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uefi: Fix a libasan failure when reading a UEFI variable

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It seems some older versions of libefi var incorrectly build the 'length' value
in the DP returned from efi_generate_file_device_path(). This means we copy past
the end of the allocated buffer when parsing the efi_update_info_t structure.

This bug seems fixed in efivar git master, and this fix is only going to help
people with older efivar versions. It's probably a good thing to be a bit more
paranoid about EFI variable data anyway.

    DEBUG: UpdateInfo:
           ? 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
    ????????????????????????????????????????????????????????????????????????????????????????????????????????
    0x0000 ? 07 00 00 00 20 d9 7b 69 cf 12 a9 4d 83 85 99 69 09 bc 65 59 00 00 05 00 00 00 00 00 00 00 00 00
    0x0020 ? 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 04 01 2a 00 01 00 00 00 00 08 00 00
    0x0040 ? 00 00 00 00 00 40 06 00 00 00 00 00 5a aa 97 5a 10 d5 7e 49 99 0b ca 8d 35 4d c8 6d 02 02 04 04
    0x0060 ? 86 00 5c 00 45 00 46 00 49 00 5c 00 66 00 65 00 64 00 6f 00 72 00 61 00 5c 00 66 00 77 00 5c 00
    0x0080 ? 66 00 77 00 75 00 70 00 64 00 2d 00 36 00 39 00 37 00 62 00 64 00 39 00 32 00 30 00 2d 00 31 00
    0x00a0 ? 32 00 63 00 66 00 2d 00 34 00 64 00 61 00 39 00 2d 00 38 00 33 00 38 00 35 00 2d 00 39 00 39 00
    0x00c0 ? 36 00 39 00 30 00 39 00 62 00 63 00 36 00 35 00 35 00 39 00 2e 00 63 00 61 00 70 00 00 00 7f ff
    0x00e0 ? 04 00
    DEBUG: DP type:0x04 subtype:0x01 size:0x002a
    DEBUG: DP type:0x04 subtype:0x04 size:0x0086
    DEBUG: found END_ENTIRE at 0x00aa
    DEBUG: DP length invalid! Truncating from 0x0086 to 0x0080
    DEBUG: DP type:0x7f subtype:0xff size:0x0004
This commit is contained in:
Richard Hughes 2019-05-02 09:58:06 +01:00
parent 8499930a45
commit 26d3da4074
6 changed files with 199 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
plugins/uefi/fu-self-test.c
View File

@ -319,6 +319,7 @@ main (int argc, char **argv)
/* only critical and error are fatal */
g_log_set_fatal_mask (NULL, G_LOG_LEVEL_ERROR | G_LOG_LEVEL_CRITICAL);
g_setenv ("G_MESSAGES_DEBUG", "all", TRUE);
/* tests go here */
g_test_add_func ("/uefi/pcrs1.2", fu_uefi_pcrs_1_2_func);

10
plugins/uefi/fu-uefi-device.c
View File

@ -15,6 +15,7 @@
#include "fu-uefi-common.h"
#include "fu-uefi-device.h"
#include "fu-uefi-devpath.h"
#include "fu-uefi-bootmgr.h"
#include "fu-uefi-pcrs.h"
#include "fu-uefi-vars.h"
@ -237,6 +238,7 @@ fu_uefi_device_build_dp_buf (const gchar *path, gsize *bufsz, GError **error)
gssize req;
gssize sz;
g_autofree guint8 *dp_buf = NULL;
g_autoptr(GPtrArray) dps = NULL;
/* get the size of the path first */
req = efi_generate_file_device_path (NULL, 0, path,
@ -275,6 +277,14 @@ fu_uefi_device_build_dp_buf (const gchar *path, gsize *bufsz, GError **error)
return NULL;
}
/* parse what we got back from efivar */
dps = fu_uefi_devpath_parse (dp_buf, (gsize) sz,
FU_UEFI_DEVPATH_PARSE_FLAG_NONE, error);
if (dps == NULL) {
fu_common_dump_raw (G_LOG_DOMAIN, "dp_buf", dp_buf, (gsize) sz);
return NULL;
}
/* success */
if (bufsz != NULL)
*bufsz = sz;

