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authorDan Carpenter <dan.carpenter@oracle.com>2011-10-13 08:05:53 +0400
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2011-10-13 08:13:11 +0400
commit05be8b81aafd4f95106a91ff3fd8581fa984fad9 (patch)
treed34da61ab5fa18f5fb57b0342a1e3871aedb36bc /drivers/input/ff-core.c
parent341deefe8f4584b09564193cb46d8cf386f491a5 (diff)
downloadlinux-05be8b81aafd4f95106a91ff3fd8581fa984fad9.tar.xz
Input: force feedback - potential integer wrap in input_ff_create()
The problem here is that max_effects can wrap on 32 bits systems. We'd allocate a smaller amount of data than sizeof(struct ff_device). The call to kcalloc() on the next line would fail but it would write the NULL return outside of the memory we just allocated causing data corruption. The call path is that uinput_setup_device() get ->ff_effects_max from the user and sets the value in the ->private_data struct. From there it is: -> uinput_ioctl_handler() -> uinput_create_device() -> input_ff_create(dev, udev->ff_effects_max); I've also changed ff_effects_max so it's an unsigned int instead of a signed int as a cleanup. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers/input/ff-core.c')
-rw-r--r--drivers/input/ff-core.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/input/ff-core.c b/drivers/input/ff-core.c
index 3367f760d75a..480eb9d9876a 100644
--- a/drivers/input/ff-core.c
+++ b/drivers/input/ff-core.c
@@ -309,9 +309,10 @@ EXPORT_SYMBOL_GPL(input_ff_event);
* Once ff device is created you need to setup its upload, erase,
* playback and other handlers before registering input device
*/
-int input_ff_create(struct input_dev *dev, int max_effects)
+int input_ff_create(struct input_dev *dev, unsigned int max_effects)
{
struct ff_device *ff;
+ size_t ff_dev_size;
int i;
if (!max_effects) {
@@ -319,8 +320,12 @@ int input_ff_create(struct input_dev *dev, int max_effects)
return -EINVAL;
}
- ff = kzalloc(sizeof(struct ff_device) +
- max_effects * sizeof(struct file *), GFP_KERNEL);
+ ff_dev_size = sizeof(struct ff_device) +
+ max_effects * sizeof(struct file *);
+ if (ff_dev_size < max_effects) /* overflow */
+ return -EINVAL;
+
+ ff = kzalloc(ff_dev_size, GFP_KERNEL);
if (!ff)
return -ENOMEM;