ec5c0e5be9
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
281 lines
8.3 KiB
C
281 lines
8.3 KiB
C
/*-
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* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <stand.h>
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#include <sys/param.h>
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#include <sys/reboot.h>
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#include <sys/linker.h>
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#include <machine/bootinfo.h>
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#include <machine/cpufunc.h>
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#include <machine/metadata.h>
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#include <machine/psl.h>
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#include <machine/specialreg.h>
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#include "bootstrap.h"
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#include "libi386.h"
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#include "btxv86.h"
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#ifdef LOADER_GELI_SUPPORT
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#include "geliboot.h"
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static const size_t keybuf_size = sizeof(struct keybuf) +
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(GELI_MAX_KEYS * sizeof(struct keybuf_ent));
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#endif
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/*
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* Copy module-related data into the load area, where it can be
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* used as a directory for loaded modules.
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*
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* Module data is presented in a self-describing format. Each datum
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* is preceded by a 32-bit identifier and a 32-bit size field.
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*
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* Currently, the following data are saved:
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*
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* MOD_NAME (variable) module name (string)
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* MOD_TYPE (variable) module type (string)
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* MOD_ARGS (variable) module parameters (string)
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* MOD_ADDR sizeof(vm_offset_t) module load address
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* MOD_SIZE sizeof(size_t) module size
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* MOD_METADATA (variable) type-specific metadata
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*/
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#define COPY32(v, a, c) { \
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u_int32_t x = (v); \
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if (c) \
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i386_copyin(&x, a, sizeof(x)); \
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a += sizeof(x); \
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}
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#define MOD_STR(t, a, s, c) { \
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COPY32(t, a, c); \
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COPY32(strlen(s) + 1, a, c); \
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if (c) \
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i386_copyin(s, a, strlen(s) + 1); \
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a += roundup(strlen(s) + 1, sizeof(u_int64_t));\
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}
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#define MOD_NAME(a, s, c) MOD_STR(MODINFO_NAME, a, s, c)
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#define MOD_TYPE(a, s, c) MOD_STR(MODINFO_TYPE, a, s, c)
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#define MOD_ARGS(a, s, c) MOD_STR(MODINFO_ARGS, a, s, c)
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#define MOD_VAR(t, a, s, c) { \
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COPY32(t, a, c); \
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COPY32(sizeof(s), a, c); \
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if (c) \
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i386_copyin(&s, a, sizeof(s)); \
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a += roundup(sizeof(s), sizeof(u_int64_t)); \
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}
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#define MOD_ADDR(a, s, c) MOD_VAR(MODINFO_ADDR, a, s, c)
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#define MOD_SIZE(a, s, c) MOD_VAR(MODINFO_SIZE, a, s, c)
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#define MOD_METADATA(a, mm, c) { \
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COPY32(MODINFO_METADATA | mm->md_type, a, c); \
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COPY32(mm->md_size, a, c); \
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if (c) \
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i386_copyin(mm->md_data, a, mm->md_size); \
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a += roundup(mm->md_size, sizeof(u_int64_t));\
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}
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#define MOD_END(a, c) { \
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COPY32(MODINFO_END, a, c); \
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COPY32(0, a, c); \
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}
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static vm_offset_t
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bi_copymodules64(vm_offset_t addr)
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{
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struct preloaded_file *fp;
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struct file_metadata *md;
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int c;
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u_int64_t v;
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c = addr != 0;
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/* start with the first module on the list, should be the kernel */
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for (fp = file_findfile(NULL, NULL); fp != NULL; fp = fp->f_next) {
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MOD_NAME(addr, fp->f_name, c); /* this field must come first */
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MOD_TYPE(addr, fp->f_type, c);
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if (fp->f_args)
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MOD_ARGS(addr, fp->f_args, c);
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v = fp->f_addr;
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MOD_ADDR(addr, v, c);
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v = fp->f_size;
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MOD_SIZE(addr, v, c);
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for (md = fp->f_metadata; md != NULL; md = md->md_next)
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if (!(md->md_type & MODINFOMD_NOCOPY))
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MOD_METADATA(addr, md, c);
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}
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MOD_END(addr, c);
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return(addr);
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}
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/*
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* Check to see if this CPU supports long mode.
