From a74204225a1e8d8e725c94ddaa53bbb900155d68 Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Tue, 3 Feb 2009 00:13:00 +0100
Subject: [PATCH] check crc of embedded compressed firmware after expansion

---
 filesystem.c |  4 ++--
 rsb-lz.c     | 62 ++++++++++++++++++++++++----------------------------
 rsb-lz.h     |  2 +-
 3 files changed, 31 insertions(+), 37 deletions(-)

diff --git a/filesystem.c b/filesystem.c
index 84c592c..175cbc4 100644
--- a/filesystem.c
+++ b/filesystem.c
@@ -107,7 +107,7 @@ void extract_files(unsigned char *fw, int len)
 
 				printf("%s: packed file found", lzname);
 
-				extract_lz_file(fent->start, (unsigned char*)lzname);
+				extract_lz_file(fent->start, (unsigned char*)lzname, 0);
 				free(lzname);
 			} else if (!strcmp(fent->name, "firmware")) {
 				unsigned char *lzpos;
@@ -121,7 +121,7 @@ void extract_files(unsigned char *fw, int len)
 				lzpos += 4;
 				if (*((unsigned int*)(lzpos)) == LZ_MAGIC) {
 					printf("%s: compressed firmware part found", lzname);
-					extract_lz_file(lzpos, (unsigned char*)lzname);
+					extract_lz_file(lzpos, (unsigned char*)lzname, 1);
 				}
 			}
 		} else {
diff --git a/rsb-lz.c b/rsb-lz.c
index 93e9d79..c23dd5a 100644
--- a/rsb-lz.c
+++ b/rsb-lz.c
@@ -136,43 +136,36 @@ void lz_expand(struct data_in_s *data_in, struct data_out_s *data_out)
 }
 
 /* Checksum is only used for the compressed firmware in 'firmware' */
-#if 0
-unsigned int crc_check_59684(unsigned char *arg1, unsigned int arg2, unsigned int magic)
+unsigned int crc_check(unsigned char *buf, unsigned int len, unsigned int magic)
 {
-	unsigned int r3;
-	unsigned int r4;
-	unsigned int r5;
+	unsigned int file_crc;
+	unsigned int my_len;
+	unsigned int crc;
+	unsigned int my_magic;
 
-#if 0
-	if (r0 < 0xc0000000)
-		return 1;
-#endif
+	my_len = *((unsigned int*)(buf + 0x20));
+	my_magic = *((unsigned int*)(buf + 0x24));
 
-	/* ??? */
-	r4 = *((unsigned int*)arg1 + 0x20);
-	r5 = *((unsigned int*)arg1 + 0x24);
-
-	printf("magic: 0x%08x <-> 0x%08x\n", r5, magic);
-	if (r5 != magic)
+	if (my_magic != magic) {
+		printf("\nmagic: 0x%08x <-> 0x%08x\n", my_magic, magic);
 		return 2;
+	}
 	
-	if (arg2 >= r4)
-		r5 = 0;
-	else
+	if (len < my_len)
 		return 3;
 
-	r5 = ~rsb_crc(~0x00, arg1, r4);
-	r3 = *((unsigned int*)(arg1 + r4));
-	printf("Checksums: 0x%02x <-> 0x%02x\n", r5, r3);
+	crc = ~rsb_crc(~0x00, buf, len);
+	file_crc = *((unsigned int*)(buf + len));
 
-	if (r3 == r5)
-		return 0;
+	if (file_crc != crc) {
+		printf("\nChecksums: 0x%08x <-> 0x%08x!\n", crc, file_crc);
+		return 4;
+	}
 
-	return 4;
+	return 0;
 }
-#endif
 
-void extract_lz_file(unsigned char *inbuf, unsigned char *name)
+void extract_lz_file(unsigned char *inbuf, unsigned char *name, unsigned char check_crc)
 {
 	unsigned int len;
 	unsigned char *outbuf;
@@ -202,16 +195,17 @@ void extract_lz_file(unsigned char *inbuf, unsigned char *name)
 
 	lz_expand(&data_in, &data_out);
 
-#if 0
-	/* Checksum is only used for the compressed firmware in 'firmware' */
-	r3 = r7 + 0x20;
-	r5 = *((unsigned int*)r3);
+	if (check_crc) {
+		unsigned int crclen;
+		int ret;
 
-	if ((ret = crc_check_59684(r7, r5, 0x46335053)) != 0) {
-		printf("crc_check return: %d\n", ret);
-		err_exit(__func__);
+		crclen = *((unsigned int*)(outbuf + 0x20));
+
+		if ((ret = crc_check(outbuf, crclen, 0x46335053)) != 0) {
+			printf("crc_check return: %d\n", ret);
+			err_exit(__func__);
+		}
 	}
-#endif
 
 	write_file((char*)name, outbuf, len);
 	
diff --git a/rsb-lz.h b/rsb-lz.h
index ed0d4fb..767ceb9 100644
--- a/rsb-lz.h
+++ b/rsb-lz.h
@@ -1,3 +1,3 @@
 #define LZ_MAGIC 0x6110beef
 
-void extract_lz_file(unsigned char *buf, unsigned char *name);
+void extract_lz_file(unsigned char *buf, unsigned char *name, unsigned char check_crc);
-- 
2.39.2