fritz-tools: add fritz_tffs_nand_read tool

A tool for reading the TFFS partitions (a name-value storage usually
found in AVM Fritz!Box based devices) on nand flash.

Copyright (c) 2018 Valentin Spreckels <Valentin.Spreckels@Informatik.Uni-Oldenburg.DE>

Based on the fritz_tffs_read tool:
    Copyright (c) 2015-2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
and on the TFFS 2.0 kernel driver from AVM:
    Copyright (c) 2004-2007 AVM GmbH <fritzbox_info@avm.de>
and the TFFS 3.0 kernel driver from AVM:
    Copyright (C) 2004-2014 AVM GmbH <fritzbox_info@avm.de>
and the OpenWrt TFFS kernel driver:
    Copyright (c) 2013 John Crispin <blogic@openwrt.org>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

Signed-off-by: Valentin Spreckels <Valentin.Spreckels@Informatik.Uni-Oldenburg.de>
Signed-off-by: Andy Binder <AndyBinder@gmx.de>

package/utils/fritz-tools/Makefile

@@ -21,6 +21,15 @@ define Package/fritz-tffs/description
  Utility to partially read the TFFS filesystems.
 endef
 
+define Package/fritz-tffs-nand
+  $(call Package/fritz-tools/Default)
+  TITLE:=Utility to partially read the TFFS filesystems on NAND flash
+endef
+
+define Package/fritz-tffs-nand/description
+ Utility to partially read the TFFS filesystems on NAND flash.
+endef
+
 define Package/fritz-caldata
   $(call Package/fritz-tools/Default)
   DEPENDS:=+zlib
@@ -36,10 +45,16 @@ define Package/fritz-tffs/install
 	$(INSTALL_BIN) $(PKG_BUILD_DIR)/fritz_tffs_read $(1)/usr/bin/fritz_tffs
 endef
 
+define Package/fritz-tffs-nand/install
+	$(INSTALL_DIR) $(1)/usr/bin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/fritz_tffs_nand_read $(1)/usr/bin/fritz_tffs_nand
+endef
+
 define Package/fritz-caldata/install
 	$(INSTALL_DIR) $(1)/usr/bin
 	$(INSTALL_BIN) $(PKG_BUILD_DIR)/fritz_cal_extract $(1)/usr/bin/
 endef
 
 $(eval $(call BuildPackage,fritz-tffs))
+$(eval $(call BuildPackage,fritz-tffs-nand))
 $(eval $(call BuildPackage,fritz-caldata))

package/utils/fritz-tools/src/CMakeLists.txt

@@ -9,7 +9,8 @@ FIND_PATH(zlib_include_dir zlib.h)
 INCLUDE_DIRECTORIES(${zlib_include_dir})
 
 ADD_EXECUTABLE(fritz_tffs_read fritz_tffs_read.c)
+ADD_EXECUTABLE(fritz_tffs_nand_read fritz_tffs_nand_read.c)
 ADD_EXECUTABLE(fritz_cal_extract fritz_cal_extract.c)
 TARGET_LINK_LIBRARIES(fritz_cal_extract z)
 
-INSTALL(TARGETS fritz_tffs_read fritz_cal_extract RUNTIME DESTINATION bin)
+INSTALL(TARGETS fritz_tffs_read fritz_tffs_nand_read fritz_cal_extract RUNTIME DESTINATION bin)

