libext2fs: strengthen i_extra_isize checks when reading/writing xattrs

Strengthen the i_extra_isize checks to look for obviously too-small
values before trying to operate on inode EAs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
9 files changed