It might be possible for two callers to race the mutex lock after the
NULL ctx check. Instead, move the lock above the check so there isn't
the possibility of leaking a crypto ctx. Additionally, report the full
algo name when failing.
Signed-off-by: Kees Cook <keescook@chromium.org>
[tyhicks: remove out label, which is no longer used]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
It doesn't make sense to check if an array is NULL. The compiler just
removes the check.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
- Remove redundant code by merging some encrypt and decrypt functions
- Get rid of a helper page allocation during page decryption by using in-place
decryption
- Better use of entire pages during page crypto operations
- Several code cleanups
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Merge tag 'ecryptfs-3.11-rc1-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs
Pull eCryptfs updates from Tyler Hicks:
"Code cleanups and improved buffer handling during page crypto
operations:
- Remove redundant code by merging some encrypt and decrypt functions
- Get rid of a helper page allocation during page decryption by using
in-place decryption
- Better use of entire pages during page crypto operations
- Several code cleanups"
* tag 'ecryptfs-3.11-rc1-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
Use ecryptfs_dentry_to_lower_path in a couple of places
eCryptfs: Make extent and scatterlist crypt function parameters similar
eCryptfs: Collapse crypt_page_offset() into crypt_extent()
eCryptfs: Merge ecryptfs_encrypt_extent() and ecryptfs_decrypt_extent()
eCryptfs: Combine page_offset crypto functions
eCryptfs: Combine encrypt_scatterlist() and decrypt_scatterlist()
eCryptfs: Decrypt pages in-place
eCryptfs: Accept one offset parameter in page offset crypto functions
eCryptfs: Simplify lower file offset calculation
eCryptfs: Read/write entire page during page IO
eCryptfs: Use entire helper page during page crypto operations
eCryptfs: Cocci spatch "memdup.spatch"
The 'dest' abbreviation is only used in crypt_scatterlist(), while all
other functions in crypto.c use 'dst' so dest_sg should be renamed to
dst_sg.
The crypt_stat parameter is typically the first parameter in internal
eCryptfs functions so crypt_stat and dst_page should be swapped in
crypt_extent().
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
crypt_page_offset() simply initialized the two scatterlists and called
crypt_scatterlist() so it is simple enough to move into the only
function that calls it.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
They are identical except if the src_page or dst_page index is used, so
they can be merged safely if page_index is conditionally assigned.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Combine ecryptfs_encrypt_page_offset() and
ecryptfs_decrypt_page_offset(). These two functions are functionally
identical so they can be safely merged if the caller can indicate
whether an encryption or decryption operation should occur.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
These two functions are identical except for a debug printk and whether
they call crypto_ablkcipher_encrypt() or crypto_ablkcipher_decrypt(), so
they can be safely merged if the caller can indicate if encryption or
decryption should occur.
The debug printk is useless so it is removed.
Two new #define's are created to indicate if an ENCRYPT or DECRYPT
operation is desired.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
When reading in a page, eCryptfs would allocate a helper page, fill it
with encrypted data from the lower filesytem, and then decrypt the data
from the encrypted page and store the result in the eCryptfs page cache
page.
The crypto API supports in-place crypto operations which means that the
allocation of the helper page is unnecessary when decrypting. This patch
gets rid of the unneeded page allocation by reading encrypted data from
the lower filesystem directly into the page cache page. The page cache
page is then decrypted in-place.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
There is no longer a need to accept different offset values for the
source and destination pages when encrypting/decrypting an extent in an
eCryptfs page. The two offsets can be collapsed into a single parameter.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Now that lower filesystem IO operations occur for complete
PAGE_CACHE_SIZE bytes, the calculation for converting an eCryptfs extent
index into a lower file offset can be simplified.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
When reading and writing encrypted pages, perform IO using the entire
page all at once rather than 4096 bytes at a time.
This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
When encrypting eCryptfs pages and decrypting pages from the lower
filesystem, utilize the entire helper page rather than only the first
4096 bytes.
This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Make the switch from the blkcipher kernel crypto interface to the
ablkcipher interface.
encrypt_scatterlist() and decrypt_scatterlist() now use the ablkcipher
interface but, from the eCryptfs standpoint, still treat the crypto
operation as a synchronous operation. They submit the async request and
then wait until the operation is finished before they return. Most of
the changes are contained inside those two functions.
