Commit Graph

52 Commits

Author SHA1 Message Date
Sebastian Lackner
9f56b33e0c fusefrontend: Fix longname handling for renames with existing target
Fixes https://github.com/rfjakob/gocryptfs/issues/170

Steps to reproduce the problem:

* Create a regular forward mount point
* Create a file with a shortname and one with a long filename
* Try to run 'mv <shortname> <longname>'

This should actually work and replace the existing file, but instead it
fails with:

    mv: cannot move '<shortname>' to '<longname>': File exists

The problem is the creation of the .name file. If the target already exists
we can safely ignore the EEXIST error and just keep the existing .name file.
2017-11-25 16:19:09 +01:00
Sebastian Lackner
c547673529 nametransform: Return error if decrypted name is '.' or '..' 2017-11-22 23:42:08 +01:00
Jakob Unterwurzacher
7da0e97c8b dirivcache: add better function comments + a sanity check on Store()
The comments were unclear on whether relative or absolute paths
have to be passed.
2017-09-03 13:53:50 +02:00
Jakob Unterwurzacher
e80b5f2049 nametransform: extend diriv cache to 100 entries
* extend the diriv cache to 100 entries
* add special handling for the immutable root diriv

The better cache allows to shed some complexity from the path
encryption logic (parent-of-parent check).

Mitigates https://github.com/rfjakob/gocryptfs/issues/127
2017-08-09 22:00:53 +02:00
Jakob Unterwurzacher
75ec94a87a nametransform: add Dir() function
Dir is like filepath.Dir but returns "" instead of ".".
This was already implemented in fusefrontend_reverse as saneDir().

We will need it in nametransform for the improved diriv caching.
2017-08-06 23:14:39 +02:00
Jakob Unterwurzacher
5190cc09bb nametransform: move diriv cache into it's own package
Needs some space to grow.

renamed:    internal/nametransform/diriv_cache.go -> internal/nametransform/dirivcache/dirivcache.go
2017-08-06 21:59:15 +02:00
Jakob Unterwurzacher
32611ff97a nametransform: deduplicate code to encryptAndHashName()
This operation has been done three time by identical
sections of code. Create a function for it.
2017-08-06 21:23:42 +02:00
Jakob Unterwurzacher
9a3f9350fe nametransform: reject all-zero dirIV
This should never happen in normal operation and is a sign of
data corruption. Catch it early.
2017-05-25 14:21:55 +02:00
Jakob Unterwurzacher
e827763f2e nametransform: harden name decryption against invalid input
This fixes a few issues I have found reviewing the code:

1) Limit the amount of data ReadLongName() will read. Previously,
you could send gocryptfs into out-of-memory by symlinking
gocryptfs.diriv to /dev/zero.

2) Handle the empty input case in unPad16() by returning an
error. Previously, it would panic with an out-of-bounds array
read. It is unclear to me if this could actually be triggered.

3) Reject empty names after base64-decoding in DecryptName().
An empty name crashes emeCipher.Decrypt().
It is unclear to me if B64.DecodeString() can actually return
a non-error empty result, but let's guard against it anyway.
2017-05-23 21:26:38 +02:00
Jakob Unterwurzacher
245b84c887 nametransform: diriv cache: fall back to the grandparent
When a user calls into a deep directory hierarchy, we often
get a sequence like this from the kernel:

LOOKUP a
LOOKUP a/b
LOOKUP a/b/c
LOOKUP a/b/c/d

The diriv cache was not effective for this pattern, because it
was designed for this:

LOOKUP a/a
LOOKUP a/b
LOOKUP a/c
LOOKUP a/d

By also using the cached entry of the grandparent we can avoid lots
of diriv reads.

This benchmark is against a large encrypted directory hosted on NFS:

Before:

  $ time ls -R nfs-backed-mount > /dev/null
  real	1m35.976s
  user	0m0.248s
  sys	0m0.281s

After:

  $ time ls -R nfs-backed-mount > /dev/null
  real	1m3.670s
  user	0m0.217s
  sys 	0m0.403s
2017-05-22 22:36:54 +02:00
Jakob Unterwurzacher
26881538e1 nametranform, fusefrontend: better errors on invalid names
nametransform.DecryptName() now always returns syscall.EBADMSG if
the name was invalid.

fusefrontend.OpenDir error messages have been normalized.
2017-05-07 20:58:27 +02:00
Jakob Unterwurzacher
7d38f80a78 nametransform: WriteDirIV: replace ioutil.WriteFile
As reported at https://github.com/rfjakob/gocryptfs/issues/105 ,
the "ioutil.WriteFile(file, iv, 0400)" call causes "permissions denied"
errors on an NFSv4 setup.