package/utils/fritz-tools/src/fritz_tffs_nand_read.c

@@ -0,0 +1,564 @@
+/*
+ * A tool for reading the TFFS partitions (a name-value storage usually
+ * found in AVM Fritz!Box based devices) on nand flash.
+ *
+ * Copyright (c) 2018 Valentin Spreckels <Valentin.Spreckels@Informatik.Uni-Oldenburg.DE>
+ *
+ * Based on the fritz_tffs_read tool:
+ *     Copyright (c) 2015-2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ * and on the TFFS 2.0 kernel driver from AVM:
+ *     Copyright (c) 2004-2007 AVM GmbH <fritzbox_info@avm.de>
+ * and the TFFS 3.0 kernel driver from AVM:
+ *     Copyright (C) 2004-2014 AVM GmbH <fritzbox_info@avm.de>
+ * and the OpenWrt TFFS kernel driver:
+ *     Copyright (c) 2013 John Crispin <john@phrozen.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <libgen.h>
+#include <getopt.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <endian.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <arpa/inet.h>
+#include <mtd/mtd-user.h>
+#include <assert.h>
+
+#define DEFAULT_TFFS_SIZE	(256 * 1024)
+
+#define TFFS_ID_END		0xffffffff
+#define TFFS_ID_TABLE_NAME	0x000001ff
+
+#define TFFS_BLOCK_HEADER_MAGIC	0x41564d5f54464653ULL
+#define TFFS_VERSION		0x0003
+#define TFFS_ENTRY_HEADER_SIZE	0x18
+#define TFFS_MAXIMUM_SEGMENT_SIZE	(0x800 - TFFS_ENTRY_HEADER_SIZE)
+
+#define TFFS_SECTOR_SIZE 0x0800
+#define TFFS_SECTOR_OOB_SIZE 0x0040
+#define TFFS_SECTORS_PER_PAGE 2
+
+#define TFFS_SEGMENT_CLEARED 0xffffffff
+
+static char *progname;
+static char *mtddev;
+static char *name_filter = NULL;
+static bool show_all = false;
+static bool print_all_key_names = false;
+static bool swap_bytes = false;
+static uint8_t readbuf[TFFS_SECTOR_SIZE];
+static uint8_t oobbuf[TFFS_SECTOR_OOB_SIZE];
+static uint32_t blocksize;
+static int mtdfd;
+struct tffs_sectors *sectors;
+
+struct tffs_sectors {
+	uint32_t num_sectors;
+	uint8_t sectors[0];
+};
+
+static inline void sector_mark_bad(int num)
+{
+	sectors->sectors[num / 8] &= ~(0x80 >> (num % 8));
+};
+
+static inline uint8_t sector_get_good(int num)
+{
+	return sectors->sectors[num / 8] & 0x80 >> (num % 8);
+};
+
+struct tffs_entry_segment {
+	uint32_t len;
+	void *val;
+};
+
+struct tffs_entry {
+	uint32_t len;
+	void *val;
+};
+
+struct tffs_name_table_entry {
+	uint32_t id;
+	char *val;
+};
+
+struct tffs_key_name_table {
+	uint32_t size;
+	struct tffs_name_table_entry *entries;
+};
+
+static inline uint8_t read_uint8(void *buf, ptrdiff_t off)
+{
+	return *(uint8_t *)(buf + off);
+}
+
+static inline uint32_t read_uint32(void *buf, ptrdiff_t off)
+{
+	uint32_t tmp = *(uint32_t *)(buf + off);
+	if (swap_bytes) {
+		tmp = be32toh(tmp);
+	}
+	return tmp;
+}
+
+static inline uint64_t read_uint64(void *buf, ptrdiff_t off)
+{
+	uint64_t tmp = *(uint64_t *)(buf + off);
+	if (swap_bytes) {
+		tmp = be64toh(tmp);
+	}
+	return tmp;
+}
+
+static int read_sector(off_t pos)
+{
+	if (pread(mtdfd, readbuf, TFFS_SECTOR_SIZE, pos) != TFFS_SECTOR_SIZE) {
+		return -1;
+	}
+
+	return 0;
+}
+
+static int read_sectoroob(off_t pos)
+{
+	struct mtd_oob_buf oob = {
+		.start = pos,
+		.length = TFFS_SECTOR_OOB_SIZE,
+		.ptr = oobbuf
+	};
+
+	if (ioctl(mtdfd, MEMREADOOB, &oob) < 0)	{
+		return -1;
+	}
+
+	return 0;
+}
+
+static inline uint32_t get_walk_size(uint32_t entry_len)
+{
+	return (entry_len + 3) & ~0x03;
+}
+