Despite waiting for the completion of the crypto operation, the
ablkcipher interface provides performance increases in most cases when
used on AES-NI capable hardware.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Reviewed-by: Zeev Zilberman <zeev@annapurnaLabs.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Thieu Le <thieule@google.com>
Cc: Li Wang <dragonylffly@163.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@iki.fi>
This is always called with a valid "sg" pointer. My static checker
complains because the call to sg_init_table() dereferences "sg" before
we reach the checks.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
the function ecryptfs_encode_for_filename() is only used in this file
Signed-off-by: Cong Ding <dinggnu@gmail.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
statfs() calls on eCryptfs files returned the wrong filesystem type and,
when using filename encryption, the wrong maximum filename length.
If mount-wide filename encryption is enabled, the cipher block size and
the lower filesystem's max filename length will determine the max
eCryptfs filename length. Pre-tested, known good lengths are used when
the lower filesystem's namelen is 255 and a cipher with 8 or 16 byte
block sizes is used. In other, less common cases, we fall back to a safe
rounded-down estimate when determining the eCryptfs namelen.
https://launchpad.net/bugs/885744
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
If pages passed to the eCryptfs extent-based crypto functions are not
mapped and the module parameter ecryptfs_verbosity=1 was specified at
loading time, a NULL pointer dereference will occur.
Note that this wouldn't happen on a production system, as you wouldn't
pass ecryptfs_verbosity=1 on a production system. It leaks private
information to the system logs and is for debugging only.
The debugging info printed in these messages is no longer very useful
and rather than doing a kmap() in these debugging paths, it will be
better to simply remove the debugging paths completely.
https://launchpad.net/bugs/913651
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Daniel DeFreez
Cc: <stable@vger.kernel.org>
Removes unneeded variable initialization in ecryptfs_read_metadata(). Also adds
a small comment to help explain metadata reading logic.
[tyhicks@canonical.com: Pulled out of for-stable patch and wrote commit msg]
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Print inode on metadata read failure. The only real
way of dealing with metadata read failures is to delete
the underlying file system file. Having the inode
allows one to 'find . -inum INODE`.
[tyhicks@canonical.com: Removed some minor not-for-stable parts]
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
From mhalcrow's original commit message:
Characters with ASCII values greater than the size of
filename_rev_map[] are valid filename characters.
ecryptfs_decode_from_filename() will access kernel memory beyond
that array, and ecryptfs_parse_tag_70_packet() will then decrypt
those characters. The attacker, using the FNEK of the crafted file,
can then re-encrypt the characters to reveal the kernel memory past
the end of the filename_rev_map[] array. I expect low security
impact since this array is statically allocated in the text area,
and the amount of memory past the array that is accessible is
limited by the largest possible ASCII filename character.
This patch solves the issue reported by mhalcrow but with an
implementation suggested by Linus to simply extend the length of
filename_rev_map[] to 256. Characters greater than 0x7A are mapped to
0x00, which is how invalid characters less than 0x7A were previously
being handled.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Michael Halcrow <mhalcrow@google.com>
Cc: stable@kernel.org
The file creation path prematurely called d_instantiate() and
unlock_new_inode() before the eCryptfs inode info was fully
allocated and initialized and before the eCryptfs metadata was written
to the lower file.
This could result in race conditions in subsequent file and inode
operations leading to unexpected error conditions or a null pointer
dereference while attempting to use the unallocated memory.
https://launchpad.net/bugs/813146
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Cc: stable@kernel.org
Now that ecryptfs_lookup_interpose() is no longer using
ecryptfs_header_cache_2 to read in metadata, the kmem_cache can be
removed and the ecryptfs_header_cache_1 kmem_cache can be renamed to
ecryptfs_header_cache.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
ecryptfs_lookup_interpose() has turned into spaghetti code over the
years. This is an effort to clean it up.
- Shorten overly descriptive variable names such as ecryptfs_dentry
- Simplify gotos and error paths
- Create helper function for reading plaintext i_size from metadata
It also includes an optimization when reading i_size from the metadata.
