diff options
Diffstat (limited to 'fs/squashfs/fragment.c')
| -rw-r--r-- | fs/squashfs/fragment.c | 37 |
1 files changed, 20 insertions, 17 deletions
diff --git a/fs/squashfs/fragment.c b/fs/squashfs/fragment.c index 7eef571443c..0ed6edbc5c7 100644 --- a/fs/squashfs/fragment.c +++ b/fs/squashfs/fragment.c @@ -2,7 +2,7 @@ * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 - * Phillip Lougher <phillip@lougher.demon.co.uk> + * Phillip Lougher <phillip@squashfs.org.uk> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -71,26 +71,29 @@ int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment, * Read the uncompressed fragment lookup table indexes off disk into memory */ __le64 *squashfs_read_fragment_index_table(struct super_block *sb, - u64 fragment_table_start, unsigned int fragments) + u64 fragment_table_start, u64 next_table, unsigned int fragments) { unsigned int length = SQUASHFS_FRAGMENT_INDEX_BYTES(fragments); - __le64 *fragment_index; - int err; + __le64 *table; - /* Allocate fragment lookup table indexes */ - fragment_index = kmalloc(length, GFP_KERNEL); - if (fragment_index == NULL) { - ERROR("Failed to allocate fragment index table\n"); - return ERR_PTR(-ENOMEM); - } + /* + * Sanity check, length bytes should not extend into the next table - + * this check also traps instances where fragment_table_start is + * incorrectly larger than the next table start + */ + if (fragment_table_start + length > next_table) + return ERR_PTR(-EINVAL); + + table = squashfs_read_table(sb, fragment_table_start, length); - err = squashfs_read_table(sb, fragment_index, fragment_table_start, - length); - if (err < 0) { - ERROR("unable to read fragment index table\n"); - kfree(fragment_index); - return ERR_PTR(err); + /* + * table[0] points to the first fragment table metadata block, this + * should be less than fragment_table_start + */ + if (!IS_ERR(table) && le64_to_cpu(table[0]) >= fragment_table_start) { + kfree(table); + return ERR_PTR(-EINVAL); } - return fragment_index; + return table; } |