Security: Add Hook to test if the particular xattr is part of a MAC model.
The interface to request security labels from user space is the xattr
interface. When requesting the security label from an NFS server it is
important to make sure the requested xattr actually is a MAC label. This allows
us to make sure that we get the desired semantics from the attribute instead of
something else such as capabilities or a time based LSM.
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: Miguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/security.h b/include/linux/security.h
index c2af462..cff3e4f 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1323,6 +1323,13 @@
* @pages contains the number of pages.
* Return 0 if permission is granted.
*
+ * @ismaclabel:
+ * Check if the extended attribute specified by @name
+ * represents a MAC label. Returns 1 if name is a MAC
+ * attribute otherwise returns 0.
+ * @name full extended attribute name to check against
+ * LSM as a MAC label.
+ *
* @secid_to_secctx:
* Convert secid to security context. If secdata is NULL the length of
* the result will be returned in seclen, but no secdata will be returned.
@@ -1604,6 +1611,7 @@
int (*getprocattr) (struct task_struct *p, char *name, char **value);
int (*setprocattr) (struct task_struct *p, char *name, void *value, size_t size);
+ int (*ismaclabel) (const char *name);
int (*secid_to_secctx) (u32 secid, char **secdata, u32 *seclen);
int (*secctx_to_secid) (const char *secdata, u32 seclen, u32 *secid);
void (*release_secctx) (char *secdata, u32 seclen);
@@ -1857,6 +1865,7 @@
int security_getprocattr(struct task_struct *p, char *name, char **value);
int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
int security_netlink_send(struct sock *sk, struct sk_buff *skb);
+int security_ismaclabel(const char *name);
int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
void security_release_secctx(char *secdata, u32 seclen);
@@ -2547,6 +2556,11 @@
return cap_netlink_send(sk, skb);
}
+static inline int security_ismaclabel(const char *name)
+{
+ return 0;
+}
+
static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return -EOPNOTSUPP;
diff --git a/security/capability.c b/security/capability.c
index 58578b4..71f9682 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -823,6 +823,11 @@
return -EINVAL;
}
+static int cap_ismaclabel(const char *name)
+{
+ return 0;
+}
+
static int cap_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return -EOPNOTSUPP;
@@ -1042,6 +1047,7 @@
set_to_cap_if_null(ops, d_instantiate);
set_to_cap_if_null(ops, getprocattr);
set_to_cap_if_null(ops, setprocattr);
+ set_to_cap_if_null(ops, ismaclabel);
set_to_cap_if_null(ops, secid_to_secctx);
set_to_cap_if_null(ops, secctx_to_secid);
set_to_cap_if_null(ops, release_secctx);
diff --git a/security/security.c b/security/security.c
index 0fe2b2e..c3ceb75 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1057,6 +1057,12 @@
return security_ops->netlink_send(sk, skb);
}
+int security_ismaclabel(const char *name)
+{
+ return security_ops->ismaclabel(name);
+}
+EXPORT_SYMBOL(security_ismaclabel);
+
int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return security_ops->secid_to_secctx(secid, secdata, seclen);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b1f7bd7..bbf219a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5454,6 +5454,11 @@
return error;
}
+static int selinux_ismaclabel(const char *name)
+{
+ return (strcmp(name, XATTR_SELINUX_SUFFIX) == 0);
+}
+
static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return security_sid_to_context(secid, secdata, seclen);
@@ -5692,6 +5697,7 @@
.getprocattr = selinux_getprocattr,
.setprocattr = selinux_setprocattr,
+ .ismaclabel = selinux_ismaclabel,
.secid_to_secctx = selinux_secid_to_secctx,
.secctx_to_secid = selinux_secctx_to_secid,
.release_secctx = selinux_release_secctx,
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d52c780..a7f485b 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3329,6 +3329,16 @@
#endif /* CONFIG_AUDIT */
/**
+ * smack_ismaclabel - check if xattr @name references a smack MAC label
+ * @name: Full xattr name to check.
+ */
+static int smack_ismaclabel(const char *name)
+{
+ return (strcmp(name, XATTR_SMACK_SUFFIX) == 0);
+}
+
+
+/**
* smack_secid_to_secctx - return the smack label for a secid
* @secid: incoming integer
* @secdata: destination
@@ -3524,6 +3534,7 @@
.audit_rule_free = smack_audit_rule_free,
#endif /* CONFIG_AUDIT */
+ .ismaclabel = smack_ismaclabel,
.secid_to_secctx = smack_secid_to_secctx,
.secctx_to_secid = smack_secctx_to_secid,
.release_secctx = smack_release_secctx,
