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Commit fe791612 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Greg Kroah-Hartman
Browse files

media: m920x: don't use stack on USB reads 

[ 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: default avatar <rkardell@mida.se>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent a821532c

drivers/media/usb/dvb-usb/m920x.c

+11 −1
Original line number Diff line number Diff line
@@ -274,6 +274,13 @@ 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. */
@@ -281,9 +288,12 @@ 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. */