On 18/10/2024 07:53, Mauro Carvalho Chehab wrote:
As detected by Coverity, the error check logic at get_ctrl() is broken: if ptr_to_user() fails to fill a control due to an error, no errors are returned and v4l2_g_ctrl() returns success on a failed operation, which may cause applications to fail.
Add an error check at get_ctrl() and ensure that it will be returned to userspace without filling the control value if get_ctrl() fails.
Fixes: 71c689dc2e73 ("media: v4l2-ctrls: split up into four source files") Cc: stable@vger.kernel.org Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org
drivers/media/v4l2-core/v4l2-ctrls-api.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c index e5a364efd5e6..a0de7eeaf085 100644 --- a/drivers/media/v4l2-core/v4l2-ctrls-api.c +++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c @@ -753,9 +753,10 @@ static int get_ctrl(struct v4l2_ctrl *ctrl, struct v4l2_ext_control *c) for (i = 0; i < master->ncontrols; i++) cur_to_new(master->cluster[i]); ret = call_op(master, g_volatile_ctrl);
new_to_user(c, ctrl);
if (!ret)ret = new_to_user(c, ctrl);
cur_to_user(c, ctrl);
ret = cur_to_user(c, ctrl);@@ -770,7 +771,10 @@ int v4l2_g_ctrl(struct v4l2_ctrl_handler *hdl, struct v4l2_control *control) if (!ctrl || !ctrl->is_int) return -EINVAL; ret = get_ctrl(ctrl, &c);
- control->value = c.value;
- if (!ret)
control->value = c.value;- return ret;
} EXPORT_SYMBOL(v4l2_g_ctrl); @@ -811,10 +815,12 @@ static int set_ctrl_lock(struct v4l2_fh *fh, struct v4l2_ctrl *ctrl, int ret; v4l2_ctrl_lock(ctrl);
- user_to_new(c, ctrl);
- ret = user_to_new(c, ctrl);
- if (ret)
return ret;
A lock was taken above and that isn't unlocked here.
It is better to write this as:
if (!ret) ret = set_ctrl(fh, ctrl, 0);
ret = set_ctrl(fh, ctrl, 0); if (!ret)
cur_to_user(c, ctrl);
ret = cur_to_user(c, ctrl);}
Regards,
Hans