lantiq: fritz_cal_extract with reverse option for AVM FritzBox 7430

This implementation of fritz_cal_extract can also retrieve firmware
data stored in reverse byte order, as found in the AVM 7430 device.

This is done by intermediate storage in a buffer presumably large enough
to hold the complete data set. Currently, this buffer size is 128kB + 1kB
(some extra space for skipped data).

In the usual case of "forward" data, this implementation should behave
like the original implementation in all common cases. limit [-l] will
determine the amount of data read and size of buffer allocated.

However, if you are reading reversed data or didn't set a limit, the buffer
may be too small to hold all data. In this case, you can choose a higher
limit [-l] to enforce a sufficient buffer size.

Signed-off-by: Dustin Gathmann <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/15501
Signed-off-by: Robert Marko <[email protected]>
(cherry picked from commit b2cac2a9785ada7c30388349f5d9a9bdcff2e730)

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

@@ -8,6 +8,9 @@
  * that is Not copyrighted -- provided to the public domain
  * Version 1.4  11 December 2005  Mark Adler
  *
+ * Modifications to also handle calibration data in reversed byte order
+ * (c) 2024 by <[email protected]>.
+ *
  * 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
@@ -28,31 +31,54 @@
 #include <assert.h>
 #include <unistd.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <stdlib.h>
 #include <endian.h>
 #include <errno.h>
 #include "zlib.h"
 
 #define CHUNK 1024
+#define DEFAULT_BUFFERSIZE (129 * 1024)
+
+#define MIN(a,b) (((a)<(b))?(a):(b))
 
-static inline size_t special_min(size_t a, size_t b)
+/* Reverse byte order in data buffer.
+ * 'top' is position of last valid data byte = (datasize - 1)
+ */
+static void buffer_reverse(unsigned char *data, unsigned int top)
 {
-	return a == 0 ? b : (a < b ? a : b);
+	register unsigned char swapbyte;
+	const unsigned int center = top / 2;
+
+	for (unsigned int bottom = 0; bottom < center; ++bottom, --top) {
+		swapbyte = data[bottom];
+		data[bottom] = data[top];
+		data[top] = swapbyte;
+	}
 }
 
-/* Decompress from file source to file dest until stream ends or EOF.
-   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
-   allocated for processing, Z_DATA_ERROR if the deflate data is
-   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
-   the version of the library linked do not match, or Z_ERRNO if there
-   is an error reading or writing the files. */
-static int inf(FILE *source, FILE *dest, size_t limit, size_t skip)
+/* Decompress from file source to data buffer until stream ends
+ * or *limit bytes have been written to buffer.
+ *
+ * On call, 'limit' must reference a variable containing the intended
+ * number of bytes to retrieve (must be <= allocated buffer size).
+ *
+ * Return values (success):
+ * Z_END_STREAM if complete data was retrieved (*limit == size of complete data),
+ * or Z_OK if data was retrieved up to limit (*limit == original value).
+ *
+ * Return values (failure):
+ * Z_MEM_ERROR if memory could not be allocated for processing, 
+ * Z_DATA_ERROR if the deflate data is invalid or incomplete, 
+ * Z_VERSION_ERROR if the version of zlib.h and the version of the 
+ * library linked do not match, or 
+ * Z_ERRNO if there is an error reading or writing the files.
+ */
+static int inflate_to_buffer(FILE *source, unsigned char *buf, size_t *limit)
 {
 	int ret;
-	size_t have;
 	z_stream strm;
 	unsigned char in[CHUNK];
-	unsigned char out[CHUNK];
 
 	/* allocate inflate state */
 	strm.zalloc = Z_NULL;
@@ -64,6 +90,10 @@ static int inf(FILE *source, FILE *dest, size_t limit, size_t skip)
 	if (ret != Z_OK)
 		return ret;
 
+	/* set data buffer as stream output */
+	strm.avail_out = *limit;
+	strm.next_out = buf;
+
 	/* decompress until deflate stream ends or end of file */
 	do {
 		strm.avail_in = fread(in, 1, CHUNK, source);
@@ -75,35 +105,28 @@ static int inf(FILE *source, FILE *dest, size_t limit, size_t skip)
 			break;
 		strm.next_in = in;
 
-		/* run inflate() on input until output buffer not full */
-		do {
-			strm.avail_out = CHUNK;
-			strm.next_out = out;
-			ret = inflate(&strm, Z_NO_FLUSH);
-			assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
-			switch (ret) {
+		/* run inflate(), fill data buffer with all available output */
+		ret = inflate(&strm, Z_FINISH);
+		assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
+
+		switch (ret) {
 			case Z_NEED_DICT:
 				ret = Z_DATA_ERROR;     /* and fall through */
 			case Z_DATA_ERROR:
 			case Z_MEM_ERROR:
 				(void)inflateEnd(&strm);
 				return ret;
-			}
-			have = special_min(limit, CHUNK - strm.avail_out) - skip;
-			if (fwrite(&out[skip], have, 1, dest) != 1 || ferror(dest)) {
-				(void)inflateEnd(&strm);
-				return Z_ERRNO;
-			}
-		skip = 0;
-		limit -= have;
-		} while (strm.avail_out == 0 && limit > 0);
+		}
+		/* done when inflate() says it's done or limit reached */
+	} while (ret != Z_STREAM_END && strm.avail_out > 0);
 
-		/* done when inflate() says it's done */
-	} while (ret != Z_STREAM_END && limit > 0);
+	/* set limit to end of retrieved data */
+	assert(strm.total_out <= *limit);
+	*limit = strm.total_out;
 
