6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Matt Johnston matt@codeconstruct.com.au
[ Upstream commit 3954502377ec05a1b37e2dc9bef0bacd4bbd71b2 ]
Disallow bind() calls that have the same arguments as existing bound sockets. Previously multiple sockets could bind() to the same type/local address, with an arbitrary socket receiving matched messages.
This is only a partial fix, a future commit will define precedence order for MCTP_ADDR_ANY versus specific EID bind(), which are allowed to exist together.
Signed-off-by: Matt Johnston matt@codeconstruct.com.au Link: https://patch.msgid.link/20250710-mctp-bind-v4-2-8ec2f6460c56@codeconstruct.... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/mctp/af_mctp.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-)
diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c index 8032cfba22d1..5f9592fb57ad 100644 --- a/net/mctp/af_mctp.c +++ b/net/mctp/af_mctp.c @@ -73,7 +73,6 @@ static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen)
lock_sock(sk);
- /* TODO: allow rebind */ if (sk_hashed(sk)) { rc = -EADDRINUSE; goto out_release; @@ -549,15 +548,36 @@ static void mctp_sk_close(struct sock *sk, long timeout) static int mctp_sk_hash(struct sock *sk) { struct net *net = sock_net(sk); + struct sock *existing; + struct mctp_sock *msk; + int rc; + + msk = container_of(sk, struct mctp_sock, sk);
/* Bind lookup runs under RCU, remain live during that. */ sock_set_flag(sk, SOCK_RCU_FREE);
mutex_lock(&net->mctp.bind_lock); + + /* Prevent duplicate binds. */ + sk_for_each(existing, &net->mctp.binds) { + struct mctp_sock *mex = + container_of(existing, struct mctp_sock, sk); + + if (mex->bind_type == msk->bind_type && + mex->bind_addr == msk->bind_addr && + mex->bind_net == msk->bind_net) { + rc = -EADDRINUSE; + goto out; + } + } + sk_add_node_rcu(sk, &net->mctp.binds); - mutex_unlock(&net->mctp.bind_lock); + rc = 0;
- return 0; +out: + mutex_unlock(&net->mctp.bind_lock); + return rc; }
static void mctp_sk_unhash(struct sock *sk)