eCryptfs: Extend array bounds for all filename chars
From: Colin Ian King <firstname.lastname@example.org>
From mhalcrow's original commit message:
Characters with ASCII values greater than the size of
filename_rev_map are valid filename characters.
ecryptfs_decode_from_filename() will access kernel memory beyond
that array, and ecryptfs_parse_tag_70_packet() will then decrypt
those characters. The attacker, using the FNEK of the crafted file,
can then re-encrypt the characters to reveal the kernel memory past
the end of the filename_rev_map array. I expect low security
impact since this array is statically allocated in the text area,
and the amount of memory past the array that is accessible is
limited by the largest possible ASCII filename character.