summaryrefslogtreecommitdiffstats
path: root/fs/squashfs/fragment.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/squashfs/fragment.c')
-rw-r--r--fs/squashfs/fragment.c37
1 files changed, 20 insertions, 17 deletions
diff --git a/fs/squashfs/fragment.c b/fs/squashfs/fragment.c
index 7eef571443c6..1516a6490bfb 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) && table[0] >= fragment_table_start) {
+ kfree(table);
+ return ERR_PTR(-EINVAL);
}
- return fragment_index;
+ return table;
}