iBoot/lib/ticket/ticket.c

558 lines
17 KiB
C

/*
* Copyright (C) 2011-2014 Apple Inc. All rights reserved.
*
* This document is the property of Apple Inc.
* It is considered confidential and proprietary.
*
* This document may not be reproduced or transmitted in any form,
* in whole or in part, without the express written permission of
* Apple Inc.
*/
#include <drivers/sha1.h>
#include <lib/fs.h>
#include <lib/blockdev.h>
#include <lib/env.h>
#include <lib/image.h>
#include <lib/mib.h>
#include <platform.h>
#include <stdlib.h>
#include <sys/menu.h>
#include <AssertMacros.h>
#include <lib/ticket.h>
#include <lib/DERApTicket.h>
/* -------------------------------------------------------------------------- */
/* <rdar://problem/9447707> Disable TICKET_LOOSE_VERIFICATION for the release build */
#if !RELEASE_BUILD
#define TICKET_LOOSE_VERIFICATION 1
#endif
#define MAX_TICKET_LENGTH 8192
/* -------------------------------------------------------------------------- */
static uint8_t *gRootTicketBuffer = NULL;
static size_t gRootTicketLength = 0;
static DERApTicket *gRootTicket = NULL;
static uint8_t gRootTicketHashBuffer[CCSHA1_OUTPUT_SIZE];
static bool gRootTicketIsRestore = false;
/* -------------------------------------------------------------------------- */
size_t sprint_hex(const uint8_t *data, unsigned data_len, char *buf, unsigned buf_len)
{
static const char kAsciiHexChars[] = "0123456789ABCDEF";
unsigned i, j;
/* ensure the output buffer is large enough to contain the hex string */
if (buf_len < (data_len * 2) + 1) {
j = -1;
goto exit;
}
j = 0;
for ( i = 0; i < data_len; ++i ) {
uint8_t octet = data[i];
buf[j++] = kAsciiHexChars[((octet & 0xF0) >> 4)];
buf[j++] = kAsciiHexChars[(octet & 0x0F)];
}
buf[j] = '\0';
exit:
return j;
}
/* -------------------------------------------------------------------------- */
typedef struct {
uint32_t type;
uint8_t boot_mode;
uint8_t hash_tag;
uint8_t trust_tag;
uint8_t build_tag;
} image3_ticket_tags;
#define kTicketBootRestore (0x1U)
#define kTicketBootNormal (0x2U)
#define kTicketBootAny (kTicketBootRestore | kTicketBootNormal)
static const image3_ticket_tags kImage3TicketTags[] = {
/* type boot_mode hash_tag trust_tag build_tag */
{ IMAGE_TYPE_DIAG, kTicketBootAny, 11, 52, 0, },
{ IMAGE_TYPE_LLB, kTicketBootNormal, 228, 231, 6, },
{ IMAGE_TYPE_IBOOT, kTicketBootAny, 7, 48, 0, },
{ IMAGE_TYPE_DEVTREE, kTicketBootNormal, 9, 50, 0, },
{ IMAGE_TYPE_KERNELCACHE, kTicketBootNormal, 10, 51, 0, },
{ IMAGE_TYPE_LOGO, kTicketBootNormal, 8, 49, 0, },
{ IMAGE_TYPE_NEEDSERVICE, kTicketBootNormal, 17, 58, 0, },
{ IMAGE_TYPE_GLYPHCHRG, kTicketBootNormal, 12, 53, 0, },
{ IMAGE_TYPE_GLYPHPLUGIN, kTicketBootNormal, 13, 54, 0, },
{ IMAGE_TYPE_BATTERYCHARGING0, kTicketBootNormal, 78, 84, 0, },
{ IMAGE_TYPE_BATTERYCHARGING1, kTicketBootNormal, 79, 85, 0, },
{ IMAGE_TYPE_BATTERYLOW0, kTicketBootNormal, 14, 55, 0, },
{ IMAGE_TYPE_BATTERYLOW1, kTicketBootNormal, 15, 56, 0, },
{ IMAGE_TYPE_BATTERYFULL, kTicketBootNormal, 80, 86, 0, },
{ IMAGE_TYPE_RECMODE, kTicketBootAny, 16, 57, 0, },
{ IMAGE_TYPE_IBSS, kTicketBootRestore, 229, 232, 20, },
{ IMAGE_TYPE_IBEC, kTicketBootRestore, 230, 233, 22, },
{ IMAGE_TYPE_LOGO, kTicketBootRestore, 23, 59, 0, },
{ IMAGE_TYPE_DEVTREE, kTicketBootRestore, 24, 60, 0, },
{ IMAGE_TYPE_KERNELCACHE, kTicketBootRestore, 25, 61, 0, },
{ IMAGE_TYPE_RAMDISK, kTicketBootRestore, 26, 62, 0, },
};
/* -------------------------------------------------------------------------- */
static const image3_ticket_tags *
ticket_get_image3_tags( uint32_t type )
{
/*
* Infer whether this is a normal boot or a restore.