+static void print_entry_value(const struct tffs_entry *entry)
+{
+	/* These are NOT NULL terminated. */
+	fwrite(entry->val, 1, entry->len, stdout);
+}
+
+static int find_entry(uint32_t id, struct tffs_entry *entry)
+{
+	uint32_t rev = 0;
+	uint32_t num_segments = 0;
+	struct tffs_entry_segment *segments = NULL;
+
+	off_t pos = 0;
+	uint8_t block_end = 0;
+	for (uint32_t sector = 0; sector < sectors->num_sectors; sector++, pos += TFFS_SECTOR_SIZE) {
+		if (block_end) {
+			if (pos % blocksize == 0) {
+				block_end = 0;
+			}
+		} else if (sector_get_good(sector)) {
+			if (read_sectoroob(pos) || read_sector(pos)) {
+				fprintf(stderr, "ERROR: sector isn't readable, but has been previously!\n");
+				exit(EXIT_FAILURE);
+			}
+			uint32_t oob_id = read_uint32(oobbuf, 0x02);
+			uint32_t oob_len = read_uint32(oobbuf, 0x06);
+			uint32_t oob_rev = read_uint32(oobbuf, 0x0a);
+			uint32_t read_id = read_uint32(readbuf, 0x00);
+			uint32_t read_len = read_uint32(readbuf, 0x04);
+			uint32_t read_rev = read_uint32(readbuf, 0x0c);
+			if (oob_id != read_id || oob_len != read_len || oob_rev != read_rev) {
+				fprintf(stderr, "Warning: sector has inconsistent metadata\n");
+				continue;
+			}
+			if (read_id == TFFS_ID_END) {
+				/* no more entries in this block */
+				block_end = 1;
+				continue;
+			}
+			if (read_len > TFFS_MAXIMUM_SEGMENT_SIZE) {
+				fprintf(stderr, "Warning: segment is longer than possible\n");
+				continue;
+			}
+			if (read_id == id) {
+				if (read_rev < rev) {
+					/* obsolete revision => ignore this */
+					continue;
+				}
+				if (read_rev > rev) {
+					/* newer revision => clear old data */
+					for (uint32_t i = 0; i < num_segments; i++) {
+						free(segments[i].val);
+					}
+					free (segments);
+					rev = read_rev;
+					num_segments = 0;
+					segments = NULL;
+				}
+
+				uint32_t seg = read_uint32(readbuf, 0x10);
+
+				if (seg == TFFS_SEGMENT_CLEARED) {
+					continue;
+				}
+
+				uint32_t next_seg = read_uint32(readbuf, 0x14);
+
+				uint32_t new_num_segs = next_seg == 0 ? seg + 1 : next_seg + 1;
+				if (new_num_segs > num_segments) {
+					segments = realloc(segments, new_num_segs * sizeof(struct tffs_entry_segment));
+					memset(segments + (num_segments * sizeof(struct tffs_entry_segment)), 0x0,
+							(new_num_segs - num_segments) * sizeof(struct tffs_entry_segment));
+					num_segments = new_num_segs;
+				}
+				segments[seg].len = read_len;
+				segments[seg].val = malloc(read_len);
+				memcpy(segments[seg].val, readbuf + TFFS_ENTRY_HEADER_SIZE, read_len);
+			}
+		}
+	}
+
+	if (num_segments == 0) {
+		return 0;
+	}
+
+	assert (segments != NULL);
+
+	uint32_t len = 0;
+	for (uint32_t i = 0; i < num_segments; i++) {
+		if (segments[i].val == NULL) {
+			/* missing segment */
+			return 0;
+		}
+
+		len += segments[i].len;
+	}
+
+	void *p = malloc(len);
+	entry->val = p;
+	entry->len = len;
+	for (uint32_t i = 0; i < num_segments; i++) {
+		memcpy(p, segments[i].val, segments[i].len);
+		p += segments[i].len;
+	}
+
+	return 1;
+}
+
+static void parse_key_names(struct tffs_entry *names_entry,
+			     struct tffs_key_name_table *key_names)
+{
+	uint32_t pos = 0, i = 0;
+	struct tffs_name_table_entry *name_item;
+
+	key_names->entries = NULL;
+
+	do {
+		key_names->entries = realloc(key_names->entries,