128
plugins/uefi/fu-uefi-devpath.c Normal file
View File

@ -0,0 +1,128 @@
/*
* Copyright (C) 2018-2019 Richard Hughes <richard@hughsie.com>
*
* SPDX-License-Identifier: LGPL-2.1+
*/
#include "config.h"
#include <efivar.h>
#include "fu-common.h"
#include "fu-uefi-devpath.h"
#include "fwupd-error.h"
typedef struct {
guint8 type;
guint8 subtype;
GBytes *data;
} FuUefiDevPath;
static void
fu_uefi_efi_dp_free (FuUefiDevPath *dp)
{
if (dp->data != NULL)
g_bytes_unref (dp->data);
g_free (dp);
}
GBytes *
fu_uefi_devpath_find_data (GPtrArray *dps, guint8 type, guint8 subtype, GError **error)
{
for (guint i = 0; i < dps->len; i++) {
FuUefiDevPath *dp = g_ptr_array_index (dps, i);
if (dp->type == type && dp->subtype == subtype)
return dp->data;
}
g_set_error (error,
FWUPD_ERROR,
FWUPD_ERROR_INTERNAL,
"no DP with type 0x%02x and subtype 0x%02x",
type, subtype);
return NULL;
}
GPtrArray *
fu_uefi_devpath_parse (const guint8 *buf, gsize sz,
FuUefiDevpathParseFlags flags, GError **error)
{
guint16 offset = 0;
g_autoptr(GPtrArray) dps = NULL;
/* sanity check */
if (sz < sizeof(efidp_header)) {
g_set_error_literal (error,
FWUPD_ERROR,
FWUPD_ERROR_INTERNAL,
"const_efidp is corrupt");
return NULL;
}
dps = g_ptr_array_new_with_free_func ((GDestroyNotify) fu_uefi_efi_dp_free);
while (1) {
FuUefiDevPath *dp;
const efidp_header *hdr = (efidp_header *) (buf + offset);
guint16 hdr_length = GUINT16_FROM_LE(hdr->length);
/* check if last entry */
g_debug ("DP type:0x%02x subtype:0x%02x size:0x%04x",
hdr->type, hdr->subtype, hdr->length);
if (hdr->type == EFIDP_END_TYPE && hdr->subtype == EFIDP_END_ENTIRE)
break;
/* work around a bug in efi_va_generate_file_device_path_from_esp */
if (offset + sizeof(efidp_header) + hdr->length > sz) {
hdr_length = 0;
fu_common_dump_full (G_LOG_DOMAIN, "efidp",
buf + offset, sz - offset, 32,
FU_DUMP_FLAGS_SHOW_ADDRESSES);
for (guint16 i = offset + 4; i <= sz - 4; i++) {
if (memcmp (buf + i, "\x7f\xff\x04\x00", 4) == 0) {
hdr_length = i - offset;
g_debug ("found END_ENTIRE at 0x%04x",
(guint) (i - offset));
break;
}
}
if (hdr_length == 0) {
g_set_error_literal (error,
FWUPD_ERROR,
FWUPD_ERROR_INTERNAL,
"DP length invalid and no END_ENTIRE "
"found, possibly data truncation?");
return NULL;
}
if ((flags & FU_UEFI_DEVPATH_PARSE_FLAG_REPAIR) == 0) {
g_set_error (error,
FWUPD_ERROR,
FWUPD_ERROR_INTERNAL,
"DP length invalid, reported 0x%04x, maybe 0x%04x",
hdr->length, hdr_length);
return NULL;
}
g_debug ("DP length invalid! Truncating from 0x%04x to 0x%04x",
hdr->length, hdr_length);
}
/* add new DP */
dp = g_new0 (FuUefiDevPath, 1);
dp->type = hdr->type;
dp->subtype = hdr->subtype;
if (hdr_length > 0)
dp->data = g_bytes_new (buf + offset + 4, hdr_length);
g_ptr_array_add (dps, dp);
/* advance to next DP */
offset += hdr_length;
if (offset + sizeof(efidp_header) > sz) {
g_set_error_literal (error,
FWUPD_ERROR,
FWUPD_ERROR_INTERNAL,
"DP length invalid after fixing");
return NULL;
}
}
return g_steal_pointer (&dps);
}

28
plugins/uefi/fu-uefi-devpath.h Normal file
View File

@ -0,0 +1,28 @@
/*
* Copyright (C) 2018-2019 Richard Hughes <richard@hughsie.com>
*
* SPDX-License-Identifier: LGPL-2.1+
*/
#pragma once
#include <glib.h>
G_BEGIN_DECLS
typedef enum {
FU_UEFI_DEVPATH_PARSE_FLAG_NONE = 0,
FU_UEFI_DEVPATH_PARSE_FLAG_REPAIR = 1 << 0,
FU_UEFI_DEVPATH_PARSE_FLAG_LAST
} FuUefiDevpathParseFlags;
GPtrArray *fu_uefi_devpath_parse (const guint8 *buf,
gsize sz,
FuUefiDevpathParseFlags flags,
GError **error);
GBytes *fu_uefi_devpath_find_data (GPtrArray *dps,
guint8 type,
guint8 subtype,
GError **error);
G_END_DECLS

