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authorAnjali Kulkarni <anjali.k.kulkarni@oracle.com>2023-07-19 23:18:18 +0300
committerDavid S. Miller <davem@davemloft.net>2023-07-23 13:34:22 +0300
commit2aa1f7a1f47ce8dac7593af605aaa859b3cf3bb1 (patch)
tree4bd4ccb2aaec83fa5e3bd30109955b386742c476 /drivers/connector
parenta4c9a56e6a2cdeeab7caef1f496b7bfefd95b50e (diff)
downloadlinux-2aa1f7a1f47ce8dac7593af605aaa859b3cf3bb1.tar.xz
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 <anjali.k.kulkarni@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/connector')
-rw-r--r--drivers/connector/cn_proc.c57
-rw-r--r--drivers/connector/connector.c21
2 files changed, 64 insertions, 14 deletions
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index ccac1c453080..1ba288ed2bf7 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -48,6 +48,21 @@ static DEFINE_PER_CPU(struct local_event, local_event) = {
.lock = INIT_LOCAL_LOCK(lock),
};
+static int cn_filter(struct sock *dsk, struct sk_buff *skb, void *data)
+{
+ enum proc_cn_mcast_op mc_op;
+
+ if (!dsk)
+ return 0;
+
+ mc_op = ((struct proc_input *)(dsk->sk_user_data))->mcast_op;
+
+ if (mc_op == PROC_CN_MCAST_IGNORE)
+ return 1;
+
+ return 0;
+}
+
static inline void send_msg(struct cn_msg *msg)
{
local_lock(&local_event.lock);
@@ -61,7 +76,8 @@ static inline void send_msg(struct cn_msg *msg)
*
* If cn_netlink_send() fails, the data is not sent.
*/
- cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
+ cn_netlink_send_mult(msg, msg->len, 0, CN_IDX_PROC, GFP_NOWAIT,
+ cn_filter, NULL);
local_unlock(&local_event.lock);
}
@@ -346,11 +362,9 @@ static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
static void cn_proc_mcast_ctl(struct cn_msg *msg,
struct netlink_skb_parms *nsp)
{
- enum proc_cn_mcast_op *mc_op = NULL;
- int err = 0;
-
- if (msg->len != sizeof(*mc_op))
- return;
+ enum proc_cn_mcast_op mc_op = 0, prev_mc_op = 0;
+ int err = 0, initial = 0;
+ struct sock *sk = NULL;
/*
* Events are reported with respect to the initial pid
@@ -367,13 +381,36 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg,
goto out;
}
- mc_op = (enum proc_cn_mcast_op *)msg->data;
- switch (*mc_op) {
+ if (msg->len == sizeof(mc_op))
+ mc_op = *((enum proc_cn_mcast_op *)msg->data);
+ else
+ return;
+
+ if (nsp->sk) {
+ sk = nsp->sk;
+ if (sk->sk_user_data == NULL) {
+ sk->sk_user_data = kzalloc(sizeof(struct proc_input),
+ GFP_KERNEL);
+ if (sk->sk_user_data == NULL) {
+ err = ENOMEM;
+ goto out;
+ }
+ initial = 1;
+ } else {
+ prev_mc_op =
+ ((struct proc_input *)(sk->sk_user_data))->mcast_op;
+ }
+ ((struct proc_input *)(sk->sk_user_data))->mcast_op = mc_op;
+ }
+
+ switch (mc_op) {
case PROC_CN_MCAST_LISTEN:
- atomic_inc(&proc_event_num_listeners);
+ if (initial || (prev_mc_op != PROC_CN_MCAST_LISTEN))
+ atomic_inc(&proc_event_num_listeners);
break;
case PROC_CN_MCAST_IGNORE:
- atomic_dec(&proc_event_num_listeners);
+ if (!initial && (prev_mc_op != PROC_CN_MCAST_IGNORE))
+ atomic_dec(&proc_event_num_listeners);
break;
default:
err = EINVAL;
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index 48ec7ce6ecac..d1179df2b0ba 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -59,7 +59,9 @@ static int cn_already_initialized;
* both, or if both are zero then the group is looked up and sent there.
*/
int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 __group,
- gfp_t gfp_mask)
+ gfp_t gfp_mask,
+ int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
+ void *filter_data)
{
struct cn_callback_entry *__cbq;
unsigned int size;
@@ -110,8 +112,9 @@ int cn_netlink_send_mult(struct cn_msg *msg, u16 len, u32 portid, u32 __group,
NETLINK_CB(skb).dst_group = group;
if (group)
- return netlink_broadcast(dev->nls, skb, portid, group,
- gfp_mask);
+ return netlink_broadcast_filtered(dev->nls, skb, portid, group,
+ gfp_mask, filter,
+ (void *)filter_data);
return netlink_unicast(dev->nls, skb, portid,
!gfpflags_allow_blocking(gfp_mask));
}
@@ -121,7 +124,8 @@ EXPORT_SYMBOL_GPL(cn_netlink_send_mult);
int cn_netlink_send(struct cn_msg *msg, u32 portid, u32 __group,
gfp_t gfp_mask)
{
- return cn_netlink_send_mult(msg, msg->len, portid, __group, gfp_mask);
+ return cn_netlink_send_mult(msg, msg->len, portid, __group, gfp_mask,
+ NULL, NULL);
}
EXPORT_SYMBOL_GPL(cn_netlink_send);
@@ -162,6 +166,14 @@ static int cn_call_callback(struct sk_buff *skb)
return err;
}
+static void cn_release(struct sock *sk, unsigned long *groups)
+{
+ if (groups && test_bit(CN_IDX_PROC - 1, groups)) {
+ kfree(sk->sk_user_data);
+ sk->sk_user_data = NULL;
+ }
+}
+
/*
* Main netlink receiving function.
*
@@ -249,6 +261,7 @@ static int cn_init(void)
struct netlink_kernel_cfg cfg = {
.groups = CN_NETLINK_USERS + 0xf,
.input = cn_rx_skb,
+ .release = cn_release,
};
dev->nls = netlink_kernel_create(&init_net, NETLINK_CONNECTOR, &cfg);