Commit Graph

144 Commits

Author SHA1 Message Date
Jakob Unterwurzacher
8951eb2472 fusefronted: add PlaintextNames special-cases for Create & Rename
gocryptfs.longname.XXX files were considered magic in PlaintextNames
mode, which was wrong.

Fix that and add tests.

Fixes https://github.com/rfjakob/gocryptfs/issues/174
2018-01-17 00:25:36 +01:00
Sebastian Lackner
a85dbcab38 fusefrontend: Use Linkat syscall to implement Link 2017-12-25 15:07:37 +01:00
Sebastian Lackner
a24342f656 fusefrontend: Handle PlaintextNames mode in Link
In PlaintextNames mode the "gocryptfs.longname." prefix does not have any
special meaning.

https://github.com/rfjakob/gocryptfs/issues/174
2017-12-25 15:07:37 +01:00
Jakob Unterwurzacher
70bcf58a9b syscallcompat: convert Getdents to fd input, add emulation
Now that we have Fstatat we can use it in Getdents to
get rid of the path name.

Also, add an emulated version of getdents for MacOS. This allows
to drop the !HaveGetdents special cases from fusefrontend.

Modify the getdents test to test both native getdents and the emulated
version.
2017-12-03 19:33:26 +01:00
Sebastian Lackner
9bcde0c09e fusefrontend: Improve documentation of mkdirWithIv and WriteDirIV
As requested in https://github.com/rfjakob/gocryptfs/pull/179
2017-12-01 09:41:52 +01:00
Jakob Unterwurzacher
e97c23e083 syscallcompat: check that we get NOFOLLOW wherever possible
...and fix the instances where the AT_SYMLINK_NOFOLLOW /
O_NOFOLLOW / O_EXCL flag was missing.
2017-11-30 19:40:53 +01:00
Sebastian Lackner
614745ee57 fusefrontend: allow_other: close race between mkdir and chown
Fixes the same problem as described in 72b975867a,
except for directories instead of device nodes.
2017-11-29 13:28:04 +01:00
Sebastian Lackner
67bcbe81e8 fusefrontend: Use Fchownat to implement Chown 2017-11-29 13:05:46 +01:00
Sebastian Lackner
0162392a28 fusefrontend: Use Fchmodat to implement Chmod 2017-11-29 12:55:41 +01:00
Sebastian Lackner
0f44c617d0 syscallcompat: Introduce unlinkat syscall with flags argument 2017-11-29 12:41:23 +01:00
Sebastian Lackner
5d44a31b41 fusefrontend: Use openBackingPath in Unlink and simplify code 2017-11-28 09:28:06 +01:00
Sebastian Lackner
2591900b69 fusefrontend: Handle PlaintextNames mode in Unlink
In PlaintextNames mode the "gocryptfs.longname." prefix does not have any
special meaning. We should not attempt to delete any .name files.

Partially fixes https://github.com/rfjakob/gocryptfs/issues/174
2017-11-28 09:28:06 +01:00
Sebastian Lackner
eba49402e4 fusefrontend: Introduce a openBackingPath helper and use it to simplify Mknod and Symlink 2017-11-28 09:28:06 +01:00
Sebastian Lackner
ad2720e0f9 fusefrontend: allow_other: close race between symlink and chown
Fixes the same problem as described in 72b975867a,
except for symlinks instead of device nodes.
2017-11-28 09:28:06 +01:00
Sebastian Lackner
5a56810603 fusefrontend: Use the Symlinkat syscall for longname handling 2017-11-28 09:28:06 +01:00
Sebastian Lackner
295c4c2b85 fusefrontend: Set owner after symlink creation in PlaintextNames mode
This is already done in regular mode, but was missing when PlaintextNames mode
is enabled. As a result, symlinks created by non-root users were still owned
by root afterwards.

Fixes https://github.com/rfjakob/gocryptfs/issues/176
2017-11-28 09:28:06 +01:00
Sebastian Lackner
3f68b0c09a fusefrontend: Handle PlaintextNames mode in Mknod
In PlaintextNames mode the "gocryptfs.longname." prefix does not have any
special meaning. We should not attempt to read the directory IV or to
create special .name files.

Partially fixes https://github.com/rfjakob/gocryptfs/issues/174
2017-11-28 09:28:06 +01:00
Jakob Unterwurzacher
72b975867a fusefronted: allow_other: close race between mknod and chown
If the user manages to replace the directory with
a symlink at just the right time, we could be tricked
into chown'ing the wrong file.

This change fixes the race by using fchownat, which
unfortunately is not available on darwin, hence a compat
wrapper is added.