A complete page-sized kmem_cache_alloc() was being done to read in 16
bytes of metadata. The buffer for that is now statically declared.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Instead of having the calling functions translate the true/false return
code to either 0 or -EINVAL, have contains_ecryptfs_marker() return 0 or
-EINVAL so that the calling functions can just reuse the return code.
Also, rename the function to ecryptfs_validate_marker() to avoid callers
mistakenly thinking that it returns true/false codes.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Only unlock and d_add() new inodes after the plaintext inode size has
been read from the lower filesystem. This fixes a race condition that
was sometimes seen during a multi-job kernel build in an eCryptfs mount.
https://bugzilla.kernel.org/show_bug.cgi?id=36002
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Reported-by: David <david@unsolicited.net>
Tested-by: David <david@unsolicited.net>
When failing to read the lower file's crypto metadata during a lookup,
eCryptfs must continue on without throwing an error. For example, there
may be a plaintext file in the lower mount point that the user wants to
delete through the eCryptfs mount.
If an error is encountered while reading the metadata in lookup(), the
eCryptfs inode's size could be incorrect. We must be sure to reread the
plaintext inode size from the metadata when performing an open() or
setattr(). The metadata is already being read in those paths, so this
adds minimal performance overhead.
This patch introduces a flag which will track whether or not the
plaintext inode size has been read so that an incorrect i_size can be
fixed in the open() or setattr() paths.
https://bugs.launchpad.net/bugs/509180
Cc: <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
This patch removes the 'num_global_auth_toks' field of the
ecryptfs_mount_crypt_stat structure, used to count the number of items in
the 'global_auth_tok_list' list. This variable is not needed because there
are no checks based upon it.
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
When creating a new eCryptfs file, the crypto metadata is written out
and then the lower file was being "grown" with 4 kB of encrypted zeroes.
I suspect that growing the encrypted file was to prevent an information
leak that the unencrypted file was empty. However, the unencrypted file
size is stored, in plaintext, in the metadata so growing the file is
unnecessary.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Commit cb55d21f6fa19d8c6c2680d90317ce88c1f57269 revealed a number of
missing 'z' length modifiers in calls to ecryptfs_printk() when
printing variables of type size_t. This patch fixes those compiler
warnings.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Add __attribute__((format... to __ecryptfs_printk
Make formats and arguments match.
Add casts to (unsigned long long) for %llu.
Signed-off-by: Joe Perches <joe@perches.com>
[tyhicks: 80 columns cleanup and fixed typo]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Fixes a regression caused by 21edad3220
When file name encryption was enabled, ecryptfs_lookup() failed to use
the encrypted and encoded version of the upper, plaintext, file name
when performing a lookup in the lower file system. This made it
impossible to lookup existing encrypted file names and any newly created
files would have plaintext file names in the lower file system.
https://bugs.launchpad.net/ecryptfs/+bug/623087
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Some ecryptfs init functions are not prefixed by __init and thus not
freed after initialization. This patch saved about 1kB in ecryptfs
module.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6:
eCryptfs: Turn lower lookup error messages into debug messages
eCryptfs: Copy lower directory inode times and size on link
ecryptfs: fix use with tmpfs by removing d_drop from ecryptfs_destroy_inode
ecryptfs: fix error code for missing xattrs in lower fs
eCryptfs: Decrypt symlink target for stat size
eCryptfs: Strip metadata in xattr flag in encrypted view
eCryptfs: Clear buffer before reading in metadata xattr
eCryptfs: Rename ecryptfs_crypt_stat.num_header_bytes_at_front
eCryptfs: Fix metadata in xattr feature regression
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
The ecryptfs_encrypted_view mount option provides a unified way of
viewing encrypted eCryptfs files. If the metadata is stored in a xattr,
the metadata is moved to the file header when the file is read inside
the eCryptfs mount. Because of this, we should strip the
ECRYPTFS_METADATA_IN_XATTR flag from the header's flag section. This
allows eCryptfs to treat the file as an eCryptfs file with a header
at the front.
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
We initially read in the first PAGE_CACHE_SIZE of a file to if the
eCryptfs header marker can be found. If it isn't found and
ecryptfs_xattr_metadata was given as a mount option, then the
user.ecryptfs xattr is read into the same buffer. Since the data from
the first page of the file wasn't cleared, it is possible that we think
we've found a second tag 3 or tag 1 packet and then error out after the
packet contents aren't as expected. This patch clears the buffer before
filling it with metadata from the user.ecryptfs xattr.
