[PATCH 3.12 190/212] media: dw2102: Dont use dynamic static allocation

From: Greg Kroah-Hartman
Date: Mon Dec 02 2013 - 14:35:20 EST

3.12-stable review patch. If anyone has any objections, please let me know.

------------------

From: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>

commit 0065a79a8698a953e4b201c5fce8db8940530578 upstream.

Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
drivers/media/usb/dvb-usb/dw2102.c:368:1: warning: 'dw2102_earda_i2c_transfer' uses dynamic stack allocation [enabled by default]
drivers/media/usb/dvb-usb/dw2102.c:449:1: warning: 'dw2104_i2c_transfer' uses dynamic stack allocation [enabled by default]
drivers/media/usb/dvb-usb/dw2102.c:512:1: warning: 'dw3101_i2c_transfer' uses dynamic stack allocation [enabled by default]
drivers/media/usb/dvb-usb/dw2102.c:621:1: warning: 's6x0_i2c_transfer' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer to be the max size of
a control URB payload data (64 bytes).

Signed-off-by: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
Reviewed-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/media/usb/dvb-usb/dw2102.c | 90 ++++++++++++++++++++++++++++++++-----
1 file changed, 80 insertions(+), 10 deletions(-)

--- a/drivers/media/usb/dvb-usb/dw2102.c
+++ b/drivers/media/usb/dvb-usb/dw2102.c
@@ -30,6 +30,9 @@
#include "stb6100_proc.h"
#include "m88rs2000.h"

