[PATCH 94/97] LSM: Hook for netlabel reconciliation
Casey Schaufler
casey at schaufler-ca.com
Thu Feb 28 22:43:53 UTC 2019
Add an LSM function security_reconcile_netlbl() which
uses the new LSM hook socket_netlbl_secattr() to decide
if the active security modules are in agreement regarding
the labeling of a network packet.
Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
---
include/linux/lsm_hooks.h | 15 +++++++++
include/linux/security.h | 9 ++++++
security/security.c | 50 +++++++++++++++++++++++++++++
security/selinux/hooks.c | 3 ++
security/selinux/include/netlabel.h | 7 ++++
security/selinux/netlabel.c | 9 ++++++
security/smack/smack_lsm.c | 9 ++++++
7 files changed, 102 insertions(+)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index fec7f86897ea..2a53465f94da 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -29,6 +29,9 @@
#include <linux/init.h>
#include <linux/rculist.h>
+#ifdef CONFIG_NETLABEL
+struct netlbl_lsm_secattr;
+#endif
/**
* union security_list_options - Linux Security Module hook function list
*
@@ -1416,6 +1419,10 @@
* @bpf_prog_free_security:
* Clean up the security information stored inside bpf prog.
*
+ * Security hooks for network labeling (Netlabel) operations.
+ *
+ * @socket_netlbl_secattr:
+ * Report the netlabel attributes this module wants for this socket.
*/
union security_list_options {
int (*binder_set_context_mgr)(struct task_struct *mgr);
@@ -1772,6 +1779,11 @@ union security_list_options {
int (*bpf_prog_alloc_security)(struct bpf_prog_aux *aux);
void (*bpf_prog_free_security)(struct bpf_prog_aux *aux);
#endif /* CONFIG_BPF_SYSCALL */
+#ifdef CONFIG_NETLABEL
+ void (*socket_netlbl_secattr)(struct sock *sk,
+ struct netlbl_lsm_secattr **secattr,
+ int *set);
+#endif
};
struct security_hook_heads {
@@ -2006,6 +2018,9 @@ struct security_hook_heads {
struct hlist_head bpf_prog_alloc_security;
struct hlist_head bpf_prog_free_security;
#endif /* CONFIG_BPF_SYSCALL */
+#ifdef CONFIG_NETLABEL
+ struct hlist_head socket_netlbl_secattr;
+#endif
} __randomize_layout;
/*
diff --git a/include/linux/security.h b/include/linux/security.h
index 7edceb91d77f..c9d7de811b53 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1878,5 +1878,14 @@ static inline void security_bpf_prog_free(struct bpf_prog_aux *aux)
#endif /* CONFIG_SECURITY */
#endif /* CONFIG_BPF_SYSCALL */
+#ifdef CONFIG_NETLABEL
+extern int security_reconcile_netlbl(struct sock *sk);
+#else
+static inline int security_reconcile_netlbl(struct sock *sk)
+{
+ return 0;
+}
+#endif
+
#endif /* ! __LINUX_SECURITY_H */
diff --git a/security/security.c b/security/security.c
index ab1050a2dce3..3c1d2f47b09f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -33,6 +33,9 @@
#include <linux/msg.h>
#include <net/flow.h>
#include <net/sock.h>
+#ifdef CONFIG_NETLABEL
+#include <net/netlabel.h>
+#endif
#define MAX_LSM_EVM_XATTR 2
@@ -2775,3 +2778,50 @@ void security_bpf_prog_free(struct bpf_prog_aux *aux)
call_void_hook(bpf_prog_free_security, aux);
}
#endif /* CONFIG_BPF_SYSCALL */
+
+#ifdef CONFIG_NETLABEL
+int security_reconcile_netlbl(struct sock *sk)
+{
+ struct netlbl_lsm_secattr *prev = NULL;
+ struct netlbl_lsm_secattr *this = NULL;
+ int prev_set = 0;
+ int this_set = 0;
+ struct security_hook_list *hp;
+
+ hlist_for_each_entry(hp, &security_hook_heads.socket_netlbl_secattr,
+ list) {
+ hp->hook.socket_netlbl_secattr(sk, &this, &this_set);
+ if (this_set == 0 || this == NULL)
+ continue;
+ if (prev != NULL) {
+ /*
+ * Both unlabeled is easily acceptable.