"strace"ing diriv creation and gocryptfs.conf creation shows this:

conf (works on the user's NFSv4 mount):
openat(AT_FDCWD, "/tmp/a/gocryptfs.conf.tmp", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0400) = 3

diriv (fails):
openat(AT_FDCWD, "/tmp/a/gocryptfs.diriv", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0400) = 3

This patch creates the diriv file with the same flags that are used for
creating the conf:
openat(AT_FDCWD, "/tmp/a/gocryptfs.diriv", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0400) = 3

Closes https://github.com/rfjakob/gocryptfs/issues/105
2017-04-29 14:15:13 +02:00
Jakob Unterwurzacher
445b5019e3 nametransform: fix Raw64 not affecting symlink targets
The symlink functions incorrectly hardcoded the padded
base64 variant.
2017-03-05 22:59:25 +01:00
Jakob Unterwurzacher
5b54577d2e nametransform: fix Raw64 not affecting longnames
HashLongName() incorrectly hardcoded the call to base64.URLEncoding.
2017-03-05 22:25:41 +01:00
Jakob Unterwurzacher
966308eeb7 Drop Go 1.4 compatability code everywhere
Yields a nice reduction in code size.
2017-03-05 17:44:14 +01:00
Jakob Unterwurzacher
e032539e2c cryptocore: use eme v1.1 interface
Version 1.1 of the EME package (github.com/rfjakob/eme) added
a more convenient interface. Use it.

Note that you have to upgrade your EME package (go get -u)!
2017-03-05 13:58:24 +01:00
Jakob Unterwurzacher
c9f4400e6d Replace all calls to naked panic() with log.Panic()
We want all panics to show up in the syslog.
2016-12-10 11:54:36 +01:00
Jakob Unterwurzacher
e3c5e3f1c8 fusefronted: preserve owner for device nodes and sockets
https://github.com/rfjakob/gocryptfs/issues/64
2016-11-28 23:09:47 +01:00
Jakob Unterwurzacher
e7f57695a6 Fix golint warnings
$ golint ./... | grep -v underscore | grep -v ALL_CAPS
internal/fusefrontend_reverse/rfs.go:52:36: exported func NewFS returns unexported type *fusefrontend_reverse.reverseFS, which can be annoying to use
internal/nametransform/raw64_go1.5.go:10:2: exported const HaveRaw64 should have comment (or a comment on this block) or be unexported
2016-11-10 00:38:01 +01:00
Jakob Unterwurzacher
df28fc5a11 nametransform: get rid of leading "./"
Paths in the root directory were encrypted to this:

    foobar -> ./N9vPc0gXUY4PDSt0-muYXQ==
2016-11-09 23:41:47 +01:00
Jakob Unterwurzacher
df1e3a10c4 nametransform: nicer error message on empty gocryptfs.diriv
Old:

	Nov 06 13:34:38 brikett gocryptfs[16228]: ReadDirIVAt: Read failed: EOF
	Nov 06 13:34:38 brikett gocryptfs[16228]: go-fuse: can't convert error type: EOF

New:

	Nov 06 14:08:43 brikett gocryptfs[17361]: ReadDirIVAt: wanted 16 bytes, got 0. Returning EINVAL.
2016-11-06 14:09:34 +01:00
Jakob Unterwurzacher
d15122d3d6 Add Go 1.4 compatibility layer for raw64
Using raw64 will not work, but at least it will compile.
2016-11-01 19:25:59 +01:00
Jakob Unterwurzacher
2b991c9743 Add support for unpadded base64 filenames, "-raw64"
Through base64.RawURLEncoding.

New command-line parameter "-raw64".
2016-11-01 18:43:22 +01:00
Jakob Unterwurzacher
944eaf2fb5 fusefronted: expire dir IV cache after one second
The Back In Time backup tool (https://github.com/bit-team/backintime)
wants to write directly into the ciphertext dir.
This may cause the cached directory IV to become out-of-date.
Having an expiry time limits the inconstency to one second, like
attr_timeout does for the kernel getattr cache.
2016-11-01 10:57:39 +01:00
Jakob Unterwurzacher
a9c7565b80 fusefrontend: refactor dirIVCache
Simplify the code a bit.
2016-11-01 10:34:41 +01:00
Jakob Unterwurzacher
aeda9721d0 Fix misspellings
Close https://github.com/rfjakob/gocryptfs/issues/54
2016-10-24 19:18:13 +02:00
Jakob Unterwurzacher
53257f4ee5 nametransform: better error code on invalid diriv length
go-fuse translates errors unknown to it into "function not
implemented", which is wrong in this case.
2016-10-07 22:40:30 +02:00
Valient Gough
b764917cd5 lint fixes 2016-10-04 23:18:33 +02:00
Jakob Unterwurzacher
28838a489d nametransform: downgrade invalid length warning
This happens all the time in reverse mode when somebody stats
an encrypted symlink target.
2016-09-25 19:50:16 +02:00
Jakob Unterwurzacher
c7b3150afc nametransform: delete unused function DecryptPathDirIV 2016-09-25 18:56:23 +02:00
Jakob Unterwurzacher
b883dd10a6 reverse: add symlink encryption and Readlink support 2016-09-25 18:01:24 +02:00
Jakob Unterwurzacher
a6a7b424f8 reverse: resolve long names in Open and GetAttr
The last patch added functionality for generating gocryptfs.longname.*
files, this patch adds support for mapping them back to the full
filenames.

