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/horus3a.c:57:19: warning: Variable length array is used.
The max usecase of the driver seems to be 5 bytes + 1 for the
register.
So, let's be safe and allocate 6 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@xxxxxxxxxxxxxxx>
---
drivers/media/dvb-frontends/horus3a.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/media/dvb-frontends/horus3a.c b/drivers/media/dvb-frontends/horus3a.c
index 46a82dc586d8..5074305b289e 100644
--- a/drivers/media/dvb-frontends/horus3a.c
+++ b/drivers/media/dvb-frontends/horus3a.c
@@ -26,6 +26,8 @@
#include "horus3a.h"
#include "dvb_frontend.h"
+#define MAX_WRITE_REGSIZE 5
+
enum horus3a_state {
STATE_UNKNOWN,
STATE_SLEEP,
@@ -54,16 +56,22 @@ static int horus3a_write_regs(struct horus3a_priv *priv,
u8 reg, const u8 *data, u32 len)
{
int ret;
- u8 buf[len+1];
+ u8 buf[MAX_WRITE_REGSIZE + 1];
struct i2c_msg msg[1] = {
{
.addr = priv->i2c_address,
.flags = 0,
- .len = sizeof(buf),
+ .len = len + 1,
.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;
+ }
+
horus3a_i2c_debug(priv, reg, 1, data, len);
buf[0] = reg;
memcpy(&buf[1], data, len);
--
2.4.3
--
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