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
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%.
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.
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.
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.
Force decode of encrypted files even if the integrity check fails, instead of
failing with an IO error. Warning messages are still printed to syslog if corrupted
files are encountered.
It can be useful to recover files from disks with bad sectors or other corrupted
media.
Closes https://github.com/rfjakob/gocryptfs/pull/102 .
go-fuse has added a new method to the nodefs.File interface that
caused this build error:
internal/fusefrontend/file.go:75: cannot use file literal (type *file) as type nodefs.File in return argument:
*file does not implement nodefs.File (missing Flock method)
Fixes https://github.com/rfjakob/gocryptfs/issues/104 and
prevents the problem from happening again.
The volatile inode numbers that we used before cause "find" to complain and error out.
Virtual inode numbers are derived from their parent file inode number by adding 10^19,
which is hopefully large enough no never cause problems in practice.
If the backing directory contains inode numbers higher than that, stat() on these files
will return EOVERFLOW.
Example directory lising after this change:
$ ls -i
926473 gocryptfs.conf
1000000000000926466 gocryptfs.diriv
944878 gocryptfs.longname.hmZojMqC6ns47eyVxLlH2ailKjN9bxfosi3C-FR8mjA
1000000000000944878 gocryptfs.longname.hmZojMqC6ns47eyVxLlH2ailKjN9bxfosi3C-FR8mjA.name
934408 Tdfbf02CKsTaGVYnAsSypA
Due to kernel readahead, we usually get multiple read requests
at the same time. These get submitted to the backing storage in
random order, which is a problem if seeking is very expensive.
Details: https://github.com/rfjakob/gocryptfs/issues/92
...if doWrite() can do it for us. This avoids the situation
that the file only consists of a file header when calling
doWrite.
A later patch will check for this condition and warn about it,
as with this change it should no longer occour in normal operation.
...but keep it disabled by default for new filesystems.
We are still missing an example filesystem and CLI arguments
to explicitely enable and disable it.
There are two independent backends, one for name encryption,
the other one, AEAD, for file content.
"BackendTypeEnum" only applies to AEAD (file content), so make that
clear in the name.
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)!
Preallocation is very slow on hdds that run btrfs. Give the
user the option to disable it. This greatly speeds up small file
operations but reduces the robustness against out-of-space errors.
Also add the option to the man page.
More info: https://github.com/rfjakob/gocryptfs/issues/63
Stat() calls are expensive on NFS as they need a full network
round-trip. We detect when a write immediately follows the
last one and skip the Stat in this case because the write
cannot create a file hole.
On my (slow) NAS, this takes the write speed from 24MB/s to
41MB/s.
Test that we get the right timestamp when extracting a tarball.
Also simplify the workaround in doTestUtimesNano() and fix the
fact that it was running no test at all.
This can happen during normal operation when the directory has
been deleted concurrently. But it can also mean that the
gocryptfs.diriv is missing due to an error, so log the event
at "info" level.
Commit af5441dcd9 has caused a
regression ( https://github.com/rfjakob/gocryptfs/issues/35 )
that is fixed by this commit.
The go-fuse library by now has all the syscall wrappers in
place to correctly handle Utimens, also for symlinks.
Instead of duplicating the effort here just call into go-fuse.
Closes#35
This fixes a build problem on 32-bit hosts:
internal/fusefrontend/file.go:400: cannot use a.Unix() (type int64) as
type int32 in assignment
internal/fusefrontend/file.go:406: cannot use m.Unix() (type int64) as
type int32 in assignment
It also enables full nanosecond timestamps for dates
after 1970.
...and convert all calls to syscall.{Fallocate,Openat}
to syscallcompat .
Both syscalls are not available on OSX. We emulate Openat and just
return EOPNOTSUPP for Fallocate.
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.
We were growing the file block-by-block which was pretty
inefficient. We now coalesce all the grows into a single
Ftruncate. Also simplifies the code!
Simplistic benchmark: Before:
$ time truncate -s 1000M foo
real 0m0.568s
After:
$ time truncate -s 1000M foo
real 0m0.205s
XFS returns a different error code if you try to overwrite
a non-empty directory with a directory:
XFS: mv: cannot move ‘foo’ to ‘bar/foo’: File exists
ext4: mv: cannot move 'foo' to 'bar/foo': Directory not empty
So have EEXIST trigger the Rmdir logic as well.
Fixes issue #20
Link: https://github.com/rfjakob/gocryptfs/issues/20
The "!fs.args.DirIV" special case was removed by b17f0465c7
but that, by accident, also removed the handling for
PlaintextNames.
Re-add it as an explicit PlaintextNames special case.
Also adds support for removing directories that miss their
gocryptfs.diriv file for some reason.
FUSE filesystems are mounted with "nosuid" by default. If we run as root,
we can use device files by passing the opposite mount option, "suid".
Also we have to use syscall.Chmod instead of os.Chmod because the
portability translation layer "syscallMode" messes up the sgid
and suid bits.
Fixes 70% of the failures in xfstests generic/193. The remaining are
related to truncate, but we err on the safe side:
$ diff -u tests/generic/193.out /home/jakob/src/fuse-xfstests/results//generic/193.out.bad
[...]
check that suid/sgid bits are cleared after successful truncate...
with no exec perm
before: -rwSr-Sr--
-after: -rw-r-Sr--
+after: -rw-r--r--
Support truncate(2) by opening the file and calling ftruncate(2)
While the glibc "truncate" wrapper seems to always use ftruncate, fsstress from
xfstests uses this a lot by calling "truncate64" directly.
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' {} +
Warnings were:
main.go:234: declaration of err shadows declaration at main.go:163:
internal/fusefrontend/file.go:401: declaration of err shadows declaration at internal/fusefrontend/file.go:379:
internal/fusefrontend/file.go:419: declaration of err shadows declaration at internal/fusefrontend/file.go:379:
internal/fusefrontend/fs_dir.go:140: declaration of err shadows declaration at internal/fusefrontend/fs_dir.go:97:
If /proc/self/fd/X did not exist, the actual error is that the file
descriptor was invalid.
go-fuse's pathfs prefers using an open fd even for path-based operations
but does not take any locks to prevent the fd from being closed.
Instead, it retries the operation by path if it get EBADF. So this
change allows the retry logic to work correctly.
This fixes the error
rsync: failed to set times on "/tmp/ping.Kgw.mnt/linux-3.0/[...]/.dvb_demux.c.N7YlEM":
No such file or directory (2)
that was triggered by pingpong-rsync.bash.
We (actually, go-fuse) used to call Chown() instead of Lchown()
which meant that the operation would fail on dangling symlinks.
Fix this by calling os.Lchown() ourself. Also add a test case
for this.
Just presenting an empty directory means that the user does not know
that things went wrong unless he checks the syslog or tries to delete
the directory.
It would be nice to report the error even if only some files were
invalid. However, go-fuse does not allow returning the valid
directory entries AND an error.
... with the "released" boolean.
For some reason, the "f.fd.Fd() < 0" check did not work reliably,
leading to nil pointer panics on the following wlock.lock().
The problem was discovered during fsstress testing and is unlikely
to happen in normal operations.
With this change, we passed 1700+ fsstress iterations.
Paths in statfs() calls were not encrypted resulting in
an Function not implemented error, when the unencrypted
path didn't exist in the underlying (encrypted)
filesystem.
$ df plain/existingdir
df: ‘plain/existingdir’: Function not implemented
Commit 730291feab properly freed wlock when the file descriptor is
closed. However, concurrently running Write and Truncates may
still want to lock it. Check if the fd has been closed first.
