From: Sasha Levin <sashal@kernel.org>
To: patches@lists.linux.dev, stable@vger.kernel.org
Cc: Namjae Jeon <linkinjeon@kernel.org>,
Steve French <stfrench@microsoft.com>,
Sasha Levin <sashal@kernel.org>,
smfrench@gmail.com, linux-cifs@vger.kernel.org
Subject: [PATCH AUTOSEL 6.17-6.1] ksmbd: use sock_create_kern interface to create kernel socket
Date: Sat, 25 Oct 2025 11:55:06 -0400 [thread overview]
Message-ID: <20251025160905.3857885-75-sashal@kernel.org> (raw)
In-Reply-To: <20251025160905.3857885-1-sashal@kernel.org>
From: Namjae Jeon <linkinjeon@kernel.org>
[ Upstream commit 3677ca67b9791481af16d86e47c3c7d1f2442f95 ]
we should use sock_create_kern() if the socket resides in kernel space.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
LLM Generated explanations, may be completely bogus:
YES – ksmbd now creates its listening sockets with `sock_create_kern()`,
so the socket is marked as a kernel socket and bypasses LSM policy
checks that would otherwise block the listener.
- `fs/smb/server/transport_tcp.c:474-505` replaces both IPv6 and IPv4
calls to `sock_create()` with
`sock_create_kern(current->nsproxy->net_ns, …)`, ensuring
`__sock_create()` runs with `kern=1` (`net/socket.c:1661-1682`).
- When `kern` stays 0 (old code) LSMs such as SELinux and AppArmor
enforce their policy hooks, which often deny kernel threads from
opening INET stream sockets (`security/selinux/hooks.c:4797-4839`,
`security/apparmor/lsm.c:1261-1301`). That failure bubbles back to
`create_socket()` and leaves the ksmbd interface unconfigured
(`fs/smb/server/transport_tcp.c:474-519`), so the server never starts
listening.
- The change aligns ksmbd with other kernel networking users (e.g., the
SMB client already calls `sock_create_kern()` in
`fs/smb/client/connect.c:3366-3374`) and introduces no behavioral or
API risk beyond correctly flagging the socket as kernel-owned.
Given that this fixes a real service outage on systems with enforcing
LSM policies, is tightly scoped, and carries minimal regression risk, it
is a strong candidate for stable backporting. Suggested verification:
bring up ksmbd under SELinux/AppArmor enforcing and confirm the listener
binds successfully.
fs/smb/server/transport_tcp.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/smb/server/transport_tcp.c b/fs/smb/server/transport_tcp.c
index 1009cb324fd51..43401d09c9db4 100644
--- a/fs/smb/server/transport_tcp.c
+++ b/fs/smb/server/transport_tcp.c
@@ -473,12 +473,13 @@ static int create_socket(struct interface *iface)
struct socket *ksmbd_socket;
bool ipv4 = false;
- ret = sock_create(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &ksmbd_socket);
+ ret = sock_create_kern(current->nsproxy->net_ns, PF_INET6, SOCK_STREAM,
+ IPPROTO_TCP, &ksmbd_socket);
if (ret) {
if (ret != -EAFNOSUPPORT)
pr_err("Can't create socket for ipv6, fallback to ipv4: %d\n", ret);
- ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,
- &ksmbd_socket);
+ ret = sock_create_kern(current->nsproxy->net_ns, PF_INET,
+ SOCK_STREAM, IPPROTO_TCP, &ksmbd_socket);
if (ret) {
pr_err("Can't create socket for ipv4: %d\n", ret);
goto out_clear;
--
2.51.0
next parent reply other threads:[~2025-10-25 16:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20251025160905.3857885-1-sashal@kernel.org>
2025-10-25 15:55 ` Sasha Levin [this message]
2025-10-25 16:00 ` [PATCH AUTOSEL 6.17-6.1] smb: client: transport: avoid reconnects triggered by pending task work Sasha Levin
2025-10-25 16:00 ` [PATCH AUTOSEL 6.17] smb: client: update cfid->last_access_time in open_cached_dir_by_dentry() Sasha Levin
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