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Message-Id: <20230309031953.2350213-3-anjali.k.kulkarni@oracle.com>
Date: Wed, 8 Mar 2023 19:19:50 -0800
From: Anjali Kulkarni <anjali.k.kulkarni@...cle.com>
To: davem@...emloft.net
Cc: edumazet@...gle.com, kuba@...nel.org, pabeni@...hat.com,
zbr@...emap.net, brauner@...nel.org, johannes@...solutions.net,
ecree.xilinx@...il.com, leon@...nel.org, keescook@...omium.org,
socketcan@...tkopp.net, petrm@...dia.com,
linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
anjali.k.kulkarni@...cle.com
Subject: [PATCH 2/5] connector/cn_proc: Add filtering to fix some bugs
One bug is 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.
Signed-off-by: Anjali Kulkarni <anjali.k.kulkarni@...cle.com>
---
drivers/connector/cn_proc.c | 54 ++++++++++++++++++++++++++++-------
drivers/connector/connector.c | 12 +++++---
drivers/w1/w1_netlink.c | 6 ++--
include/linux/connector.h | 6 +++-
include/uapi/linux/cn_proc.h | 43 ++++++++++++++++------------
net/netlink/af_netlink.c | 10 +++++--
6 files changed, 94 insertions(+), 37 deletions(-)
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
index ccac1c453080..ef3820b43b5c 100644
--- a/drivers/connector/cn_proc.c
+++ b/drivers/connector/cn_proc.c
@@ -48,6 +48,22 @@ static DEFINE_PER_CPU(struct local_event, local_event) = {
.lock = INIT_LOCAL_LOCK(lock),
};
+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;
+}
+EXPORT_SYMBOL_GPL(cn_filter);
+
static inline void send_msg(struct cn_msg *msg)
{
local_lock(&local_event.lock);
@@ -61,7 +77,8 @@ 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 +363,9 @@ 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 +382,32 @@ 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);
+ 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..1b7851b1aa0f 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);
diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
index db110cc442b1..691978cddab7 100644
--- a/drivers/w1/w1_netlink.c
+++ b/drivers/w1/w1_netlink.c
@@ -65,7 +65,8 @@ static void w1_unref_block(struct w1_cb_block *block)
u16 len = w1_reply_len(block);
if (len) {
cn_netlink_send_mult(block->first_cn, len,
- block->portid, 0, GFP_KERNEL);
+ block->portid, 0,
+ GFP_KERNEL, NULL, NULL);
}
kfree(block);
}
@@ -83,7 +84,8 @@ static void w1_reply_make_space(struct w1_cb_block *block, u16 space)
{
u16 len = w1_reply_len(block);
if (len + space >= block->maxlen) {
- cn_netlink_send_mult(block->first_cn, len, block->portid, 0, GFP_KERNEL);
+ cn_netlink_send_mult(block->first_cn, len, block->portid,
+ 0, GFP_KERNEL, NULL, NULL);
block->first_cn->len = 0;
block->cn = NULL;
block->msg = NULL;
diff --git a/include/linux/connector.h b/include/linux/connector.h
index 487350bb19c3..1336a5e7dd2f 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -96,7 +96,11 @@ void cn_del_callback(const struct cb_id *id);
*
* 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.
diff --git a/include/uapi/linux/cn_proc.h b/include/uapi/linux/cn_proc.h
index db210625cee8..6a06fb424313 100644
--- a/include/uapi/linux/cn_proc.h
+++ b/include/uapi/linux/cn_proc.h
@@ -30,6 +30,30 @@ enum proc_cn_mcast_op {
PROC_CN_MCAST_IGNORE = 2
};
+enum proc_cn_event {
+ /* Use successive bits so the enums can be used to record
+ * sets of events as well
+ */
+ PROC_EVENT_NONE = 0x00000000,
+ PROC_EVENT_FORK = 0x00000001,
+ PROC_EVENT_EXEC = 0x00000002,
+ PROC_EVENT_UID = 0x00000004,
+ PROC_EVENT_GID = 0x00000040,
+ PROC_EVENT_SID = 0x00000080,
+ PROC_EVENT_PTRACE = 0x00000100,
+ PROC_EVENT_COMM = 0x00000200,
+ /* "next" should be 0x00000400 */
+ /* "last" is the last process event: exit,
+ * while "next to last" is coredumping event
+ */
+ PROC_EVENT_COREDUMP = 0x40000000,
+ PROC_EVENT_EXIT = 0x80000000
+};
+
+struct proc_input {
+ enum proc_cn_mcast_op mcast_op;
+};
+
/*
* From the user's point of view, the process
* ID is the thread group ID and thread ID is the internal
@@ -44,24 +68,7 @@ enum proc_cn_mcast_op {
*/
struct proc_event {
- enum what {
- /* Use successive bits so the enums can be used to record
- * sets of events as well
- */
- PROC_EVENT_NONE = 0x00000000,
- PROC_EVENT_FORK = 0x00000001,
- PROC_EVENT_EXEC = 0x00000002,
- PROC_EVENT_UID = 0x00000004,
- PROC_EVENT_GID = 0x00000040,
- PROC_EVENT_SID = 0x00000080,
- PROC_EVENT_PTRACE = 0x00000100,
- PROC_EVENT_COMM = 0x00000200,
- /* "next" should be 0x00000400 */
- /* "last" is the last process event: exit,
- * while "next to last" is coredumping event */
- PROC_EVENT_COREDUMP = 0x40000000,
- PROC_EVENT_EXIT = 0x80000000
- } what;
+ enum proc_cn_event what;
__u32 cpu;
__u64 __attribute__((aligned(8))) timestamp_ns;
/* Number of nano seconds since system boot */
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 003c7e6ec9be..b311375b8c4c 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -63,6 +63,7 @@
#include <linux/net_namespace.h>
#include <linux/nospec.h>
#include <linux/btf_ids.h>
+#include <linux/connector.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
@@ -767,9 +768,14 @@ static int netlink_release(struct socket *sock)
/* must not acquire netlink_table_lock in any way again before unbind
* and notifying genetlink is done as otherwise it might deadlock
*/
- if (nlk->netlink_unbind) {
+ if (nlk->netlink_unbind && nlk->groups) {
int i;
-
+ if (sk->sk_protocol == NETLINK_CONNECTOR) {
+ if (test_bit(CN_IDX_PROC - 1, nlk->groups)) {
+ kfree(sk->sk_user_data);
+ sk->sk_user_data = NULL;
+ }
+ }
for (i = 0; i < nlk->ngroups; i++)
if (test_bit(i, nlk->groups))
nlk->netlink_unbind(sock_net(sk), i + 1);
--
2.39.2
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