[PATCH v8 14/19] media: uvcvideo: Check controls flags before accessing them
From: Ricardo Ribalda <hidden>
Date: 2021-03-19 17:10:23
Also in:
lkml
Subsystem:
media input infrastructure (v4l/dvb), the rest, usb video class · Maintainers:
Mauro Carvalho Chehab, Linus Torvalds, Laurent Pinchart, Hans de Goede
We can figure out if reading/writing a set of controls can fail without
accessing them by checking their flags.
This way we can honor the API closer:
If an error is found when validating the list of controls passed with
VIDIOC_G_EXT_CTRLS, then error_idx shall be set to ctrls->count to
indicate to userspace that no actual hardware was touched.
Fixes v4l2-compliance:
Control ioctls (Input 0):
warn: v4l2-test-controls.cpp(765): g_ext_ctrls(0) invalid error_idx 0
fail: v4l2-test-controls.cpp(645): invalid error index write only control
test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
Reviewed-by: Hans Verkuil <redacted>
Signed-off-by: Ricardo Ribalda <redacted>
---
drivers/media/usb/uvc/uvc_ctrl.c | 22 ++++++++++++++++++
drivers/media/usb/uvc/uvc_v4l2.c | 39 ++++++++++++++++++++++++++++----
drivers/media/usb/uvc/uvcvideo.h | 2 ++
3 files changed, 58 insertions(+), 5 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index 929e70dff11a..24fd5afc4e4f 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c@@ -1046,6 +1046,28 @@ static int uvc_query_v4l2_class(struct uvc_video_chain *chain, u32 req_id, return 0; } +int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id, + bool read) +{ + struct uvc_control_mapping *mapping; + struct uvc_control *ctrl; + + if (__uvc_query_v4l2_class(chain, v4l2_id, 0) >= 0) + return -EACCES; + + ctrl = uvc_find_control(chain, v4l2_id, &mapping); + if (!ctrl) + return -EINVAL; + + if (!(ctrl->info.flags & UVC_CTRL_FLAG_GET_CUR) && read) + return -EACCES; + + if (!(ctrl->info.flags & UVC_CTRL_FLAG_SET_CUR) && !read) + return -EACCES; + + return 0; +} + static const char *uvc_map_get_name(const struct uvc_control_mapping *map) { const char *name;
diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index 28ccaa8b9e42..a3ee1dc003fc 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c@@ -991,6 +991,26 @@ static int uvc_ioctl_query_ext_ctrl(struct file *file, void *fh, return 0; } +static int uvc_ctrl_check_access(struct uvc_video_chain *chain, + struct v4l2_ext_controls *ctrls, + unsigned long ioctl) +{ + struct v4l2_ext_control *ctrl = ctrls->controls; + unsigned int i; + int ret = 0; + + for (i = 0; i < ctrls->count; ++ctrl, ++i) { + ret = uvc_ctrl_is_accessible(chain, ctrl->id, + ioctl == VIDIOC_G_EXT_CTRLS); + if (ret) + break; + } + + ctrls->error_idx = ioctl == VIDIOC_TRY_EXT_CTRLS ? i : ctrls->count; + + return ret; +} + static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh, struct v4l2_ext_controls *ctrls) {
@@ -1000,6 +1020,10 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh, unsigned int i; int ret; + ret = uvc_ctrl_check_access(chain, ctrls, VIDIOC_G_EXT_CTRLS); + if (ret < 0) + return ret; + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) { for (i = 0; i < ctrls->count; ++ctrl, ++i) { struct v4l2_queryctrl qc = { .id = ctrl->id };
@@ -1036,13 +1060,17 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void *fh, static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle, struct v4l2_ext_controls *ctrls, - bool commit) + unsigned long ioctl) { struct v4l2_ext_control *ctrl = ctrls->controls; struct uvc_video_chain *chain = handle->chain; unsigned int i; int ret; + ret = uvc_ctrl_check_access(chain, ctrls, ioctl); + if (ret < 0) + return ret; + ret = uvc_ctrl_begin(chain); if (ret < 0) return ret;
@@ -1051,14 +1079,15 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh *handle, ret = uvc_ctrl_set(handle, ctrl); if (ret < 0) { uvc_ctrl_rollback(handle); - ctrls->error_idx = commit ? ctrls->count : i; + ctrls->error_idx = ioctl == VIDIOC_S_EXT_CTRLS ? + ctrls->count : i; return ret; } } ctrls->error_idx = 0; - if (commit) + if (ioctl == VIDIOC_S_EXT_CTRLS) return uvc_ctrl_commit(handle, ctrls->controls, ctrls->count); else return uvc_ctrl_rollback(handle);
@@ -1069,7 +1098,7 @@ static int uvc_ioctl_s_ext_ctrls(struct file *file, void *fh, { struct uvc_fh *handle = fh; - return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, true); + return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, VIDIOC_S_EXT_CTRLS); } static int uvc_ioctl_try_ext_ctrls(struct file *file, void *fh,
@@ -1077,7 +1106,7 @@ static int uvc_ioctl_try_ext_ctrls(struct file *file, void *fh, { struct uvc_fh *handle = fh; - return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, false); + return uvc_ioctl_s_try_ext_ctrls(handle, ctrls, VIDIOC_TRY_EXT_CTRLS); } static int uvc_ioctl_querymenu(struct file *file, void *fh,
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index dc20021f7ee0..9471c342a310 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h@@ -902,6 +902,8 @@ static inline int uvc_ctrl_rollback(struct uvc_fh *handle) int uvc_ctrl_get(struct uvc_video_chain *chain, struct v4l2_ext_control *xctrl); int uvc_ctrl_set(struct uvc_fh *handle, struct v4l2_ext_control *xctrl); +int uvc_ctrl_is_accessible(struct uvc_video_chain *chain, u32 v4l2_id, + bool read); int uvc_xu_ctrl_query(struct uvc_video_chain *chain, struct uvc_xu_control_query *xqry);
--
2.31.0.rc2.261.g7f71774620-goog