[PATCH] Squashfs: fix xattr id and id lookup sanity checks

[Phillip Lougher]

The checks for maximum metadata block size is
missing SQUASHFS_BLOCK_OFFSET (the two byte length
count).

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
---
 fs/squashfs/id.c       | 6 ++++--
 fs/squashfs/xattr_id.c | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/squashfs/id.c b/fs/squashfs/id.c
index 11581bf31af4..ea5387679723 100644
--- a/fs/squashfs/id.c
+++ b/fs/squashfs/id.c
@@ -97,14 +97,16 @@ __le64 *squashfs_read_id_index_table(struct super_block *sb,
 		start = le64_to_cpu(table[n]);
 		end = le64_to_cpu(table[n + 1]);
 
-		if (start >= end || (end - start) > SQUASHFS_METADATA_SIZE) {
+		if (start >= end || (end - start) >
+				(SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
 			kfree(table);
 			return ERR_PTR(-EINVAL);
 		}
 	}
 
 	start = le64_to_cpu(table[indexes - 1]);
-	if (start >= id_table_start || (id_table_start - start) > SQUASHFS_METADATA_SIZE) {
+	if (start >= id_table_start || (id_table_start - start) >
+				(SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
 		kfree(table);
 		return ERR_PTR(-EINVAL);
 	}
diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c
index ead66670b41a..087cab8c78f4 100644
--- a/fs/squashfs/xattr_id.c
+++ b/fs/squashfs/xattr_id.c
@@ -109,14 +109,16 @@ __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 table_start,
 		start = le64_to_cpu(table[n]);
 		end = le64_to_cpu(table[n + 1]);
 
-		if (start >= end || (end - start) > SQUASHFS_METADATA_SIZE) {
+		if (start >= end || (end - start) >
+				(SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
 			kfree(table);
 			return ERR_PTR(-EINVAL);
 		}
 	}
 
 	start = le64_to_cpu(table[indexes - 1]);
-	if (start >= table_start || (table_start - start) > SQUASHFS_METADATA_SIZE) {
+	if (start >= table_start || (table_start - start) >
+				(SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
 		kfree(table);
 		return ERR_PTR(-EINVAL);
 	}
-- 
2.29.2