selinux: cleanup and consolidate the XFRM alloc/clone/delete/free code

The SELinux labeled IPsec code state management functions have been
long neglected and could use some cleanup and consolidation.

Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

1 files changed, 40 insertions, 31 deletions

diff --git a/security/selinux/xfrm.c b/security/selinux/xfrm.c
index 07ae0c06dfc3..f8d71262b45d 100644
--- a/security/selinux/xfrm.c
+++ b/security/selinux/xfrm.c
@@ -122,6 +122,33 @@ err:
 }
 
 /*
+ * Free the xfrm_sec_ctx structure.
+ */
+static void selinux_xfrm_free(struct xfrm_sec_ctx *ctx)
+{
+        if (!ctx)
+                return;
+
+        atomic_dec(&selinux_xfrm_refcount);
+        kfree(ctx);
+}
+
+/*
+ * Authorize the deletion of a labeled SA or policy rule.
+ */
+static int selinux_xfrm_delete(struct xfrm_sec_ctx *ctx)
+{
+        const struct task_security_struct *tsec = current_security();
+
+        if (!ctx)
+                return 0;
+
+        return avc_has_perm(tsec->sid, ctx->ctx_sid,
+                            SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
+                            NULL);
+}
+
+/*
  * LSM hook implementation that authorizes that a flow can use
  * a xfrm policy rule.
  */
@@ -258,17 +285,16 @@ int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
 {
         struct xfrm_sec_ctx *new_ctx;
 
-        if (old_ctx) {
-                new_ctx = kmalloc(sizeof(*old_ctx) + old_ctx->ctx_len,
-                                  GFP_ATOMIC);
-                if (!new_ctx)
-                        return -ENOMEM;
+        if (!old_ctx)
+                return 0;
+
+        new_ctx = kmalloc(sizeof(*old_ctx) + old_ctx->ctx_len, GFP_ATOMIC);
+        if (!new_ctx)
+                return -ENOMEM;
+        memcpy(new_ctx, old_ctx, sizeof(*old_ctx) + old_ctx->ctx_len);
+        atomic_inc(&selinux_xfrm_refcount);
+        *new_ctxp = new_ctx;
 
-                memcpy(new_ctx, old_ctx, sizeof(*new_ctx));
-                memcpy(new_ctx->ctx_str, old_ctx->ctx_str, new_ctx->ctx_len);
-                atomic_inc(&selinux_xfrm_refcount);
-                *new_ctxp = new_ctx;
-        }
         return 0;
 }
 
@@ -277,8 +303,7 @@ int selinux_xfrm_policy_clone(struct xfrm_sec_ctx *old_ctx,
  */
 void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
 {
-        atomic_dec(&selinux_xfrm_refcount);
-        kfree(ctx);
+        selinux_xfrm_free(ctx);
 }
 
 /*
@@ -286,14 +311,7 @@ void selinux_xfrm_policy_free(struct xfrm_sec_ctx *ctx)
  */
 int selinux_xfrm_policy_delete(struct xfrm_sec_ctx *ctx)
 {
-        const struct task_security_struct *tsec = current_security();
-
-        if (!ctx)
-                return 0;
-
-        return avc_has_perm(tsec->sid, ctx->ctx_sid,
-                            SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
-                            NULL);
+        return selinux_xfrm_delete(ctx);
 }
 
 /*
@@ -349,8 +367,7 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
  */
 void selinux_xfrm_state_free(struct xfrm_state *x)
 {
-        atomic_dec(&selinux_xfrm_refcount);
-        kfree(x->security);
+        selinux_xfrm_free(x->security);
 }
 
  /*
@@ -358,15 +375,7 @@ void selinux_xfrm_state_free(struct xfrm_state *x)
   */
 int selinux_xfrm_state_delete(struct xfrm_state *x)
 {
-        const struct task_security_struct *tsec = current_security();
-        struct xfrm_sec_ctx *ctx = x->security;
-
-        if (!ctx)
-                return 0;
-
-        return avc_has_perm(tsec->sid, ctx->ctx_sid,
-                            SECCLASS_ASSOCIATION, ASSOCIATION__SETCONTEXT,
-                            NULL);
+        return selinux_xfrm_delete(x->security);
 }
 
 /*