kernel_optimize_test/include/linux/tpm_eventlog.h
Jerry Snitselaar e658c82be5 efi/tpm: Only set 'efi_tpm_final_log_size' after successful event log parsing
If __calc_tpm2_event_size() fails to parse an event it will return 0,
resulting tpm2_calc_event_log_size() returning -1. Currently there is
no check of this return value, and 'efi_tpm_final_log_size' can end up
being set to this negative value resulting in a crash like this one:

  BUG: unable to handle page fault for address: ffffbc8fc00866ad
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page

  RIP: 0010:memcpy_erms+0x6/0x10
  Call Trace:
   tpm_read_log_efi()
   tpm_bios_log_setup()
   tpm_chip_register()
   tpm_tis_core_init.cold.9+0x28c/0x466
   tpm_tis_plat_probe()
   platform_drv_probe()
   ...

Also __calc_tpm2_event_size() returns a size of 0 when it fails
to parse an event, so update function documentation to reflect this.

The root cause of the issue that caused the failure of event parsing
in this case is resolved by Peter Jone's patchset dealing with large
event logs where crossing over a page boundary causes the page with
the event count to be unmapped.

Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Dave Young <dyoung@redhat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Matthew Garrett <mjg59@google.com>
Cc: Octavian Purdila <octavian.purdila@intel.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Talbert <swt@techie.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: c46f340569 ("tpm: Reserve the TPM final events table")
Link: https://lkml.kernel.org/r/20191002165904.8819-6-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-07 15:24:36 +02:00

