[PATCH AUTOSEL 6.1 7/9] media: imon: fix access to invalid resource for the second interface

[Sasha Levin]

From: Takashi Iwai <tiwai@xxxxxxx>

[ Upstream commit a1766a4fd83befa0b34d932d532e7ebb7fab1fa7 ]

imon driver probes two USB interfaces, and at the probe of the second
interface, the driver assumes blindly that the first interface got
bound with the same imon driver.  It's usually true, but it's still
possible that the first interface is bound with another driver via a
malformed descriptor.  Then it may lead to a memory corruption, as
spotted by syzkaller; imon driver accesses the data from drvdata as
struct imon_context object although it's a completely different one
that was assigned by another driver.

This patch adds a sanity check -- whether the first interface is
really bound with the imon driver or not -- for avoiding the problem
above at the probe time.

Reported-by: syzbot+59875ffef5cb9c9b29e9@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/all/000000000000a838aa0603cc74d6@xxxxxxxxxx/
Tested-by: Ricardo B. Marliere <ricardo@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20230922005152.163640-1-ricardo@xxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Sean Young <sean@xxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/media/rc/imon.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c
index 74546f7e34691..5719dda6e0f0e 100644
--- a/drivers/media/rc/imon.c
+++ b/drivers/media/rc/imon.c
@@ -2427,6 +2427,12 @@ static int imon_probe(struct usb_interface *interface,
 		goto fail;
 	}
 
+	if (first_if->dev.driver != interface->dev.driver) {
+		dev_err(&interface->dev, "inconsistent driver matching\n");
+		ret = -EINVAL;
+		goto fail;
+	}
+
 	if (ifnum == 0) {
 		ictx = imon_init_intf0(interface, id);
 		if (!ictx) {
-- 
2.42.0