin(&x, a, sizeof(x)); \
a += sizeof(x); \
}
#define MOD_STR(t, a, s, c) { \
COPY32(t, a, c); \
COPY32(strlen(s) + 1, a, c); \
if (c) \
i386_copyin(s, a, strlen(s) + 1); \
a += roundup(strlen(s) + 1, sizeof(u_long));\
}
#define MOD_NAME(a, s, c) MOD_STR(MODINFO_NAME, a, s, c)
#define MOD_TYPE(a, s, c) MOD_STR(MODINFO_TYPE, a, s, c)
#define MOD_ARGS(a, s, c) MOD_STR(MODINFO_ARGS, a, s, c)
#define MOD_VAR(t, a, s, c) { \
COPY32(t, a, c); \
COPY32(sizeof(s), a, c); \
if (c) \
i386_copyin(&s, a, sizeof(s)); \
a += roundup(sizeof(s), sizeof(u_long)); \
}
#define MOD_ADDR(a, s, c) MOD_VAR(MODINFO_ADDR, a, s, c)
#define MOD_SIZE(a, s, c) MOD_VAR(MODINFO_SIZE, a, s, c)
#define MOD_METADATA(a, mm, c) { \
COPY32(MODINFO_METADATA | mm->md_type, a, c); \
COPY32(mm->md_size, a, c); \
if (c) \
i386_copyin(mm->md_data, a, mm->md_size); \
a += roundup(mm->md_size, sizeof(u_long));\
}
#define MOD_END(a, c) { \
COPY32(MODINFO_END, a, c); \
COPY32(0, a, c); \
}
static vm_offset_t
bi_copymodules32(vm_offset_t addr)
{
struct preloaded_file *fp;
struct file_metadata *md;
int c;
c = addr != 0;
/* start with the first module on the list, should be the kernel */
for (fp = file_findfile(NULL, NULL); fp != NULL; fp = fp->f_next) {
MOD_NAME(addr, fp->f_name, c); /* this field must come first */
MOD_TYPE(addr, fp->f_type, c);
if (fp->f_args)
MOD_ARGS(addr, fp->f_args, c);
MOD_ADDR(addr, fp->f_addr, c);
MOD_SIZE(addr, fp->f_size, c);
for (md = fp->f_metadata; md != NULL; md = md->md_next)
if (!(md->md_type & MODINFOMD_NOCOPY))
MOD_METADATA(addr, md, c);
}
MOD_END(addr, c);
return(addr);
}
/*
* Load the information expected by an i386 kernel.
*
* - The 'boothowto' argument is constructed
* - The 'bootdev' argument is constructed
* - The 'bootinfo' struct is constructed, and copied into the kernel space.
* - The kernel environment is copied into kernel space.
* - Module metadata are formatted and placed in kernel space.
*/
int
bi_load32(char *args, int *howtop, int *bootdevp, vm_offset_t *bip, vm_offset_t *modulep, vm_offset_t *kernendp)
{
struct preloaded_file *xp, *kfp;
struct i386_devdesc *rootdev;
struct file_metadata *md;
vm_offset_t addr;
vm_offset_t kernend;
vm_offset_t envp;
vm_offset_t size;
vm_offset_t ssym, esym;
char *rootdevname;
int bootdevnr, i, howto;
char *kernelname;
const char *kernelpath;
#ifdef LOADER_GELI_SUPPORT
char buf[keybuf_size];
struct keybuf *keybuf = (struct keybuf *)buf;
#endif
howto = bi_getboothowto(args);
/*
* Allow the environment variable 'rootdev' to override the supplied device
* This should perhaps go to MI code and/or have $rootdev tested/set by
* MI code before launching the kernel.
