UBIFS's recovery code strictly assumes that a deleted inode will never
come back, therefore it removes all data which belongs to that inode
as soon it faces an inode with link count 0 in the replay list.
Before O_TMPFILE this assumption was perfectly fine. With O_TMPFILE
it can lead to data loss upon a power-cut.
Consider a journal with entries like:
0: inode X (nlink = 0) /* O_TMPFILE was created */
1: data for inode X /* Someone writes to the temp file */
2: inode X (nlink = 0) /* inode was changed, xattr, chmod, … */
3: inode X (nlink = 1) /* inode was re-linked via linkat() */
Upon replay of entry #2 UBIFS will drop all data that belongs to inode X,
this will lead to an empty file after mounting.
As solution for this problem, scan the replay list for a re-link entry
before dropping data.
Fixes: 474b93704f ("ubifs: Implement O_TMPFILE")
Cc: stable@vger.kernel.org
Cc: Russell Senior <russell@personaltelco.net>
Cc: Rafał Miłecki <zajec5@gmail.com>
Reported-by: Russell Senior <russell@personaltelco.net>
Reported-by: Rafał Miłecki <zajec5@gmail.com>
Tested-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Richard Weinberger <richard@nod.at>
When ubifs is build without the LZO compressor and no compressor is
given the creation of the default file system will fail. before
selection the LZO compressor check if it is present and if not fall back
to the zlib or none.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
If the call to ubifs_read_nnode() fails in ubifs_lpt_calc_hash() an
error is returned without freeing the memory allocated to 'buf'.
Read and check the root node before allocating the buffer.
Detected by CoverityScan, CID 1441025 ("Resource leak")
Signed-off-by: Garry McNulty <garrmcnu@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The new authentication support causes a build failure
when CONFIG_KEYS is disabled, so add a dependency.
fs/ubifs/auth.c: In function 'ubifs_init_authentication':
fs/ubifs/auth.c:249:16: error: implicit declaration of function 'request_key'; did you mean 'request_irq'? [-Werror=implicit-function-declaration]
keyring_key = request_key(&key_type_logon, c->auth_key_name, NULL);
Fixes: d8a22773a1 ("ubifs: Enable authentication support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Instead of adding yet another dependency on UBIFS_FS, wrap the whole
block of ubifs config options in a single "if UBIFS_FS".
Fixes: d8a22773a1 ("ubifs: Enable authentication support")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Having two shash descriptors on the stack cause a very significant kernel
stack usage that can cross the warning threshold:
fs/ubifs/replay.c: In function 'authenticate_sleb':
fs/ubifs/replay.c:633:1: error: the frame size of 1144 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
Normally, gcc optimizes the out, but with CONFIG_CC_OPTIMIZE_FOR_DEBUGGING,
it does not. Splitting the two stack allocations into separate functions
means that they will use the same memory again. In normal configurations
(optimizing for size or performance), those should get inlined and we get
the same behavior as before.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
With the preparations all being done this patch now enables authentication
support for UBIFS. Authentication is enabled when the newly introduced
auth_key and auth_hash_name mount options are passed. auth_key provides
the key which is used for authentication whereas auth_hash_name provides
the hashing algorithm used for this FS. Passing these options make
authentication mandatory and only UBIFS images that can be authenticated
with the given key are allowed.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
In authenticated mode we cannot fixup the inode sizes in-place
during recovery as this would invalidate the hashes and HMACs
we stored for this inode.
Instead, we just write the updated inodes to the journal. We can
only do this after ubifs_rcvry_gc_commit() is done though, so for
authenticated mode call ubifs_recover_size() after
ubifs_rcvry_gc_commit() and not vice versa as normally done.
Calling ubifs_recover_size() after ubifs_rcvry_gc_commit() has the
drawback that after a commit the size fixup information is gone, so
when a powercut happens while recovering from another powercut
we may lose some data written right before the first powercut.
