dm: introduce DM_GET_TARGET_VERSION

2019-09-16T14:18:01+00:00

This commit introduces a new ioctl DM_GET_TARGET_VERSION. It will load a
target that is specified in the "name" entry in the parameter structure
and return its version.

This functionality is intended to be used by cryptsetup, so that it can
query kernel capabilities before activating the device.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm: make dm_table_find_target return NULL

2019-08-23T14:13:12+00:00

Currently, if we pass too high sector number to dm_table_find_target, it
returns zeroed dm_target structure and callers test if the structure is
zeroed with the macro dm_target_is_valid.

However, returning NULL is common practice to indicate errors.

This patch refactors the dm code, so that dm_table_find_target returns
NULL and its callers test the returned value for NULL. The macro
dm_target_is_valid is deleted. In alloc_targets, we no longer allocate an
extra zeroed target.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm ioctl: fix hang in early create error condition

2019-05-16T13:52:06+00:00

The dm_early_create() function (which deals with "dm-mod.create=" kernel
command line option) calls dm_hash_insert() who gets an extra reference
to the md object.

In case of failure, this reference wasn't being released, causing
dm_destroy() to hang, thus hanging the whole boot process.

Fix this by calling __hash_remove() in the error path.

Fixes: 6bbc923dfcf57d ("dm: add support to directly boot to a mapped device")
Cc: stable@vger.kernel.org
Signed-off-by: Helen Koike 
Signed-off-by: Mike Snitzer

dm: add support to directly boot to a mapped device

2019-03-05T19:53:50+00:00

Add a "create" module parameter, which allows device-mapper targets to
be configured at boot time. This enables early use of DM targets in the
boot process (as the root device or otherwise) without the need of an
initramfs.

The syntax used in the boot param is based on the concise format from
the dmsetup tool to follow the rule of least surprise:

	dmsetup table --concise /dev/mapper/lroot

Which is:
	dm-mod.create=,,,,[,
+][;,,,,
[,+]+]

Where,
			::= The device name.
			::= xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx | ""
			::= The device minor number | ""
			::= "ro" | "rw"
	
		::=    
		::= "verity" | "linear" | ...

For example, the following could be added in the boot parameters:
dm-mod.create="lroot,,,rw, 0 4096 linear 98:16 0, 4096 4096 linear 98:32 0" root=/dev/dm-0

Only the targets that were tested are allowed and the ones that don't
change any block device when the device is create as read-only. For
example, mirror and cache targets are not allowed. The rationale behind
this is that if the user makes a mistake, choosing the wrong device to
be the mirror or the cache can corrupt data.

The only targets initially allowed are:
* crypt
* delay
* linear
* snapshot-origin
* striped
* verity

Co-developed-by: Will Drewry 
Co-developed-by: Kees Cook 
Co-developed-by: Enric Balletbo i Serra 
Signed-off-by: Helen Koike 
Reviewed-by: Kees Cook 
Signed-off-by: Mike Snitzer 




dm ioctl: harden copy_params()'s copy_from_user() from malicious users
2018-10-18T15:54:07+00:00

In copy_params(), the struct 'dm_ioctl' is first copied from the user
space buffer 'user' to 'param_kernel' and the field 'data_size' is
checked against 'minimum_data_size' (size of 'struct dm_ioctl' payload
up to its 'data' member).  If the check fails, an error code EINVAL will be
returned.  Otherwise, param_kernel->data_size is used to do a second copy,
which copies from the same user-space buffer to 'dmi'.  After the second
copy, only 'dmi->data_size' is checked against 'param_kernel->data_size'.
Given that the buffer 'user' resides in the user space, a malicious
user-space process can race to change the content in the buffer between
the two copies.  This way, the attacker can inject inconsistent data
into 'dmi' (versus previously validated 'param_kernel').

Fix redundant copying of 'minimum_data_size' from user-space buffer by
using the first copy stored in 'param_kernel'.  Also remove the
'data_size' check after the second copy because it is now unnecessary.

Cc: stable@vger.kernel.org
Signed-off-by: Wenwen Wang 
Signed-off-by: Mike Snitzer 




dm: report which conflicting type caused error during table_load()
2018-06-08T13:50:15+00:00

Eases troubleshooting to know the before vs after types.

Signed-off-by: Mike Snitzer 




dm: allow targets to return output from messages they are sent
2018-04-03T19:04:10+00:00

Could be useful for a target to return stats or other information.
If a target does DMEMIT() anything to @result from its .message method
then it must return 1 to the caller.

Signed-off-By: Mike Snitzer 




vfs: do bulk POLL* -> EPOLL* replacement
2018-02-11T22:34:03+00:00

This is the mindless scripted replacement of kernel use of POLL*
variables as described by Al, done by this script:

    for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do
        L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'`
        for f in $L; do sed -i "-es/^\([^\"]*\)\(\\)/\\1E\\2/" $f; done
    done

with de-mangling cleanups yet to come.

NOTE! On almost all architectures, the EPOLL* constants have the same
values as the POLL* constants do.  But they keyword here is "almost".
For various bad reasons they aren't the same, and epoll() doesn't
actually work quite correctly in some cases due to this on Sparc et al.

The next patch from Al will sort out the final differences, and we
should be all done.

Scripted-by: Al Viro 
Signed-off-by: Linus Torvalds 




the rest of drivers/*: annotate ->poll() instances
2017-11-28T16:06:58+00:00

Signed-off-by: Al Viro 




dm ioctl: fix alignment of event number in the device list
2017-09-25T15:18:29+00:00

The size of struct dm_name_list is different on 32-bit and 64-bit
kernels (so "(nl + 1)" differs between 32-bit and 64-bit kernels).

This mismatch caused some harmless difference in padding when using 32-bit
or 64-bit kernel. Commit 23d70c5e52dd ("dm ioctl: report event number in
DM_LIST_DEVICES") added reporting event number in the output of
DM_LIST_DEVICES_CMD. This difference in padding makes it impossible for
userspace to determine the location of the event number (the location
would be different when running on 32-bit and 64-bit kernels).

Fix the padding by using offsetof(struct dm_name_list, name) instead of
sizeof(struct dm_name_list) to determine the location of entries.

Also, the ioctl version number is incremented to 37 so that userspace
can use the version number to determine that the event number is present
and correctly located.

In addition, a global event is now raised when a DM device is created,
removed, renamed or when table is swapped, so that the user can monitor
for device changes.

Reported-by: Eugene Syromiatnikov 
Fixes: 23d70c5e52dd ("dm ioctl: report event number in DM_LIST_DEVICES")
Cc: stable@vger.kernel.org # 4.13
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

linux-toradex.git/drivers/md/dm-ioctl.c, branch v5.5

dm: introduce DM_GET_TARGET_VERSION

dm: make dm_table_find_target return NULL

dm ioctl: fix hang in early create error condition

dm: add support to directly boot to a mapped device

dm ioctl: harden copy_params()'s copy_from_user() from malicious users

dm: report which conflicting type caused error during table_load()

dm: allow targets to return output from messages they are sent

vfs: do bulk POLL* -> EPOLL* replacement

the rest of drivers/*: annotate ->poll() instances

dm ioctl: fix alignment of event number in the device list