[PATCH 6.6 134/638] sock_diag: annotate data-races around sock_diag_handlers[family]

Sasha Levin
2024-03-24T23:03:29Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit efd402537673f9951992aea4ef0f5ff51d858f4b ]

__sock_diag_cmd() and sock_diag_bind() read sock_diag_handlers[family]
without a lock held.

Use READ_ONCE()/WRITE_ONCE() annotations to avoid potential issues.

Fixes: 8ef874bfc729 ("sock_diag: Move the sock_ code to net/core/")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/sock_diag.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index b1e29e18d1d60..c53b731f2d672 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -193,7 +193,7 @@ int sock_diag_register(const struct sock_diag_handler *hndl)
if (sock_diag_handlers[hndl->family])
err = -EBUSY;
else
- sock_diag_handlers[hndl->family] = hndl;
+ WRITE_ONCE(sock_diag_handlers[hndl->family], hndl);
mutex_unlock(&sock_diag_table_mutex);

return err;
@@ -209,7 +209,7 @@ void sock_diag_unregister(const struct sock_diag_handler *hnld)

mutex_lock(&sock_diag_table_mutex);
BUG_ON(sock_diag_handlers[family] != hnld);
- sock_diag_handlers[family] = NULL;
+ WRITE_ONCE(sock_diag_handlers[family], NULL);
mutex_unlock(&sock_diag_table_mutex);
}
EXPORT_SYMBOL_GPL(sock_diag_unregister);
@@ -227,7 +227,7 @@ static int __sock_diag_cmd(struct sk_buff *skb, struct nlmsghdr *nlh)
return -EINVAL;
req->sdiag_family = array_index_nospec(req->sdiag_family, AF_MAX);

- if (sock_diag_handlers[req->sdiag_family] == NULL)
+ if (READ_ONCE(sock_diag_handlers[req->sdiag_family]) == NULL)
sock_load_diag_module(req->sdiag_family, 0);

mutex_lock(&sock_diag_table_mutex);
@@ -286,12 +286,12 @@ static int sock_diag_bind(struct net *net, int group)
switch (group) {
case SKNLGRP_INET_TCP_DESTROY:
case SKNLGRP_INET_UDP_DESTROY:
- if (!sock_diag_handlers[AF_INET])
+ if (!READ_ONCE(sock_diag_handlers[AF_INET]))
sock_load_diag_module(AF_INET, 0);
break;
case SKNLGRP_INET6_TCP_DESTROY:
case SKNLGRP_INET6_UDP_DESTROY:
- if (!sock_diag_handlers[AF_INET6])
+ if (!READ_ONCE(sock_diag_handlers[AF_INET6]))
sock_load_diag_module(AF_INET6, 0);
break;
}
--
2.43.0