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
This patch renames the num_header_bytes_at_front variable to
metadata_size since it now contains the max size of the metadata.
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Fixes regression in 8faece5f90
When using the ecryptfs_xattr_metadata mount option, eCryptfs stores the
metadata (normally stored at the front of the file) in the user.ecryptfs
xattr. This causes ecryptfs_crypt_stat.num_header_bytes_at_front to be
0, since there is no header data at the front of the file. This results
in too much memory being requested and ENOMEM being returned from
ecryptfs_write_metadata().
This patch fixes the problem by using the num_header_bytes_at_front
variable for specifying the max size of the metadata, despite whether it
is stored in the header or xattr.
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
The "full_alg_name" variable is used on a couple error paths, so we
shouldn't free it until the end.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Errors returned from vfs_read() and vfs_write() calls to the lower
filesystem were being masked as -EINVAL. This caused some confusion to
users who saw EINVAL instead of ENOSPC when the disk was full, for
instance.
Also, the actual bytes read or written were not accessible by callers to
ecryptfs_read_lower() and ecryptfs_write_lower(), which may be useful in
some cases. This patch updates the error handling logic where those
functions are called in order to accept positive return codes indicating
success.
Cc: Eric Sandeen <esandeen@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Returns -ENOTSUPP when attempting to use filename encryption with
something other than a password authentication token, such as a private
token from openssl. Using filename encryption with a userspace eCryptfs
key module is a future goal. Until then, this patch handles the
situation a little better than simply using a BUG_ON().
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Cc: stable <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Returns an error when an unrecognized cipher code is present in a tag 3
packet or an ecryptfs_crypt_stat cannot be initialized. Also sets an
crypt_stat->tfm error pointer to NULL to ensure that it will not be
incorrectly freed in ecryptfs_destroy_crypt_stat().
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Cc: stable <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
So, I compiled a 2.6.31-rc5 kernel with ecryptfs and loaded its module.
When it came time to mount my filesystem, I got this in dmesg, and it
refused to mount:
[93577.776637] Unable to allocate crypto cipher with name [aes]; rc = [-2]
[93577.783280] Error attempting to initialize key TFM cipher with name = [aes]; rc = [-2]
[93577.791183] Error attempting to initialize cipher with name = [aes] and key size = [32]; rc = [-2]
[93577.800113] Error parsing options; rc = [-22]
I figured from the error message that I'd either forgotten to load "aes"
or that my key size was bogus. Neither one of those was the case. In
fact, I was missing the CRYPTO_ECB config option and the 'ecb' module.
Unfortunately, there's no trace of 'ecb' in that error message.
I've done two things to fix this. First, I've modified ecryptfs's
Kconfig entry to select CRYPTO_ECB and CRYPTO_CBC. I also took CRYPTO
out of the dependencies since the 'select' will take care of it for us.
I've also modified the error messages to print a string that should
contain both 'ecb' and 'aes' in my error case. That will give any
future users a chance of finding the right modules and Kconfig options.
I also wonder if we should:
select CRYPTO_AES if !EMBEDDED
since I think most ecryptfs users are using AES like me.
Cc: ecryptfs-devel@lists.launchpad.net
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Dustin Kirkland <kirkland@canonical.com>
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
[tyhicks@linux.vnet.ibm.com: Removed extra newline, 80-char violation]
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Lockdep reports the following valid-looking possible AB-BA deadlock with
global_auth_tok_list_mutex and keysig_list_mutex:
ecryptfs_new_file_context() ->
ecryptfs_copy_mount_wide_sigs_to_inode_sigs() ->
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
-> ecryptfs_add_keysig() ->
mutex_lock(&crypt_stat->keysig_list_mutex);
vs
ecryptfs_generate_key_packet_set() ->
mutex_lock(&crypt_stat->keysig_list_mutex);
-> ecryptfs_find_global_auth_tok_for_sig() ->
mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
ie the two mutexes are taken in opposite orders in the two different
code paths. I'm not sure if this is a real bug where two threads could
actually hit the two paths in parallel and deadlock, but it at least
makes lockdep impossible to use with ecryptfs since this report triggers
every time and disables future lockdep reporting.
