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From:   Aditya Pakki <pakki001@umn.edu>
To:     pakki001@umn.edu
Cc:     kjlu@umn.edu, Andreas Noever <andreas.noever@gmail.com>,
        Michael Jamet <michael.jamet@intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2] thunderbolt: Fix to check for kmemdup failure
Date:   Wed, 20 Mar 2019 10:57:54 -0500
Message-Id: <20190320155754.29731-1-pakki001@umn.edu>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Memory allocated via kmemdup might fail and return a NULL pointer.
This patch adds a check on the return value of kmemdup and passes the
error upstream.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>

---
v1: Missed check on tb_sw_read, suggested by Mukesh
---
 drivers/thunderbolt/switch.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index cd96994dc094..504365d46827 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -1294,13 +1294,14 @@ int tb_switch_configure(struct tb_switch *sw)
 	return tb_plug_events_active(sw, true);
 }
 
-static void tb_switch_set_uuid(struct tb_switch *sw)
+static int tb_switch_set_uuid(struct tb_switch *sw)
 {
 	u32 uuid[4];
-	int cap;
+	int cap, ret;
 
+	ret = 0;
 	if (sw->uuid)
-		return;
+		return ret;
 
 	/*
 	 * The newer controllers include fused UUID as part of link
@@ -1308,7 +1309,9 @@ static void tb_switch_set_uuid(struct tb_switch *sw)
 	 */
 	cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
 	if (cap > 0) {
-		tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
+		ret = tb_sw_read(sw, uuid, TB_CFG_SWITCH, cap + 3, 4);
+		if (ret)
+			return ret;
 	} else {
 		/*
 		 * ICM generates UUID based on UID and fills the upper
@@ -1323,6 +1326,9 @@ static void tb_switch_set_uuid(struct tb_switch *sw)
 	}
 
 	sw->uuid = kmemdup(uuid, sizeof(uuid), GFP_KERNEL);
+	if (!sw->uuid)
+		ret = -ENOMEM;
+	return ret;
 }
 
 static int tb_switch_add_dma_port(struct tb_switch *sw)
@@ -1372,7 +1378,9 @@ static int tb_switch_add_dma_port(struct tb_switch *sw)
 
 	if (status) {
 		tb_sw_info(sw, "switch flash authentication failed\n");
-		tb_switch_set_uuid(sw);
+		ret = tb_switch_set_uuid(sw);
+		if (ret)
+			return ret;
 		nvm_set_auth_status(sw, status);
 	}
 
@@ -1422,7 +1430,9 @@ int tb_switch_add(struct tb_switch *sw)
 		}
 		tb_sw_dbg(sw, "uid: %#llx\n", sw->uid);
 
-		tb_switch_set_uuid(sw);
+		ret = tb_switch_set_uuid(sw);
+		if (ret)
+			return ret;
 
 		for (i = 0; i <= sw->config.max_port_number; i++) {
 			if (sw->ports[i].disabled) {
-- 
2.17.1