[RFC PATCH 5/7] selinux: Implement Infiniband PKey "Access" access vector

Dan Jurgens
2016-04-04T21:48:22Z

From: Daniel Jurgens <danielj@mellanox.com>

Add a type and access vector for PKeys. Implement the 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 <danielj@mellanox.com>
Reviewed-by: Eli Cohen <eli@mellanox.com>
---
include/linux/lsm_audit.h | 7 ++++
security/selinux/hooks.c | 25 +++++++++++++
security/selinux/include/classmap.h | 2 +
security/selinux/include/initial_sid_to_string.h | 1 +
security/selinux/include/security.h | 2 +
security/selinux/ss/services.c | 41 ++++++++++++++++++++++
6 files changed, 78 insertions(+), 0 deletions(-)

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/selinux/hooks.c b/security/selinux/hooks.c
index cd0c6f4..829746b 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5937,6 +5937,30 @@ static int selinux_key_getsecurity(struct key *key, char **_buffer)
#endif

#ifdef CONFIG_SECURITY_INFINIBAND
+static int selinux_pkey_access(u64 subnet_prefix, u16 pkey_val, void *security)
+{
+ struct common_audit_data ad;
+ int err;
+ u32 sid = 0;
+ struct infiniband_security_struct *sec = security;
+ struct lsm_pkey_audit pkey;
+
+ err = security_pkey_sid(subnet_prefix, pkey_val, &sid);
+
+ if (err)
+ goto out;
+
+ ad.type = LSM_AUDIT_DATA_PKEY;
+ pkey.subnet_prefix = subnet_prefix;
+ pkey.pkey = pkey_val;
+ ad.u.pkey = &pkey;
+ err = avc_has_perm(sec->sid, sid,
+ SECCLASS_INFINIBAND_PKEY,
+ INFINIBAND_PKEY__ACCESS, &ad);
+out:
+ return err;
+}
+
static int selinux_infiniband_alloc_security(void **security)
{
struct infiniband_security_struct *sec;
@@ -6138,6 +6162,7 @@ static struct security_hook_list selinux_hooks[] = {
LSM_HOOK_INIT(tun_dev_open, selinux_tun_dev_open),

#ifdef CONFIG_SECURITY_INFINIBAND
+ LSM_HOOK_INIT(pkey_access, selinux_pkey_access),
LSM_HOOK_INIT(infiniband_alloc_security,
selinux_infiniband_alloc_security),
LSM_HOOK_INIT(infiniband_free_security,
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index ef83c4b..46eb7a1 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -157,5 +157,7 @@ struct security_class_mapping secclass_map[] = {
{ COMMON_SOCK_PERMS, "attach_queue", NULL } },
{ "binder", { "impersonate", "call", "set_context_mgr", "transfer",
NULL } },
+ { "infiniband_pkey",
+ { "access", NULL } },
{ NULL }
};
diff --git a/security/selinux/include/initial_sid_to_string.h b/security/selinux/include/initial_sid_to_string.h
index a59b64e..8f2eefc 100644
--- a/security/selinux/include/initial_sid_to_string.h
+++ b/security/selinux/include/initial_sid_to_string.h
@@ -29,5 +29,6 @@ static const char *initial_sid_to_string[] =
"policy",
"scmp_packet",
"devnull",
+ "pkey",
};

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 ebda973..2fc48c5 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_PKEY;
+ }
+
+out:
+ read_unlock(&policy_rwlock);
+ return rc;
+}
+
+/**
* security_netif_sid - Obtain the SID for a network interface.
* @name: interface name
* @if_sid: interface SID
--
1.7.1