57
plugins/uefi/fu-uefi-update-info.c
View File

@ -7,6 +7,7 @@
#include "config.h"
#include "fu-common.h"
#include "fu-uefi-devpath.h"
#include "fu-uefi-update-info.h"
#include "fu-uefi-common.h"
#include "fu-ucs2.h"
@ -36,42 +37,41 @@ fu_uefi_update_info_status_to_string (FuUefiUpdateInfoStatus status)
}
static gchar *
fu_uefi_update_info_parse_dp (const guint8 *buf, gsize sz)
fu_uefi_update_info_parse_dp (const guint8 *buf, gsize sz, GError **error)
{
const_efidp idp;
guint16 ucs2sz = 0;
GBytes *dp_data;
const gchar *data;
gsize ucs2sz = 0;
g_autofree gchar *relpath = NULL;
g_autofree guint16 *ucs2file = NULL;
g_autoptr(GPtrArray) dps = NULL;
g_return_val_if_fail (buf != NULL, NULL);
g_return_val_if_fail (sz != 0, NULL);
/* find UCS2 string */
idp = (const_efidp) buf;
while (1) {
if (efidp_type (idp) == EFIDP_END_TYPE &&
efidp_subtype (idp) == EFIDP_END_ENTIRE)
break;
if (efidp_type(idp) != EFIDP_MEDIA_TYPE ||
efidp_subtype (idp) != EFIDP_MEDIA_FILE) {
if (efidp_next_node (idp, &idp) < 0)
break;
continue;
}
ucs2sz = efidp_node_size (idp) - 4;
/* get all headers */
dps = fu_uefi_devpath_parse (buf, sz, FU_UEFI_DEVPATH_PARSE_FLAG_REPAIR, error);
if (dps == NULL)
return NULL;
dp_data = fu_uefi_devpath_find_data (dps,
EFIDP_MEDIA_TYPE,
EFIDP_MEDIA_FILE,
error);
if (dp_data == NULL)
return NULL;
/* convert to UTF-8 */
data = g_bytes_get_data (dp_data, &ucs2sz);
ucs2file = g_new0 (guint16, (ucs2sz / 2) + 1);
memcpy (ucs2file, (guint8 *)idp + 4, ucs2sz);
break;
}
/* nothing found */
if (ucs2file == NULL || ucs2sz == 0)
return NULL;
/* convert to something sane */
memcpy (ucs2file, data, ucs2sz);
relpath = fu_ucs2_to_uft8 (ucs2file, ucs2sz / sizeof (guint16));
if (relpath == NULL)
if (relpath == NULL) {
g_set_error_literal (error,
FWUPD_ERROR,
FWUPD_ERROR_INTERNAL,
"cannot convert to UTF-8");
return NULL;
}
g_strdelimit (relpath, "\\", '/');
return g_steal_pointer (&relpath);
}
@ -106,7 +106,10 @@ fu_uefi_update_info_parse (FuUefiUpdateInfo *self, const guint8 *buf, gsize sz,
}
if (sz > sizeof(efi_update_info_t)) {
self->capsule_fn = fu_uefi_update_info_parse_dp (buf + sizeof(efi_update_info_t),
sz - sizeof(efi_update_info_t));
sz - sizeof(efi_update_info_t),
error);
if (self->capsule_fn == NULL)
return FALSE;
}
return TRUE;
}

3
plugins/uefi/meson.build
View File

@ -20,6 +20,7 @@ shared_module('fu_plugin_uefi',
'fu-uefi-bootmgr.c',
'fu-uefi-common.c',
'fu-uefi-device.c',
'fu-uefi-devpath.c',
'fu-uefi-pcrs.c',
'fu-uefi-update-info.c',
'fu-uefi-vars.c',
@ -53,6 +54,7 @@ executable(
'fu-uefi-bootmgr.c',
'fu-uefi-common.c',
'fu-uefi-device.c',
'fu-uefi-devpath.c',
'fu-uefi-pcrs.c',
'fu-uefi-update-info.c',
'fu-uefi-vars.c',
@ -94,6 +96,7 @@ if get_option('tests')
'fu-uefi-bootmgr.c',
'fu-uefi-common.c',
'fu-uefi-device.c',
'fu-uefi-devpath.c',
'fu-uefi-pcrs.c',
'fu-uefi-update-info.c',
'fu-uefi-vars.c',