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[media] cxd2841er: don't use variable length arrays 

The Linux stack is short; we need to be able to count the number
of bytes used at stack on each function. So, we don't like to
use variable-length arrays, as complained by smatch:

	drivers/media/dvb-frontends/cxd2841er.c:205:19: warning: Variable length array is used.

The max usecase of the driver seems to be 15 bytes + 1 for the
register.

So, let's be safe and allocate 17 bytes for the write buffer.
This should be enough to cover all cases. If not, let's print
an error message.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Mauro Carvalho Chehab 2015-08-11 15:22:36 -03:00
parent 52b1eaf4c5
commit d13a7b674a
1 changed files with 10 additions and 2 deletions
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12
drivers/media/dvb-frontends/cxd2841er.c
View File

@ -33,6 +33,8 @@
#include "cxd2841er.h" #include "cxd2841er.h"
#include "cxd2841er_priv.h" #include "cxd2841er_priv.h"
#define MAX_WRITE_REGSIZE 16
enum cxd2841er_state { enum cxd2841er_state {
STATE_SHUTDOWN = 0, STATE_SHUTDOWN = 0,
STATE_SLEEP_S, STATE_SLEEP_S,
@ -202,18 +204,24 @@ static int cxd2841er_write_regs(struct cxd2841er_priv *priv,
u8 addr, u8 reg, const u8 *data, u32 len) u8 addr, u8 reg, const u8 *data, u32 len)
{ {
int ret; int ret;
u8 buf[len+1]; u8 buf[MAX_WRITE_REGSIZE + 1];
u8 i2c_addr = (addr == I2C_SLVX ? u8 i2c_addr = (addr == I2C_SLVX ?
priv->i2c_addr_slvx : priv->i2c_addr_slvt); priv->i2c_addr_slvx : priv->i2c_addr_slvt);
struct i2c_msg msg[1] = { struct i2c_msg msg[1] = {
{ {
.addr = i2c_addr, .addr = i2c_addr,
.flags = 0, .flags = 0,
.len = sizeof(buf), .len = len + 1,
.buf = buf, .buf = buf,
} }
}; };
if (len + 1 >= sizeof(buf)) {
dev_warn(&priv->i2c->dev,"wr reg=%04x: len=%d is too big!\n",
reg, len + 1);
return -E2BIG;
}
cxd2841er_i2c_debug(priv, i2c_addr, reg, 1, data, len); cxd2841er_i2c_debug(priv, i2c_addr, reg, 1, data, len);
buf[0] = reg; buf[0] = reg;
memcpy(&buf[1], data, len); memcpy(&buf[1], data, len);