From 6c42227c3467549ddc65efe99c869021d2f4a570 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Fri, 26 Jun 2020 12:44:26 +0200
Subject: [PATCH] cec-api: prevent leaking memory through hole in structure
Git-commit: 6c42227c3467549ddc65efe99c869021d2f4a570
Patch-mainline: v5.9-rc1
References: CVE-2020-36766 bsc#1215299
Fix this smatch warning:
drivers/media/cec/core/cec-api.c:156 cec_adap_g_log_addrs() warn: check that 'log_addrs' doesn't leak information (struct has a hole after
'features')
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/cec/cec-api.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/media/cec/cec-api.c
+++ b/drivers/media/cec/cec-api.c
@@ -141,7 +141,13 @@ static long cec_adap_g_log_addrs(struct
struct cec_log_addrs log_addrs;
mutex_lock(&adap->lock);
- log_addrs = adap->log_addrs;
+ /*
+ * We use memcpy here instead of assignment since there is a
+ * hole at the end of struct cec_log_addrs that an assignment
+ * might ignore. So when we do copy_to_user() we could leak
+ * one byte of memory.
+ */
+ memcpy(&log_addrs, &adap->log_addrs, sizeof(log_addrs));
if (!adap->is_configured)
memset(log_addrs.log_addr, CEC_LOG_ADDR_INVALID,
sizeof(log_addrs.log_addr));