+ */
+ if (prev_set == NETLBL_NLTYPE_UNLABELED &&
+ this_set == NETLBL_NLTYPE_UNLABELED)
+ continue;
+ /*
+ * The nltype being different means that
+ * the secattrs aren't comparible. Except
+ * that ADDRSELECT means that couldn't know
+ * when the socket was created.
+ */
+ if (prev_set != this_set &&
+ prev_set != NETLBL_NLTYPE_ADDRSELECT &&
+ this_set != NETLBL_NLTYPE_ADDRSELECT)
+ return -EACCES;
+ /*
+ * Count on the Netlabel system's judgement.
+ */
+ if (!netlbl_secattr_equal(prev, this))
+ return -EACCES;
+ }
+ prev = this;
+ prev_set = this_set;
+ }
+ /*
+ * No conflicts have been found.
+ */
+ return 0;
+}
+#endif /* CONFIG_NETLABEL */
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 22a190f291c0..84bfcf7ca08b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6769,6 +6769,9 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bpf_map_free_security, selinux_bpf_map_free),
LSM_HOOK_INIT(bpf_prog_free_security, selinux_bpf_prog_free),
#endif
+#ifdef CONFIG_NETLABEL
+ LSM_HOOK_INIT(socket_netlbl_secattr, selinux_socket_netlbl_secattr),
+#endif
};
static __init int selinux_init(void)
diff --git a/security/selinux/include/netlabel.h b/security/selinux/include/netlabel.h
index 8671de09c363..b316c62e7bcc 100644
--- a/security/selinux/include/netlabel.h
+++ b/security/selinux/include/netlabel.h
@@ -69,6 +69,9 @@ int selinux_netlbl_socket_setsockopt(struct socket *sock,
int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr);
int selinux_netlbl_socket_connect_locked(struct sock *sk,
struct sockaddr *addr);
+void selinux_socket_netlbl_secattr(struct sock *sk,
+ struct netlbl_lsm_secattr **secattr,
+ int *set);
#else
static inline void selinux_netlbl_cache_invalidate(void)
@@ -165,6 +168,10 @@ static inline int selinux_netlbl_socket_connect_locked(struct sock *sk,
{
return 0;
}
+static inline void selinux_socket_netlbl_secattr(struct sock *sk,
+ struct netlbl_lsm_secattr **secattr)
+{
+}
#endif /* CONFIG_NETLABEL */
#endif
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index b6fd905e6e9e..56ae261d2805 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -642,3 +642,12 @@ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr)
return rc;
}
+
+void selinux_socket_netlbl_secattr(struct sock *sk,
+ struct netlbl_lsm_secattr **secattr,
+ int *set)
+{
+ struct sk_security_struct *sksec = selinux_sock(sk);
+ *secattr = sksec->nlbl_secattr;
+ *set = sksec->nlbl_set;
+}
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 1b9c7e5e801a..885e1799df00 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4487,6 +4487,14 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
}
return 0;
}
+void smack_socket_netlbl_secattr(struct sock *sk,
+ struct netlbl_lsm_secattr **secattr,
+ int *set)
+{
+ struct socket_smack *ssp = smack_sock(sk);
+ *secattr = &ssp->smk_out->smk_netlabel;
+ *set = ssp->smk_set;
+}
struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
.lbs_cred = sizeof(struct task_smack),
@@ -4638,6 +4646,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up),
LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr),
LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as),
+ LSM_HOOK_INIT(socket_netlbl_secattr, smack_socket_netlbl_secattr),
};
--
2.17.0
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