[PATCH v2 1/5] lsm: Add hook unix_path_connect
From: Günther Noack <hidden>
Date: 2026-01-10 14:34:31
Also in:
linux-security-module
Subsystem:
networking [general], networking [unix sockets], security subsystem, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
From: Justin Suess <redacted> Adds an LSM hook unix_path_connect. This hook is called to check the path of a named unix socket before a connection is initiated. Cc: Günther Noack <redacted> Signed-off-by: Justin Suess <redacted> --- include/linux/lsm_hook_defs.h | 4 ++++ include/linux/security.h | 11 +++++++++++ net/unix/af_unix.c | 9 +++++++++ security/security.c | 20 ++++++++++++++++++++ 4 files changed, 44 insertions(+)
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 8c42b4bde09c..1dee5d8d52d2 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h@@ -317,6 +317,10 @@ LSM_HOOK(int, 0, post_notification, const struct cred *w_cred, LSM_HOOK(int, 0, watch_key, struct key *key) #endif /* CONFIG_SECURITY && CONFIG_KEY_NOTIFICATIONS */ +#if defined(CONFIG_SECURITY_NETWORK) && defined(CONFIG_SECURITY_PATH) +LSM_HOOK(int, 0, unix_path_connect, const struct path *path, int type, int flags) +#endif /* CONFIG_SECURITY_NETWORK && CONFIG_SECURITY_PATH */ + #ifdef CONFIG_SECURITY_NETWORK LSM_HOOK(int, 0, unix_stream_connect, struct sock *sock, struct sock *other, struct sock *newsk)
diff --git a/include/linux/security.h b/include/linux/security.h
index 83a646d72f6f..382612af27a6 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h@@ -1931,6 +1931,17 @@ static inline int security_mptcp_add_subflow(struct sock *sk, struct sock *ssk) } #endif /* CONFIG_SECURITY_NETWORK */ +#if defined(CONFIG_SECURITY_NETWORK) && defined(CONFIG_SECURITY_PATH) + +int security_unix_path_connect(const struct path *path, int type, int flags); + +#else /* CONFIG_SECURITY_NETWORK && CONFIG_SECURITY_PATH */ +static inline int security_unix_path_connect(const struct path *path, int type, int flags) +{ + return 0; +} +#endif /* CONFIG_SECURITY_NETWORK && CONFIG_SECURITY_PATH */ + #ifdef CONFIG_SECURITY_INFINIBAND int security_ib_pkey_access(void *sec, u64 subnet_prefix, u16 pkey); int security_ib_endport_manage_subnet(void *sec, const char *name, u8 port_num);
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 55cdebfa0da0..3aabe2d489ae 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c@@ -1226,6 +1226,15 @@ static struct sock *unix_find_bsd(struct sockaddr_un *sunaddr, int addr_len, if (!S_ISSOCK(inode->i_mode)) goto path_put; + /* + * We call the hook because we know that the inode is a socket + * and we hold a valid reference to it via the path. + */ + err = security_unix_path_connect(&path, type, flags); + if (err) + goto path_put; + + err = -ECONNREFUSED; sk = unix_find_socket_byinode(inode); if (!sk) goto path_put;
diff --git a/security/security.c b/security/security.c
index 31a688650601..0cee3502db83 100644
--- a/security/security.c
+++ b/security/security.c@@ -4731,6 +4731,26 @@ int security_mptcp_add_subflow(struct sock *sk, struct sock *ssk) #endif /* CONFIG_SECURITY_NETWORK */ +#if defined(CONFIG_SECURITY_NETWORK) && defined(CONFIG_SECURITY_PATH) +/* + * security_unix_path_connect() - Check if a named AF_UNIX socket can connect + * @path: path of the socket being connected to + * @type: type of the socket + * @flags: flags associated with the socket + * + * This hook is called to check permissions before connecting to a named + * AF_UNIX socket. + * + * Return: Returns 0 if permission is granted. + */ +int security_unix_path_connect(const struct path *path, int type, int flags) +{ + return call_int_hook(unix_path_connect, path, type, flags); +} +EXPORT_SYMBOL(security_unix_path_connect); + +#endif /* CONFIG_SECURITY_NETWORK && CONFIG_SECURITY_PATH */ + #ifdef CONFIG_SECURITY_INFINIBAND /** * security_ib_pkey_access() - Check if access to an IB pkey is allowed
--
2.52.0