Note that resolving a long name needs a full readdir. A cache
will be implemented later on to improve performance.
2016-09-25 16:43:17 +02:00
Jakob Unterwurzacher
b34a665da4 nametransform: implement ReadDirIV without Openat
As ReadDirIV operates on a path anyway, opening the directory
has no clear safety advantage w.r.t. concurrent renames.

If the backing directory is a reverse-mounted gocryptfs filesystem,
each directory open is an OPENDIR, and this causes a full directory
read!

This patch improves the "ls -lR" performance of an

  DIR --> gocryptfs-reverse --> gocryptfs

chain by a factor of ~10.

OPENDIR counts for ls -lR:
  Before 15570
  After   2745
2016-09-25 16:43:17 +02:00
Jakob Unterwurzacher
01c18dbcab nametransform: return EINVAL on invalid padding
With the generic fmt.Errorf we trigger a warning from go-fuse:

  2016/09/21 21:42:31 can't convert error type: Invalid padding
2016-09-25 16:43:17 +02:00
Jakob Unterwurzacher
ac1221395e nametransform: export DirIVLen constant
Will be needed by reverse mode.
2016-09-25 16:43:17 +02:00
Jakob Unterwurzacher
e8a234f658 Add godoc comments to all internal packages 2016-07-06 21:51:25 +02:00
Jakob Unterwurzacher
d8524c7369 syscallcompat: OSX: add Unlinkat wrapper
Also, replace remaining naked syscall.Openat calls.
2016-07-03 20:17:40 +02:00
Jakob Unterwurzacher
e574a6cc1f nametransform: hide detailed padding error behind the debug flag
unPad16 returns detailed errors including the position of the
incorrect bytes. Kill a possible padding oracle by lumping
everything into a generic error.

The detailed error is only logged if debug is active.
2016-07-03 15:35:58 +02:00
Jakob Unterwurzacher
3d59a72ba9 Drop deprecated "-emenames" option
The EMENames feature flag is already mandatory, dropping the command
line option is the final step.
2016-06-23 21:56:50 +02:00
Jakob Unterwurzacher
e970b1fdb5 nametransform: drop unused noiv functions
As DirIV is now mandatory there is no user for the noiv functions.
2016-06-23 21:39:04 +02:00
Jakob Unterwurzacher
7e92ebe16a Rename nametransform, contentenc source files
Let's have shorter names, and merge *_api.go into the "main"
file.

No code changes.
2016-06-16 19:02:47 +02:00
Jakob Unterwurzacher
6c3f97399a Rename internal "toggledlog" package to "tlog"
tlog is used heavily everywhere and deserves a shorter name.

Renamed using sed magic, without any manual rework:

   find * -type f -exec sed -i 's/toggledlog/tlog/g' {} +
2016-06-15 23:30:44 +02:00
Jakob Unterwurzacher
80b027f830 nametransform, main: better error messages 2016-06-01 20:07:43 +02:00
Jakob Unterwurzacher
db72fcea41 longnames: fix fsstress failure, use dirfd
Using dirfd-relative operations allows safe lockless handling
of the ".name" files.
2016-04-10 21:31:08 +02:00
Jakob Unterwurzacher
63d3e51734 longnames: use symbolic constants instead of naked ints 2016-04-10 12:36:43 +02:00
Jakob Unterwurzacher
37a9b4c3ee Enable openssl in tests to support old Go versions
Go 1.4 and older do not support 128-bit IVs which caused
the tests to panic.
2016-03-03 00:59:58 +01:00
Jakob Unterwurzacher
653d4a619c longnames part II: Rename, Unlink, Rmdir, Mknod, Mkdir + tests 2016-02-07 14:02:09 +01:00
Jakob Unterwurzacher
e111e20649 longnames part I: Create and OpenDir work with long filenames > 176 bytes
Todo: Rename, Unlink, Rmdir, Mknod, Mkdir
2016-02-06 22:54:14 +01:00
Jakob Unterwurzacher
6b27b6a1e7 Move dirIVCache to its own file 2016-02-06 20:27:28 +01:00
Jakob Unterwurzacher
c74772bc8d Run go fmt 2016-02-06 20:23:36 +01:00