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*/
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static int
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bi_checkcpu(void)
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{
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char *cpu_vendor;
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int vendor[3];
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int eflags;
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unsigned int regs[4];
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/* Check for presence of "cpuid". */
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eflags = read_eflags();
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write_eflags(eflags ^ PSL_ID);
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if (!((eflags ^ read_eflags()) & PSL_ID))
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return (0);
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/* Fetch the vendor string. */
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do_cpuid(0, regs);
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vendor[0] = regs[1];
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vendor[1] = regs[3];
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vendor[2] = regs[2];
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cpu_vendor = (char *)vendor;
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/* Check for vendors that support AMD features. */
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if (strncmp(cpu_vendor, INTEL_VENDOR_ID, 12) != 0 &&
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strncmp(cpu_vendor, AMD_VENDOR_ID, 12) != 0 &&
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strncmp(cpu_vendor, CENTAUR_VENDOR_ID, 12) != 0)
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return (0);
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/* Has to support AMD features. */
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do_cpuid(0x80000000, regs);
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if (!(regs[0] >= 0x80000001))
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return (0);
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/* Check for long mode. */
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do_cpuid(0x80000001, regs);
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return (regs[3] & AMDID_LM);
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}
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/*
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* Load the information expected by an amd64 kernel.
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*
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* - The 'boothowto' argument is constructed
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* - The 'bootdev' argument is constructed
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* - The 'bootinfo' struct is constructed, and copied into the kernel space.
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* - The kernel environment is copied into kernel space.
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* - Module metadata are formatted and placed in kernel space.
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*/
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int
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bi_load64(char *args, vm_offset_t addr, vm_offset_t *modulep,
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vm_offset_t *kernendp, int add_smap)
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{
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struct preloaded_file *xp, *kfp;
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struct i386_devdesc *rootdev;
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struct file_metadata *md;
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u_int64_t kernend;
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u_int64_t envp;
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u_int64_t module;
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vm_offset_t size;
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char *rootdevname;
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int howto;
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#ifdef LOADER_GELI_SUPPORT
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char buf[keybuf_size];
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struct keybuf *keybuf = (struct keybuf *)buf;
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#endif
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if (!bi_checkcpu()) {
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printf("CPU doesn't support long mode\n");
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return (EINVAL);
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}
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howto = bi_getboothowto(args);
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/*
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* Allow the environment variable 'rootdev' to override the supplied device
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* This should perhaps go to MI code and/or have $rootdev tested/set by
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* MI code before launching the kernel.
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*/
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rootdevname = getenv("rootdev");
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i386_getdev((void **)(&rootdev), rootdevname, NULL);
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if (rootdev == NULL) { /* bad $rootdev/$currdev */
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printf("can't determine root device\n");
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return(EINVAL);
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}
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/* Try reading the /etc/fstab file to select the root device */
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getrootmount(i386_fmtdev((void *)rootdev));
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if (addr == 0) {
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/* find the last module in the chain */
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for (xp = file_findfile(NULL, NULL); xp != NULL; xp = xp->f_next) {
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if (addr < (xp->f_addr + xp->f_size))
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addr = xp->f_addr + xp->f_size;
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}
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}
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/* pad to a page boundary */
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addr = roundup(addr, PAGE_SIZE);
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/* place the metadata before anything */
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module = *modulep = addr;
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kfp = file_findfile(NULL, "elf kernel");
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if (kfp == NULL)
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kfp = file_findfile(NULL, "elf64 kernel");
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if (kfp == NULL)
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panic("can't find kernel file");
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kernend = 0; /* fill it in later */
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file_addmetadata(kfp, MODINFOMD_HOWTO, sizeof howto, &howto);
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file_addmetadata(kfp, MODINFOMD_ENVP, sizeof envp, &envp);
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file_addmetadata(kfp, MODINFOMD_KERNEND, sizeof kernend, &kernend);
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file_addmetadata(kfp, MODINFOMD_MODULEP, sizeof module, &module);
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if (add_smap != 0)
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bios_addsmapdata(kfp);
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#ifdef LOADER_GELI_SUPPORT
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geli_fill_keybuf(keybuf);
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file_addmetadata(kfp, MODINFOMD_KEYBUF, keybuf_size, buf);
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bzero(buf, sizeof(buf));
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#endif
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size = bi_copymodules64(0);
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/* copy our environment */
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envp = roundup(addr + size, PAGE_SIZE);
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addr = bi_copyenv(envp);
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/* set kernend */
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kernend = roundup(addr, PAGE_SIZE);
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*kernendp = kernend;
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/* patch MODINFOMD_KERNEND */
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md = file_findmetadata(kfp, MODINFOMD_KERNEND);
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bcopy(&kernend, md->md_data, sizeof kernend);
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/* patch MODINFOMD_ENVP */
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md = file_findmetadata(kfp, MODINFOMD_ENVP);
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bcopy(&envp, md->md_data, sizeof envp);
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/* copy module list and metadata */
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(void)bi_copymodules64(*modulep);
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return(0);
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}
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