ext4: add more inode number paranoia checks
commit c37e9e013469521d9adb932d17a1795c139b36db upstream.
If there is a directory entry pointing to a system inode (such as a
journal inode), complain and declare the file system to be corrupted.
Also, if the superblock's first inode number field is too small,
refuse to mount the file system.
This addresses CVE-2018-10882.
https://bugzilla.kernel.org/show_bug.cgi?id=200069
Issue: SEC-1680
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: I90c1aada9e290f629dd636b7ba4815069bedd1ec
(cherry picked from commit 765500b10116d1a3ac835dc274b6106d78929d74)
3 files changed