@@ -312,10 +312,60 @@ void dm_ima_measure_on_device_remove(struct mapped_device *md)
kfree(md->ima.device_data);
}
+/*
+ * measure ima data on table clear
+ */
+void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map)
+{
+ unsigned int noio_flag, l;
+ char *device_table_data;
+ char inactive[] = "inactive_table_hash=";
+ unsigned int inactive_len = strlen(inactive);
+
+ noio_flag = memalloc_noio_save();
+ device_table_data = kzalloc(DM_IMA_DEVICE_BUF_LEN, GFP_KERNEL);
+ memalloc_noio_restore(noio_flag);
+
+ if (!device_table_data)
+ goto bad;
+
+ l = strlen(md->ima.device_data);
+ memcpy(device_table_data, md->ima.device_data, l);
+ memcpy(device_table_data + l, inactive, inactive_len);
+ l += inactive_len;
+
+ memcpy(device_table_data + l, md->ima.inactive_table_hash,
+ md->ima.inactive_table_hash_len);
+
+ l += md->ima.inactive_table_hash_len;
+
+ memcpy(device_table_data + l, ";", 1);
+ l++;
+
+ dm_ima_measure_data("table_clear", device_table_data, l);
+
+ if (new_map) {
+ kfree(md->ima.inactive_table_hash);
+ md->ima.inactive_table_hash = NULL;
+ md->ima.inactive_table_hash_len = 0;
+
+ if (md->ima.active_table_hash) {
+ md->ima.inactive_table_hash = md->ima.active_table_hash;
+ md->ima.inactive_table_hash_len = md->ima.active_table_hash_len;
+ }
+
+ }
+
+ kfree(device_table_data);
+bad:
+ return;
+}
+
#else
void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags) {}
void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap) {}
void dm_ima_measure_on_device_remove(struct mapped_device *md) {}
+void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map) {}
#endif
MODULE_AUTHOR("Tushar Sugandhi <tusharsu@linux.microsoft.com>");
MODULE_DESCRIPTION("Enables IMA measurements for DM targets");
@@ -35,4 +35,6 @@ struct dm_ima_measurements {
void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags);
void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap);
void dm_ima_measure_on_device_remove(struct mapped_device *md);
+void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map);
+
#endif /*DM_IMA_H*/
@@ -1509,6 +1509,7 @@ static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_s
struct hash_cell *hc;
struct mapped_device *md;
struct dm_table *old_map = NULL;
+ bool has_new_map = false;
down_write(&_hash_lock);
@@ -1522,6 +1523,7 @@ static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_s
if (hc->new_map) {
old_map = hc->new_map;
hc->new_map = NULL;
+ has_new_map = true;
}
param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
@@ -1533,6 +1535,7 @@ static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_s
dm_sync_table(md);
dm_table_destroy(old_map);
}
+ dm_ima_measure_on_table_clear(md, has_new_map);
dm_put(md);
return 0;
For a given block device, an inactive table slot contains the parameters to configure the device with. The inactive table can be cleared multiple times, accidentally or maliciously, which may impact the functionality of the device, and compromise the system. Therefore it is important to measure and log the event when a table is cleared. Measure device parameters, and table hashes when the inactive table slot is cleared. Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com> --- drivers/md/dm-ima.c | 50 +++++++++++++++++++++++++++++++++++++++++++ drivers/md/dm-ima.h | 2 ++ drivers/md/dm-ioctl.c | 3 +++ 3 files changed, 55 insertions(+)