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); } else { - cur_to_user(c, ctrl); + ret = cur_to_user(c, ctrl); } v4l2_ctrl_unlock(master); return ret; @@ -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; ret = set_ctrl(fh, ctrl, 0); if (!ret) - cur_to_user(c, ctrl); + ret = cur_to_user(c, ctrl); v4l2_ctrl_unlock(ctrl); return ret; }
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
Em Fri, 18 Oct 2024 08:13:01 +0200 Hans Verkuil hverkuil@xs4all.nl escreveu:
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);}
True. See below.
Thanks, Mauro
-
[PATCH v3] media: v4l2-ctrls-api: fix error handling for v4l2_g_ctrl()
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 | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c index e5a364efd5e6..95a2202879d8 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); } else { - cur_to_user(c, ctrl); + ret = cur_to_user(c, ctrl); } v4l2_ctrl_unlock(master); return ret; @@ -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 +815,11 @@ 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 = set_ctrl(fh, ctrl, 0); + ret = user_to_new(c, ctrl); + if (!ret) + ret = set_ctrl(fh, ctrl, 0); if (!ret) - cur_to_user(c, ctrl); + ret = cur_to_user(c, ctrl); v4l2_ctrl_unlock(ctrl); return ret; }
linux-stable-mirror@lists.linaro.org
-
Hans Verkuil -
Mauro Carvalho Chehab