selinux: fix possible memory leak

Free 'ctx_str' when necessary.
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Moore <pmoore@redhat.com>

security/selinux/xfrm.c

@@ -327,19 +327,22 @@ int selinux_xfrm_state_alloc_acquire(struct xfrm_state *x,
 		return rc;
 
 	ctx = kmalloc(sizeof(*ctx) + str_len, GFP_ATOMIC);
-	if (!ctx)
-		return -ENOMEM;
+	if (!ctx) {
+		rc = -ENOMEM;
+		goto out;
+	}
 
 	ctx->ctx_doi = XFRM_SC_DOI_LSM;
 	ctx->ctx_alg = XFRM_SC_ALG_SELINUX;
 	ctx->ctx_sid = secid;
 	ctx->ctx_len = str_len;
 	memcpy(ctx->ctx_str, ctx_str, str_len);
-	kfree(ctx_str);
 
 	x->security = ctx;
 	atomic_inc(&selinux_xfrm_refcount);
-	return 0;
+out:
+	kfree(ctx_str);
+	return rc;
 }
 
 /*