media: v4l2-ioctl: fix some "too small" warnings
While the code there is right, it produces three false positives:
drivers/media/v4l2-core/v4l2-ioctl.c:2868 video_usercopy() error: copy_from_user() 'parg' too small (128 vs 16383)
drivers/media/v4l2-core/v4l2-ioctl.c:2868 video_usercopy() error: copy_from_user() 'parg' too small (128 vs 16383)
drivers/media/v4l2-core/v4l2-ioctl.c:2876 video_usercopy() error: memset() 'parg' too small (128 vs 16383)
Store the ioctl size on a cache var, in order to suppress those.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 672ab22..a5dab16 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -2833,14 +2833,15 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
size_t array_size = 0;
void __user *user_ptr = NULL;
void **kernel_ptr = NULL;
+ size_t size = _IOC_SIZE(cmd);
/* Copy arguments into temp kernel buffer */
if (_IOC_DIR(cmd) != _IOC_NONE) {
- if (_IOC_SIZE(cmd) <= sizeof(sbuf)) {
+ if (size <= sizeof(sbuf)) {
parg = sbuf;
} else {
/* too big to allocate from stack */
- mbuf = kvmalloc(_IOC_SIZE(cmd), GFP_KERNEL);
+ mbuf = kvmalloc(size, GFP_KERNEL);
if (NULL == mbuf)
return -ENOMEM;
parg = mbuf;
@@ -2848,7 +2849,7 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
err = -EFAULT;
if (_IOC_DIR(cmd) & _IOC_WRITE) {
- unsigned int n = _IOC_SIZE(cmd);
+ unsigned int n = size;
/*
* In some cases, only a few fields are used as input,
@@ -2869,11 +2870,11 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
goto out;
/* zero out anything we don't copy from userspace */
- if (n < _IOC_SIZE(cmd))
- memset((u8 *)parg + n, 0, _IOC_SIZE(cmd) - n);
+ if (n < size)
+ memset((u8 *)parg + n, 0, size - n);
} else {
/* read-only ioctl */
- memset(parg, 0, _IOC_SIZE(cmd));
+ memset(parg, 0, size);
}
}
@@ -2931,7 +2932,7 @@ video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
switch (_IOC_DIR(cmd)) {
case _IOC_READ:
case (_IOC_WRITE | _IOC_READ):
- if (copy_to_user((void __user *)arg, parg, _IOC_SIZE(cmd)))
+ if (copy_to_user((void __user *)arg, parg, size))
err = -EFAULT;
break;
}