releases/5.5.8/ipmi-ssif-handle-a-possible-null-pointer-reference.patch

From 5c46b80630bd07771d7dab4c4c48ab1d37854271 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Mon, 23 Dec 2019 10:42:19 -0600
Subject: ipmi:ssif: Handle a possible NULL pointer reference

From: Corey Minyard <cminyard@mvista.com>

[ Upstream commit 6b8526d3abc02c08a2f888e8c20b7ac9e5776dfe ]

In error cases a NULL can be passed to memcpy.  The length will always
be zero, so it doesn't really matter, but go ahead and check for NULL,
anyway, to be more precise and avoid static analysis errors.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/char/ipmi/ipmi_ssif.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
index 22c6a2e612360..8ac390c2b5147 100644
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -775,10 +775,14 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
 	flags = ipmi_ssif_lock_cond(ssif_info, &oflags);
 	msg = ssif_info->curr_msg;
 	if (msg) {
+		if (data) {
+			if (len > IPMI_MAX_MSG_LENGTH)
+				len = IPMI_MAX_MSG_LENGTH;
+			memcpy(msg->rsp, data, len);
+		} else {
+			len = 0;
+		}
 		msg->rsp_size = len;
-		if (msg->rsp_size > IPMI_MAX_MSG_LENGTH)
-			msg->rsp_size = IPMI_MAX_MSG_LENGTH;
-		memcpy(msg->rsp, data, msg->rsp_size);
 		ssif_info->curr_msg = NULL;
 	}
 
-- 
2.20.1