From: Phillip Lougher <phillip@lougher.demon.co.uk>
Date: Tue, 24 May 2011 02:20:27 +0000 (+0100)
Subject: Squashfs: add sanity checks to xattr reading at mount time
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6f04864515365e135adc9f1cee4ac1251bb0ed35;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git

Squashfs: add sanity checks to xattr reading at mount time

These checks add sanity checking of the mount-time xattr structures.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
---

diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c
index 51a7bd0cc449..f60fb3cce183 100644
--- a/fs/squashfs/xattr_id.c
+++ b/fs/squashfs/xattr_id.c
@@ -76,6 +76,17 @@ __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
 	*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
 	*xattr_ids = le32_to_cpu(id_table->xattr_ids);
 	kfree(id_table);
+
+	/* Sanity check values */
+
+	/* there is always at least one xattr id */
+	if (*xattr_ids == 0)
+		return ERR_PTR(-EINVAL);
+
+	/* xattr_table should be less than start */
+	if (*xattr_table_start >= start)
+		return ERR_PTR(-EINVAL);
+
 	len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
 
 	TRACE("In read_xattr_index_table, length %d\n", len);