[v3,7/9] selinux: Implement Infiniband PKey "Access" access vector

Commit Message

Daniel Jurgens July 29, 2016, 1:53 p.m. UTC

From: Daniel Jurgens <[e-mail]>

Add a type and access vector for PKeys. Implement the ib_pkey_access
hook to check that the caller has permission to access the PKey on the
given subnet prefix. Add an interface to get the PKey SID. Walk the PKey
ocontexts to find an entry for the given subnet prefix and pkey.

Signed-off-by: Daniel Jurgens <[e-mail]>

---
v2:
- Use void* blobs for security structs. Paul Moore
- Add pkey specific data to the audit log. Paul Moore
- Don't introduce a new initial sid, use unlabeled. Stephen Smalley

v3:
- Reorder parameters to pkey_access hook. Paul Moore

 include/linux/lsm_audit.h           |  7 +++++++
 security/lsm_audit.c                | 13 ++++++++++++
 security/selinux/hooks.c            | 23 +++++++++++++++++++++
 security/selinux/include/classmap.h |  2 ++
 security/selinux/include/security.h |  2 ++
 security/selinux/ss/services.c      | 41 +++++++++++++++++++++++++++++++++++++
 6 files changed, 88 insertions(+)

Patch

diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h
index ffb9c9d..8ff7eae 100644
--- a/include/linux/lsm_audit.h
+++ b/include/linux/lsm_audit.h
@@ -45,6 +45,11 @@  struct lsm_ioctlop_audit {
 	u16 cmd;
 };
 
+struct lsm_pkey_audit {
+	u64	subnet_prefix;
+	u16	pkey;
+};
+
 /* Auxiliary data to use in generating the audit record. */
 struct common_audit_data {
 	char type;
@@ -59,6 +64,7 @@  struct common_audit_data {
 #define LSM_AUDIT_DATA_INODE	9
 #define LSM_AUDIT_DATA_DENTRY	10
 #define LSM_AUDIT_DATA_IOCTL_OP	11
+#define LSM_AUDIT_DATA_PKEY	12
 	union 	{
 		struct path path;
 		struct dentry *dentry;
@@ -75,6 +81,7 @@  struct common_audit_data {
 #endif
 		char *kmod_name;
 		struct lsm_ioctlop_audit *op;
+		struct lsm_pkey_audit *pkey;
 	} u;
 	/* this union contains LSM specific data */
 	union {
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index cccbf30..2546d82 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -397,6 +397,19 @@  static void dump_common_audit_data(struct audit_buffer *ab,
 		audit_log_format(ab, " kmod=");
 		audit_log_untrustedstring(ab, a->u.kmod_name);
 		break;
+	case LSM_AUDIT_DATA_PKEY: {
+		struct in6_addr sbn_pfx;
+
+		memset(&sbn_pfx.s6_addr, 0,
+		       sizeof(sbn_pfx.s6_addr));
+
+		memcpy(&sbn_pfx.s6_addr, &a->u.pkey->subnet_prefix,
+		       sizeof(a->u.pkey->subnet_prefix));
+
+		audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c",
+				 a->u.pkey->pkey, &sbn_pfx);
+		break;
+	}
 	} /* switch (a->type) */
 }
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ef1088c..101ea82 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5995,6 +5995,28 @@  static int selinux_key_getsecurity(struct key *key, char **_buffer)
 #endif
 
 #ifdef CONFIG_SECURITY_INFINIBAND
+static int selinux_ib_pkey_access(void *ib_sec, u64 subnet_prefix, u16 pkey_val)
+{
+	struct common_audit_data ad;
+	int err;
+	u32 sid = 0;
+	struct ib_security_struct *sec = ib_sec;
+	struct lsm_pkey_audit pkey;
+
+	err = security_pkey_sid(subnet_prefix, pkey_val, &sid);
+
+	if (err)
+		return err;
+
+	ad.type = LSM_AUDIT_DATA_PKEY;
+	pkey.subnet_prefix = subnet_prefix;
+	pkey.pkey = pkey_val;
+	ad.u.pkey = &pkey;
+	return avc_has_perm(sec->sid, sid,
+			    SECCLASS_INFINIBAND_PKEY,
+			    INFINIBAND_PKEY__ACCESS, &ad);
+}
+
 static int selinux_ib_alloc_security(void **ib_sec)
 {
 	struct ib_security_struct *sec;
@@ -6196,6 +6218,7 @@  static struct security_hook_list selinux_hooks[] = {
 	LSM_HOOK_INIT(tun_dev_attach, selinux_tun_dev_attach),
 	LSM_HOOK_INIT(tun_dev_open, selinux_tun_dev_open),
 #ifdef CONFIG_SECURITY_INFINIBAND
+	LSM_HOOK_INIT(ib_pkey_access, selinux_ib_pkey_access),
 	LSM_HOOK_INIT(ib_alloc_security, selinux_ib_alloc_security),
 	LSM_HOOK_INIT(ib_free_security, selinux_ib_free_security),
 #endif
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 1f1f4b2..d42dd4d 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -165,5 +165,7 @@  struct security_class_mapping secclass_map[] = {
 	  { COMMON_CAP_PERMS, NULL } },
 	{ "cap2_userns",
 	  { COMMON_CAP2_PERMS, NULL } },
+	{ "infiniband_pkey",
+	  { "access", NULL } },
 	{ NULL }
   };
diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
index a7e6ed2..8f1a66e 100644
--- a/security/selinux/include/security.h
+++ b/security/selinux/include/security.h
@@ -180,6 +180,8 @@  int security_get_user_sids(u32 callsid, char *username,
 
 int security_port_sid(u8 protocol, u16 port, u32 *out_sid);
 
+int security_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *out_sid);
+
 int security_netif_sid(char *name, u32 *if_sid);
 
 int security_node_sid(u16 domain, void *addr, u32 addrlen,
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 89df646..ba346da 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2229,6 +2229,47 @@  out:
 }
 
 /**
+ * security_pkey_sid - Obtain the SID for a pkey.
+ * @subnet_prefix: Subnet Prefix
+ * @pkey_num: pkey number
+ * @out_sid: security identifier
+ */
+int security_pkey_sid(u64 subnet_prefix, u16 pkey_num, u32 *out_sid)
+{
+	struct ocontext *c;
+	int rc = 0;
+
+	read_lock(&policy_rwlock);
+
+	c = policydb.ocontexts[OCON_PKEY];
+	while (c) {
+		if (c->u.pkey.low_pkey <= pkey_num &&
+		    c->u.pkey.high_pkey >= pkey_num &&
+		    c->u.pkey.subnet_prefix == subnet_prefix)
+			break;
+
+		c = c->next;
+	}
+
+	if (c) {
+		if (!c->sid[0]) {
+			rc = sidtab_context_to_sid(&sidtab,
+						   &c->context[0],
+						   &c->sid[0]);
+			if (rc)
+				goto out;
+		}
+		*out_sid = c->sid[0];
+	} else {
+		*out_sid = SECINITSID_UNLABELED;
+	}
+
+out:
+	read_unlock(&policy_rwlock);
+	return rc;
+}
+
+/**
  * security_netif_sid - Obtain the SID for a network interface.
  * @name: interface name
  * @if_sid: interface SID