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| author | Phillip Lougher <phillip@squashfs.org.uk> | 2013-09-04 02:58:12 +0100 |
|---|---|---|
| committer | Phillip Lougher <phillip@squashfs.org.uk> | 2013-09-06 04:57:54 +0100 |
| commit | 9e012423869e1efbae3762b87ceab509027231c9 (patch) | |
| tree | dd451cda9f1a82f6ea83c645807bb459c51b4bf8 /fs/squashfs | |
| parent | f960cae5357d8e52b8af91e8b1621cae565dffb3 (diff) | |
| download | lwn-9e012423869e1efbae3762b87ceab509027231c9.tar.gz lwn-9e012423869e1efbae3762b87ceab509027231c9.zip | |
Squashfs: add corruption check for type in squashfs_readdir()
We read the type field from disk. This value should be sanity
checked for correctness to avoid an out of bounds access when
reading the squashfs_filetype_table array.
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Diffstat (limited to 'fs/squashfs')
| -rw-r--r-- | fs/squashfs/dir.c | 7 | ||||
| -rw-r--r-- | fs/squashfs/squashfs_fs.h | 5 |
2 files changed, 9 insertions, 3 deletions
diff --git a/fs/squashfs/dir.c b/fs/squashfs/dir.c index bd7155b198a9..d8c2d747be28 100644 --- a/fs/squashfs/dir.c +++ b/fs/squashfs/dir.c @@ -112,8 +112,8 @@ static int squashfs_readdir(struct file *file, struct dir_context *ctx) struct inode *inode = file_inode(file); 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, type, err; - unsigned int inode_number, dir_count, size; + int offset = squashfs_i(inode)->offset, length, err; + unsigned int inode_number, dir_count, size, type; struct squashfs_dir_header dirh; struct squashfs_dir_entry *dire; @@ -206,6 +206,9 @@ static int squashfs_readdir(struct file *file, struct dir_context *ctx) ((short) le16_to_cpu(dire->inode_number)); type = le16_to_cpu(dire->type); + if (type > SQUASHFS_MAX_DIR_TYPE) + goto failed_read; + if (!dir_emit(ctx, dire->name, size, inode_number, squashfs_filetype_table[type])) diff --git a/fs/squashfs/squashfs_fs.h b/fs/squashfs/squashfs_fs.h index 9e2349d07cb1..4b2beda49498 100644 --- a/fs/squashfs/squashfs_fs.h +++ b/fs/squashfs/squashfs_fs.h @@ -87,7 +87,7 @@ #define SQUASHFS_COMP_OPTS(flags) SQUASHFS_BIT(flags, \ SQUASHFS_COMP_OPT) -/* Max number of types and file types */ +/* Inode types including extended types */ #define SQUASHFS_DIR_TYPE 1 #define SQUASHFS_REG_TYPE 2 #define SQUASHFS_SYMLINK_TYPE 3 @@ -103,6 +103,9 @@ #define SQUASHFS_LFIFO_TYPE 13 #define SQUASHFS_LSOCKET_TYPE 14 +/* Max type value stored in directory entry */ +#define SQUASHFS_MAX_DIR_TYPE 7 + /* Xattr types */ #define SQUASHFS_XATTR_USER 0 #define SQUASHFS_XATTR_TRUSTED 1 |