Merge git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/pkl/squashfs-linus:
  Squashfs: Use vmalloc rather than kmalloc for zlib workspace
  Squashfs: handle corruption of directory structure
  Squashfs: wrap squashfs_mount() definition
  Squashfs: xz_wrapper doesn't need to include squashfs_fs_i.h anymore
  Squashfs: Update documentation to include compression options
  Squashfs: Update Kconfig help text to include xz compression
  Squashfs: add compression options support to xz decompressor
  Squashfs: extend decompressor framework to handle compression options

Documentation/filesystems/squashfs.txt

@@ -59,12 +59,15 @@ obtained from this site also.
 3. SQUASHFS FILESYSTEM DESIGN
 -----------------------------
 
-A squashfs filesystem consists of a maximum of eight parts, packed together on a byte
-alignment:
+A squashfs filesystem consists of a maximum of nine parts, packed together on a
+byte alignment:
 
 	 ---------------
 	|  superblock 	|
 	|---------------|
+	|  compression  |
+	|    options    |
+	|---------------|
 	|  datablocks   |
 	|  & fragments  |
 	|---------------|
@@ -91,7 +94,14 @@ the source directory, and checked for duplicates.  Once all file data has been
 written the completed inode, directory, fragment, export and uid/gid lookup
 tables are written.
 
-3.1 Inodes
+3.1 Compression options
+-----------------------
+
+Compressors can optionally support compression specific options (e.g.
+dictionary size).  If non-default compression options have been used, then
+these are stored here.
+
+3.2 Inodes
 ----------
 
 Metadata (inodes and directories) are compressed in 8Kbyte blocks.  Each
@@ -114,7 +124,7 @@ directory inode are defined: inodes optimised for frequently occurring
 regular files and directories, and extended types where extra
 information has to be stored.
 
-3.2 Directories
+3.3 Directories
 ---------------
 
 Like inodes, directories are packed into compressed metadata blocks, stored
@@ -144,7 +154,7 @@ decompressed to do a lookup irrespective of the length of the directory.
 This scheme has the advantage that it doesn't require extra memory overhead
 and doesn't require much extra storage on disk.
 
-3.3 File data
+3.4 File data
 -------------
 
 Regular files consist of a sequence of contiguous compressed blocks, and/or a
@@ -163,7 +173,7 @@ Larger files use multiple slots, with 1.75 TiB files using all 8 slots.
 The index cache is designed to be memory efficient, and by default uses
 16 KiB.
 
-3.4 Fragment lookup table
+3.5 Fragment lookup table
 -------------------------
 
 Regular files can contain a fragment index which is mapped to a fragment
@@ -173,7 +183,7 @@ A second index table is used to locate these.  This second index table for
 speed of access (and because it is small) is read at mount time and cached
 in memory.
 
-3.5 Uid/gid lookup table
+3.6 Uid/gid lookup table
 ------------------------
 
 For space efficiency regular files store uid and gid indexes, which are
@@ -182,7 +192,7 @@ stored compressed into metadata blocks.  A second index table is used to
 locate these.  This second index table for speed of access (and because it
 is small) is read at mount time and cached in memory.
 
-3.6 Export table
+3.7 Export table
 ----------------
 
 To enable Squashfs filesystems to be exportable (via NFS etc.) filesystems
@@ -196,7 +206,7 @@ This table is stored compressed into metadata blocks.  A second index table is
 used to locate these.  This second index table for speed of access (and because
 it is small) is read at mount time and cached in memory.
 
-3.7 Xattr table
+3.8 Xattr table
 ---------------
 
 The xattr table contains extended attributes for each inode.  The xattrs

fs/squashfs/Kconfig

@@ -5,12 +5,12 @@ config SQUASHFS
 	help
 	  Saying Y here includes support for SquashFS 4.0 (a Compressed
 	  Read-Only File System).  Squashfs is a highly compressed read-only
-	  filesystem for Linux.  It uses zlib/lzo compression to compress both
-	  files, inodes and directories.  Inodes in the system are very small
-	  and all blocks are packed to minimise data overhead. Block sizes
-	  greater than 4K are supported up to a maximum of 1 Mbytes (default
-	  block size 128K).  SquashFS 4.0 supports 64 bit filesystems and files
-	  (larger than 4GB), full uid/gid information, hard links and
+	  filesystem for Linux.  It uses zlib, lzo or xz compression to
+	  compress both files, inodes and directories.  Inodes in the system
+	  are very small and all blocks are packed to minimise data overhead.
+	  Block sizes greater than 4K are supported up to a maximum of 1 Mbytes
+	  (default block size 128K).  SquashFS 4.0 supports 64 bit filesystems
+	  and files (larger than 4GB), full uid/gid information, hard links and
 	  timestamps.
 