Since ecryptfs_add_keysig() is called only from the single callsite in
ecryptfs_copy_mount_wide_sigs_to_inode_sigs(), the simplest fix seems to
be to move the lock of keysig_list_mutex back up outside of the where
global_auth_tok_list_mutex is taken. This patch does that, and fixes
the lockdep report on my system (and ecryptfs still works OK).
The full output of lockdep fixed by this patch is:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.31-2-generic #14~rbd2
-------------------------------------------------------
gdm/2640 is trying to acquire lock:
(&mount_crypt_stat->global_auth_tok_list_mutex){+.+.+.}, at: [<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
but task is already holding lock:
(&crypt_stat->keysig_list_mutex){+.+.+.}, at: [<ffffffff81217728>] ecryptfs_generate_key_packet_set+0x58/0x2b0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&crypt_stat->keysig_list_mutex){+.+.+.}:
[<ffffffff8108c897>] check_prev_add+0x2a7/0x370
[<ffffffff8108cfc1>] validate_chain+0x661/0x750
[<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
[<ffffffff8121526a>] ecryptfs_add_keysig+0x5a/0xb0
[<ffffffff81213299>] ecryptfs_copy_mount_wide_sigs_to_inode_sigs+0x59/0xb0
[<ffffffff81214b06>] ecryptfs_new_file_context+0xa6/0x1a0
[<ffffffff8120e42a>] ecryptfs_initialize_file+0x4a/0x140
[<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
[<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
[<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
[<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
[<ffffffff8112d8d9>] do_sys_open+0x69/0x140
[<ffffffff8112d9f0>] sys_open+0x20/0x30
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
-> #0 (&mount_crypt_stat->global_auth_tok_list_mutex){+.+.+.}:
[<ffffffff8108c675>] check_prev_add+0x85/0x370
[<ffffffff8108cfc1>] validate_chain+0x661/0x750
[<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
[<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff812177d5>] ecryptfs_generate_key_packet_set+0x105/0x2b0
[<ffffffff81212f49>] ecryptfs_write_headers_virt+0xc9/0x120
[<ffffffff8121306d>] ecryptfs_write_metadata+0xcd/0x200
[<ffffffff8120e44b>] ecryptfs_initialize_file+0x6b/0x140
[<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
[<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
[<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
[<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
[<ffffffff8112d8d9>] do_sys_open+0x69/0x140
[<ffffffff8112d9f0>] sys_open+0x20/0x30
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
other info that might help us debug this:
2 locks held by gdm/2640:
#0: (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8113cb8b>] do_filp_open+0x3cb/0xae0
#1: (&crypt_stat->keysig_list_mutex){+.+.+.}, at: [<ffffffff81217728>] ecryptfs_generate_key_packet_set+0x58/0x2b0
stack backtrace:
Pid: 2640, comm: gdm Tainted: G C 2.6.31-2-generic #14~rbd2
Call Trace:
[<ffffffff8108b988>] print_circular_bug_tail+0xa8/0xf0
[<ffffffff8108c675>] check_prev_add+0x85/0x370
[<ffffffff81094912>] ? __module_text_address+0x12/0x60
[<ffffffff8108cfc1>] validate_chain+0x661/0x750
[<ffffffff81017275>] ? print_context_stack+0x85/0x140
[<ffffffff81089c68>] ? find_usage_backwards+0x38/0x160
[<ffffffff8108d2e7>] __lock_acquire+0x237/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff8108b0b0>] ? check_usage_backwards+0x0/0xb0
[<ffffffff815526cd>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff8121591e>] ? ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff8108c02c>] ? mark_held_locks+0x6c/0xa0
