mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 12:11:40 +00:00
47f04616f2
Add a NULL check for the 'bdev' parameter of
dm_verity_loadpin_is_bdev_trusted(). The function is called
by loadpin_check(), which passes the block device that
corresponds to the super block of the file system from which
a file is being loaded. Generally a super_block structure has
an associated block device, however that is not always the
case (e.g. tmpfs).
Cc: stable@vger.kernel.org # v6.0+
Fixes: b6c1c5745c ("dm: Add verity helpers for LoadPin")
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Link: https://lore.kernel.org/r/20230627202800.1.Id63f7f59536d20f1ab83e1abdc1fda1471c7d031@changeid
Signed-off-by: Kees Cook <keescook@chromium.org>
87 lines
1.7 KiB
C
87 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
|
|
#include <linux/list.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/dm-verity-loadpin.h>
|
|
|
|
#include "dm.h"
|
|
#include "dm-core.h"
|
|
#include "dm-verity.h"
|
|
|
|
#define DM_MSG_PREFIX "verity-loadpin"
|
|
|
|
LIST_HEAD(dm_verity_loadpin_trusted_root_digests);
|
|
|
|
static bool is_trusted_verity_target(struct dm_target *ti)
|
|
{
|
|
int verity_mode;
|
|
u8 *root_digest;
|
|
unsigned int digest_size;
|
|
struct dm_verity_loadpin_trusted_root_digest *trd;
|
|
bool trusted = false;
|
|
|
|
if (!dm_is_verity_target(ti))
|
|
return false;
|
|
|
|
verity_mode = dm_verity_get_mode(ti);
|
|
|
|
if ((verity_mode != DM_VERITY_MODE_EIO) &&
|
|
(verity_mode != DM_VERITY_MODE_RESTART) &&
|
|
(verity_mode != DM_VERITY_MODE_PANIC))
|
|
return false;
|
|
|
|
if (dm_verity_get_root_digest(ti, &root_digest, &digest_size))
|
|
return false;
|
|
|
|
list_for_each_entry(trd, &dm_verity_loadpin_trusted_root_digests, node) {
|
|
if ((trd->len == digest_size) &&
|
|
!memcmp(trd->data, root_digest, digest_size)) {
|
|
trusted = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
kfree(root_digest);
|
|
|
|
return trusted;
|
|
}
|
|
|
|
/*
|
|
* Determines whether the file system of a superblock is located on
|
|
* a verity device that is trusted by LoadPin.
|
|
*/
|
|
bool dm_verity_loadpin_is_bdev_trusted(struct block_device *bdev)
|
|
{
|
|
struct mapped_device *md;
|
|
struct dm_table *table;
|
|
struct dm_target *ti;
|
|
int srcu_idx;
|
|
bool trusted = false;
|
|
|
|
if (bdev == NULL)
|
|
return false;
|
|
|
|
if (list_empty(&dm_verity_loadpin_trusted_root_digests))
|
|
return false;
|
|
|
|
md = dm_get_md(bdev->bd_dev);
|
|
if (!md)
|
|
return false;
|
|
|
|
table = dm_get_live_table(md, &srcu_idx);
|
|
|
|
if (table->num_targets != 1)
|
|
goto out;
|
|
|
|
ti = dm_table_get_target(table, 0);
|
|
|
|
if (is_trusted_verity_target(ti))
|
|
trusted = true;
|
|
|
|
out:
|
|
dm_put_live_table(md, srcu_idx);
|
|
dm_put(md);
|
|
|
|
return trusted;
|
|
}
|