+			 sizeof(struct tffs_name_table_entry) * (i + 1));
+		if (key_names->entries == NULL) {
+			fprintf(stderr, "ERROR: memory allocation failed!\n");
+			exit(EXIT_FAILURE);
+		}
+		name_item = &key_names->entries[i];
+
+		name_item->id = read_uint32(names_entry->val, pos);
+		pos += sizeof(uint32_t);
+		name_item->val = strdup((const char *)(names_entry->val + pos));
+
+		/*
+		 * There is no "length" field because the string values are
+		 * simply NULL-terminated -> strlen() gives us the size.
+		 */
+		pos += get_walk_size(strlen(name_item->val) + 1);
+
+		++i;
+	} while (pos < names_entry->len);
+
+	key_names->size = i;
+}
+
+static void show_all_key_names(struct tffs_key_name_table *key_names)
+{
+	for (uint32_t i = 0; i < key_names->size; i++)
+		printf("%s\n", key_names->entries[i].val);
+}
+
+static int show_all_key_value_pairs(struct tffs_key_name_table *key_names)
+{
+	uint8_t has_value = 0;
+	struct tffs_entry tmp;
+
+	for (uint32_t i = 0; i < key_names->size; i++) {
+		if (find_entry(key_names->entries[i].id, &tmp)) {
+			printf("%s=", (const char *)key_names->entries[i].val);
+			print_entry_value(&tmp);
+			printf("\n");
+			has_value++;
+			free(tmp.val);
+		}
+	}
+
+	if (!has_value) {
+		fprintf(stderr, "ERROR: no values found!\n");
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}
+
+static int show_matching_key_value(struct tffs_key_name_table *key_names)
+{
+	struct tffs_entry tmp;
+	const char *name;
+
+	for (uint32_t i = 0; i < key_names->size; i++) {
+		name = key_names->entries[i].val;
+
+		if (strncmp(name, name_filter, strlen(name)) == 0) {
+			if (find_entry(key_names->entries[i].id, &tmp)) {
+				print_entry_value(&tmp);
+				printf("\n");
+				free(tmp.val);
+				return EXIT_SUCCESS;
+			} else {
+				fprintf(stderr,
+					"ERROR: no value found for name %s!\n",
+					name);
+				return EXIT_FAILURE;
+			}
+		}
+	}
+
+	fprintf(stderr, "ERROR: Unknown key name %s!\n", name_filter);
+	return EXIT_FAILURE;
+}
+
+static int check_sector(off_t pos)
+{
+	if (read_sectoroob(pos)) {
+		return 0;
+	}
+	if (read_uint8(oobbuf, 0x00) != 0xff) {
+		/* block is bad */
+		return 0;
+	}
+	if (read_uint8(oobbuf, 0x01) != 0xff) {
+		/* sector is bad */
+		return 0;
+	}
+	return 1;
+}
+
+static int check_block(off_t pos, uint32_t sector)
+{
+	if (!check_sector(pos)) {
+		return 0;
+	}
+	if (read_sector(pos)) {
+		return 0;
+	}
+	if (read_uint64(readbuf, 0x00) != TFFS_BLOCK_HEADER_MAGIC) {
+		fprintf(stderr, "Warning: block without magic header. Skipping block\n");
+		return 0;
+	}
+	if (read_uint32(readbuf, 0x0c) != TFFS_SECTORS_PER_PAGE) {
+		fprintf(stderr, "Warning: block with wrong number of sectors per page. Skipping block\n");
+		return 0;
+	}
+
+	uint32_t num_hdr_bad = read_uint32(readbuf, 0x0c);
+	for (uint32_t i = 0; i < num_hdr_bad; i++) {
+		uint32_t bad = sector + read_uint64(readbuf, 0x1c + sizeof(uint64_t)*i);
+		sector_mark_bad(bad);
+	}
+
+	return 1;
+}
+
+static int scan_mtd(void)
+{
+	struct mtd_info_user info;
+
+	if (ioctl(mtdfd, MEMGETINFO, &info)) {
+		return 0;
+	}
+
+	blocksize = info.erasesize;
+
+	sectors = malloc(sizeof(*sectors) + (info.size / TFFS_SECTOR_SIZE + 7) / 8);
+	if (sectors == NULL) {
+		fprintf(stderr, "ERROR: memory allocation failed!\n");
+		exit(EXIT_FAILURE);
+	}
+	sectors->num_sectors = info.size / TFFS_SECTOR_SIZE;
