kernel/git/next/linux-next.git/drivers/md/dm-ima.h, branch master

dm-ima: use active table's size if available

2026-05-04T12:53:52+00:00

It is possible that the dm_ima_measure_on_* functions run at the same time as a table is getting swapped, but before the md->ima.active_table is updated by dm_ima_measure_on_device_resume(). Instead of using the current device size, use the size of the active table that is being measured (assuming there is one), so the information is consistent. Also, don't allocate a separate string to hold the capactiy. Just print it directly to the measurement buffer. Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka

dm-ima: remove new_map from dm_ima_measure_on_device_clear

2026-05-04T12:53:19+00:00

Now that two processes can't modify md->ima in dm_ima_measure_on_device_clear() at the same time, there's no need to track if an inactive table was actually removed. We might as well clean it up unconditionally, on the off chance that a previous ima measurement failed and left md->ima.inactive_table behind. Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka

dm-ima: Fix UAF errors and measuring incorrect context

2026-05-04T12:53:09+00:00

the dm-ima code did not keep the dm_ima_measure_on_* functions from running at the same time. This could lead to various errors. If two processes were updating the device state, one could update the state first, but the other could measure the state first, causing the the current device state to appear incorrect. If a table load happened while a device was resuming, the IMA measurement could report the wrong table being active. And if two dm_ima_measure_on_* functions ran at the same time, one of them could free data that the other was accessing, causing a crash. All the core dm functions that call a dm_ima_measure_on_* function update the device state they want to measure under the _hash_lock, except for do_resume(). But holding the _hash_lock is not a good way to synchronize these functions. It's a global mutex, that is needed in many dm operations, and the dm_ima_measure_* functions can sleep, blocking any dm operation on any device that needs the _hash_lock. To serialize and order the IMA measurement functions, the dm_ima_measurements now has two counters, update_idx and measure_idx. update_idx is incremented while holding the _hash_lock and saved, along with the device name and uuid, in a dm_ima_context struct. Once the _hash_lock is dropped, the dm_ima_measure_* function is called. It waits until measure_idx matches the saved value of update_idx, ensuring that the updates and measurements happen in the same order if there are multiple processes changing the device at the same time. Then it measures the device, updates measure_idx, and wakes up any other process waiting to do a measurement. This makes sure that the measurements are serialized and done in the order that the _hash_lock was acquired in. But they only block other measurements for the same device, which are unlikely to happen at the same time. do_resume() is trickier, because it removes the inactive table while holding the _hash_lock, but doesn't hold it while updating md->map. To make sure it is also ordered, the IMA code grabs the _hash_lock after md->map is updated. Then it makes sure that the device isn't being removed and that another do_resume() hasn't already changed the active table again, and serializes like the other functions do. Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka

dm-ima: Remove status_flags from dm_ima_measure_on_table_load()

2026-05-04T12:52:37+00:00

There is no status flag that is is used for STATUSTYPE_IMA type status() calls, and STATUSTYPE_IMA itself is not a valid status flag. Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka

dm-ima: remove dm_ima_reset_data()

2026-05-04T12:52:18+00:00

There's no point in saving the string length of DM_IMA_VERSION_STR. It's a constant, so the compiler will precompute it. dm_create() will already zero out the rest of dm->ima. Signed-off-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka

dm-ima: use SHA-256 library

2026-03-02T16:02:09+00:00

Make dm_ima_measure_on_table_load() use the SHA-256 library API instead of crypto_shash to calculate the SHA-256 hash value that it needs. This is simpler and more efficient. It also ensures that SHA-256 is actually available and doesn't fail due to the unreliable loading by name. While doing this, also use kasprintf() to simplify building the string version of the digest. Signed-off-by: Eric Biggers Signed-off-by: Mikulas Patocka

dm: avoid inline filenames

2023-02-14T19:23:07+00:00

Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm: add missing SPDX-License-Indentifiers

2023-02-14T19:23:06+00:00

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has deprecated its use. Suggested-by: John Wiele Signed-off-by: Heinz Mauelshagen Signed-off-by: Mike Snitzer

dm ima: add version info to dm related events in ima log

2021-08-20T19:59:47+00:00

The DM events present in the ima log contain various attributes in the key=value format. The attributes' names/values may change in future, and new attributes may also get added. The attestation server needs some versioning to determine which attributes are supported and are expected in the ima log. Add version information to the DM events present in the ima log to help attestation servers to correctly process the attributes across different versions. Signed-off-by: Tushar Sugandhi Suggested-by: Mimi Zohar Signed-off-by: Mike Snitzer

dm ima: prefix dm table hashes in ima log with hash algorithm

2021-08-20T19:59:43+00:00

The active/inactive table hashes measured in the ima log do not contain the information about hash algorithm. This information is useful for the attestation servers to recreate the hashes and compare them with the ones present in the ima log to verify the table contents. Prefix the table hashes in various DM events in ima log with the hash algorithm used to compute those hashes. Signed-off-by: Tushar Sugandhi Suggested-by: Mimi Zohar Signed-off-by: Mike Snitzer