[PATCH net v1 2/2] net/rds: Restrict use of RDS/IB to the initial network namespace

Allison Henderson
2026-04-05T04:16:16Z

From: Greg Jumper <greg.jumper@oracle.com>

Prevent using RDS/IB in network namespaces other than the initial one.
The existing RDS/IB code will not work properly in non-initial network
namespaces, and there are currently no plans to support such use.

Fixes: d5a8ac28a7ff ("RDS-TCP: Make RDS-TCP work correctly when it is set up in a netns other than init_net")
Reported-by: syzbot+da8e060735ae02c8f3d1@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=da8e060735ae02c8f3d1
Signed-off-by: Greg Jumper <greg.jumper@oracle.com>
Signed-off-by: Allison Henderson <achender@kernel.org>
---
net/rds/af_rds.c | 10 ++++++++--
net/rds/ib.c | 7 ++++++-
2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/net/rds/af_rds.c b/net/rds/af_rds.c
index b396c673dfaf..896d4cfda5c3 100644
--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -357,7 +357,8 @@ static int rds_cong_monitor(struct rds_sock *rs, sockptr_t optval, int optlen)
return ret;
}

-static int rds_set_transport(struct rds_sock *rs, sockptr_t optval, int optlen)
+static int rds_set_transport(struct net *net, struct rds_sock *rs,
+ sockptr_t optval, int optlen)
{
int t_type;

@@ -373,6 +374,10 @@ static int rds_set_transport(struct rds_sock *rs, sockptr_t optval, int optlen)
if (t_type < 0 || t_type >= RDS_TRANS_COUNT)
return -EINVAL;

+ /* Only RDS/TCP supports non-initial network namespaces */
+ if (t_type != RDS_TRANS_TCP && !net_eq(net, &init_net))
+ return -EPROTOTYPE;
+
rs->rs_transport = rds_trans_get(t_type);

return rs->rs_transport ? 0 : -ENOPROTOOPT;
@@ -433,6 +438,7 @@ static int rds_setsockopt(struct socket *sock, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct rds_sock *rs = rds_sk_to_rs(sock->sk);
+ struct net *net = sock_net(sock->sk);
int ret;

if (level != SOL_RDS) {
@@ -461,7 +467,7 @@ static int rds_setsockopt(struct socket *sock, int level, int optname,
break;
case SO_RDS_TRANSPORT:
lock_sock(sock->sk);
- ret = rds_set_transport(rs, optval, optlen);
+ ret = rds_set_transport(net, rs, optval, optlen);
release_sock(sock->sk);
break;
case SO_TIMESTAMP_OLD:
diff --git a/net/rds/ib.c b/net/rds/ib.c
index 73e01984ee9a..1bdbe8eaf3fc 100644
--- a/net/rds/ib.c
+++ b/net/rds/ib.c
@@ -490,8 +490,13 @@ static int rds_ib_laddr_check_cm(struct net *net, const struct in6_addr *addr,
static int rds_ib_laddr_check(struct net *net, const struct in6_addr *addr,
__u32 scope_id)
{
- struct rds_ib_device *rds_ibdev = rds_ib_get_device(addr->s6_addr32[3]);
+ struct rds_ib_device *rds_ibdev;
+
+ /* RDS/IB is only supported in the initial network namespace */
+ if (!net_eq(net, &init_net))
+ return -EPROTOTYPE;

+ rds_ibdev = rds_ib_get_device(addr->s6_addr32[3]);
if (rds_ibdev) {
rds_ib_dev_put(rds_ibdev);

--
2.43.0