fwupd/libfwupdplugin/fu-fmap-firmware.c

/*
 * Copyright (C) 2020 Benson Leung <bleung@chromium.org>
 *
 * SPDX-License-Identifier: LGPL-2.1+
 */

#include "config.h"

#include <string.h>

#include "fu-common.h"
#include "fu-fmap-firmware.h"

#define FMAP_SIGNATURE		"__FMAP__"
#define FMAP_AREANAME		"FMAP"

typedef struct {
	guint64			 base;
	gsize			 offset;
} FuFmapFirmwarePrivate;

G_DEFINE_TYPE_WITH_PRIVATE (FuFmapFirmware, fu_fmap_firmware, FU_TYPE_FIRMWARE)
#define GET_PRIVATE(o) (fu_fmap_firmware_get_instance_private (o))

static gboolean
fu_fmap_firmware_find_offset (FuFmapFirmware *self,
			      const guint8 *buf, gsize bufsz,
			      GError **error)
{
#ifdef HAVE_MEMMEM
	FuFmapFirmwarePrivate *priv = GET_PRIVATE (self);
	const guint8 *tmp;

	g_return_val_if_fail (buf != NULL, FALSE);

	/* trust glibc to do a binary or linear search as appropriate */
	tmp = memmem (buf, bufsz, FMAP_SIGNATURE, 8);
	if (tmp == NULL) {
		g_set_error_literal (error,
				     G_IO_ERROR,
				     G_IO_ERROR_INVALID_DATA,
				     "fmap header not found");
		return FALSE;
	}
	priv->offset = tmp - buf;
	return TRUE;
#else
	g_set_error_literal (error,
			     G_IO_ERROR,
			     G_IO_ERROR_INVALID_DATA,
			     "memmem() not available");
	return FALSE;
#endif
}

static void
fu_fmap_firmware_export (FuFirmware *firmware,
			 FuFirmwareExportFlags flags,
			 XbBuilderNode *bn)
{
	FuFmapFirmware *self = FU_FMAP_FIRMWARE (firmware);
	FuFmapFirmwarePrivate *priv = GET_PRIVATE (self);
	fu_xmlb_builder_insert_kx (bn, "offset", priv->offset);
	fu_xmlb_builder_insert_kx (bn, "base", priv->base);
}

static gboolean
fu_fmap_firmware_parse (FuFirmware *firmware,
			GBytes *fw,
			guint64 addr_start,
			guint64 addr_end,
			FwupdInstallFlags flags,
			GError **error)
{
	FuFmapFirmware *self = FU_FMAP_FIRMWARE (firmware);
	FuFmapFirmwarePrivate *priv = GET_PRIVATE (self);
	FuFmapFirmwareClass *klass_firmware = FU_FMAP_FIRMWARE_GET_CLASS (firmware);
	gsize bufsz;
	const guint8 *buf = g_bytes_get_data (fw, &bufsz);
	gsize offset = 0;
	FuFmap fmap;

	/* corrupt */
	if (g_bytes_get_size (fw) < sizeof (FuFmap)) {
		g_set_error_literal (error,
				     G_IO_ERROR,
				     G_IO_ERROR_INVALID_DATA,
				     "firmware too small for fmap");
		return FALSE;
	}

	/* only search for the fmap signature if not fuzzing */
	if ((flags & FWUPD_INSTALL_FLAG_NO_SEARCH) == 0) {
		if (!fu_fmap_firmware_find_offset (self, buf, bufsz, error))
			return FALSE;
	}

	/* load header */
	if (!fu_memcpy_safe ((guint8 *) &fmap, sizeof(fmap), 0x0,	/* dst */
			     buf, bufsz, priv->offset,			/* src */
			     sizeof(fmap), error))
		return FALSE;
	priv->base = GUINT64_FROM_LE (fmap.base);

	if (GUINT32_FROM_LE (fmap.size) != bufsz) {
		g_set_error (error,
			     G_IO_ERROR,
			     G_IO_ERROR_INVALID_DATA,
			     "file size incorrect, expected 0x%04x got 0x%04x",
			     (guint) fmap.size,
			     (guint) bufsz);
		return FALSE;
	}
	if (GUINT16_FROM_LE (fmap.nareas) < 1) {
		g_set_error (error,
			     G_IO_ERROR,
			     G_IO_ERROR_INVALID_DATA,
			     "number of areas too small, got %" G_GUINT16_FORMAT,
			     GUINT16_FROM_LE (fmap.nareas));
		return FALSE;
	}
	offset = priv->offset + sizeof(fmap);

	for (gsize i = 0; i < GUINT16_FROM_LE (fmap.nareas); i++) {
		FuFmapArea area;
		g_autoptr(FuFirmware) img = NULL;
		g_autoptr(GBytes) bytes = NULL;
		g_autofree gchar *area_name = NULL;

		/* load area */
		if (!fu_memcpy_safe ((guint8 *) &area, sizeof(area), 0x0,	/* dst */
				     buf, bufsz, offset,			/* src */
				     sizeof(area), error))
			return FALSE;

