[firmware-utils] bcmblob: new tool for reading Broadcom's BLOBs

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9b70226..31e0a06 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,6 +32,7 @@  FW_UTIL(asustrx "" "" "")
 FW_UTIL(avm-wasp-checksum "" --std=gnu99 "")
 FW_UTIL(bcm4908asus "" "" "")
 FW_UTIL(bcm4908kernel "" "" "")
+FW_UTIL(bcmblob "" "" "")
 FW_UTIL(buffalo-enc src/buffalo-lib.c "" "")
 FW_UTIL(buffalo-tag src/buffalo-lib.c "" "")
 FW_UTIL(buffalo-tftp src/buffalo-lib.c "" "")
diff --git a/src/bcmblob.c b/src/bcmblob.c
new file mode 100644
index 0000000..f11a8a5
--- /dev/null
+++ b/src/bcmblob.c
@@ -0,0 +1,455 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2023 Rafał Miłecki <rafal@milecki.pl>
+ */
+
+#include <byteswap.h>
+#include <endian.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#if !defined(__BYTE_ORDER)
+#error "Unknown byte order"
+#endif
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+#define cpu_to_le32(x)	bswap_32(x)
+#define le32_to_cpu(x)	bswap_32(x)
+#define cpu_to_be32(x)	(x)
+#define be32_to_cpu(x)	(x)
+#elif __BYTE_ORDER == __LITTLE_ENDIAN
+#define cpu_to_le32(x)	(x)
+#define le32_to_cpu(x)	(x)
+#define cpu_to_be32(x)	bswap_32(x)
+#define be32_to_cpu(x)	bswap_32(x)
+#else
+#error "Unsupported endianness"
+#endif
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
+
+#define BCMBLOB_MAGIC		"BLOB"
+
+/* Raw data */
+
+struct bcmblob_entry {
+	uint32_t unk0;
+	uint32_t offset;
+	uint32_t size;
+	uint32_t crc32;
+	uint32_t unk1;
+};
+
+struct bcmblob_header {
+	char magic[4];
+	uint32_t hdr_len;
+	uint32_t crc32;
+	uint32_t unk0;
+	uint32_t unk1;
+	struct bcmblob_entry entries[2];
+};
+
+/* Parsed info */
+
+struct bcmblob_entry_info {
+	struct bcmblob_entry header;
+	size_t offset;
+	size_t size;
+	uint32_t crc32;
+};
+
+struct bcmblob_info {
+	struct bcmblob_header header;
+	struct bcmblob_entry_info entries[2];
+	size_t file_size;
+	uint32_t crc32;
+};
+
+static inline size_t bcmblob_min(size_t x, size_t y)
+{
+	return x < y ? x : y;
+}
+
+/**************************************************
+ * CRC32
+ **************************************************/
+
+static const uint32_t crc32_tbl[] = {
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
+	0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+	0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
+	0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+	0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
+	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
+	0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+	0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+	0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
+	0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
+	0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+	0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+	0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
+	0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+	0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+	0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+	0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
+	0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
+	0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+	0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+	0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+	0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
+	0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+	0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+	0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
+	0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
+	0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+	0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+	0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
+	0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
