[PATCH net 9/9] rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy

Matthieu Baerts (NGI0)
2025-01-08T15:35:55Z

The per-netns structure can be obtained from the table->data using
container_of(), then the 'net' one can be retrieved from the listen
socket (if available).

Fixes: c6a58ffed536 ("RDS: TCP: Add sysctl tunables for sndbuf/rcvbuf on rds-tcp socket")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/67769ecb.050a0220.3a8527.003f.GAE@google.com [1]
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
net/rds/tcp.c | 39 ++++++++++++++++++++++++++++++++-------
1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index 351ac1747224a3a1c8b0e297ba53cdbbcbc55401..0581c53e6517043ad6c2ad4207b26ab169989ed8 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -61,8 +61,10 @@ static atomic_t rds_tcp_unloading = ATOMIC_INIT(0);

static struct kmem_cache *rds_tcp_conn_slab;

-static int rds_tcp_skbuf_handler(const struct ctl_table *ctl, int write,
- void *buffer, size_t *lenp, loff_t *fpos);
+static int rds_tcp_sndbuf_handler(const struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *fpos);
+static int rds_tcp_rcvbuf_handler(const struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *fpos);

static int rds_tcp_min_sndbuf = SOCK_MIN_SNDBUF;
static int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;
@@ -74,7 +76,7 @@ static struct ctl_table rds_tcp_sysctl_table[] = {
/* data is per-net pointer */
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = rds_tcp_skbuf_handler,
+ .proc_handler = rds_tcp_sndbuf_handler,
.extra1 = &rds_tcp_min_sndbuf,
},
#define RDS_TCP_RCVBUF 1
@@ -83,7 +85,7 @@ static struct ctl_table rds_tcp_sysctl_table[] = {
/* data is per-net pointer */
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = rds_tcp_skbuf_handler,
+ .proc_handler = rds_tcp_rcvbuf_handler,
.extra1 = &rds_tcp_min_rcvbuf,
},
};
@@ -682,10 +684,10 @@ static void rds_tcp_sysctl_reset(struct net *net)
spin_unlock_irq(&rds_tcp_conn_lock);
}

-static int rds_tcp_skbuf_handler(const struct ctl_table *ctl, int write,
+static int rds_tcp_skbuf_handler(struct rds_tcp_net *rtn,
+ const struct ctl_table *ctl, int write,
void *buffer, size_t *lenp, loff_t *fpos)
{
- struct net *net = current->nsproxy->net_ns;
int err;

err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
@@ -694,11 +696,34 @@ static int rds_tcp_skbuf_handler(const struct ctl_table *ctl, int write,
*(int *)(ctl->extra1));
return err;
}
- if (write)
+
+ if (write && rtn->rds_tcp_listen_sock && rtn->rds_tcp_listen_sock->sk) {
+ struct net *net = sock_net(rtn->rds_tcp_listen_sock->sk);
+
rds_tcp_sysctl_reset(net);
+ }
+
return 0;
}

+static int rds_tcp_sndbuf_handler(const struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *fpos)
+{
+ struct rds_tcp_net *rtn = container_of(ctl->data, struct rds_tcp_net,
+ sndbuf_size);
+
+ return rds_tcp_skbuf_handler(rtn, ctl, write, buffer, lenp, fpos);
+}
+
+static int rds_tcp_rcvbuf_handler(const struct ctl_table *ctl, int write,
+ void *buffer, size_t *lenp, loff_t *fpos)
+{
+ struct rds_tcp_net *rtn = container_of(ctl->data, struct rds_tcp_net,
+ rcvbuf_size);
+
+ return rds_tcp_skbuf_handler(rtn, ctl, write, buffer, lenp, fpos);
+}
+
static void rds_tcp_exit(void)
{
rds_tcp_set_unloading();

--
2.47.1