linux-kernel - [PATCH 4.9 085/157] media: m920x: dont use stack on USB reads

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 24 Jan 2022 19:42:55 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, rkardell@...a.se,
        Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.9 085/157] media: m920x: dont use stack on USB reads

From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>

[ Upstream commit a2ab06d7c4d6bfd0b545a768247a70463e977e27 ]

Using stack-allocated pointers for USB message data don't work.
This driver is almost OK with that, except for the I2C read
logic.

Fix it by using a temporary read buffer, just like on all other
calls to m920x_read().

Link: https://lore.kernel.org/all/ccc99e48-de4f-045e-0fe4-61e3118e3f74@mida.se/
Reported-by: rkardell@...a.se
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/media/usb/dvb-usb/m920x.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/dvb-usb/m920x.c b/drivers/media/usb/dvb-usb/m920x.c
index eafc5c82467f4..5b806779e2106 100644
--- a/drivers/media/usb/dvb-usb/m920x.c
+++ b/drivers/media/usb/dvb-usb/m920x.c
@@ -284,6 +284,13 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu
 			/* Should check for ack here, if we knew how. */
 		}
 		if (msg[i].flags & I2C_M_RD) {
+			char *read = kmalloc(1, GFP_KERNEL);
+			if (!read) {
+				ret = -ENOMEM;
+				kfree(read);
+				goto unlock;
+			}
+
 			for (j = 0; j < msg[i].len; j++) {
 				/* Last byte of transaction?
 				 * Send STOP, otherwise send ACK. */
@@ -291,9 +298,12 @@ static int m920x_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msg[], int nu
 
 				if ((ret = m920x_read(d->udev, M9206_I2C, 0x0,
 						      0x20 | stop,
-						      &msg[i].buf[j], 1)) != 0)
+						      read, 1)) != 0)
 					goto unlock;
+				msg[i].buf[j] = read[0];
 			}
+
+			kfree(read);
 		} else {
 			for (j = 0; j < msg[i].len; j++) {
 				/* Last byte of transaction? Then send STOP. */
-- 
2.34.1