[PATCH net v5 3/4] dpll: fix userspace availability of pins

From: Arkadiusz Kubalewski
Date: Thu Jan 18 2024 - 06:12:06 EST


If parent pin was unregistered but child pin was not, the userspace
would see the "zombie" pins - the ones that were registered with
a parent pin (dpll_pin_on_pin_register(..)).
Technically those are not available - as there is no dpll device in the
system. Do not dump those pins and prevent userspace from any
interaction with them. Provide a unified function to determine if the
pin is available and use it before acting/responding for user requests.

Fixes: 9d71b54b65b1 ("dpll: netlink: Add DPLL framework base functions")
Reviewed-by: Jan Glaza <jan.glaza@xxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@xxxxxxxxx>
---
v5:
- make this patch third in series, previously was second

drivers/dpll/dpll_netlink.c | 29 +++++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index 30f5be020862..314bb3775465 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -553,6 +553,24 @@ __dpll_device_change_ntf(struct dpll_device *dpll)
return dpll_device_event_send(DPLL_CMD_DEVICE_CHANGE_NTF, dpll);
}

+static bool dpll_pin_available(struct dpll_pin *pin)
+{
+ struct dpll_pin_ref *par_ref;
+ unsigned long i;
+
+ if (!xa_get_mark(&dpll_pin_xa, pin->id, DPLL_REGISTERED))
+ return false;
+ xa_for_each(&pin->parent_refs, i, par_ref)
+ if (xa_get_mark(&dpll_pin_xa, par_ref->pin->id,
+ DPLL_REGISTERED))
+ return true;
+ xa_for_each(&pin->dpll_refs, i, par_ref)
+ if (xa_get_mark(&dpll_device_xa, par_ref->dpll->id,
+ DPLL_REGISTERED))
+ return true;
+ return false;
+}
+
/**
* dpll_device_change_ntf - notify that the dpll device has been changed
* @dpll: registered dpll pointer
@@ -579,7 +597,7 @@ dpll_pin_event_send(enum dpll_cmd event, struct dpll_pin *pin)
int ret = -ENOMEM;
void *hdr;

- if (WARN_ON(!xa_get_mark(&dpll_pin_xa, pin->id, DPLL_REGISTERED)))
+ if (!dpll_pin_available(pin))
return -ENODEV;

msg = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
@@ -1130,6 +1148,10 @@ int dpll_nl_pin_id_get_doit(struct sk_buff *skb, struct genl_info *info)
}
pin = dpll_pin_find_from_nlattr(info);
if (!IS_ERR(pin)) {
+ if (!dpll_pin_available(pin)) {
+ nlmsg_free(msg);
+ return -ENODEV;
+ }
ret = dpll_msg_add_pin_handle(msg, pin);
if (ret) {
nlmsg_free(msg);
@@ -1179,6 +1201,8 @@ int dpll_nl_pin_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)

xa_for_each_marked_start(&dpll_pin_xa, i, pin, DPLL_REGISTERED,
ctx->idx) {
+ if (!dpll_pin_available(pin))
+ continue;
hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
&dpll_nl_family, NLM_F_MULTI,
@@ -1441,7 +1465,8 @@ int dpll_pin_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
}
info->user_ptr[0] = xa_load(&dpll_pin_xa,
nla_get_u32(info->attrs[DPLL_A_PIN_ID]));
- if (!info->user_ptr[0]) {
+ if (!info->user_ptr[0] ||
+ !dpll_pin_available(info->user_ptr[0])) {
NL_SET_ERR_MSG(info->extack, "pin not found");
ret = -ENODEV;
goto unlock_dev;
--
2.38.1