+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE 64
+
#ifndef USB_PID_DW2102
#define USB_PID_DW2102 0x2102
#endif
@@ -308,7 +311,14 @@ static int dw2102_earda_i2c_transfer(str
case 2: {
/* read */
/* first write first register number */
- u8 ibuf[msg[1].len + 2], obuf[3];
+ u8 ibuf[MAX_XFER_SIZE], obuf[3];
+
+ if (2 + msg[1].len > sizeof(ibuf)) {
+ warn("i2c rd: len=%d is too big!\n",
+ msg[1].len);
+ return -EOPNOTSUPP;
+ }
+
obuf[0] = msg[0].addr << 1;
obuf[1] = msg[0].len;
obuf[2] = msg[0].buf[0];
@@ -325,7 +335,14 @@ static int dw2102_earda_i2c_transfer(str
switch (msg[0].addr) {
case 0x68: {
/* write to register */
- u8 obuf[msg[0].len + 2];
+ u8 obuf[MAX_XFER_SIZE];
+
+ if (2 + msg[0].len > sizeof(obuf)) {
+ warn("i2c wr: len=%d is too big!\n",
+ msg[1].len);
+ return -EOPNOTSUPP;
+ }
+
obuf[0] = msg[0].addr << 1;
obuf[1] = msg[0].len;
memcpy(obuf + 2, msg[0].buf, msg[0].len);
@@ -335,7 +352,14 @@ static int dw2102_earda_i2c_transfer(str
}
case 0x61: {
/* write to tuner */
- u8 obuf[msg[0].len + 2];
+ u8 obuf[MAX_XFER_SIZE];
+
+ if (2 + msg[0].len > sizeof(obuf)) {
+ warn("i2c wr: len=%d is too big!\n",
+ msg[1].len);
+ return -EOPNOTSUPP;
+ }
+
obuf[0] = msg[0].addr << 1;
obuf[1] = msg[0].len;
memcpy(obuf + 2, msg[0].buf, msg[0].len);
@@ -401,7 +425,14 @@ static int dw2104_i2c_transfer(struct i2
default: {
if (msg[j].flags == I2C_M_RD) {
/* read registers */
- u8 ibuf[msg[j].len + 2];
+ u8 ibuf[MAX_XFER_SIZE];
+
+ if (2 + msg[j].len > sizeof(ibuf)) {
+ warn("i2c rd: len=%d is too big!\n",
+ msg[j].len);
+ return -EOPNOTSUPP;
+ }
+
dw210x_op_rw(d->udev, 0xc3,
(msg[j].addr << 1) + 1, 0,
ibuf, msg[j].len + 2,
@@ -430,7 +461,14 @@ static int dw2104_i2c_transfer(struct i2
} while (len > 0);
} else {
/* write registers */
- u8 obuf[msg[j].len + 2];
+ u8 obuf[MAX_XFER_SIZE];
+
+ if (2 + msg[j].len > sizeof(obuf)) {
+ warn("i2c wr: len=%d is too big!\n",
+ msg[j].len);
+ return -EOPNOTSUPP;
+ }
+
obuf[0] = msg[j].addr << 1;
obuf[1] = msg[j].len;
memcpy(obuf + 2, msg[j].buf, msg[j].len);
@@ -463,7 +501,13 @@ static int dw3101_i2c_transfer(struct i2
case 2: {
/* read */
/* first write first register number */
- u8 ibuf[msg[1].len + 2], obuf[3];
+ u8 ibuf[MAX_XFER_SIZE], obuf[3];
+
+ if (2 + msg[1].len > sizeof(ibuf)) {
+ warn("i2c rd: len=%d is too big!\n",
+ msg[1].len);
+ return -EOPNOTSUPP;
+ }
obuf[0] = msg[0].addr << 1;
obuf[1] = msg[0].len;
obuf[2] = msg[0].buf[0];
@@ -481,7 +525,13 @@ static int dw3101_i2c_transfer(struct i2
case 0x60:
case 0x0c: {
/* write to register */
- u8 obuf[msg[0].len + 2];
+ u8 obuf[MAX_XFER_SIZE];
+
+ if (2 + msg[0].len > sizeof(obuf)) {
+ warn("i2c wr: len=%d is too big!\n",
+ msg[0].len);
+ return -EOPNOTSUPP;
+ }
obuf[0] = msg[0].addr << 1;
obuf[1] = msg[0].len;
memcpy(obuf + 2, msg[0].buf, msg[0].len);
@@ -563,7 +613,14 @@ static int s6x0_i2c_transfer(struct i2c_
default: {
if (msg[j].flags == I2C_M_RD) {
/* read registers */
- u8 ibuf[msg[j].len];
+ u8 ibuf[MAX_XFER_SIZE];
+
+ if (msg[j].len > sizeof(ibuf)) {
+ warn("i2c rd: len=%d is too big!\n",
+ msg[j].len);
+ return -EOPNOTSUPP;
+ }
+
dw210x_op_rw(d->udev, 0x91, 0, 0,
ibuf, msg[j].len,
DW210X_READ_MSG);
@@ -590,7 +647,14 @@ static int s6x0_i2c_transfer(struct i2c_
} while (len > 0);
} else if (j < (num - 1)) {
/* write register addr before read */
- u8 obuf[msg[j].len + 2];
+ u8 obuf[MAX_XFER_SIZE];
+
+ if (2 + msg[j].len > sizeof(obuf)) {
+ warn("i2c wr: len=%d is too big!\n",
+ msg[j].len);
+ return -EOPNOTSUPP;
+ }
+
obuf[0] = msg[j + 1].len;
obuf[1] = (msg[j].addr << 1);
memcpy(obuf + 2, msg[j].buf, msg[j].len);
@@ -602,7 +666,13 @@ static int s6x0_i2c_transfer(struct i2c_
break;
} else {
/* write registers */
- u8 obuf[msg[j].len + 2];
+ u8 obuf[MAX_XFER_SIZE];
+
+ if (2 + msg[j].len > sizeof(obuf)) {
+ warn("i2c wr: len=%d is too big!\n",
+ msg[j].len);
+ return -EOPNOTSUPP;
+ }
obuf[0] = msg[j].len + 1;
obuf[1] = (msg[j].addr << 1);
memcpy(obuf + 2, msg[j].buf, msg[j].len);


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