dm ima: measure data on table load
DM configures a block device with various target specific attributes
passed to it as a table. DM loads the table, and calls each target’s
respective constructors with the attributes as input parameters.
Some of these attributes are critical to ensure the device meets
certain security bar. Thus, IMA should measure these attributes, to
ensure they are not tampered with, during the lifetime of the device.
So that the external services can have high confidence in the
configuration of the block-devices on a given system.
Some devices may have large tables. And a given device may change its
state (table-load, suspend, resume, rename, remove, table-clear etc.)
many times. Measuring these attributes each time when the device
changes its state will significantly increase the size of the IMA logs.
Further, once configured, these attributes are not expected to change
unless a new table is loaded, or a device is removed and recreated.
Therefore the clear-text of the attributes should only be measured
during table load, and the hash of the active/inactive table should be
measured for the remaining device state changes.
Export IMA function ima_measure_critical_data() to allow measurement
of DM device parameters, as well as target specific attributes, during
table load. Compute the hash of the inactive table and store it for
measurements during future state change. If a load is called multiple
times, update the inactive table hash with the hash of the latest
populated table. So that the correct inactive table hash is measured
when the device transitions to different states like resume, remove,
rename, etc.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com> # leak fix
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:58 +03:00
/* SPDX-License-Identifier: GPL-2.0
*
* Copyright ( C ) 2021 Microsoft Corporation
*
* Author : Tushar Sugandhi < tusharsu @ linux . microsoft . com >
*
* File : dm - ima . h
* Header file for device mapper IMA measurements .
*/
# ifndef DM_IMA_H
# define DM_IMA_H
# define DM_IMA_MEASUREMENT_BUF_LEN 4096
# define DM_IMA_DEVICE_BUF_LEN 1024
# define DM_IMA_TARGET_METADATA_BUF_LEN 128
# define DM_IMA_TARGET_DATA_BUF_LEN 2048
dm ima: measure data on device resume
A given block device can load a table multiple times, with different
input parameters, before eventually resuming it. Further, a device may
be suspended and then resumed. The device may never resume after a
table-load. Because of the above valid scenarios for a given device,
it is important to measure and log the device resume event using IMA.
Also, if the table is large, measuring it in clear-text each time the
device changes state, will unnecessarily increase the size of IMA log.
Since the table clear-text is already measured during table-load event,
measuring the hash during resume should be sufficient to validate the
table contents.
Measure the device parameters, and hash of the active table, when the
device is resumed.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:59 +03:00
# define DM_IMA_DEVICE_CAPACITY_BUF_LEN 128
dm ima: measure data on table load
DM configures a block device with various target specific attributes
passed to it as a table. DM loads the table, and calls each target’s
respective constructors with the attributes as input parameters.
Some of these attributes are critical to ensure the device meets
certain security bar. Thus, IMA should measure these attributes, to
ensure they are not tampered with, during the lifetime of the device.
So that the external services can have high confidence in the
configuration of the block-devices on a given system.
Some devices may have large tables. And a given device may change its
state (table-load, suspend, resume, rename, remove, table-clear etc.)
many times. Measuring these attributes each time when the device
changes its state will significantly increase the size of the IMA logs.
Further, once configured, these attributes are not expected to change
unless a new table is loaded, or a device is removed and recreated.
Therefore the clear-text of the attributes should only be measured
during table load, and the hash of the active/inactive table should be
measured for the remaining device state changes.
Export IMA function ima_measure_critical_data() to allow measurement
of DM device parameters, as well as target specific attributes, during
table load. Compute the hash of the inactive table and store it for
measurements during future state change. If a load is called multiple
times, update the inactive table hash with the hash of the latest
populated table. So that the correct inactive table hash is measured
when the device transitions to different states like resume, remove,
rename, etc.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com> # leak fix
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:58 +03:00
# ifdef CONFIG_IMA
struct dm_ima_device_table_metadata {
/*
* Contains data specific to the device which is common across
* all the targets in the table ( e . g . name , uuid , major , minor , etc ) .
* The values are stored in comma separated list of key1 = val1 , key2 = val2 ;
* pairs delimited by a semicolon at the end of the list .
*/
char * device_metadata ;
unsigned int device_metadata_len ;
unsigned int num_targets ;
/*
* Contains the sha256 hashes of the IMA measurements of the target
* attributes ' key - value pairs from the active / inactive tables .
*/
char * hash ;
unsigned int hash_len ;
} ;
/*
* This structure contains device metadata , and table hash for
* active and inactive tables for ima measurements .