[<ffffffff81125b0d>] ? kmem_cache_alloc+0xfd/0x1a0
[<ffffffff8108c34d>] ? trace_hardirqs_on_caller+0x14d/0x190
[<ffffffff81552b56>] mutex_lock_nested+0x46/0x60
[<ffffffff8121591e>] ecryptfs_find_global_auth_tok_for_sig+0x2e/0x90
[<ffffffff812177d5>] ecryptfs_generate_key_packet_set+0x105/0x2b0
[<ffffffff81212f49>] ecryptfs_write_headers_virt+0xc9/0x120
[<ffffffff8121306d>] ecryptfs_write_metadata+0xcd/0x200
[<ffffffff81210240>] ? ecryptfs_init_persistent_file+0x60/0xe0
[<ffffffff8120e44b>] ecryptfs_initialize_file+0x6b/0x140
[<ffffffff8120e54d>] ecryptfs_create+0x2d/0x60
[<ffffffff8113a7d4>] vfs_create+0xb4/0xe0
[<ffffffff8113a8c4>] __open_namei_create+0xc4/0x110
[<ffffffff8113d1c1>] do_filp_open+0xa01/0xae0
[<ffffffff8129a93e>] ? _raw_spin_unlock+0x5e/0xb0
[<ffffffff8155410b>] ? _spin_unlock+0x2b/0x40
[<ffffffff81139e9b>] ? getname+0x3b/0x240
[<ffffffff81148a5a>] ? alloc_fd+0xfa/0x140
[<ffffffff8112d8d9>] do_sys_open+0x69/0x140
[<ffffffff81553b8f>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff8112d9f0>] sys_open+0x20/0x30
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
In ecryptfs_destroy_inode(), inode_info->lower_file_mutex is locked,
and just after the mutex is unlocked, the code does:
kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
This means that if another context could possibly try to take the same
mutex as ecryptfs_destroy_inode(), then it could end up getting the
mutex just before the data structure containing the mutex is freed.
So any such use would be an obvious use-after-free bug (catchable with
slab poisoning or mutex debugging), and therefore the locking in
ecryptfs_destroy_inode() is not needed and can be dropped.
Similarly, in ecryptfs_destroy_crypt_stat(), crypt_stat->keysig_list_mutex
is locked, and then the mutex is unlocked just before the code does:
memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
Therefore taking this mutex is similarly not necessary.
Removing this locking fixes false-positive lockdep reports such as the
following (and they are false-positives for exactly the same reason
that the locking is not needed):
=================================
[ INFO: inconsistent lock state ]
2.6.31-2-generic #14~rbd3
---------------------------------
inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
kswapd0/323 [HC0[0]:SC0[0]:HE1:SE1] takes:
(&inode_info->lower_file_mutex){+.+.?.}, at: [<ffffffff81210d34>] ecryptfs_destroy_inode+0x34/0x100
{RECLAIM_FS-ON-W} state was registered at:
[<ffffffff8108c02c>] mark_held_locks+0x6c/0xa0
[<ffffffff8108c10f>] lockdep_trace_alloc+0xaf/0xe0
[<ffffffff81125a51>] kmem_cache_alloc+0x41/0x1a0
[<ffffffff8113117a>] get_empty_filp+0x7a/0x1a0
[<ffffffff8112dd46>] dentry_open+0x36/0xc0
[<ffffffff8121a36c>] ecryptfs_privileged_open+0x5c/0x2e0
[<ffffffff81210283>] ecryptfs_init_persistent_file+0xa3/0xe0
[<ffffffff8120e838>] ecryptfs_lookup_and_interpose_lower+0x278/0x380
[<ffffffff8120f97a>] ecryptfs_lookup+0x12a/0x250
[<ffffffff8113930a>] real_lookup+0xea/0x160
[<ffffffff8113afc8>] do_lookup+0xb8/0xf0
[<ffffffff8113b518>] __link_path_walk+0x518/0x870
[<ffffffff8113bd9c>] path_walk+0x5c/0xc0
[<ffffffff8113be5b>] do_path_lookup+0x5b/0xa0
[<ffffffff8113bfe7>] user_path_at+0x57/0xa0
[<ffffffff811340dc>] vfs_fstatat+0x3c/0x80
[<ffffffff8113424b>] vfs_stat+0x1b/0x20
[<ffffffff81134274>] sys_newstat+0x24/0x50
[<ffffffff81013132>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 7811
hardirqs last enabled at (7811): [<ffffffff810c037f>] call_rcu+0x5f/0x90
hardirqs last disabled at (7810): [<ffffffff810c0353>] call_rcu+0x33/0x90