*/
unsigned boot_mode;
uint32_t product = mib_get_u32(kMIBTargetApplicationProduct);
if ((product == MIB_APP_PROD_IBOOT) || (product == MIB_APP_PROD_LLB)) {
boot_mode = (type == IMAGE_TYPE_IBEC) ? kTicketBootRestore : kTicketBootNormal;
} else {
boot_mode = kTicketBootRestore;
}
TICKETLOG( " boot mode: %s", (boot_mode == kTicketBootRestore) ? "restore" : "normal" );
unsigned i;
unsigned count = sizeof(kImage3TicketTags) / sizeof(kImage3TicketTags[0]);
const image3_ticket_tags *found = NULL;
for ( i = 0; i < count; ++i ) {
if ( kImage3TicketTags[i].type == type && kImage3TicketTags[i].boot_mode & boot_mode ) {
found = &kImage3TicketTags[i];
break;
}
}
return found;
}
/* -------------------------------------------------------------------------- */
bool
ticket_validation_required()
{
bool required;
/*
* <rdar://problem/9391858> Revised iBoot ticket policy
* <rdar://problem/9414797> Don't allow replay of old iBECs on customer units
* <rdar://problem/9790456> Modify ticket validation policy for K66
*/
#if RELEASE_BUILD
required = !( platform_get_chip_id() == 0x8930 && platform_get_board_id() == 0x10 );
#else
required = false;
#endif
return required;
}
/* -------------------------------------------------------------------------- */
bool
ticket_copy_tag_data( DERTag tag, uint8_t *buffer, size_t *ioLength )
{
int status = -1;
DERReturn derstat;
DERSize dataLength = (DERSize) *ioLength;
require_action( gRootTicket != NULL, exit, TICKETLOG("no ticket") );
derstat = DERApTicketCopyTagData( &(gRootTicket->body), tag, buffer, &dataLength );
require( derstat == DR_Success, exit );
*ioLength = (size_t) dataLength;
status = 0;
exit:
return (status == 0);
}
/* -------------------------------------------------------------------------- */
bool
ticket_validate_image3( uint32_t type, uint32_t expectedType, uint8_t *hashBuffer, size_t hashBufferSize, bool *outIsUntrusted )
{
bool valid = false;
const image3_ticket_tags *ticketTags;
uint8_t ticketEntryHashBuffer[CCSHA1_OUTPUT_SIZE];
size_t ticketEntryHashSize = sizeof(ticketEntryHashBuffer);
uint32_t trustedEncoding;
size_t trustedEncodingSize = sizeof(trustedEncoding);
char hashLog[2 * CCSHA1_OUTPUT_SIZE + 1];
TICKETLOG( "examining image: type=0x%08x ('%c%c%c%c')", type, (type >> 24) & 0xFF, (type >> 16) & 0xFF, (type >> 8) & 0xFF, type & 0xFF );
if ( expectedType != IMAGE_TYPE_ANY && expectedType != type ) {
TICKETLOG( " expected image: type=0x%08x ('%c%c%c%c')", expectedType, (expectedType >> 24) & 0xFF, (expectedType >> 16) & 0xFF, (expectedType >> 8) & 0xFF, expectedType & 0xFF );
goto exit;
}
ticketTags = ticket_get_image3_tags(type);
if (ticketTags == NULL) {
TICKETLOG("this image isn't supported by the ticket model");
goto exit;
}
if (ticketTags->boot_mode == kTicketBootRestore && gRootTicket != NULL && !gRootTicketIsRestore) {
TICKETLOG("a restore ticket is required");
goto exit;
}
if (!ticket_copy_tag_data(ticketTags->hash_tag, ticketEntryHashBuffer, &ticketEntryHashSize)) {
TICKETLOG("this tag (%d) isn't in the ticket", ticketTags->hash_tag);
goto exit;
}
if (ticketEntryHashSize != sizeof(ticketEntryHashBuffer)) {
TICKETLOG("unrecognized ticket encoding for hash tag (%d)", ticketTags->hash_tag);
goto exit;
}
sprint_hex(ticketEntryHashBuffer, sizeof(ticketEntryHashBuffer), hashLog, sizeof(hashLog));
TICKETLOG(" ticket hash: %s", hashLog);
sprint_hex(hashBuffer, hashBufferSize, hashLog, sizeof(hashLog));
TICKETLOG(" image hash: %s", hashLog);
/* compare hash_buffer to the hash of the image3 */