+	0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+	0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+	0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
+	0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+	0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+	0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+	0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
+	0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
+	0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+	0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
+};
+
+uint32_t bcmblob_crc32(uint32_t crc, const void *buf, size_t len)
+{
+	const uint8_t *in = buf;
+
+	while (len) {
+		crc = crc32_tbl[(crc ^ *in) & 0xff] ^ (crc >> 8);
+		in++;
+		len--;
+	}
+
+	return crc;
+}
+
+/**************************************************
+ * Helpers
+ **************************************************/
+
+static FILE *bcmblob_open(const char *pathname, const char *mode)
+{
+	struct stat st;
+
+	if (pathname)
+		return fopen(pathname, mode);
+
+	if (isatty(fileno(stdin))) {
+		fprintf(stderr, "Reading from TTY stdin is unsupported\n");
+		return NULL;
+	}
+
+	if (fstat(fileno(stdin), &st)) {
+		fprintf(stderr, "Failed to fstat stdin: %d\n", -errno);
+		return NULL;
+	}
+
+	if (S_ISFIFO(st.st_mode)) {
+		fprintf(stderr, "Reading from pipe stdin is unsupported\n");
+		return NULL;
+	}
+
+	return stdin;
+}
+
+static void bcmblob_close(FILE *fp)
+{
+	if (fp != stdin)
+		fclose(fp);
+}
+
+/**************************************************
+ * Existing BLOB parser
+ **************************************************/
+
+static int bcmblob_parse(FILE *fp, struct bcmblob_info *info)
+{
+	struct bcmblob_header *header = &info->header;
+	struct stat st;
+	uint8_t buf[1024];
+	size_t length;
+	size_t bytes;
+	int i;
+	int err = 0;
+
+	memset(info, 0, sizeof(*info));
+
+	/* File size */
+
+	if (fstat(fileno(fp), &st)) {
+		err = -errno;
+		fprintf(stderr, "Failed to fstat: %d\n", err);
+		return err;
+	}
+	info->file_size = st.st_size;
+
+	/* Header */
+
+	if (fread(header, 1, sizeof(*header), fp) != sizeof(*header)) {
+		fprintf(stderr, "Failed to read BLOB header\n");
+		return -EIO;
+	}
+
+	if (strncmp(header->magic, BCMBLOB_MAGIC, 4)) {
+		fprintf(stderr, "Invalid BLOB header magic\n");
+		return -EPROTO;
+	}
+
+	/* CRC32 */
+
+	fseek(fp, 12, SEEK_SET);
+
+	info->crc32 = 0xffffffff;
+	length = sizeof(struct bcmblob_header) - 12;
+	while (length && (bytes = fread(buf, 1, bcmblob_min(sizeof(buf), length), fp)) > 0) {
+		info->crc32 = bcmblob_crc32(info->crc32, buf, bytes);
+		length -= bytes;
+	}
+	if (length) {
+		fprintf(stderr, "Failed to read last %zd B of data\n", length);
+		return -EIO;
+	}
+	info->crc32 ^= ~0U;
+
+	if (info->crc32 != le32_to_cpu(header->crc32)) {
+		fprintf(stderr, "Invalid data crc32: 0x%08x instead of 0x%08x\n", info->crc32, le32_to_cpu(header->crc32));
+		return -EPROTO;
+	}
+
+	/* Entries */
+
+	for (i = 0; i < ARRAY_SIZE(header->entries); i++) {
+		struct bcmblob_entry_info *entry_info = &info->entries[i];
+
+		entry_info->offset = le32_to_cpu(header->entries[i].offset);
+		entry_info->size = le32_to_cpu(header->entries[i].size);
+
+		fseek(fp, entry_info->offset, SEEK_SET);
+
+		entry_info->crc32 = 0xffffffff;
+		length = entry_info->size;
+		while (length && (bytes = fread(buf, 1, bcmblob_min(sizeof(buf), length), fp)) > 0) {
+			entry_info->crc32 = bcmblob_crc32(entry_info->crc32, buf, bytes);
+			length -= bytes;
+		}
+		if (length) {
+			fprintf(stderr, "Failed to read last %zd B of data\n", length);
+			return -EIO;
+		}
+		entry_info->crc32 ^= ~0U;
+
+		if (entry_info->crc32 != le32_to_cpu(header->entries[i].crc32)) {
+			fprintf(stderr, "Invalid entry's crc32: 0x%08x instead of 0x%08x\n", entry_info->crc32, le32_to_cpu(header->entries[i].crc32));
+			return -EPROTO;
+		}
+
+		if (header->entries[i].unk0) {
