From: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 382caf200ba16..c313f51688f44 100644
--- a/drivers/media/pci/ttpci/av7110.c
+++ b/drivers/media/pci/ttpci/av7110.c
@@ -426,14 +426,15 @@ 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