 	  Squashfs is intended for general read-only filesystem use, for

fs/squashfs/decompressor.c

@@ -23,6 +23,7 @@
 
 #include <linux/types.h>
 #include <linux/mutex.h>
+#include <linux/slab.h>
 #include <linux/buffer_head.h>
 
 #include "squashfs_fs.h"
@@ -74,3 +75,36 @@ const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
 
 	return decompressor[i];
 }
+
+
+void *squashfs_decompressor_init(struct super_block *sb, unsigned short flags)
+{
+	struct squashfs_sb_info *msblk = sb->s_fs_info;
+	void *strm, *buffer = NULL;
+	int length = 0;
+
+	/*
+	 * Read decompressor specific options from file system if present
+	 */
+	if (SQUASHFS_COMP_OPTS(flags)) {
+		buffer = kmalloc(PAGE_CACHE_SIZE, GFP_KERNEL);
+		if (buffer == NULL)
+			return ERR_PTR(-ENOMEM);
+
+		length = squashfs_read_data(sb, &buffer,
+			sizeof(struct squashfs_super_block), 0, NULL,
+			PAGE_CACHE_SIZE, 1);
+
+		if (length < 0) {
+			strm = ERR_PTR(length);
+			goto finished;
+		}
+	}
+
+	strm = msblk->decompressor->init(msblk, buffer, length);
+
+finished:
+	kfree(buffer);
+
+	return strm;
+}

fs/squashfs/decompressor.h

@@ -24,7 +24,7 @@
  */
 
 struct squashfs_decompressor {
-	void	*(*init)(struct squashfs_sb_info *);
+	void	*(*init)(struct squashfs_sb_info *, void *, int);
 	void	(*free)(void *);
 	int	(*decompress)(struct squashfs_sb_info *, void **,
 		struct buffer_head **, int, int, int, int, int);
@@ -33,11 +33,6 @@ struct squashfs_decompressor {
 	int	supported;
 };
 
-static inline void *squashfs_decompressor_init(struct squashfs_sb_info *msblk)
-{
-	return msblk->decompressor->init(msblk);
-}
-
 static inline void squashfs_decompressor_free(struct squashfs_sb_info *msblk,
 	void *s)
 {

fs/squashfs/dir.c

@@ -172,6 +172,11 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 		length += sizeof(dirh);
 
 		dir_count = le32_to_cpu(dirh.count) + 1;
+
+		/* dir_count should never be larger than 256 */
+		if (dir_count > 256)
+			goto failed_read;
+
 		while (dir_count--) {
 			/*
 			 * Read directory entry.
@@ -183,6 +188,10 @@ static int squashfs_readdir(struct file *file, void *dirent, filldir_t filldir)
 
 			size = le16_to_cpu(dire->size) + 1;
 
+			/* size should never be larger than SQUASHFS_NAME_LEN */
+			if (size > SQUASHFS_NAME_LEN)
+				goto failed_read;
+
 			err = squashfs_read_metadata(inode->i_sb, dire->name,
 					&block, &offset, size);
 			if (err < 0)

fs/squashfs/lzo_wrapper.c

@@ -37,7 +37,7 @@ struct squashfs_lzo {
 	void	*output;
 };
 
-static void *lzo_init(struct squashfs_sb_info *msblk)
+static void *lzo_init(struct squashfs_sb_info *msblk, void *buff, int len)
 {
 	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
 
@@ -58,7 +58,7 @@ static void *lzo_init(struct squashfs_sb_info *msblk)
 failed:
 	ERROR("Failed to allocate lzo workspace\n");
 	kfree(stream);
-	return NULL;
+	return ERR_PTR(-ENOMEM);
 }
 
 

fs/squashfs/namei.c

@@ -176,6 +176,11 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
 		length += sizeof(dirh);
 
 		dir_count = le32_to_cpu(dirh.count) + 1;
+
+		/* dir_count should never be larger than 256 */
+		if (dir_count > 256)
+			goto data_error;
+
 		while (dir_count--) {
 			/*
 			 * Read directory entry.
@@ -187,6 +192,10 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
 
 			size = le16_to_cpu(dire->size) + 1;
 
+			/* size should never be larger than SQUASHFS_NAME_LEN */
+			if (size > SQUASHFS_NAME_LEN)
+				goto data_error;
+
 			err = squashfs_read_metadata(dir->i_sb, dire->name,
 					&block, &offset, size);
 			if (err < 0)
@@ -228,6 +237,9 @@ static struct dentry *squashfs_lookup(struct inode *dir, struct dentry *dentry,
 	d_add(dentry, inode);
 	return ERR_PTR(0);
 
+data_error:
+	err = -EIO;
+
 read_failure:
 	ERROR("Unable to read directory block [%llx:%x]\n",
 		squashfs_i(dir)->start + msblk->directory_table,

fs/squashfs/squashfs.h

@@ -48,6 +48,7 @@ extern int squashfs_read_table(struct super_block *, void *, u64, int);
 
