[PATCH AUTOSEL 5.8 13/62] media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in debiirq()

[PATCH AUTOSEL 5.8 13/62] media: pci: ttpci: av7110: fix possible buffer overflow caused by bad DMA value in debiirq()

[Sasha Levin]

From: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>

[ Upstream commit 6499a0db9b0f1e903d52f8244eacc1d4be00eea2 ]

The value av7110->debi_virt is stored in DMA memory, and it is assigned
to data, and thus data[0] can be modified at any time by malicious
hardware. In this case, "if (data[0] < 2)" can be passed, but then
data[0] can be changed into a large number, which may cause buffer
overflow when the code "av7110->ci_slot[data[0]]" is used.

To fix this possible bug, data[0] is assigned to a local variable, which
replaces the use of data[0].

Signed-off-by: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/pci/ttpci/av7110.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/pci/ttpci/av7110.c b/drivers/media/pci/ttpci/av7110.c
index d0cdee1c6eb0b..bf36b1e22b635 100644
--- a/drivers/media/pci/ttpci/av7110.c
+++ b/drivers/media/pci/ttpci/av7110.c
@@ -406,14 +406,15 @@ static void debiirq(unsigned long cookie)
 	case DATA_CI_GET:
 	{
 		u8 *data = av7110->debi_virt;
+		u8 data_0 = data[0];
 
-		if ((data[0] < 2) && data[2] == 0xff) {
+		if (data_0 < 2 && data[2] == 0xff) {
 			int flags = 0;
 			if (data[5] > 0)
 				flags |= CA_CI_MODULE_PRESENT;
 			if (data[5] > 5)
 				flags |= CA_CI_MODULE_READY;
-			av7110->ci_slot[data[0]].flags = flags;
+			av7110->ci_slot[data_0].flags = flags;
 		} else
 			ci_get_data(&av7110->ci_rbuffer,
 				    av7110->debi_virt,
-- 
2.25.1

[PATCH AUTOSEL 5.8 44/62] cec-api: prevent leaking memory through hole in structure

[Sasha Levin]

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

[ Upstream commit 6c42227c3467549ddc65efe99c869021d2f4a570 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/media/cec/core/cec-api.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/media/cec/core/cec-api.c b/drivers/media/cec/core/cec-api.c
index 17d1cb2e5f976..f922a2196b2b7 100644
--- a/drivers/media/cec/core/cec-api.c
+++ b/drivers/media/cec/core/cec-api.c
@@ -147,7 +147,13 @@ static long cec_adap_g_log_addrs(struct cec_adapter *adap,
 	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));
-- 
2.25.1