+	memset(sectors->sectors, 0xff, (info.size / TFFS_SECTOR_SIZE + 7) / 8);
+
+	uint32_t sector = 0, valid_blocks = 0;
+	uint8_t block_ok = 0;
+	for (off_t pos = 0; pos < info.size; sector++, pos += TFFS_SECTOR_SIZE) {
+		if (pos % info.erasesize == 0) {
+			block_ok = check_block(pos, sector);
+			/* first sector of the block contains metadata
+			   => handle it like a bad sector */
+			sector_mark_bad(sector);
+			if (block_ok) {
+				valid_blocks++;
+			}
+		} else if (!block_ok || !sector_get_good(sector) || !check_sector(pos)) {
+			sector_mark_bad(sector);
+		}
+	}
+
+	return valid_blocks;
+}
+
+static void usage(int status)
+{
+	FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
+
+	fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
+	fprintf(stream,
+	"\n"
+	"Options:\n"
+	"  -a              list all key value pairs found in the TFFS file/device\n"
+	"  -d <mtd>        inspect the TFFS on mtd device <mtd>\n"
+	"  -h              show this screen\n"
+	"  -l              list all supported keys\n"
+	"  -n <key name>   display the value of the given key\n"
+	);
+
+	exit(status);
+}
+
+static void parse_options(int argc, char *argv[])
+{
+	while (1) {
+		int c;
+
+		c = getopt(argc, argv, "abd:hln:");
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 'a':
+			show_all = true;
+			name_filter = NULL;
+			print_all_key_names = false;
+			break;
+		case 'b':
+			swap_bytes = 1;
+			break;
+		case 'd':
+			mtddev = optarg;
+			break;
+		case 'h':
+			usage(EXIT_SUCCESS);
+			break;
+		case 'l':
+			print_all_key_names = true;
+			show_all = false;
+			name_filter = NULL;
+			break;
+		case 'n':
+			name_filter = optarg;
+			show_all = false;
+			print_all_key_names = false;
+			break;
+		default:
+			usage(EXIT_FAILURE);
+			break;
+		}
+	}
+
+	if (!mtddev) {
+		fprintf(stderr, "ERROR: No input file (-d <file>) given!\n");
+		usage(EXIT_FAILURE);
+	}
+
+	if (!show_all && !name_filter && !print_all_key_names) {
+		fprintf(stderr,
+			"ERROR: either -l, -a or -n <key name> is required!\n");
+		usage(EXIT_FAILURE);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	int ret = EXIT_FAILURE;
+	struct tffs_entry name_table;
+	struct tffs_key_name_table key_names;
+
+	progname = basename(argv[0]);
+
+	parse_options(argc, argv);
+
+	mtdfd = open(mtddev, O_RDONLY);
+	if (mtdfd < 0) {
+		fprintf(stderr, "ERROR: Failed to open tffs device %s\n",
+			mtddev);
+		goto out;
+	}
+
+	if (!scan_mtd()) {
+		fprintf(stderr, "ERROR: Parsing blocks from tffs device %s failed\n", mtddev);
+		fprintf(stderr, "       Is byte-swapping (-b) required?\n");
+		goto out_close;
+	}
+
+	if (!find_entry(TFFS_ID_TABLE_NAME, &name_table)) {
+		fprintf(stderr, "ERROR: No name table found on tffs device %s\n",
+			mtddev);
+		goto out_free_sectors;
+	}
+
+	parse_key_names(&name_table, &key_names);
+	if (key_names.size < 1) {
+		fprintf(stderr, "ERROR: No name table found on tffs device %s\n",
+			mtddev);
+		goto out_free_entry;
+	}
+
+	if (print_all_key_names) {
+		show_all_key_names(&key_names);
+		ret = EXIT_SUCCESS;
+	} else if (show_all) {
+		ret = show_all_key_value_pairs(&key_names);
+	} else {
+		ret = show_matching_key_value(&key_names);
+	}
+
+	free(key_names.entries);
+out_free_entry:
+	free(name_table.val);
+out_free_sectors:
+	free(sectors);
+out_close:
+	close(mtdfd);
+out:
+	return ret;
+}