1 files changed, 38 insertions, 20 deletions

diff --git a/lib/ext2fs/csum.c b/lib/ext2fs/csum.c
index 9fa3f24f..669f8068 100644
--- a/lib/ext2fs/csum.c
+++ b/lib/ext2fs/csum.c
@@ -32,27 +32,23 @@
 
 __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 {
+	struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
+							 group);
+	size_t size = EXT2_DESC_SIZE(fs->super);
 	__u16 crc = 0;
-	struct ext2_group_desc *desc;
-	size_t size;
-
-	size = fs->super->s_desc_size;
-	if (size < EXT2_MIN_DESC_SIZE)
-		size = EXT2_MIN_DESC_SIZE;
-	if (size > sizeof(struct ext4_group_desc)) {
-		printf("%s: illegal s_desc_size(%zd)\n", __func__, size);
-		size = sizeof(struct ext4_group_desc);
-	}
-
-	desc = ext2fs_group_desc(fs, fs->group_desc, group);
 
 	if (fs->super->s_feature_ro_compat & EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
 		size_t offset = offsetof(struct ext2_group_desc, bg_checksum);
 
 #ifdef WORDS_BIGENDIAN
 		struct ext4_group_desc swabdesc;
+		size_t save_size = size;
+		const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
+		struct ext2_group_desc *save_desc = desc;
 
 		/* Have to swab back to little-endian to do the checksum */
+		if (size > ext4_bg_size)
+			size = ext4_bg_size;
 		memcpy(&swabdesc, desc, size);
 		ext2fs_swap_group_desc2(fs,
 					(struct ext2_group_desc *) &swabdesc);
@@ -70,6 +66,17 @@ __u16 ext2fs_group_desc_csum(ext2_filsys fs, dgrp_t group)
 			crc = ext2fs_crc16(crc, (char *)desc + offset,
 					   size - offset);
 		}
+#ifdef WORDS_BIGENDIAN
+		/*
+		 * If the size of the bg descriptor is greater than 64
+		 * bytes, which is the size of the traditional ext4 bg
+		 * descriptor, checksum the rest of the descriptor here
+		 */
+		if (save_size > ext4_bg_size)
+			crc = ext2fs_crc16(crc,
+					   (char *)save_desc + ext4_bg_size,
+					   save_size - ext4_bg_size);
+#endif
 	}
 
 	return crc;
@@ -166,21 +173,22 @@ void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 {
 	__u16 crc1, crc2, crc3;
 	dgrp_t swabgroup;
- 	struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc, group);
-	size_t size;
+	struct ext2_group_desc *desc = ext2fs_group_desc(fs, fs->group_desc,
+							 group);
+	size_t size = EXT2_DESC_SIZE(fs->super);
 	struct ext2_super_block *sb = fs->super;
 	int offset = offsetof(struct ext2_group_desc, bg_checksum);
 #ifdef WORDS_BIGENDIAN
 	struct ext4_group_desc swabdesc;
+	struct ext2_group_desc *save_desc = desc;
+	const size_t ext4_bg_size = sizeof(struct ext4_group_desc);
+	size_t save_size = size;
 #endif
 
-	size = fs->super->s_desc_size;
-	if (size < EXT2_MIN_DESC_SIZE)
-		size = EXT2_MIN_DESC_SIZE;
-	if (size > sizeof(struct ext4_group_desc))
-		size = sizeof(struct ext4_group_desc);
 #ifdef WORDS_BIGENDIAN
 	/* Have to swab back to little-endian to do the checksum */
+	if (size > ext4_bg_size)
+		size = ext4_bg_size;
 	memcpy(&swabdesc, desc, size);
 	ext2fs_swap_group_desc2(fs, (struct ext2_group_desc *) &swabdesc);
 	desc = (struct ext2_group_desc *) &swabdesc;
@@ -197,8 +205,13 @@ void print_csum(const char *msg, ext2_filsys fs, dgrp_t group)
 	/* for checksum of struct ext4_group_desc do the rest...*/
 	if (offset < size)
 		crc3 = ext2fs_crc16(crc3, (char *)desc + offset, size - offset);
+#ifdef WORDS_BIGENDIAN
+	if (save_size > ext4_bg_size)
+		crc3 = ext2fs_crc16(crc3, (char *)save_desc + ext4_bg_size,
+				    save_size - ext4_bg_size);
+#endif
 
-	printf("%s: UUID %s(%04x), grp %u(%04x): %04x=%04x\n",
+	printf("%s UUID %s=%04x, grp %u=%04x: %04x=%04x\n",
 	       msg, e2p_uuid2str(sb->s_uuid), crc1, group, crc2, crc3,
 	       ext2fs_group_desc_csum(fs, group));
 }
@@ -216,6 +229,11 @@ int main(int argc, char **argv)
 
 	memset(&param, 0, sizeof(param));
 	ext2fs_blocks_count_set(&param, 32768);
+#if 0
+	param.s_feature_incompat |= EXT4_FEATURE_INCOMPAT_64BIT;
+	param.s_desc_size = 128;
+	csum_known = 0x5b6e;
+#endif
 
 	retval = ext2fs_initialize("test fs", EXT2_FLAG_64BITS, &param,
 				   test_io_manager, &fs);