The new contrib/maxlen.bash showed that we have exponential
runtime with respect to directory depth.
The new recursive diriv caching is a lot smarter as it caches
intermediate lookups. maxlen.bash now completes in a few seconds.
xfstests results same as
2d158e4c82/screenlog.0 :
Failures: generic/035 generic/062 generic/080 generic/093 generic/099 generic/215 generic/285 generic/319 generic/426 generic/444 generic/467 generic/477 generic/523
Failed 13 of 580 tests
benchmark.bash results are identical:
$ ./benchmark.bash
Testing gocryptfs at /tmp/benchmark.bash.BdQ: gocryptfs v2.0.1-17-g6b09bc0; go-fuse v2.1.1-0.20210611132105-24a1dfe6b4f8; 2021-06-25 go1.16.5 linux/amd64
/tmp/benchmark.bash.BdQ.mnt is a mountpoint
WRITE: 262144000 bytes (262 MB, 250 MiB) copied, 0,4821 s, 544 MB/s
READ: 262144000 bytes (262 MB, 250 MiB) copied, 0,266061 s, 985 MB/s
UNTAR: 8,280
MD5: 4,564
LS: 1,745
RM: 2,244
This proposal is the counterpart of the modifications from the `-badname`
parameter. It modifies the plain -> cipher mapping for filenames when using
`-badname` parameter. The new function `EncryptAndHashBadName` tries to find a
cipher filename for the given plain name with the following steps:
1. If `badname` is disabled or direct mapping is successful: Map directly
(default and current behaviour)
2. If a file with badname flag has a valid cipher file, this is returned
(=File just ends with the badname flag)
3. If a file with a badname flag exists where only the badname flag was added,
this is returned (=File cipher name could not be decrypted by function
`DecryptName` and just the badname flag was added)
4. Search for all files which cipher file name extists when cropping more and
more characters from the end. If only 1 file is found, return this
5. Return an error otherwise
This allows file access in the file browsers but most important it allows that
you rename files with undecryptable cipher names in the plain directories.
Renaming those files will then generate a proper cipher filename One
backdraft: When mounting the cipher dir with -badname parameter, you can never
create (or rename to) files whose file name ends with the badname file flag
(at the moment this is " GOCRYPTFS_BAD_NAME"). This will cause an error.
I modified the CLI test function to cover additional test cases. Test [Case
7](https://github.com/DerDonut/gocryptfs/blob/badnamecontent/tests/cli/cli_test.go#L712)
cannot be performed since the cli tests are executed in panic mode. The
testing is stopped on error. Since the function`DecryptName` produces internal
errors when hitting non-decryptable file names, this test was omitted.
This implementation is a proposal where I tried to change the minimum amount
of existing code. Another possibility would be instead of creating the new
function `EncryptAndHashBadName` to modify the signature of the existing
function `EncryptAndHashName(name string, iv []byte)` to
`EncryptAndHashName(name string, iv []byte, dirfd int)` and integrate the
functionality into this function directly. You may allow calling with dirfd=-1
or other invalid values an then performing the current functionality.
gocryptfs 2.0 introduced the regression that the size
reported at symlink creation was the ciphertext size,
which is wrong.
Report the plaintext size.
Fixes https://github.com/rfjakob/gocryptfs/issues/574
Jakob Unterwurzacher