Add an extra mount time sanity check, plus some code cleanups and bug fixes.

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Merge tag 'squashfs-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next

Pull squashfs updates from Phillip Lougher:
 "Add an extra mount time sanity check, plus some code cleanups and bug
  fixes."

* tag 'squashfs-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-next:
  Squashfs: add mount time sanity check for block_size and block_log match
  Squashfs: fix f_pos check in get_dir_index_using_offset
  Squashfs: get rid of obsolete definitions in header file
  Squashfs: remove redundant length initialisation in squashfs_lookup
  Squashfs: remove redundant length initialisation in squashfs_readdir
  Squashfs: update comment removing reference to zlib only
  Squashfs: use define instead of constant

fs/squashfs/block.c

@@ -83,7 +83,8 @@ static struct buffer_head *get_block_length(struct super_block *sb,
  * filesystem), otherwise the length is obtained from the first two bytes of
  * the metadata block.  A bit in the length field indicates if the block
  * is stored uncompressed in the filesystem (usually because compression
- * generated a larger block - this does occasionally happen with zlib).
+ * generated a larger block - this does occasionally happen with compression
+ * algorithms).
  */
 int squashfs_read_data(struct super_block *sb, void **buffer, u64 index,
 			int length, u64 *next_index, int srclength, int pages)

fs/squashfs/dir.c

@@ -64,7 +64,7 @@ static int get_dir_index_using_offset(struct super_block *sb,
 	 * is offset by 3 because we invent "." and ".." entries which are
 	 * not actually stored in the directory.
 	 */
-	if (f_pos < 3)
+	if (f_pos <= 3)
 		return f_pos;
 	f_pos -= 3;
 
@@ -105,7 +105,7 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 	struct inode *inode = file->f_dentry->d_inode;
 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
 	u64 block = squashfs_i(inode)->start + msblk->directory_table;
-	int offset = squashfs_i(inode)->offset, length = 0, dir_count, size,
+	int offset = squashfs_i(inode)->offset, length, dir_count, size,
 				type, err;
 	unsigned int inode_number;
 	struct squashfs_dir_header dirh;
@@ -173,8 +173,7 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 
 		dir_count = le32_to_cpu(dirh.count) + 1;
 
-		/* dir_count should never be larger than 256 */
-		if (dir_count > 256)
+		if (dir_count > SQUASHFS_DIR_COUNT)
 			goto failed_read;
 
 		while (dir_count--) {

fs/squashfs/namei.c

@@ -144,7 +144,7 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
 	struct squashfs_dir_entry *dire;
 	u64 block = squashfs_i(dir)->start + msblk->directory_table;
 	int offset = squashfs_i(dir)->offset;
-	int err, length = 0, dir_count, size;
+	int err, length, dir_count, size;
 
 	TRACE("Entered squashfs_lookup [%llx:%x]\n", block, offset);
 
@@ -177,8 +177,7 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
 
 		dir_count = le32_to_cpu(dirh.count) + 1;
 
-		/* dir_count should never be larger than 256 */
-		if (dir_count > 256)
+		if (dir_count > SQUASHFS_DIR_COUNT)
 			goto data_error;
 
 		while (dir_count--) {

fs/squashfs/squashfs_fs.h

@@ -30,11 +30,6 @@
 
 /* size of metadata (inode and directory) blocks */
 #define SQUASHFS_METADATA_SIZE		8192
-#define SQUASHFS_METADATA_LOG		13
-
-/* default size of data blocks */
-#define SQUASHFS_FILE_SIZE		131072
-#define SQUASHFS_FILE_LOG		17
 
 /* default size of block device I/O */
 #ifdef CONFIG_SQUASHFS_4K_DEVBLK_SIZE
@@ -46,12 +41,12 @@
 #define SQUASHFS_FILE_MAX_SIZE		1048576
 #define SQUASHFS_FILE_MAX_LOG		20
 
-/* Max number of uids and gids */
-#define SQUASHFS_IDS			65536
-
 /* Max length of filename (not 255) */
 #define SQUASHFS_NAME_LEN		256
 
+/* Max value for directory header count*/
+#define SQUASHFS_DIR_COUNT		256
+
 #define SQUASHFS_INVALID_FRAG		(0xffffffffU)
 #define SQUASHFS_INVALID_XATTR		(0xffffffffU)
 #define SQUASHFS_INVALID_BLK		(-1LL)
@@ -142,9 +137,6 @@
 #define SQUASHFS_MKINODE(A, B)		((long long)(((long long) (A)\
 					<< 16) + (B)))
 
-/* Translate between VFS mode and squashfs mode */
-#define SQUASHFS_MODE(A)		((A) & 0xfff)
-
 /* fragment and fragment table defines */
 #define SQUASHFS_FRAGMENT_BYTES(A)	\
 				((A) * sizeof(struct squashfs_fragment_entry))
@@ -215,11 +207,6 @@
 /* cached data constants for filesystem */
 #define SQUASHFS_CACHED_BLKS		8
 
-#define SQUASHFS_MAX_FILE_SIZE_LOG	64
-
-#define SQUASHFS_MAX_FILE_SIZE		(1LL << \
-					(SQUASHFS_MAX_FILE_SIZE_LOG - 2))
-
 /* meta index cache */
 #define SQUASHFS_META_INDEXES	(SQUASHFS_METADATA_SIZE / sizeof(unsigned int))
 #define SQUASHFS_META_ENTRIES	127

fs/squashfs/super.c

@@ -158,10 +158,15 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 	}
 
+	/* Check block log for sanity */
 	msblk->block_log = le16_to_cpu(sblk->block_log);
 	if (msblk->block_log > SQUASHFS_FILE_MAX_LOG)
 		goto failed_mount;
 
+	/* Check that block_size and block_log match */
+	if (msblk->block_size != (1 << msblk->block_log))
+		goto failed_mount;
+
 	/* Check the root inode for sanity */
 	root_inode = le64_to_cpu(sblk->root_inode);
 	if (SQUASHFS_INODE_OFFSET(root_inode) > SQUASHFS_METADATA_SIZE)