if (memcmp(hashBuffer, ticketEntryHashBuffer, sizeof(ticketEntryHashBuffer)) != 0) {
TICKETLOG("this image doesn't match the one specified by ticket tag (%d)", ticketTags->hash_tag);
goto exit;
}
if (!ticket_copy_tag_data(ticketTags->trust_tag, (void *) &trustedEncoding, &trustedEncodingSize)) {
TICKETLOG("ticket lacks trust tag (%d) for this image; assuming untrusted", ticketTags->trust_tag);
*outIsUntrusted = true;
}
else {
if (trustedEncodingSize != sizeof(trustedEncoding)) {
TICKETLOG("unrecognized ticket encoding for trust tag (%d)", ticketTags->trust_tag);
goto exit;
}
TICKETLOG(" explicit trust: %s", trustedEncoding ? "yes" : "no");
*outIsUntrusted = trustedEncoding ? false : true;
}
valid = true;
exit:
return valid;
}
/* -------------------------------------------------------------------------- */
int
ticket_set( const uint8_t *buffer, size_t length, bool isRestore, size_t *outTicketLength )
{
int status = -1;
DERReturn derstat;
DERItem ticketItem;
size_t ticketLength;
uint8_t *ticketBuffer = NULL;
DERApTicket *apTicket = NULL;
require( buffer != NULL, exit );
require( length > 0, exit );
/* Parse just enough of the buffer to determine the ticket length */
derstat = DERApTicketParseLengthFromBuffer( buffer, length, &ticketLength );
require_action( derstat == DR_Success, exit, TICKETLOG("can't parse ticket length") );
require_action( ticketLength > 0 && ticketLength < MAX_TICKET_LENGTH, exit, TICKETLOG("unreasonable ticket length: %d bytes", ticketLength) );
/* Copy the ticket data to a separate buffer */
ticketBuffer = (uint8_t *) malloc( ticketLength );
require_action( ticketBuffer != NULL, exit, TICKETLOG("failed to alloc ticket buffer") );
memcpy( ticketBuffer, buffer, ticketLength );
/* Allocate a ticket structure */
apTicket = (DERApTicket *) calloc( 1, sizeof(DERApTicket) );
require_action( apTicket != NULL, exit, TICKETLOG("failed to alloc ticket structure") );
/* Decode */
ticketItem.data = (DERByte *) ticketBuffer;
ticketItem.length = (DERSize) ticketLength;
derstat = DERApTicketDecode( &ticketItem, apTicket, (DERSize *) &ticketLength );
require_action( derstat == DR_Success, exit, TICKETLOG("malformed ticket") );
/* Validate */
derstat = DERApTicketValidate( apTicket, isRestore );
#if TICKET_LOOSE_VERIFICATION
derstat = DR_Success;
#endif
require_action( derstat == DR_Success, exit, TICKETLOG("ticket rejected") );
/* Destroy any older ticket */
if ( gRootTicketBuffer != NULL ) {
free( gRootTicketBuffer );
gRootTicketBuffer = NULL;
gRootTicketLength = 0;
}
if ( gRootTicket != NULL ) {
free( gRootTicket );
gRootTicket = NULL;
}
/* Cache this ticket */
gRootTicketBuffer = ticketBuffer;
gRootTicketLength = ticketLength;
gRootTicket = apTicket;
gRootTicketIsRestore = isRestore;
/* Cache the new ticket digest */
sha1_calculate( gRootTicketBuffer, gRootTicketLength, gRootTicketHashBuffer );
/* Debug logging */
{
char hashStr[2 * CCSHA1_OUTPUT_SIZE + 1];
sprint_hex(gRootTicketHashBuffer, sizeof(gRootTicketHashBuffer), hashStr, sizeof(hashStr));
TICKETLOG( "cached ticket (%u bytes) hash: %s", ticketLength, hashStr );
}
if ( outTicketLength != NULL ) {
*outTicketLength = ticketLength;
}
/* success */
status = 0;
exit:
if ( status != 0 ) {
if ( ticketBuffer != NULL ) {
free( ticketBuffer );
}
if ( apTicket != NULL ) {
free( apTicket );
}
}
return status;
}
/* -------------------------------------------------------------------------- */
/*
* "ticket" command handler
* This command allows the host to specify a temporary RAM-based ticket.