*/
rootdevname = getenv("rootdev");
i386_getdev((void **)(&rootdev), rootdevname, NULL);
if (rootdev == NULL) { /* bad $rootdev/$currdev */
printf("can't determine root device\n");
return(EINVAL);
}
/* Try reading the /etc/fstab file to select the root device */
getrootmount(i386_fmtdev((void *)rootdev));
/* Do legacy rootdev guessing */
/* XXX - use a default bootdev of 0. Is this ok??? */
bootdevnr = 0;
switch(rootdev->d_type) {
case DEVT_CD:
/* Pass in BIOS device number. */
bi.bi_bios_dev = bc_unit2bios(rootdev->d_unit);
bootdevnr = bc_getdev(rootdev);
break;
case DEVT_DISK:
/* pass in the BIOS device number of the current disk */
bi.bi_bios_dev = bd_unit2bios(rootdev->d_unit);
bootdevnr = bd_getdev(rootdev);
break;
case DEVT_NET:
case DEVT_ZFS:
break;
default:
printf("WARNING - don't know how to boot from device type %d\n", rootdev->d_type);
}
if (bootdevnr == -1) {
printf("root device %s invalid\n", i386_fmtdev(rootdev));
return (EINVAL);
}
free(rootdev);
/* find the last module in the chain */
addr = 0;
for (xp = file_findfile(NULL, NULL); xp != NULL; xp = xp->f_next) {
if (addr < (xp->f_addr + xp->f_size))
addr = xp->f_addr + xp->f_size;
}
/* pad to a page boundary */
addr = roundup(addr, PAGE_SIZE);
/* copy our environment */
envp = addr;
addr = bi_copyenv(addr);
/* pad to a page boundary */
addr = roundup(addr, PAGE_SIZE);
kfp = file_findfile(NULL, "elf kernel");
if (kfp == NULL)
kfp = file_findfile(NULL, "elf32 kernel");
if (kfp == NULL)
panic("can't find kernel file");
kernend = 0; /* fill it in later */
file_addmetadata(kfp, MODINFOMD_HOWTO, sizeof howto, &howto);
file_addmetadata(kfp, MODINFOMD_ENVP, sizeof envp, &envp);
file_addmetadata(kfp, MODINFOMD_KERNEND, sizeof kernend, &kernend);
bios_addsmapdata(kfp);
#ifdef LOADER_GELI_SUPPORT
geli_fill_keybuf(keybuf);
file_addmetadata(kfp, MODINFOMD_KEYBUF, keybuf_size, buf);
bzero(buf, sizeof(buf));
#endif
/* Figure out the size and location of the metadata */
*modulep = addr;
size = bi_copymodules32(0);
kernend = roundup(addr + size, PAGE_SIZE);
*kernendp = kernend;
/* patch MODINFOMD_KERNEND */
md = file_findmetadata(kfp, MODINFOMD_KERNEND);
bcopy(&kernend, md->md_data, sizeof kernend);
/* copy module list and metadata */
(void)bi_copymodules32(addr);
ssym = esym = 0;
md = file_findmetadata(kfp, MODINFOMD_SSYM);
if (md != NULL)
ssym = *((vm_offset_t *)&(md->md_data));
md = file_findmetadata(kfp, MODINFOMD_ESYM);
if (md != NULL)
esym = *((vm_offset_t *)&(md->md_data));
if (ssym == 0 || esym == 0)
ssym = esym = 0; /* sanity */
/* legacy bootinfo structure */
kernelname = getenv("kernelname");
i386_getdev(NULL, kernelname, &kernelpath);
bi.bi_version = BOOTINFO_VERSION;
bi.bi_kernelname = 0; /* XXX char * -> kernel name */
bi.bi_nfs_diskless = 0; /* struct nfs_diskless * */
bi.bi_n_bios_used = 0; /* XXX would have to hook biosdisk driver for these */
for (i = 0; i < N_BIOS_GEOM; i++)
bi.bi_bios_geom[i] = bd_getbigeom(i);
bi.bi_size = sizeof(bi);
bi.bi_memsizes_valid = 1;
bi.bi_basemem = bios_basemem / 1024;
bi.bi_extmem = bios_extmem / 1024;
bi.bi_envp = envp;
bi.bi_modulep = *modulep;
bi.bi_kernend = kernend;
bi.bi_kernelname = VTOP(kernelpath);
bi.bi_symtab = ssym; /* XXX this is only the primary kernel symtab */
bi.bi_esymtab = esym;
/* legacy boot arguments */
*howtop = howto | RB_BOOTINFO;
*bootdevp = bootdevnr;
*bip = VTOP(&bi);
return(0);
}