From: Martin Rubli <martin_ru...@logitech.com>
This patch removes the sysadmin requirements for UVCIOC_CTRL_MAP (and the stub
implementation of UVCIOC_CTRL_ADD). This requirement no longer makes sense with
the new XU control access mechanisms since XU controls can be accessed without
adding control mappings first.
A maximum number (currently 1024) of control mappings per device is enforced to
avoid excess memory consumption caused by careless user space applications.
Signed-off-by: Martin Rubli <martin_ru...@logitech.com>
---
drivers/media/video/uvc/uvc_ctrl.c | 14 ++++++++++++++
drivers/media/video/uvc/uvc_driver.c | 1 +
drivers/media/video/uvc/uvc_v4l2.c | 6 ------
drivers/media/video/uvc/uvcvideo.h | 4 ++++
4 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/drivers/media/video/uvc/uvc_ctrl.c
b/drivers/media/video/uvc/uvc_ctrl.c
index 2c81b7f..531a3e1 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -1435,6 +1435,7 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
struct uvc_entity *entity;
struct uvc_control *ctrl;
int found = 0;
+ int ret;
if (mapping->id & ~V4L2_CTRL_ID_MASK) {
uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', control "
@@ -1478,7 +1479,20 @@ int uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
}
}
+ /* Prevent excess memory consumption */
+ if (atomic_inc_return(&dev->nmappings) > UVC_MAX_CONTROL_MAPPINGS) {
+ atomic_dec(&dev->nmappings);
+ uvc_trace(UVC_TRACE_CONTROL, "Can't add mapping '%s', maximum "
+ "mappings count (%u) exceeded.\n", mapping->name,
+ UVC_MAX_CONTROL_MAPPINGS);
+ ret = -ENOMEM;
+ goto done;
+ }
+
ret = __uvc_ctrl_add_mapping(dev, ctrl, mapping);
+ if (ret < 0)
+ atomic_dec(&dev->nmappings);
+
done:
mutex_unlock(&chain->ctrl_mutex);
return ret;
diff --git a/drivers/media/video/uvc/uvc_driver.c
b/drivers/media/video/uvc/uvc_driver.c
index 71efda7..a1e9dfb 100644
--- a/drivers/media/video/uvc/uvc_driver.c
+++ b/drivers/media/video/uvc/uvc_driver.c
@@ -1760,6 +1760,7 @@ static int uvc_probe(struct usb_interface *intf,
INIT_LIST_HEAD(&dev->streams);
atomic_set(&dev->nstreams, 0);
atomic_set(&dev->users, 0);
+ atomic_set(&dev->nmappings, 0);
dev->udev = usb_get_dev(udev);
dev->intf = usb_get_intf(intf);
diff --git a/drivers/media/video/uvc/uvc_v4l2.c
b/drivers/media/video/uvc/uvc_v4l2.c
index 4a51048..6d15de9 100644
--- a/drivers/media/video/uvc/uvc_v4l2.c
+++ b/drivers/media/video/uvc/uvc_v4l2.c
@@ -1025,16 +1025,10 @@ static long uvc_v4l2_do_ioctl(struct file *file,
unsigned int cmd, void *arg)
/* Dynamic controls. */
case UVCIOC_CTRL_ADD:
/* Legacy ioctl, kept for API compatibility reasons */
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
return -EEXIST;
case UVCIOC_CTRL_MAP_OLD:
case UVCIOC_CTRL_MAP:
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
return uvc_ioctl_ctrl_map(chain, arg,
cmd == UVCIOC_CTRL_MAP_OLD);
diff --git a/drivers/media/video/uvc/uvcvideo.h
b/drivers/media/video/uvc/uvcvideo.h
index 34637fb..39e9e36 100644
--- a/drivers/media/video/uvc/uvcvideo.h
+++ b/drivers/media/video/uvc/uvcvideo.h
@@ -172,6 +172,9 @@ struct uvc_xu_control {
#define UVC_CTRL_CONTROL_TIMEOUT 300
#define UVC_CTRL_STREAMING_TIMEOUT 5000
+/* Maximum allowed number of control mappings per device */
+#define UVC_MAX_CONTROL_MAPPINGS 1024
+
/* Devices quirks */
#define UVC_QUIRK_STATUS_INTERVAL 0x00000001
#define UVC_QUIRK_PROBE_MINMAX 0x00000002
@@ -472,6 +475,7 @@ struct uvc_device {
enum uvc_device_state state;
atomic_t users;
+ atomic_t nmappings;
/* Video control interface */
__u16 uvc_version;
--
1.7.2.2
--
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