From: Phillip Lougher <phil...@squashfs.org.uk>

commit 8b44ca2b634527151af07447a8090a5f3a043321 upstream.

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

Link: 
https://lkml.kernel.org/r/2069685113.2081245.1614583677...@webmail.123-reg.co.uk
Fixes: f37aa4c7366e23f ("squashfs: add more sanity checks in id lookup")
Signed-off-by: Phillip Lougher <phil...@squashfs.org.uk>
Cc: Sean Nyekjaer <s...@geanix.com>
Cc: <sta...@vger.kernel.org>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 fs/squashfs/id.c       |    6 ++++--
 fs/squashfs/xattr_id.c |    6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

--- a/fs/squashfs/id.c
+++ b/fs/squashfs/id.c
@@ -110,14 +110,16 @@ __le64 *squashfs_read_id_index_table(str
                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);
        }
--- a/fs/squashfs/xattr_id.c
+++ b/fs/squashfs/xattr_id.c
@@ -122,14 +122,16 @@ __le64 *squashfs_read_xattr_id_table(str
                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);
        }


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