+			fprintf(stderr, "Unexpected entry's unk0 value: 0x%08x\n", le32_to_cpu(header->entries[i].unk0));
+		}
+
+		if (header->entries[i].unk1) {
+			fprintf(stderr, "Unexpected entry's unk1 value: 0x%08x\n", le32_to_cpu(header->entries[i].unk1));
+		}
+	}
+
+	/* Verify */
+
+	if (le32_to_cpu(header->unk0) != 1) {
+		fprintf(stderr, "Unexpected unk0 value: 0x%08x\n", le32_to_cpu(header->unk0));
+	}
+
+	if (le32_to_cpu(header->unk1) != 2) {
+		fprintf(stderr, "Unexpected unk1 value: 0x%08x\n", le32_to_cpu(header->unk1));
+	}
+
+	return 0;
+}
+
+/**************************************************
+ * Info
+ **************************************************/
+
+static int bcmblob_info(int argc, char **argv)
+{
+	struct bcmblob_info info;
+	const char *pathname = NULL;
+	FILE *fp;
+	int i;
+	int c;
+	int err = 0;
+
+	while ((c = getopt(argc, argv, "i:")) != -1) {
+		switch (c) {
+		case 'i':
+			pathname = optarg;
+			break;
+		}
+	}
+
+	fp = bcmblob_open(pathname, "r");
+	if (!fp) {
+		fprintf(stderr, "Failed to open BLOB\n");
+		err = -EACCES;
+		goto out;
+	}
+
+	err = bcmblob_parse(fp, &info);
+	if (err) {
+		fprintf(stderr, "Failed to parse BLOB\n");
+		goto err_close;
+	}
+
+	printf("CRC32: 0x%08x\n", info.crc32);
+	for (i = 0; i < ARRAY_SIZE(info.entries); i++) {
+		struct bcmblob_entry_info *entry_info = &info.entries[i];
+
+		printf("[Entry %d] offset:0x%08zx size:0x%08zx crc32:0x%08x\n", i, entry_info->offset, entry_info->size, entry_info->crc32);
+	}
+
+err_close:
+	bcmblob_close(fp);
+out:
+	return err;
+}
+
+/**************************************************
+ * Extract
+ **************************************************/
+
+static int bcmblob_extract(int argc, char **argv)
+{
+	struct bcmblob_entry_info *entry_info;
+	struct bcmblob_info info;
+	const char *pathname = NULL;
+	uint8_t buf[1024];
+	size_t size = 0;
+	int index = -1;
+	size_t bytes;
+	FILE *fp;
+	int c;
+	int err = 0;
+
+	while ((c = getopt(argc, argv, "i:n:")) != -1) {
+		switch (c) {
+		case 'i':
+			pathname = optarg;
+			break;
+		case 'n':
+			index = strtoul(optarg, NULL, 0);
+			break;
+		}
+	}
+
+	if (index < 0 || index >= ARRAY_SIZE(info.entries)) {
+		err = -EINVAL;
+		fprintf(stderr, "No valid entry index specified\n");
+		goto err_out;
+	}
+
+	fp = bcmblob_open(pathname, "r");
+	if (!fp) {
+		fprintf(stderr, "Failed to open BLOB\n");
+		err = -EACCES;
+		goto err_out;
+	}
+
+	err = bcmblob_parse(fp, &info);
+	if (err) {
+		fprintf(stderr, "Failed to parse BLOB\n");
+		goto err_close;
+	}
+
+	entry_info = &info.entries[index];
+
+	fseek(fp, entry_info->offset, SEEK_SET);
+	for (size = entry_info->size;
+	     size && (bytes = fread(buf, 1, bcmblob_min(sizeof(buf), size), fp)) > 0;
+	     size -= bytes) {
+		fwrite(buf, bytes, 1, stdout);
+	}
+	if (size) {
+		err = -EIO;
+		fprintf(stderr, "Failed to read last %zd B of data\n", size);
+		goto err_close;
+	}
+
+err_close:
+	bcmblob_close(fp);
+err_out:
+	return err;
+}
+
+/**************************************************
+ * Start
+ **************************************************/
+
+static void usage()
+{
+	printf("Usage:\n");
+	printf("\n");
+	printf("Info about a BLOB:\n");
+	printf("\tbcmblob info <options>\n");
+	printf("\t-i <file>\t\t\t\t\tinput BLOB\n");
+	printf("\n");
+	printf("Extracting from a BLOB:\n");
+	printf("\tbcmblob extract <options>\n");
+	printf("\t-i <file>\t\t\t\t\tinput BLOB\n");
+	printf("\t-n <index>\t\t\t\t\tindex of entry to extract\n");
+	printf("\n");
+	printf("Examples:\n");
+	printf("\tbcmblob info -i cyfmac4354-sdio.clm_blob\n");
+	printf("\tbcmblob extract -i cyfmac4354-sdio.clm_blob -n 1 | hexdump -C\n");
+}
+
+int main(int argc, char **argv)
+{
+	if (argc > 1) {
+		optind++;
+		if (!strcmp(argv[1], "info"))
+			return bcmblob_info(argc, argv);
+		else if (!strcmp(argv[1], "extract"))
+			return bcmblob_extract(argc, argv);
+	}
+
+	usage();
+
+	return 0;
+}