 /* decompressor.c */
 extern const struct squashfs_decompressor *squashfs_lookup_decompressor(int);
+extern void *squashfs_decompressor_init(struct super_block *, unsigned short);
 
 /* export.c */
 extern __le64 *squashfs_read_inode_lookup_table(struct super_block *, u64,

fs/squashfs/squashfs_fs.h

@@ -57,6 +57,7 @@
 #define SQUASHFS_ALWAYS_FRAG		5
 #define SQUASHFS_DUPLICATE		6
 #define SQUASHFS_EXPORT			7
+#define SQUASHFS_COMP_OPT		10
 
 #define SQUASHFS_BIT(flag, bit)		((flag >> bit) & 1)
 
@@ -81,6 +82,9 @@
 #define SQUASHFS_EXPORTABLE(flags)		SQUASHFS_BIT(flags, \
 						SQUASHFS_EXPORT)
 
+#define SQUASHFS_COMP_OPTS(flags)		SQUASHFS_BIT(flags, \
+						SQUASHFS_COMP_OPT)
+
 /* Max number of types and file types */
 #define SQUASHFS_DIR_TYPE		1
 #define SQUASHFS_REG_TYPE		2

fs/squashfs/super.c

@@ -199,10 +199,6 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 
 	err = -ENOMEM;
 
-	msblk->stream = squashfs_decompressor_init(msblk);
-	if (msblk->stream == NULL)
-		goto failed_mount;
-
 	msblk->block_cache = squashfs_cache_init("metadata",
 			SQUASHFS_CACHED_BLKS, SQUASHFS_METADATA_SIZE);
 	if (msblk->block_cache == NULL)
@@ -215,6 +211,13 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 	}
 
+	msblk->stream = squashfs_decompressor_init(sb, flags);
+	if (IS_ERR(msblk->stream)) {
+		err = PTR_ERR(msblk->stream);
+		msblk->stream = NULL;
+		goto failed_mount;
+	}
+
 	/* Allocate and read id index table */
 	msblk->id_table = squashfs_read_id_index_table(sb,
 		le64_to_cpu(sblk->id_table_start), le16_to_cpu(sblk->no_ids));
@@ -370,8 +373,8 @@ static void squashfs_put_super(struct super_block *sb)
 }
 
 
-static struct dentry *squashfs_mount(struct file_system_type *fs_type, int flags,
-				const char *dev_name, void *data)
+static struct dentry *squashfs_mount(struct file_system_type *fs_type,
+				int flags, const char *dev_name, void *data)
 {
 	return mount_bdev(fs_type, flags, dev_name, data, squashfs_fill_super);
 }

fs/squashfs/xz_wrapper.c

@@ -26,10 +26,10 @@
 #include <linux/buffer_head.h>
 #include <linux/slab.h>
 #include <linux/xz.h>
+#include <linux/bitops.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
-#include "squashfs_fs_i.h"
 #include "squashfs.h"
 #include "decompressor.h"
 
@@ -38,24 +38,57 @@ struct squashfs_xz {
 	struct xz_buf buf;
 };
 
-static void *squashfs_xz_init(struct squashfs_sb_info *msblk)
+struct comp_opts {
+	__le32 dictionary_size;
+	__le32 flags;
+};
+
+static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff,
+	int len)
 {
-	int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
+	struct comp_opts *comp_opts = buff;
+	struct squashfs_xz *stream;
+	int dict_size = msblk->block_size;
+	int err, n;
+
+	if (comp_opts) {
+		/* check compressor options are the expected length */
+		if (len < sizeof(*comp_opts)) {
+			err = -EIO;
+			goto failed;
+		}
 
-	struct squashfs_xz *stream = kmalloc(sizeof(*stream), GFP_KERNEL);
-	if (stream == NULL)
+		dict_size = le32_to_cpu(comp_opts->dictionary_size);
+
+		/* the dictionary size should be 2^n or 2^n+2^(n+1) */
+		n = ffs(dict_size) - 1;
+		if (dict_size != (1 << n) && dict_size != (1 << n) +
+						(1 << (n + 1))) {
+			err = -EIO;
+			goto failed;
+		}
+	}
+
+	dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE);
+
+	stream = kmalloc(sizeof(*stream), GFP_KERNEL);
+	if (stream == NULL) {
+		err = -ENOMEM;
 		goto failed;
+	}
 
-	stream->state = xz_dec_init(XZ_PREALLOC, block_size);
-	if (stream->state == NULL)
+	stream->state = xz_dec_init(XZ_PREALLOC, dict_size);
+	if (stream->state == NULL) {
+		kfree(stream);
+		err = -ENOMEM;
 		goto failed;
+	}
 
 	return stream;
 
 failed:
-	ERROR("Failed to allocate xz workspace\n");
-	kfree(stream);
-	return NULL;
+	ERROR("Failed to initialise xz decompressor\n");
+	return ERR_PTR(err);
 }