[dm-devel] [PATCH 4/6] dm ima: add a warning in dm_init if duplicate ima events are not measured

[Tushar Sugandhi]

The end-users of DM devices/targets may remove and re-create the same
device multiple times.  IMA does not measure such duplicate events if the
configuration CONFIG_IMA_DISABLE_HTABLE is set to 'n'.
To avoid confusion, the end-users need some indication on the client
if that configuration option is disabled.

Add a one-time warning to dmesg during dm_init if
CONFIG_IMA_DISABLE_HTABLE is set to 'n', to notify the end-users that
duplicate events will not be measured in the ima log.

Signed-off-by: Tushar Sugandhi <tusharsu at linux.microsoft.com>
---
 drivers/md/dm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2e82757b4ab7..948cb0dc5fc4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -265,6 +265,12 @@ static int __init dm_init(void)
 
 	int r, i;
 
+#if (IS_ENABLED(CONFIG_BLK_DEV_DM) && IS_ENABLED(CONFIG_IMA) \
+	&& !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE))
+	DMWARN("CONFIG_IMA_DISABLE_HTABLE is disabled."
+	       " Duplicate IMA measurements will not be recorded in the IMA log.");
+#endif
+
 	for (i = 0; i < count; i++) {
 		r = _inits[i]();
 		if (r)
-- 
2.32.0