Re: [patch] [media] rc: divide by zero bugs in s_tx_carrier()

2012-08-19 Thread Ben Hutchings 
On Sat, 2012-08-18 at 18:58 +0300, Dan Carpenter wrote:
 carrier comes from a get_user() in ir_lirc_ioctl().  We need to test
 that it's not zero before using it as a divisor.

Other RC drivers seem to have the same problem, only more deeply buried.
I think it's better to put this check in ir_lirc_ioctl() instead,
consistent with LIRC_SET_REC_CARRIER.

Ben.

 Signed-off-by: Dan Carpenter dan.carpen...@oracle.com
 
 diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c
 index 647dd95..d05ac15 100644
 --- a/drivers/media/rc/ene_ir.c
 +++ b/drivers/media/rc/ene_ir.c
 @@ -881,10 +881,13 @@ static int ene_set_tx_mask(struct rc_dev *rdev, u32 
 tx_mask)
  static int ene_set_tx_carrier(struct rc_dev *rdev, u32 carrier)
  {
   struct ene_device *dev = rdev-priv;
 - u32 period = 200 / carrier;
 + u32 period;
  
   dbg(TX: attempt to set tx carrier to %d kHz, carrier);
 + if (carrier == 0)
 + return -EINVAL;
  
 + period = 200 / carrier;
   if (period  (period  ENE_CIRMOD_PRD_MAX ||
   period  ENE_CIRMOD_PRD_MIN)) {
  
 diff --git a/drivers/media/rc/nuvoton-cir.c b/drivers/media/rc/nuvoton-cir.c
 index 699eef3..2ea913a 100644
 --- a/drivers/media/rc/nuvoton-cir.c
 +++ b/drivers/media/rc/nuvoton-cir.c
 @@ -517,6 +517,9 @@ static int nvt_set_tx_carrier(struct rc_dev *dev, u32 
 carrier)
   struct nvt_dev *nvt = dev-priv;
   u16 val;
  
 + if (carrier == 0)
 + return -EINVAL;
 +
   nvt_cir_reg_write(nvt, 1, CIR_CP);
   val = 300 / (carrier) - 1;
   nvt_cir_reg_write(nvt, val  0xff, CIR_CC);
 

-- 
Ben Hutchings
I say we take off; nuke the site from orbit.  It's the only way to be sure.


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[patch] [media] rc: divide by zero bugs in s_tx_carrier()

2012-08-18 Thread Dan Carpenter 
carrier comes from a get_user() in ir_lirc_ioctl().  We need to test
that it's not zero before using it as a divisor.

Signed-off-by: Dan Carpenter dan.carpen...@oracle.com

diff --git a/drivers/media/rc/ene_ir.c b/drivers/media/rc/ene_ir.c
index 647dd95..d05ac15 100644
--- a/drivers/media/rc/ene_ir.c
+++ b/drivers/media/rc/ene_ir.c
@@ -881,10 +881,13 @@ static int ene_set_tx_mask(struct rc_dev *rdev, u32 
tx_mask)
 static int ene_set_tx_carrier(struct rc_dev *rdev, u32 carrier)
 {
struct ene_device *dev = rdev-priv;
-   u32 period = 200 / carrier;
+   u32 period;
 
dbg(TX: attempt to set tx carrier to %d kHz, carrier);
+   if (carrier == 0)
+   return -EINVAL;
 
+   period = 200 / carrier;
if (period  (period  ENE_CIRMOD_PRD_MAX ||
period  ENE_CIRMOD_PRD_MIN)) {
 
diff --git a/drivers/media/rc/nuvoton-cir.c b/drivers/media/rc/nuvoton-cir.c
index 699eef3..2ea913a 100644
--- a/drivers/media/rc/nuvoton-cir.c
+++ b/drivers/media/rc/nuvoton-cir.c
@@ -517,6 +517,9 @@ static int nvt_set_tx_carrier(struct rc_dev *dev, u32 
carrier)
struct nvt_dev *nvt = dev-priv;
u16 val;
 
+   if (carrier == 0)
+   return -EINVAL;
+
nvt_cir_reg_write(nvt, 1, CIR_CP);
val = 300 / (carrier) - 1;
nvt_cir_reg_write(nvt, val  0xff, CIR_CC);
--
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