This is why we only do this in authenticated mode and leave the
behaviour for unauthenticated mode untouched.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
This patch calculates the necessary hashes and HMACs for the default
filesystem so that the dynamically created default fs can be
authenticated.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
This adds a HMAC covering the super block node and adds the logic that
decides if a filesystem shall be mounted unauthenticated or
authenticated.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
During creation of the default filesystem on an empty flash the default
LPT is created. With this patch a hash over the default LPT is
calculated which can be added to the default filesystems master node.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
The master node contains hashes over the root index node and the LPT.
This patch adds a HMAC to authenticate the master node itself.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
The LPT needs to be authenticated aswell. Since the LPT is only written
during commit it is enough to authenticate the whole LPT with a single
hash which is stored in the master node. Only the leaf nodes (pnodes)
are hashed which makes the implementation much simpler than it would be
to hash the complete LPT.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Make sure that during replay all buds can be authenticated. To do
this we calculate the hash chain until we find an authentication
node and check the HMAC in that node against the current status
of the hash chain.
After a power cut it can happen that some nodes have been written, but
not yet the authentication node for them. These nodes have to be
discarded during replay.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
To be able to authenticate the garbage collector journal head add
authentication nodes to the buds the garbage collector creates.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Nodes that are written to flash can only be authenticated through the
index after the next commit. When a journal replay is necessary the
nodes are not yet referenced by the index and thus can't be
authenticated.
This patch overcomes this situation by creating a hash over all nodes
beginning from the commit start node over the reference node(s) and
the buds themselves. From
time to time we insert authentication nodes. Authentication nodes
contain a HMAC from the current hash state, so that they can be
used to authenticate a journal replay up to the point where the
authentication node is. The hash is continued afterwards
so that theoretically we would only have to check the HMAC of
the last authentication node we find.
Overall we get this picture:
,,,,,,,,
,......,...........................................
,. CS , hash1.----. hash2.----.
,. | , . |hmac . |hmac
,. v , . v . v
,.REF#0,-> bud -> bud -> bud.-> auth -> bud -> bud.-> auth ...
,..|...,...........................................
, | ,
, | ,,,,,,,,,,,,,,,
. | hash3,----.
, | , |hmac
, v , v
, REF#1 -> bud -> bud,-> auth ...
,,,|,,,,,,,,,,,,,,,,,,
v
REF#2 -> ...
|
V
...
Note how hash3 covers CS, REF#0 and REF#1 so that it is not possible to
exchange or skip any reference nodes. Unlike the picture suggests the
auth nodes themselves are not hashed.
With this it is possible for an offline attacker to cut each journal
head or to drop the last reference node(s), but not to skip any journal
heads or to reorder any operations.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
With this patch the hashes over the index nodes stored in the tree node
cache are written to flash and are checked when read back from flash.
The hash of the root index node is stored in the master node.
During journal replay the hashes are regenerated from the read nodes
and stored in the tree node cache. This means the nodes must previously
be authenticated by other means. This is done in a later patch.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
As part of the UBIFS authentication support every branch in the index
gets a hash covering the referenced node. To make that happen the tree
node cache needs hashes over the nodes. This patch adds a hash argument
to ubifs_tnc_add() and ubifs_tnc_add_nm(). The hashes are calculated
from the callers of these functions which actually prepare the nodes.
With this patch all the leaf nodes of the index tree get hashes, but
currently nothing is done with these hashes, this is left for a later
patch.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
With authentication support some nodes (master node, super block node)
get a HMAC embedded into them. This patch adds functions to prepare and
write such a node.
The difficulty is that besides the HMAC the nodes also have a CRC which
must stay valid. This means we first have to initialize all fields in
the node, then calculate the HMAC (not covering the CRC) and finally
calculate the CRC.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
This patch adds the various helper functions needed for authentication
support. We need functions to hash nodes, to embed HMACs into a node and
to compare hashes and HMACs. Most functions first check if this
filesystem is authenticated and bail out early if not, which makes the
functions safe to be called with disabled authentication.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
When adding authentication support we will embed a HMAC into some
nodes. To prepare these nodes we have to first initialize the nodes,
then add a HMAC and finally add a CRC. To accomplish this add separate
ubifs_init_node/ubifs_crc_node functions.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
This patch adds the changes to the on disk format needed for
authentication support. We'll add:
* a HMAC covering super block node
* a HMAC covering the master node
* a hash over the root index node to the master node
* a hash over the LPT to the master node
* a flag to the filesystem flag indicating the filesystem is
authenticated
* an authentication node necessary to authenticate the nodes written
to the journal heads while they are written.
