From 2aa1f7a1f47ce8dac7593af605aaa859b3cf3bb1 Mon Sep 17 00:00:00 2001 From: Anjali Kulkarni Date: Wed, 19 Jul 2023 13:18:18 -0700 Subject: connector/cn_proc: Add filtering to fix some bugs The current proc connector code has the foll. bugs - if there are more than one listeners for the proc connector messages, and one of them deregisters for listening using PROC_CN_MCAST_IGNORE, they will still get all proc connector messages, as long as there is another listener. Another issue is if one client calls PROC_CN_MCAST_LISTEN, and another one calls PROC_CN_MCAST_IGNORE, then both will end up not getting any messages. This patch adds filtering and drops packet if client has sent PROC_CN_MCAST_IGNORE. This data is stored in the client socket's sk_user_data. In addition, we only increment or decrement proc_event_num_listeners once per client. This fixes the above issues. cn_release is the release function added for NETLINK_CONNECTOR. It uses the newly added netlink_release function added to netlink_sock. It will free sk_user_data. Signed-off-by: Anjali Kulkarni Reviewed-by: Liam R. Howlett Signed-off-by: David S. Miller --- include/linux/connector.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/connector.h b/include/linux/connector.h index 487350bb19c3..cec2d99ae902 100644 --- a/include/linux/connector.h +++ b/include/linux/connector.h @@ -90,13 +90,19 @@ void cn_del_callback(const struct cb_id *id); * If @group is not zero, then message will be delivered * to the specified group. * @gfp_mask: GFP mask. + * @filter: Filter function to be used at netlink layer. + * @filter_data:Filter data to be supplied to the filter function * * It can be safely called from softirq context, but may silently * fail under strong memory pressure. * * If there are no listeners for given group %-ESRCH can be returned. */ -int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 group, gfp_t gfp_mask); +int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, + u32 group, gfp_t gfp_mask, + int (*filter)(struct sock *dsk, struct sk_buff *skb, + void *data), + void *filter_data); /** * cn_netlink_send - Sends message to the specified groups. -- cgit v1.2.3