Scenario, as described by @slackner at
https://github.com/rfjakob/gocryptfs/issues/177 :

1. Create a forward mount point with `plaintextnames` enabled
2. Mount as root user with `allow_other`
3. For testing purposes create a file `/tmp/file_owned_by_root`
   which is owned by the root user
4. As a regular user run inside of the GoCryptFS mount:

```
mkdir tempdir
mknod tempdir/file_owned_by_root p &
mv tempdir tempdir2
ln -s /tmp tempdir
```

When the steps are done fast enough and in the right order
(run in a loop!), the device file will be created in
`tempdir`, but the `lchown` will be executed by following
the symlink. As a result, the ownership of the file located
at `/tmp/file_owned_by_root` will be changed.
2017-11-27 21:04:45 +01:00
Sebastian Lackner
95870e841e fusefrontend: Skip gocryptfs.diriv handling when directory was deleted successfully
Fixes https://github.com/rfjakob/gocryptfs/issues/171

Steps to reproduce:

* Create a regular forward mount point
* Create a new directory in the mount point
* Manually delete the gocryptfs.diriv file from the corresponding ciphertext
  directory
* Attempt to delete the directory with 'rmdir <dirname>'

Although the code explicitly checks for empty directories, it will still attempt
to move the non-existent gocryptfs.diriv file and fails with:

    rmdir: failed to remove '<dirname>': No such file or directory
2017-11-25 16:20:00 +01:00
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
Jakob Unterwurzacher
268e0484e2 Revert most of "fusefrontend: clamp oversized reads"
We cannot return less data than requested to the kernel!

From https://libfuse.github.io/doxygen/structfuse__operations.html:

  Read should return exactly the number of bytes
  requested except on EOF or error, otherwise the
  rest of the data will be substituted with
  zeroes.

Reverts commit 3009ec9852 minus
the formatting improvements we want to keep.

Fixes https://github.com/rfjakob/gocryptfs/issues/147
Reopens https://github.com/rfjakob/gocryptfs/issues/145
2017-10-21 17:43:21 +02:00
Jakob Unterwurzacher
3009ec9852 fusefrontend: clamp oversized reads
Our byte cache pools are sized acc. to MAX_KERNEL_WRITE, but the
running kernel may have a higher limit set. Clamp to what we can
handle.

Fixes a panic on a Synology NAS reported at
https://github.com/rfjakob/gocryptfs/issues/145
2017-10-17 21:48:29 +02:00
Jakob Unterwurzacher
604b0779d4 macos: automatically remove .DS_Store on Rmdir
MacOS sprinkles .DS_Store files everywhere. This is hard to avoid for
users, so handle it transparently in Rmdir().

Mitigates https://github.com/rfjakob/gocryptfs/issues/140
2017-09-05 22:47:15 +02:00
Jakob Unterwurzacher
6f3b65d924 fusefrontend: reorder logic in Rmdir to get rid of one indentation level
Handle the errors first so that the normal code path is not indented.

This should not cause any behavoir changes.
2017-09-05 22:10:08 +02:00
Jakob Unterwurzacher
3a5a783b54 macos: don't throw IO errors because of .DS_Store files
MacOS creates lots of these files, and if the directory is otherwise
empty, we would throw an IO error to the unsuspecting user.

With this patch, we log a warning, but otherwise pretend we did not
see it.

Mitigates https://github.com/rfjakob/gocryptfs/issues/140
2017-09-05 21:47:05 +02:00
Jakob Unterwurzacher
538cae610c syscallcompat: Getdents: warn once if we get DT_UNKNOWN
...and if Getdents is not available at all.

Due to this warning I now know that SSHFS always returns DT_UNKNOWN:

    gocryptfs[8129]: Getdents: convertDType: received DT_UNKNOWN, falling back to Lstat

This behavoir is confirmed at http://ahefner.livejournal.com/16875.html:

    "With sshfs, I finally found that obscure case. The dtype is always set to DT_UNKNOWN [...]"
2017-09-03 15:05:54 +02:00
Jakob Unterwurzacher
276567eb13 fusefrontend: use DirIVCache in OpenDir()
Previously, OpenDir() did not use the cache at all, missing
an opportunity to speed up repeated directory reads.
2017-09-03 13:59:53 +02:00
Jakob Unterwurzacher
989b880989 fusefrontend: use Getdents if available
Getdents avoids calling Lstat on each file.
2017-08-15 19:04:02 +02:00
Jakob Unterwurzacher
0c520845f3 main: purge masterkey from memory as soon as possible
Remove the "Masterkey" field from fusefrontend.Args because it
should not be stored longer than neccessary. Instead pass the
masterkey as a separate argument to the filesystem initializers.

Then overwrite it with zeros immediately so we don't have
to wait for garbage collection.

Note that the crypto implementation still stores at least a
masterkey-derived value, so this change makes it harder, but not
impossible, to extract the encryption keys from memory.

