[PATCH 5.4 047/411] ipmi:ssif: Check for NULL msg when handling events and messages

Greg Kroah-Hartman
2022-06-13T11:05:17Z

From: Corey Minyard <cminyard@mvista.com>

[ Upstream commit 7602b957e2404e5f98d9a40b68f1fd27f0028712 ]

Even though it's not possible to get into the SSIF_GETTING_MESSAGES and
SSIF_GETTING_EVENTS states without a valid message in the msg field,
it's probably best to be defensive here and check and print a log, since
that means something else went wrong.

Also add a default clause to that switch statement to release the lock
and print a log, in case the state variable gets messed up somehow.

Reported-by: Haowen Bai <baihaowen@meizu.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/char/ipmi/ipmi_ssif.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index bb42a1c92cae..60fb6c62f224 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -845,6 +845,14 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
break;

case SSIF_GETTING_EVENTS:
+ if (!msg) {
+ /* Should never happen, but just in case. */
+ dev_warn(&ssif_info->client->dev,
+ "No message set while getting events\n");
+ ipmi_ssif_unlock_cond(ssif_info, flags);
+ break;
+ }
+
if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
/* Error getting event, probably done. */
msg->done(msg);
@@ -869,6 +877,14 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
break;

case SSIF_GETTING_MESSAGES:
+ if (!msg) {
+ /* Should never happen, but just in case. */
+ dev_warn(&ssif_info->client->dev,
+ "No message set while getting messages\n");
+ ipmi_ssif_unlock_cond(ssif_info, flags);
+ break;
+ }
+
if ((result < 0) || (len < 3) || (msg->rsp[2] != 0)) {
/* Error getting event, probably done. */
msg->done(msg);
@@ -892,6 +908,13 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
deliver_recv_msg(ssif_info, msg);
}
break;
+
+ default:
+ /* Should never happen, but just in case. */
+ dev_warn(&ssif_info->client->dev,
+ "Invalid state in message done handling: %d\n",
+ ssif_info->ssif_state);
+ ipmi_ssif_unlock_cond(ssif_info, flags);
}

flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
--
2.35.1