This patch supports to handle 64/32 compatible array parameter,
such as below:
struct v4l2_fd_result {
__u32 buf_index;
__u32 face_cnt;
__u32 reserved[6];
struct v4l2_fd_detection fd[];
};
With this patch, the pointer to user space array needn't be passed
to kernel any more.
Cc: Arnd Bergmann <a...@arndb.de>
Signed-off-by: Ming Lei <ming....@canonical.com>
---
drivers/media/video/v4l2-ioctl.c | 33 +++++++++++++++++++++++++++++++--
1 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index e1da8fc..ded8b72 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -2239,6 +2239,11 @@ static int check_array_args(unsigned int cmd, void
*parg, size_t *array_size,
return ret;
}
+static int is_64_32_array_args(unsigned int cmd, void *parg, int *extra_len)
+{
+ return 0;
+}
+
long
video_usercopy(struct file *file, unsigned int cmd, unsigned long arg,
v4l2_kioctl func)
@@ -2251,6 +2256,7 @@ 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;
+ int extra = 0;
/* Copy arguments into temp kernel buffer */
if (_IOC_DIR(cmd) != _IOC_NONE) {
@@ -2280,9 +2286,32 @@ video_usercopy(struct file *file, unsigned int cmd,
unsigned long arg,
}
}
- err = check_array_args(cmd, parg, &array_size, &user_ptr, &kernel_ptr);
+ if (is_64_32_array_args(cmd, parg, &extra)) {
+ int size;
+ void *old_mbuf;
+
+ err = 0;
+ if (!extra)
+ goto handle_array_args;
+ old_mbuf = mbuf;
+ size = extra + _IOC_SIZE(cmd);
+ mbuf = kmalloc(size, GFP_KERNEL);
+ if (NULL == mbuf) {
+ mbuf = old_mbuf;
+ err = -ENOMEM;
+ goto out;
+ }
+ memcpy(mbuf, parg, _IOC_SIZE(cmd));
+ parg = mbuf;
+ kfree(old_mbuf);
+ } else {
+ err = check_array_args(cmd, parg, &array_size,
+ &user_ptr, &kernel_ptr);
+ }
+
if (err < 0)
goto out;
+handle_array_args:
has_array_args = err;
if (has_array_args) {
@@ -2321,7 +2350,7 @@ out_array_args:
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, _IOC_SIZE(cmd) +
extra))
err = -EFAULT;
break;
}
--
1.7.5.4
--
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