* a HMAC of a well known message to the super block node to be able
to check if the correct key is provided
And finally, not visible in this patch, nevertheless explained here:
* hashes over the referenced child nodes in each branch of a index node
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
The superblock node is read/modified/written several times throughout
the UBIFS code. Instead of reading it from the device each time just
keep a copy in memory and write back the modified copy when necessary.
This patch helps for authentication support, here we not only have to
read the superblock node, but also have to authenticate it, which
is easier if we do it once during initialization.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
write_node() is used only once and can easily be replaced with calls
to ubifs_prepare_node()/write_head() which makes the code a bit shorter.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
ubifs_lpt_lookup() starts by looking up the nth pnode in the LPT. We
already have this functionality in ubifs_pnode_lookup(). Use this
function rather than open coding its functionality.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
ubifs_lpt_lookup could be implemented using pnode_lookup. To make that
possible move pnode_lookup from lpt.c to lpt_commit.c. Rename it to
ubifs_pnode_lookup since it's now exported.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
read_znode() takes len, lnum and offs arguments which the caller all
extracts from the same struct ubifs_zbranch *. When adding authentication
support we would have to add a pointer to a hash to the arguments which
is also part of struct ubifs_zbranch. Pass the ubifs_zbranch * instead
so that we do not have to add another argument.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
try_read_node() takes len, lnum and offs arguments which the caller all
extracts from the same struct ubifs_zbranch *. When adding authentication
support we would have to add a pointer to a hash to the arguments which
is also part of struct ubifs_zbranch. Pass the ubifs_zbranch * instead
so that we do not have to add another argument.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
create_default_filesystem() allocates memory for a node, writes that
node and frees the memory directly afterwards. With this patch we
allocate memory for all nodes at the beginning of the function and
free the memory at the end. This makes it easier to implement
authentication support since with authentication support we'll need
the contents of some nodes when creating other nodes.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
ubifs_assert() is not WARN_ON(), so we have to invert
the checks.
Randy faced this warning with UBIFS being a module, since
most users use UBIFS as builtin because UBIFS is the rootfs
nobody noticed so far. :-(
Including me.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Fixes: 54169ddd38 ("ubifs: Turn two ubifs_assert() into a WARN_ON()")
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 11a6fc3dc7.
UBIFS wants to assert that xattr operations are only issued on files
with positive link count. The said patch made this operations return
-ENOENT for unlinked files such that the asserts will no longer trigger.
This was wrong since xattr operations are perfectly fine on unlinked
files.
Instead the assertions need to be fixed/removed.
Cc: <stable@vger.kernel.org>
Fixes: 11a6fc3dc7 ("ubifs: xattr: Don't operate on deleted inodes")
Reported-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Richard Weinberger <richard@nod.at>
The following sequence triggers
ubifs_assert(c, c->lst.taken_empty_lebs > 0);
at the end of ubifs_remount_fs():
mount -t ubifs /dev/ubi0_0 /mnt
echo 1 > /sys/kernel/debug/ubifs/ubi0_0/ro_error
umount /mnt
mount -t ubifs -o ro /dev/ubix_y /mnt
mount -o remount,ro /mnt
The resulting
UBIFS assert failed in ubifs_remount_fs at 1878 (pid 161)
is a false positive. In the case above c->lst.taken_empty_lebs has
never been changed from its initial zero value. This will only happen
when the deferred recovery is done.
Fix this by doing the assertion only when recovery has been done
already.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
The requested device name can be NULL or an empty string.
Check for that and refuse to continue. UBIFS has to do this manually
since we cannot use mount_bdev(), which checks for this condition.