 	/* clean up and return */
 	(void)inflateEnd(&strm);
-	return (limit == 0 ? Z_OK : (ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR));
+	return (ret == Z_STREAM_END ? Z_STREAM_END : (strm.avail_out == 0 ? Z_OK : Z_DATA_ERROR));
 }
 
 /* report a zlib or i/o error */
@@ -140,7 +163,8 @@ static unsigned int get_num(char *str)
 
 static void usage(void)
 {
-	fprintf(stderr, "Usage: fritz_cal_extract [-s seek offset] [-i skip] [-o output file] [-l limit] [infile] -e entry_id\n"
+	fprintf(stderr, "Usage: fritz_cal_extract -e entry_id [-s seek offset] [-l limit]\n"
+			"\t[-r reverse extracted data] [-i skip n bytes] [-o output file] [infile]\n"
 			"Finds and extracts zlib compressed calibration data in the EVA loader\n");
 	exit(EXIT_FAILURE);
 }
@@ -154,15 +178,18 @@ struct cal_entry {
 int main(int argc, char **argv)
 {
 	struct cal_entry cal = { .len = 0 };
+	unsigned char *buf = NULL;
 	FILE *in = stdin;
 	FILE *out = stdout;
+	size_t datasize = DEFAULT_BUFFERSIZE;
 	size_t limit = 0, skip = 0;
 	int initial_offset = 0;
 	int entry = -1;
+	bool reversed = false, limit_was_set = true;
 	int ret;
 	int opt;
 
-	while ((opt = getopt(argc, argv, "s:e:o:l:i:")) != -1) {
+	while ((opt = getopt(argc, argv, "s:e:o:l:i:r")) != -1) {
 		switch (opt) {
 		case 's':
 			initial_offset = (int)get_num(optarg);
@@ -199,6 +226,9 @@ int main(int argc, char **argv)
 				goto out_bad;
 			}
 			break;
+		case 'r':
+			reversed = true;
+			break;
 		default: /* '?' */
 			usage();
 		}
@@ -243,11 +273,50 @@ int main(int argc, char **argv)
 		goto out_bad;
 	}
 
-	ret = inf(in, out, limit, skip);
-	if (ret == Z_OK)
-		goto out;
+	/* Set boundaries. Only keep default datasize if we need complete data
+	 * for reversal and didn't set a higher limit. */
+	if (!limit) {
+		limit_was_set = false;
+		limit = datasize - skip;
+	}
+	datasize = (reversed && datasize >= limit + skip) ? datasize : (limit + skip);
+
+	/* Create data buffer. */
+	buf = malloc(datasize);
+	assert(buf != NULL);
+
+	ret = inflate_to_buffer(in, buf, &datasize);
+
+	if ((reversed || !limit_was_set) && ret != Z_STREAM_END) { /* didn't read to stream end */
+		fprintf(stderr, "Failed: Data exceeds buffer size of %u. Refusing to reverse"
+				" or store incomplete data."
+				" Use a higher limit [-l] to increase buffer size.\n",
+				(unsigned int) datasize);
+		goto out_bad;
+	}
+
+	ret = (ret == Z_STREAM_END) ? Z_OK : ret; /* normalize return value */
+	if (ret != Z_OK) {
+		zerr(ret);
+		goto out_bad;
+	}
+
+	if (reversed)
+		buffer_reverse(buf, datasize - 1);
+
+	if (datasize <= skip) {
+		fprintf(stderr, "Failed to skip %u bytes, total data size is %u!\n", 
+				(unsigned int)skip, (unsigned int)datasize);
+		goto out_bad;
+	}
+
+	limit = MIN(limit, datasize - skip);
+	if (fwrite(&buf[skip], limit, 1, out) != 1 || ferror(out)) {
+		fprintf(stderr, "Failed to write data buffer to output file");
+		goto out_bad;
+	}
 
-	zerr(ret);
+	goto out;
 
 out_bad:
 	ret = EXIT_FAILURE;
@@ -257,5 +326,6 @@ out:
 		fclose(in);
 	if (out)
 		fclose(out);
+	free(buf);
 	return ret;
 }

target/linux/lantiq/xrx200/base-files/etc/hotplug.d/firmware/12-ath9k-eeprom

@@ -19,11 +19,14 @@ case "$FIRMWARE" in
 			avm,fritz3390)
 				caldata_extract_reverse "urlader" 0x2546 0x440
 				;;
-			avm,fritz7412|\
-			avm,fritz7430)
+			avm,fritz7412)
 				/usr/bin/fritz_cal_extract -i 1 -s 0x1e000 -e 0x207 -l 5120 -o /lib/firmware/$FIRMWARE $(find_mtd_chardev "urlader") || \
 				/usr/bin/fritz_cal_extract -i 1 -s 0x1e800 -e 0x207 -l 5120 -o /lib/firmware/$FIRMWARE $(find_mtd_chardev "urlader")
 				;;
+			avm,fritz7430)
+				/usr/bin/fritz_cal_extract -r -i 4 -s 0x1e000 -e 0x207 -l 5120 -o /lib/firmware/$FIRMWARE $(find_mtd_chardev "urlader") || \
+				/usr/bin/fritz_cal_extract -r -i 4 -s 0x1e800 -e 0x207 -l 5120 -o /lib/firmware/$FIRMWARE $(find_mtd_chardev "urlader")
+				;;
 			bt,homehub-v5a)
 				caldata_extract_ubi "caldata" 0x1000 0x1000
 				ath9k_patch_mac_crc $(macaddr_add $(mtd_get_mac_binary_ubi caldata 0x110c) 2) 0x10c