Hi Thore,
On 1/6/2022 12:34 PM, Thore Sommer wrote:
On first corruption the verity targets triggers a dm_target_update event.
This allows other systems to check using IMA if the state of the device is
still trustworthy via remote attestation.
In the patch description please state the existing problem (or,
limitation in the existing implementation) and then describe how the
proposed change addresses the issue.
Signed-off-by: Thore Sommer <public@xxxxxxxx>
---
drivers/md/dm-verity-target.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 80133aae0db3..09696e25bf1c 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -16,6 +16,7 @@
#include "dm-verity.h"
#include "dm-verity-fec.h"
#include "dm-verity-verify-sig.h"
+#include "dm-ima.h"
#include <linux/module.h>
#include <linux/reboot.h>
#include <linux/scatterlist.h>
@@ -218,10 +219,15 @@ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
char *envp[] = { verity_env, NULL };
const char *type_str = "";
struct mapped_device *md = dm_table_get_md(v->ti->table);
+ int old_hash_failed = v->hash_failed;
/* Corruption should be visible in device status in all modes */
v->hash_failed = 1;
+ /* Only remeasure on first failure */
+ if (!old_hash_failed)
+ dm_ima_measure_on_target_update(v->ti);
It is not obvious to me why the call to measure on target update is not
done here immediately. Updating the comment to explain the logic would help.
thanks,
-lakshmi
+
if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS)
goto out;
