squashfs: fix xattr id and id lookup sanity checks

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

Link: https://lkml.kernel.org/r/2069685113.2081245.1614583677427@webmail.123-reg.co.uk
Fixes: f37aa4c7366e23f ("squashfs: add more sanity checks in id lookup")
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Sean Nyekjaer <sean@geanix.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/squashfs/id.c b/fs/squashfs/id.c
index 11581bf..ea53876 100644 (file)
--- 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 ead6667..087cab8 100644 (file)
--- 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);
        }