ecryptfs: split packet parser length fixes

This v2 splits the packet parser hardening into three separate fixes as requested by Tyler Hicks:

1. pass the actual packet set buffer size into ecryptfs_parse_packet_set()
2. fix the tag 11 exact-fit size check
3. reject too-small tag 70 packet bodies before size subtraction

Changes in v2:
- Split the original patch into three independent fixes.
- Dropped the unrelated trailing blank line removal in keystore.c.

Yichong Chen (3):
ecryptfs: pass packet set buffer size to parser
ecryptfs: fix tag 11 packet exact-fit size check
ecryptfs: reject too-small tag 70 packets

 fs/ecryptfs/crypto.c          |  2 +-
 fs/ecryptfs/ecryptfs_kernel.h |  3 ++-
 fs/ecryptfs/keystore.c        | 31 +++++++++++++++++++++++++++----
 3 files changed, 30 insertions(+), 6 deletions(-)

2.51.0