linux-toradex.git/drivers/md/dm-ioctl.c, branch v3.4.2

dm: reject trailing characters in sccanf input

2012-03-28T17:41:26+00:00

Device mapper uses sscanf to convert arguments to numbers. The problem is that
the way we use it ignores additional unmatched characters in the scanned string.

For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number,
but also it will match number with some garbage appended, like "123abc".

As a result, device mapper accepts garbage after some numbers. For example
the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"'
will pass without an error.

This patch fixes all sscanf uses in device mapper. It appends "%c" with
a pointer to a dummy character variable to every sscanf statement.

The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds
only if string is a null-terminated number (optionally preceded by some
whitespace characters). If there is some character appended after the number,
sscanf matches "%c", writes the character to the dummy variable and returns 2.
We check the return value for 1 and consequently reject numbers with some
garbage appended.

Signed-off-by: Mikulas Patocka 
Acked-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm ioctl: do not leak argv if target message only contains whitespace

2012-03-07T19:09:34+00:00

If 'argc' is zero we jump to the 'out:' label, but this leaks the
(unused) memory that 'dm_split_args()' allocated for 'argv' if the
string being split consisted entirely of whitespace.  Jump to the
'out_argv:' label instead to free up that memory.

Signed-off-by: Jesper Juhl 
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon

dm table: add immutable feature

2011-10-31T20:19:04+00:00

Introduce DM_TARGET_IMMUTABLE to indicate that the target type cannot be mixed
with any other target type, and once loaded into a device, it cannot be
replaced with a table containing a different type.

The thin provisioning pool device will use this.

Signed-off-by: Alasdair G Kergon

dm ioctl: forbid multiple device specifiers

2011-08-02T11:32:06+00:00

Exactly one of name, uuid or device must be specified when referencing
an existing device.  This removes the ambiguity (risking the wrong
device being updated) if two conflicting parameters were specified.
Previously one parameter got used and any others were ignored silently.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm ioctl: introduce __get_dev_cell

2011-08-02T11:32:06+00:00

Move logic to find device based on major/minor number to a separate
function __get_dev_cell (similar to __get_uuid_cell and __get_name_cell).
This makes the function __find_device_hash_cell more straightforward.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm ioctl: fill in device parameters in more ioctls

2011-08-02T11:32:06+00:00

Move parameter filling from find_device to __find_device_hash_cell.

This patch causes ioctls using __find_device_hash_cell
(DM_DEV_REMOVE_CMD, DM_DEV_SUSPEND_CMD - resume, DM_TABLE_CLEAR_CMD)
to return device parameters, bringing them into line with the other
ioctls.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Alasdair G Kergon

dm ioctl: prevent empty message

2011-08-02T11:32:03+00:00

Detect invalid empty messages in core dm instead of requiring every target to
check this.

Signed-off-by: Alasdair G Kergon

dm ioctl: add flag to wipe buffers for secure data

2011-03-24T13:54:30+00:00

Add DM_SECURE_DATA_FLAG which userspace can use to ensure
that all buffers allocated for dm-ioctl are wiped
immediately after use.

The user buffer is wiped as well (we do not want to keep
and return sensitive data back to userspace if the flag is set).

Wiping is useful for cryptsetup to ensure that the key
is present in memory only in defined places and only
for the time needed.

(For crypt, key can be present in table during load or table
status, wait and message commands).

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon

dm ioctl: prepare for crypt key wiping

2011-03-24T13:54:28+00:00

Prepare code for implementing buffer wipe flag.
No functional change in this patch.

Signed-off-by: Milan Broz 
Acked-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

dm ioctl: suppress needless warning messages

2011-01-13T19:59:55+00:00

The device-mapper should not send warning messages to syslog
if a device is not found. This can be done by userspace
according to the returned dm-ioctl error code.

So move these messages to debug level and use rate limiting
to not flood syslog.

Signed-off-by: Milan Broz 
Signed-off-by: Alasdair G Kergon