Fixes: 1e51764a3c ("UBIFS: add new flash file system")
Reported-by: syzbot+38bd0f7865e5c6379280@syzkaller.appspotmail.com
Signed-off-by: Richard Weinberger <richard@nod.at>
This empty file sneaked into the tree by mistake.
Remove it.
Fixes: 6eb61d587f ("ubifs: Pass struct ubifs_info to ubifs_assert()")
Signed-off-by: Richard Weinberger <richard@nod.at>
Traditionally UBIFS just reported a failed assertion and moved on. The
drawback is that users will notice UBIFS bugs when it is too late, most
of the time when it is no longer about to mount. This makes bug hunting
problematic since valuable information from failing asserts is long gone
when UBIFS is dead. The other extreme, panic'ing on a failing assert is
also not worthwhile, we want users and developers give a chance to
collect as much debugging information as possible if UBIFS hits an
assert. Therefore go for the third option, switch to read-only mode when
an assert fails. That way UBIFS will not write possible bad data to the
MTD and gives users the chance to collect debugging information.
Signed-off-by: Richard Weinberger <richard@nod.at>
With having access to struct ubifs_info in ubifs_assert() we can
give more information when an assert is failing.
By using ubifs_err() we can tell which UBIFS instance failed.
Also multiple actions can be taken now.
We support:
- report: This is what UBIFS did so far, just report the failure and go
on.
- read-only: Switch to read-only mode.
- panic: shoot the kernel in the head.
Signed-off-by: Richard Weinberger <richard@nod.at>
This allows us to have more context in ubifs_assert()
and take different actions depending on the configuration.
Signed-off-by: Richard Weinberger <richard@nod.at>
We are going to pass struct ubifs_info to ubifs_assert()
but while unloading the UBIFS module we don't have the info
struct anymore.
Therefore replace the asserts by a regular WARN_ON().
Signed-off-by: Richard Weinberger <richard@nod.at>
Since commit 6da2ec5605 ("treewide: kmalloc() -> kmalloc_array()")
we use kmalloc_array() for kmalloc() that computes the length with
a multiplication.
Cc: Kees Cook <keescook@chromium.org>
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Check whether the size is within bounds before using it.
If the size is not correct, abort and dump the bad data node.
Cc: Kees Cook <keescook@chromium.org>
Cc: Silvio Cesare <silvio.cesare@gmail.com>
Cc: stable@vger.kernel.org
Fixes: 1e51764a3c ("UBIFS: add new flash file system")
Reported-by: Silvio Cesare <silvio.cesare@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
This reverts commit 353748a359.
It bypassed the linux-mtd review process and fixes the issue not as it
should.
Cc: Kees Cook <keescook@chromium.org>
Cc: Silvio Cesare <silvio.cesare@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Richard Weinberger <richard@nod.at>
Every single time I come across that code, I get confused
because it looks like a possible dead lock.
Help myself by adding a comment.
Signed-off-by: Richard Weinberger <richard@nod.at>
Allow to disable extended attribute support.
This aids in reliability testing, especially since some xattr
related bugs have surfaced.
Also an embedded system might not need it, so this allows for a
slightly smaller kernel (about 4KiB).
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Richard Weinberger <richard@nod.at>
Make use of the swap macro and remove unnecessary variable *t*. This
makes the code easier to read and maintain.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
The tnc uses get_seconds() based timestamps to check the age of a znode,
which has two problems: on 32-bit architectures this may overflow in
2038 or 2106, and it gives incorrect information when the system time
is updated using settimeofday().
Using montonic timestamps with ktime_get_seconds() solves both thes
problems.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
Both vfs and the on-disk inode structures can deal with fine-grained
timestamps now, so this is the last missing piece to make ubifs
y2038-safe on 32-bit architectures.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
xattr operations can race with unlink and the following assert triggers:
UBIFS assert failed in ubifs_jnl_change_xattr at 1606 (pid 6256)
Fix this by checking i_nlink before working on the host inode.
Cc: <stable@vger.kernel.org>
Fixes: 1e51764a3c ("UBIFS: add new flash file system")
Signed-off-by: Richard Weinberger <richard@nod.at>
