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cx18: introduce a helper function to void array overrun

PATCH In review Ethan Zhao 2 participants 3 messages Jan 5, 2014 – Jan 6, 2014

Subsystems (2)
Media (V4L/DVB) CX18 VIDEO4LINUX driver
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Ethan Zhao

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#0 lore raw

PATCH 1/1 cx18: introduce a helper function to void array overrun

cx18_i2c_register() is called in cx18_init_subdevs() with index greater than length of hw_bus array, that will cause array overrun, introduce a helper cx18_get_max_bus_num() to void it.

Signed-off-by Ethan Zhao <[email protected]>
---
 drivers/media/pci/cx18/cx18-driver.c | 2 +-
 drivers/media/pci/cx18/cx18-i2c.c    | 5 +++++
 drivers/media/pci/cx18/cx18-i2c.h    | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)
drivers/media/pci/cx18/cx18-driver.c +1 -1
index 6386ced..dadcd4a 100644
@@ -856,7 +856,7 @@ static void cx18_init_subdevs(struct cx18 *cx)
 	u32 device;
 	int i;
 
-	for (i = 0, device = 1; i < 32; i++, device <<= 1) {
+	for (i = 0, device = 1; i < cx18_get_max_bus_num(); i++, device <<= 1) {
 
 		if (!(device & hw))
 			continue;
drivers/media/pci/cx18/cx18-i2c.c +5 -0
index 4af8cd6..e0e8193 100644
@@ -108,6 +108,11 @@ static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw,
 	       -1 : 0;
 }
 
+int cx18_get_max_bus_num()
+{
+	return sizeof(hw_bus);
+}
+
 int cx18_i2c_register(struct cx18 *cx, unsigned idx)
 {
 	struct v4l2_subdev *sd;
drivers/media/pci/cx18/cx18-i2c.h +1 -0
index 1180fdc..8cce205 100644
@@ -21,6 +21,7 @@
  *  02111-1307  USA
  */
 
+int cx18_get_max_bus_num();
 int cx18_i2c_register(struct cx18 *cx, unsigned idx);
 struct v4l2_subdev *cx18_find_hw(struct cx18 *cx, u32 hw);
Signature · 1 line
1.8.3.4 (Apple Git-47)
#1 lore raw

Hi Ethan,

Quoted 3 lines · Ethan Zhao

cx18_i2c_register() is called in cx18_init_subdevs() with index greater than length of hw_bus array, that will cause array overrun, introduce a helper cx18_get_max_bus_num() to void it.

s/void/avoid/

Quoted 26 lines
Signed-off-by Ethan Zhao <[email protected]>
---
 drivers/media/pci/cx18/cx18-driver.c | 2 +-
 drivers/media/pci/cx18/cx18-i2c.c    | 5 +++++
 drivers/media/pci/cx18/cx18-i2c.h    | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)
drivers/media/pci/cx18/cx18-driver.c +1 -1
index 6386ced..dadcd4a 100644
@@ -856,7 +856,7 @@ static void cx18_init_subdevs(struct cx18 *cx)
 	u32 device;
 	int i;
 
-	for (i = 0, device = 1; i < 32; i++, device <<= 1) {
+	for (i = 0, device = 1; i < cx18_get_max_bus_num(); i++, device <<= 1) {
 
 		if (!(device & hw))
 			continue;
drivers/media/pci/cx18/cx18-i2c.c +0 -0
index 4af8cd6..e0e8193 100644

drivers/media/pci/cx18/cx18-i2c.c static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw, · line 111

Quoted 4 lines
drivers/media/pci/cx18/cx18-i2c.c +1 -0
@@ -108,6 +108,11 @@ static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw,
 	       -1 : 0;
 }
 
+int cx18_get_max_bus_num()

This should be "int cx18_get_max_bus_num(void)" since we are using C and not C++.

drivers/media/pci/cx18/cx18-i2c.c static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw, · line 113

Quoted 2 lines
drivers/media/pci/cx18/cx18-i2c.c +2 -0
+{
+	return sizeof(hw_bus);

I'd rather see

	return ARRAY_SIZE(hw_bus);

Thanks.

Signature · 1 line
Dmitry
author
#2 lore raw
Quoted 8 lines · Dmitry Torokhov

Hi Ethan,

Quoted 3 lines · Ethan Zhao

cx18_i2c_register() is called in cx18_init_subdevs() with index greater than length of hw_bus array, that will cause array overrun, introduce a helper cx18_get_max_bus_num() to void it.

s/void/avoid/

Oops, typo.

Quoted 30 lines
Quoted 30 lines
Signed-off-by Ethan Zhao <[email protected]>
---
 drivers/media/pci/cx18/cx18-driver.c | 2 +-
 drivers/media/pci/cx18/cx18-i2c.c    | 5 +++++
 drivers/media/pci/cx18/cx18-i2c.h    | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)
drivers/media/pci/cx18/cx18-driver.c +1 -1
index 6386ced..dadcd4a 100644
@@ -856,7 +856,7 @@ static void cx18_init_subdevs(struct cx18 *cx)
      u32 device;
      int i;
 
-     for (i = 0, device = 1; i < 32; i++, device <<= 1) {
+     for (i = 0, device = 1; i < cx18_get_max_bus_num(); i++, device <<= 1) {
 
              if (!(device & hw))
                      continue;
drivers/media/pci/cx18/cx18-i2c.c +0 -0
index 4af8cd6..e0e8193 100644
@@ -108,6 +108,11 @@ static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw,
             -1 : 0;
 }
Quoted 4 lines

drivers/media/pci/cx18/cx18-i2c.c static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw, · line 111

Quoted 1 line
drivers/media/pci/cx18/cx18-i2c.c +1 -0
+int cx18_get_max_bus_num()

This should be "int cx18_get_max_bus_num(void)" since we are using C and not C++.

agree, no parameter function, f(void) much clearer than any parameters function f() in C.

Quoted 7 lines

drivers/media/pci/cx18/cx18-i2c.c static int cx18_i2c_new_ir(struct cx18 *cx, struct i2c_adapter *adap, u32 hw, · line 113

Quoted 3 lines
drivers/media/pci/cx18/cx18-i2c.c +2 -0
+{
+     return sizeof(hw_bus);

I'd rather see

        return ARRAY_SIZE(hw_bus);

Yes, looks better ! will send v2, thanks.

Quoted 5 lines

Thanks.

--
Dmitry