Suggested at https://github.com/rfjakob/gocryptfs/issues/137
2017-08-11 19:02:26 +02:00
Jakob Unterwurzacher
3062de6187 fusefronted: enable writing to write-only files
Due to RMW, we always need read permissions on the backing file. This is a
problem if the file permissions do not allow reading (i.e. 0200 permissions).
This patch works around that problem by chmod'ing the file, obtaining a fd,
and chmod'ing it back.

Test included.

Issue reported at: https://github.com/rfjakob/gocryptfs/issues/125
2017-07-11 23:19:58 +02:00
Jakob Unterwurzacher
52ab0462a4 fusefrontend: doRead: skip decryption for an empty read
Previously we ran through the decryption steps even for an empty
ciphertext slice. The functions handle it correctly, but returning
early skips all the extra calls.

Speeds up the tar extract benchmark by about 4%.
2017-07-02 16:02:13 +02:00
Jakob Unterwurzacher
12c0101a23 contentenc: add PReqPool and use it in DecryptBlocks
This gets us a massive speed boost in streaming reads.
2017-06-30 23:30:57 +02:00
Jakob Unterwurzacher
b2a23e94d1 fusefrontend: doRead: use CReqPool for ciphertext buffer
Easily saves lots of allocations.
2017-06-30 23:15:31 +02:00
Jakob Unterwurzacher
06398e82d9 fusefrontend: Read: use provided buffer
This will allow us to return internal buffers to a pool.
2017-06-30 23:11:38 +02:00
Jakob Unterwurzacher
80676c685f contentenc: add safer "bPool" pool variant; add pBlockPool
bPool verifies the lengths of slices going in and out.

Also, add a plaintext block pool - pBlockPool - and use
it for decryption.
2017-06-29 23:44:32 +02:00
Jakob Unterwurzacher
3c6fe98eb1 contentenc: use sync.Pool memory pools for encryption
We use two levels of buffers:

1) 4kiB+overhead for each ciphertext block
2) 128kiB+overhead for each FUSE write (32 ciphertext blocks)

This commit adds a sync.Pool for both levels.

The memory-efficiency for small writes could be improved,
as we now always use a 128kiB buffer.
2017-06-20 21:22:00 +02:00
Charles Duffy
da1bd74246 Fix missing Owner coercion for already-open files (#117) 2017-06-09 22:04:56 +02:00
Jakob Unterwurzacher
a24faa3ba5 fusefrontend: write: consolidate and move encryption to contentenc
Collect all the plaintext and pass everything to contentenc in
one call.

This will allow easier parallization of the encryption.

https://github.com/rfjakob/gocryptfs/issues/116
2017-06-01 22:19:27 +02:00
Charles Duffy
cf1ded5236 Implement force_owner option to display ownership as a specific user. 2017-06-01 00:26:17 +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
ad7942f434 fusefrontend: implement path decryption via ctlsock
Closes https://github.com/rfjakob/gocryptfs/issues/84 .
2017-05-07 21:01:39 +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
c52e1abc58 fusefrontend: log "too many open files" errors
This usually indicates that the open file limit for gocryptfs is
too low. We should report this to the user.
2017-05-03 23:46:52 +02:00
Jakob Unterwurzacher
fb3cc6ea40 openfiletable: rename WriteLock to ContentLock
...and IDLock to HeaderLock. This matches what the locks actually
protect.
2017-05-01 21:57:18 +02:00
Jakob Unterwurzacher
f322ee87e3 fusefrontend: rely on nodefs.defaultFile for no-op functions
Now that we embed nodefs.NewDefaultFile(), we can drop our own
no-ops.
2017-05-01 19:12:37 +02:00
Jakob Unterwurzacher
9ab11aa4d7 fusefrontend: drop writeOnly flag
We do not have to track the writeOnly status because the kernel
will not forward read requests on a write-only FD to us anyway.

I have verified this behavoir manually on a 4.10.8 kernel and also
added a testcase.
2017-05-01 17:49:37 +02:00
Jakob Unterwurzacher
514f515dd7 fusefronted, openfiletable: move the open file table to its own package
The open file table code needs some room to grow for the upcoming
FD multiplexing implementation.
2017-05-01 17:26:50 +02:00
Jakob Unterwurzacher
863c3ca36f fusefrontend: rename write_lock.go -> open_file_table.go
The data structure was originally called write lock table, but
is now simply called the open file table. Rename the file to
reflect that.
2017-04-29 22:24:38 +02:00
Jakob Unterwurzacher
b66e03486a fusefronted: drop unused file.String() function
This is a very old leftover.
2017-04-29 18:20:39 +02:00
Jakob Unterwurzacher
edb3e19cb5 fix golint complaints 2017-04-29 14:50:58 +02:00