softirqs last enabled at (3764): [<ffffffff810631da>] __do_softirq+0x14a/0x220
softirqs last disabled at (3751): [<ffffffff8101440c>] call_softirq+0x1c/0x30
other info that might help us debug this:
2 locks held by kswapd0/323:
#0: (shrinker_rwsem){++++..}, at: [<ffffffff810f67ed>] shrink_slab+0x3d/0x190
#1: (&type->s_umount_key#35){.+.+..}, at: [<ffffffff811429a1>] prune_dcache+0xd1/0x1b0
stack backtrace:
Pid: 323, comm: kswapd0 Tainted: G C 2.6.31-2-generic #14~rbd3
Call Trace:
[<ffffffff8108ad6c>] print_usage_bug+0x18c/0x1a0
[<ffffffff8108aff0>] ? check_usage_forwards+0x0/0xc0
[<ffffffff8108bac2>] mark_lock_irq+0xf2/0x280
[<ffffffff8108bd87>] mark_lock+0x137/0x1d0
[<ffffffff81164710>] ? fsnotify_clear_marks_by_inode+0x30/0xf0
[<ffffffff8108bee6>] mark_irqflags+0xc6/0x1a0
[<ffffffff8108d337>] __lock_acquire+0x287/0x430
[<ffffffff8108d585>] lock_acquire+0xa5/0x150
[<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
[<ffffffff8108d2e7>] ? __lock_acquire+0x237/0x430
[<ffffffff815526ad>] __mutex_lock_common+0x4d/0x3d0
[<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
[<ffffffff81164710>] ? fsnotify_clear_marks_by_inode+0x30/0xf0
[<ffffffff81210d34>] ? ecryptfs_destroy_inode+0x34/0x100
[<ffffffff8129a91e>] ? _raw_spin_unlock+0x5e/0xb0
[<ffffffff81552b36>] mutex_lock_nested+0x46/0x60
[<ffffffff81210d34>] ecryptfs_destroy_inode+0x34/0x100
[<ffffffff81145d27>] destroy_inode+0x87/0xd0
[<ffffffff81146b4c>] generic_delete_inode+0x12c/0x1a0
[<ffffffff81145832>] iput+0x62/0x70
[<ffffffff811423c8>] dentry_iput+0x98/0x110
[<ffffffff81142550>] d_kill+0x50/0x80
[<ffffffff81142623>] prune_one_dentry+0xa3/0xc0
[<ffffffff811428b1>] __shrink_dcache_sb+0x271/0x290
[<ffffffff811429d9>] prune_dcache+0x109/0x1b0
[<ffffffff81142abf>] shrink_dcache_memory+0x3f/0x50
[<ffffffff810f68dd>] shrink_slab+0x12d/0x190
[<ffffffff810f9377>] balance_pgdat+0x4d7/0x640
[<ffffffff8104c4c0>] ? finish_task_switch+0x40/0x150
[<ffffffff810f63c0>] ? isolate_pages_global+0x0/0x60
[<ffffffff810f95f7>] kswapd+0x117/0x170
[<ffffffff810777a0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff810f94e0>] ? kswapd+0x0/0x170
[<ffffffff810773be>] kthread+0x9e/0xb0
[<ffffffff8101430a>] child_rip+0xa/0x20
[<ffffffff81013c90>] ? restore_args+0x0/0x30
[<ffffffff81077320>] ? kthread+0x0/0xb0
[<ffffffff81014300>] ? child_rip+0x0/0x20
Signed-off-by: Roland Dreier <roland@digitalvampire.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
ecryptfs_passthrough is a mount option that allows eCryptfs to allow
data to be written to non-eCryptfs files in the lower filesystem. The
passthrough option was causing data corruption due to it not always
being treated as a non-eCryptfs file.
The first 8 bytes of an eCryptfs file contains the decrypted file size.
This value was being written to the non-eCryptfs files, too. Also,
extra 0x00 characters were being written to make the file size a
multiple of PAGE_CACHE_SIZE.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
If ecryptfs_encrypted_view or ecryptfs_xattr_metadata were being
specified as mount options, a NULL pointer dereference of crypt_stat
was possible during lookup.
This patch moves the crypt_stat assignment into
ecryptfs_lookup_and_interpose_lower(), ensuring that crypt_stat
will not be NULL before we attempt to dereference it.
Thanks to Dan Carpenter and his static analysis tool, smatch, for
finding this bug.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: Dustin Kirkland <kirkland@canonical.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