*/
struct dm_ima_measurements {
struct dm_ima_device_table_metadata active_table ;
struct dm_ima_device_table_metadata inactive_table ;
} ;
void dm_ima_reset_data ( struct mapped_device * md ) ;
void dm_ima_measure_on_table_load ( struct dm_table * table , unsigned int status_flags ) ;
dm ima: measure data on device resume
A given block device can load a table multiple times, with different
input parameters, before eventually resuming it. Further, a device may
be suspended and then resumed. The device may never resume after a
table-load. Because of the above valid scenarios for a given device,
it is important to measure and log the device resume event using IMA.
Also, if the table is large, measuring it in clear-text each time the
device changes state, will unnecessarily increase the size of IMA log.
Since the table clear-text is already measured during table-load event,
measuring the hash during resume should be sufficient to validate the
table contents.
Measure the device parameters, and hash of the active table, when the
device is resumed.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:59 +03:00
void dm_ima_measure_on_device_resume ( struct mapped_device * md , bool swap ) ;
2021-07-13 03:49:00 +03:00
void dm_ima_measure_on_device_remove ( struct mapped_device * md , bool remove_all ) ;
2021-07-13 03:49:01 +03:00
void dm_ima_measure_on_table_clear ( struct mapped_device * md , bool new_map ) ;
dm ima: measure data on table load
DM configures a block device with various target specific attributes
passed to it as a table. DM loads the table, and calls each target’s
respective constructors with the attributes as input parameters.
Some of these attributes are critical to ensure the device meets
certain security bar. Thus, IMA should measure these attributes, to
ensure they are not tampered with, during the lifetime of the device.
So that the external services can have high confidence in the
configuration of the block-devices on a given system.
Some devices may have large tables. And a given device may change its
state (table-load, suspend, resume, rename, remove, table-clear etc.)
many times. Measuring these attributes each time when the device
changes its state will significantly increase the size of the IMA logs.
Further, once configured, these attributes are not expected to change
unless a new table is loaded, or a device is removed and recreated.
Therefore the clear-text of the attributes should only be measured
during table load, and the hash of the active/inactive table should be
measured for the remaining device state changes.
Export IMA function ima_measure_critical_data() to allow measurement
of DM device parameters, as well as target specific attributes, during
table load. Compute the hash of the inactive table and store it for
measurements during future state change. If a load is called multiple
times, update the inactive table hash with the hash of the latest
populated table. So that the correct inactive table hash is measured
when the device transitions to different states like resume, remove,
rename, etc.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com> # leak fix
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:58 +03:00
# else
static inline void dm_ima_reset_data ( struct mapped_device * md ) { }
static inline void dm_ima_measure_on_table_load ( struct dm_table * table , unsigned int status_flags ) { }
dm ima: measure data on device resume
A given block device can load a table multiple times, with different
input parameters, before eventually resuming it. Further, a device may
be suspended and then resumed. The device may never resume after a
table-load. Because of the above valid scenarios for a given device,
it is important to measure and log the device resume event using IMA.
Also, if the table is large, measuring it in clear-text each time the
device changes state, will unnecessarily increase the size of IMA log.
Since the table clear-text is already measured during table-load event,
measuring the hash during resume should be sufficient to validate the
table contents.
Measure the device parameters, and hash of the active table, when the
device is resumed.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:59 +03:00
static inline void dm_ima_measure_on_device_resume ( struct mapped_device * md , bool swap ) { }
2021-07-13 03:49:00 +03:00
static inline void dm_ima_measure_on_device_remove ( struct mapped_device * md , bool remove_all ) { }
2021-07-13 03:49:01 +03:00
static inline void dm_ima_measure_on_table_clear ( struct mapped_device * md , bool new_map ) { }
dm ima: measure data on table load
DM configures a block device with various target specific attributes
passed to it as a table. DM loads the table, and calls each target’s
respective constructors with the attributes as input parameters.
Some of these attributes are critical to ensure the device meets
certain security bar. Thus, IMA should measure these attributes, to
ensure they are not tampered with, during the lifetime of the device.
So that the external services can have high confidence in the
configuration of the block-devices on a given system.
Some devices may have large tables. And a given device may change its
state (table-load, suspend, resume, rename, remove, table-clear etc.)
many times. Measuring these attributes each time when the device
changes its state will significantly increase the size of the IMA logs.
Further, once configured, these attributes are not expected to change
unless a new table is loaded, or a device is removed and recreated.
Therefore the clear-text of the attributes should only be measured
during table load, and the hash of the active/inactive table should be
measured for the remaining device state changes.
Export IMA function ima_measure_critical_data() to allow measurement
of DM device parameters, as well as target specific attributes, during
table load. Compute the hash of the inactive table and store it for
measurements during future state change. If a load is called multiple
times, update the inactive table hash with the hash of the latest
populated table. So that the correct inactive table hash is measured
when the device transitions to different states like resume, remove,
rename, etc.
Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com> # leak fix
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2021-07-13 03:48:58 +03:00
# endif /* CONFIG_IMA */
# endif /* DM_IMA_H */
