Commit 76424a58cb enabled unique IV
for reverse mode by default, to get more testing and to increase
security of reverse mode.
The downside is that all IVs change when the inode numbers change,
which means that all of the ciphertext changes.
This may bite people who copied the plaintext to a new filesystem
- they will find out that they have to rsync everything again.
This commit disables unique IV for reverse mode by default. It can
still be enabled through expert mode.
Disabling the kernel cache make sure the encrypted view is always
up-to-date, however, it causes a factor 3 slowdown.
Please use --nocache manually if you want to disable caching.
Closes#60.
Also replaces the magic identifiers 513 and 514 by proper defines.
Example Results
* Seagate Barracuda 7200.9, model ST3250824AS
* Linux 3.16.3
* EncFS 1c5c75c44f
Test | EncFS | eCryptfs | EncFS advantage
----------------|--------------|--------------|----------------
stream_write | 32 MiB/s | 38 MiB/s | 0.84
extract | 28744 ms | 30027 ms | 1.04
du | 495 MB | 784 MB | 1.58
rsync | 3319 ms | 62486 ms | 18.83
delete | 6462 ms | 74652 ms | 11.55
(eCryptfs is very slow for stat() on a classical HDD)
This prevents unexpected failures when you have set that variable.
Also, give Test::More the number of tests that will be run for
more informative output.
Writing to the ciphertext files can rewrite the header. This
would mean we had to re-encrypt the whole file with the new IV.
This could be made more fine-grained, for example allowing
writes to everywhere but the header. However, this is
something that needs a lot of testing to ensure correctness.
Writing to the ciphertext is a niche use case of the niche
use case of using reverse mode, so it is unlikely it would
get the test coverage it needs.
To be safe, we deny all modifications of the ciphertext with
read-only filesystem error (EROFS) if uniqueIV is enabled.
Reverse mode with uniqueIV disabled still supports writing,
if somebody really needs it. This use case is not covered
by the test suite at the moment.
For now, the IVs are constant. This is fixed in a later commit.
They are enabled by default to make testing easier.
The whole thing passes the test suite on x86 and x86_64.
Disable block cache (in EncFS) and stat cache (in kernel).
This is needed if the backing files may be modified
behind the back of EncFS (for example, when you mount
an encrypted filesystem exported by encfs --reverse).
The reverse grow tests fail when this option is not passed to the
decrypting mount.
Use "make test" or "make test-verbose" to run.
Note that "make test" seems to be more common than "make tests", hence the
change.
Also, use a new clean directory directory as a working area for each run
Created using mkdtemp and deleted in cleanup()
Add a simple cli-based test infrastructure with a few tests
to prepare future code changes.
Note that these cannot be run on Travis CI as it does not support
FUSE.
Expected output:
$ tests/run.sh
1 Running unit tests: OK
*** running test_corruption.sh
2 Reading file: OK
3 Reading corrupted file: OK
4 Reading file with MAC: OK
5 Corruption with MAC returns IO error: OK
*** running test_file_expansion.sh
6 Creating files of different sizes: : OK
7 Growing file: OK
8 Internal modification: OK
*** All tests OK