276 lines
5.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_TPM_EVENTLOG_H__
#define __LINUX_TPM_EVENTLOG_H__
#include <linux/tpm.h>
#define TCG_EVENT_NAME_LEN_MAX 255
#define MAX_TEXT_EVENT 1000 /* Max event string length */
#define ACPI_TCPA_SIG "TCPA" /* 0x41504354 /'TCPA' */
#define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
#define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 0x2
#ifdef CONFIG_PPC64
#define do_endian_conversion(x) be32_to_cpu(x)
#else
#define do_endian_conversion(x) x
#endif
enum bios_platform_class {
BIOS_CLIENT = 0x00,
BIOS_SERVER = 0x01,
};
struct tcpa_event {
u32 pcr_index;
u32 event_type;
u8 pcr_value[20]; /* SHA1 */
u32 event_size;
u8 event_data[0];
};
enum tcpa_event_types {
PREBOOT = 0,
POST_CODE,
UNUSED,
NO_ACTION,
SEPARATOR,
ACTION,
EVENT_TAG,
SCRTM_CONTENTS,
SCRTM_VERSION,
CPU_MICROCODE,
PLATFORM_CONFIG_FLAGS,
TABLE_OF_DEVICES,
COMPACT_HASH,
IPL,
IPL_PARTITION_DATA,
NONHOST_CODE,
NONHOST_CONFIG,
NONHOST_INFO,
};
struct tcpa_pc_event {
u32 event_id;
u32 event_size;
u8 event_data[0];
};
enum tcpa_pc_event_ids {
SMBIOS = 1,
BIS_CERT,
POST_BIOS_ROM,
ESCD,
CMOS,
NVRAM,
OPTION_ROM_EXEC,
OPTION_ROM_CONFIG,
OPTION_ROM_MICROCODE = 10,
S_CRTM_VERSION,
S_CRTM_CONTENTS,
POST_CONTENTS,
HOST_TABLE_OF_DEVICES,
};
/* http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/ */
struct tcg_efi_specid_event_algs {
u16 alg_id;
u16 digest_size;
} __packed;
struct tcg_efi_specid_event_head {
u8 signature[16];
u32 platform_class;
u8 spec_version_minor;
u8 spec_version_major;
u8 spec_errata;
u8 uintnsize;
u32 num_algs;
struct tcg_efi_specid_event_algs digest_sizes[];
} __packed;
struct tcg_pcr_event {
u32 pcr_idx;
u32 event_type;
u8 digest[20];
u32 event_size;
u8 event[0];
} __packed;
struct tcg_event_field {
u32 event_size;
u8 event[0];
} __packed;
struct tcg_pcr_event2_head {
u32 pcr_idx;
u32 event_type;
u32 count;
struct tpm_digest digests[];
} __packed;
struct tcg_algorithm_size {
u16 algorithm_id;
u16 algorithm_size;
};
struct tcg_algorithm_info {
u8 signature[16];
u32 platform_class;
u8 spec_version_minor;
u8 spec_version_major;
u8 spec_errata;
u8 uintn_size;
u32 number_of_algorithms;
struct tcg_algorithm_size digest_sizes[];
};
#ifndef TPM_MEMREMAP
#define TPM_MEMREMAP(start, size) NULL
#endif
#ifndef TPM_MEMUNMAP
#define TPM_MEMUNMAP(start, size) do{} while(0)
#endif
/**
* __calc_tpm2_event_size - calculate the size of a TPM2 event log entry
* @event: Pointer to the event whose size should be calculated
* @event_header: Pointer to the initial event containing the digest lengths
* @do_mapping: Whether or not the event needs to be mapped
*
* The TPM2 event log format can contain multiple digests corresponding to
* separate PCR banks, and also contains a variable length of the data that
* was measured. This requires knowledge of how long each digest type is,
* and this information is contained within the first event in the log.
*
* We calculate the length by examining the number of events, and then looking
* at each event in turn to determine how much space is used for events in
* total. Once we've done this we know the offset of the data length field,
* and can calculate the total size of the event.
*
* Return: size of the event on success, 0 on failure
*/
static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
struct tcg_pcr_event *event_header,
bool do_mapping)
{
struct tcg_efi_specid_event_head *efispecid;
struct tcg_event_field *event_field;
void *mapping = NULL;
int mapping_size;
void *marker;
void *marker_start;
u32 halg_size;
size_t size;
u16 halg;
int i;
int j;
u32 count, event_type;
marker = event;
marker_start = marker;
marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
+ sizeof(event->count);
/* Map the event header */
if (do_mapping) {
mapping_size = marker - marker_start;
mapping = TPM_MEMREMAP((unsigned long)marker_start,
mapping_size);
if (!mapping) {
size = 0;
goto out;
}
} else {
mapping = marker_start;
}
event = (struct tcg_pcr_event2_head *)mapping;
/*
* The loop below will unmap these fields if the log is larger than
* one page, so save them here for reference:
*/
count = READ_ONCE(event->count);
event_type = READ_ONCE(event->event_type);
efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
/* Check if event is malformed. */
if (count > efispecid->num_algs) {
size = 0;
goto out;
}
for (i = 0; i < count; i++) {
halg_size = sizeof(event->digests[i].alg_id);
/* Map the digest's algorithm identifier */
if (do_mapping) {
TPM_MEMUNMAP(mapping, mapping_size);
mapping_size = halg_size;
mapping = TPM_MEMREMAP((unsigned long)marker,
mapping_size);
if (!mapping) {
size = 0;
goto out;
}
} else {
mapping = marker;
}
memcpy(&halg, mapping, halg_size);
marker = marker + halg_size;
for (j = 0; j < efispecid->num_algs; j++) {
if (halg == efispecid->digest_sizes[j].alg_id) {
marker +=
efispecid->digest_sizes[j].digest_size;
break;
}
}
/* Algorithm without known length. Such event is unparseable. */
if (j == efispecid->num_algs) {
size = 0;
goto out;
}
}
/*
* Map the event size - we don't read from the event itself, so
* we don't need to map it
*/
if (do_mapping) {
TPM_MEMUNMAP(mapping, mapping_size);
mapping_size += sizeof(event_field->event_size);
mapping = TPM_MEMREMAP((unsigned long)marker,
mapping_size);
if (!mapping) {
size = 0;
goto out;
}
} else {
mapping = marker;
}
event_field = (struct tcg_event_field *)mapping;
marker = marker + sizeof(event_field->event_size)
+ event_field->event_size;
size = marker - marker_start;
if (event_type == 0 && event_field->event_size == 0)
size = 0;
out:
if (do_mapping)
TPM_MEMUNMAP(mapping, mapping_size);
return size;
}
#endif