*/
int
do_ticket( int argc, struct cmd_arg *argv )
{
int status = -1;
size_t ticketLength;
size_t bufferLength;
bufferLength = env_get_uint( "filesize", 0 );
require_action( bufferLength > 0, exit, status = -1; TICKETLOG("filesize invalid or not set") );
require_action( bufferLength < MAX_TICKET_LENGTH, exit, status = -1; TICKETLOG("filesize too large") );
check( MAX_TICKET_LENGTH <= mib_get_size(kMIBTargetDefaultLoadSize) );
status = ticket_set( (uint8_t *) mib_get_addr(kMIBTargetDefaultLoadAddress), bufferLength, true, &ticketLength );
require( status == 0, exit );
require_action( ticketLength == bufferLength, exit, status = -1; TICKETLOG("garbage following ticket") );
/* success */
status = 0;
exit:
return status;
}
/* -------------------------------------------------------------------------- */
#if DEBUG_BUILD
int
do_ticket_dump( int argc, struct cmd_arg *argv )
{
int status = -1;
if ( gRootTicketBuffer == NULL ) {
printf( "no ticket\n");
goto exit;
}
hexdump( gRootTicketBuffer, gRootTicketLength );
status = 0;
exit:
return status;
}
#endif
/* -------------------------------------------------------------------------- */
bool
ticket_get_hash( uint8_t *buffer, size_t length )
{
bool copied;
if ( gRootTicketBuffer != NULL && length >= sizeof(gRootTicketHashBuffer) ) {
memcpy( buffer, gRootTicketHashBuffer, sizeof(gRootTicketHashBuffer) );
copied = true;
}
else {
copied = false;
}
return copied;
}
/* ========================================================================== */
/*
* Load a ticket from a file.
*/
int
ticket_load_file( const char *filePath, uintptr_t bufferAddress, size_t bufferLength )
{
int status = -1;
size_t fileLength = bufferLength;
size_t ticketLength;
status = fs_load_file(filePath, bufferAddress, &fileLength);
require_action( status == 0, exit, status = -1; TICKETLOG("failed to load ticket file: %s", filePath) );
status = ticket_set( (uint8_t *) bufferAddress, fileLength, true, &ticketLength );
require_action( status == 0, exit, status = -1; TICKETLOG("unable to set ticket") );
require_action( ticketLength == fileLength, exit, status = -1; TICKETLOG("garbage following ticket") );
status = 0;
TICKETLOG("successfully loaded ticket file: %s", filePath);
exit:
return status;
}
int
do_ticket_file( int argc, struct cmd_arg *args )
{
int status = -1;
require_action( argc == 2, exit, printf("%s <path>\n", args[0].str) );
status = ticket_load_file( args[1].str,
mib_get_addr(kMIBTargetDefaultLoadAddress),
mib_get_size(kMIBTargetDefaultLoadSize) );
require( status == 0, exit );
status = 0;
exit:
return status;
}
/* -------------------------------------------------------------------------- */
int
ticket_load()
{
int status = -1;
struct image_info *imageInfo;
uint8_t *dataBuffer;
size_t dataLength;
size_t ticketLength;
size_t objectLength;
uint8_t *objectBuffer = NULL;
bool restoreTicket;
/* Find the ticket image */
imageInfo = image_find( 'SCAB' );
require_action( imageInfo != NULL, exit, TICKETLOG("no ticket found") );
require_action( imageInfo->imagePrivateMagic == IMAGE3_IMAGE_INFO_MAGIC, exit, TICKETLOG("ticket is not image3") );
/*
* Allocate a buffer for the image and load it into the buffer
* without attempting to validate it.
*/
objectLength = imageInfo->imageAllocation;
objectBuffer = (uint8_t *) malloc( objectLength );
imageInfo->imageOptions |= IMAGE_OPTION_JUST_LOAD;
/*
* Accept any type (pass NULL)
*/
if ( image_load(imageInfo, NULL, 0, NULL, (void **)&objectBuffer, &objectLength) ) {
TICKETLOG( "failed to load ticket image3" );
goto exit;
}
/*
* The ticket is always supplied in an image3 object with tags in
* the order TYPE, DATA, resulting in an offset from the buffer to
* the actual ticket data of 0x40 bytes.
*
* We don't try to introspect or validate the image here -
* ticket_set below will reject the data if it is not a
* well-formed ticket.
*/
if (objectLength < 0x40)
goto exit;
dataBuffer = objectBuffer + 0x40;
dataLength = objectLength - 0x40;
if (dataLength > MAX_TICKET_LENGTH)
goto exit;
/* If the ticket comes from a memory blockdev,
use the stricter restore ticket validation */
restoreTicket = (imageInfo->imageOptions & IMAGE_OPTION_MEMORY) != 0;
/*
* Parse the ticket data.
*/
status = ticket_set( dataBuffer, dataLength, restoreTicket, &ticketLength );
exit:
if ( objectBuffer != NULL ) {
free( objectBuffer );
}
TICKETLOG( "exiting" );
return status;
}
/* -------------------------------------------------------------------------- */
int
do_ticket_load( int argc, struct cmd_arg *argv )
{
int status = -1;
status = ticket_load();
require( status == 0, exit );
/* success */
status = 0;
exit:
return status;
}
/* -------------------------------------------------------------------------- */