		/* skip */
		if (area.size == 0)
			continue;

		bytes = fu_common_bytes_new_offset (fw,
						    (gsize) GUINT32_FROM_LE (area.offset),
						    (gsize) GUINT32_FROM_LE (area.size),
						    error);
		if (bytes == NULL)
			return FALSE;
		area_name = g_strndup ((const gchar *) area.name, FU_FMAP_FIRMWARE_STRLEN);
		img = fu_firmware_new_from_bytes (bytes);
		fu_firmware_set_id (img, area_name);
		fu_firmware_set_idx (img, i + 1);
		fu_firmware_set_addr (img, GUINT32_FROM_LE (area.offset));
		fu_firmware_add_image (firmware, img);

		if (g_strcmp0 (area_name, FMAP_AREANAME) == 0) {
			g_autofree gchar *version = NULL;
			version = g_strdup_printf ("%d.%d",
						   fmap.ver_major,
						   fmap.ver_minor);
			fu_firmware_set_version (img, version);
		}
		offset += sizeof(area);
	}

	/* subclassed */
	if (klass_firmware->parse != NULL) {
		if (!klass_firmware->parse (firmware, fw, addr_start, addr_end, flags, error))
			return FALSE;
	}

	/* success */
	return TRUE;
}

static GBytes *
fu_fmap_firmware_write (FuFirmware *firmware, GError **error)
{
	FuFmapFirmware *self = FU_FMAP_FIRMWARE (firmware);
	FuFmapFirmwarePrivate *priv = GET_PRIVATE (self);
	gsize total_sz;
	gsize offset;
	g_autoptr(GPtrArray) images = fu_firmware_get_images (firmware);
	g_autoptr(GByteArray) buf = g_byte_array_new ();
	FuFmap hdr = {
		.signature = { FMAP_SIGNATURE },
		.ver_major = 0x1,
		.ver_minor = 0x1,
		.base = GUINT64_TO_LE (priv->base),
		.size = 0x0,
		.name = "",
		.nareas = GUINT16_TO_LE (images->len),
	};

	/* pad to offset */
	if (priv->offset > 0)
		fu_byte_array_set_size (buf, priv->offset);

	/* add header */
	total_sz = offset = sizeof(hdr) + (sizeof(FuFmapArea) * images->len);
	for (guint i = 0; i < images->len; i++) {
		FuFirmware *img = g_ptr_array_index (images, i);
		g_autoptr(GBytes) fw = fu_firmware_get_bytes (img, error);
		if (fw == NULL)
			return NULL;
		total_sz += g_bytes_get_size (fw);
	}
	hdr.size = GUINT32_TO_LE (priv->offset + total_sz);
	g_byte_array_append (buf, (const guint8 *) &hdr, sizeof(hdr));

	/* add each area */
	for (guint i = 0; i < images->len; i++) {
		FuFirmware *img = g_ptr_array_index (images, i);
		const gchar *id = fu_firmware_get_id (img);
		g_autoptr(GBytes) fw = fu_firmware_get_bytes (img, NULL);
		FuFmapArea area = {
			.offset = GUINT32_TO_LE (priv->offset + offset),
			.size = GUINT32_TO_LE (g_bytes_get_size (fw)),
			.name = { "" },
			.flags = 0x0,
		};
		if (id != NULL)
			strncpy ((gchar *) area.name, id, sizeof(area.name) - 1);
		g_byte_array_append (buf, (const guint8 *) &area, sizeof(area));
		offset += g_bytes_get_size (fw);
	}

	/* add the images */
	for (guint i = 0; i < images->len; i++) {
		FuFirmware *img = g_ptr_array_index (images, i);
		g_autoptr(GBytes) fw = fu_firmware_get_bytes (img, NULL);
		fu_byte_array_append_bytes (buf, fw);
	}

	/* success */
	return g_byte_array_free_to_bytes (g_steal_pointer (&buf));
}

static gboolean
fu_fmap_firmware_build (FuFirmware *firmware, XbNode *n, GError **error)
{
	FuFmapFirmware *self = FU_FMAP_FIRMWARE (firmware);
	FuFmapFirmwarePrivate *priv = GET_PRIVATE (self);
	guint64 tmp;

	/* simple properties */
	tmp = xb_node_query_text_as_uint (n, "base", NULL);
	if (tmp != G_MAXUINT64)
		priv->base = tmp;
	tmp = xb_node_query_text_as_uint (n, "offset", NULL);
	if (tmp != G_MAXUINT64)
		priv->offset = tmp;

	/* success */
	return TRUE;
}

static void
fu_fmap_firmware_init (FuFmapFirmware *self)
{
}

static void
fu_fmap_firmware_class_init (FuFmapFirmwareClass *klass)
{
	FuFirmwareClass *klass_firmware = FU_FIRMWARE_CLASS (klass);
	klass_firmware->export = fu_fmap_firmware_export;
	klass_firmware->parse = fu_fmap_firmware_parse;
	klass_firmware->write = fu_fmap_firmware_write;
	klass_firmware->build = fu_fmap_firmware_build;
}

/**
 * fu_fmap_firmware_new
 *
 * Creates a new #FuFirmware of sub type fmap
 *
 * Since: 1.5.0
 **/
FuFirmware *
fu_fmap_firmware_new (void)
{
	return FU_FIRMWARE (g_object_new (FU_TYPE_FMAP_FIRMWARE, NULL));
}