unix,win: add uv_random()

Add an API for obtaining cryptographically strong random data from the
system PRNG.

Co-authored-by: Saúl Ibarra Corretgé <s@saghul.net>
Refs: https://github.com/libuv/libuv/pull/1055
PR-URL: https://github.com/libuv/libuv/pull/2347
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>

1 files changed, 120 insertions, 0 deletions

diff --git a/src/random.c b/src/random.c
new file mode 100644
index 00000000..233b486d
--- /dev/null
+++ b/src/random.c
@@ -0,0 +1,120 @@
+/* Copyright libuv contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "uv-common.h"
+
+#ifdef _WIN32
+#  include "win/internal.h"
+#else
+#  include "unix/internal.h"
+#endif
+
+static int uv__random(void* buf, size_t buflen) {
+  int rc;
+
+#if defined(__PASE__)
+  rc = uv__random_readpath("/dev/urandom", buf, buflen);
+#elif defined(_AIX)
+  rc = uv__random_readpath("/dev/random", buf, buflen);
+#elif defined(__APPLE__) || defined(__OpenBSD__)
+  rc = uv__random_getentropy(buf, buflen);
+  if (rc == UV_ENOSYS)
+    rc = uv__random_devurandom(buf, buflen);
+#elif defined(__FreeBSD__) || defined(__linux__)
+  rc = uv__random_getrandom(buf, buflen);
+  if (rc == UV_ENOSYS)
+    rc = uv__random_devurandom(buf, buflen);
+# if defined(__linux__)
+  switch (rc) {
+    case UV_EACCES:
+    case UV_EIO:
+    case UV_ELOOP:
+    case UV_EMFILE:
+    case UV_ENFILE:
+    case UV_ENOENT:
+    case UV_EPERM:
+      rc = uv__random_sysctl(buf, buflen);
+      break;
+  }
+# endif
+#elif defined(_WIN32)
+  uv__once_init();
+  rc = uv__random_rtlgenrandom(buf, buflen);
+#else
+  rc = uv__random_devurandom(buf, buflen);
+#endif
+
+  return rc;
+}
+
+
+static void uv__random_work(struct uv__work* w) {
+  uv_random_t* req;
+
+  req = container_of(w, uv_random_t, work_req);
+  req->status = uv__random(req->buf, req->buflen);
+}
+
+
+static void uv__random_done(struct uv__work* w, int status) {
+  uv_random_t* req;
+
+  req = container_of(w, uv_random_t, work_req);
+  uv__req_unregister(req->loop, req);
+
+  if (status == 0)
+    status = req->status;
+
+  req->cb(req, status, req->buf, req->buflen);
+}
+
+
+int uv_random(uv_loop_t* loop,
+              uv_random_t* req,
+              void *buf,
+              size_t buflen,
+              unsigned flags,
+              uv_random_cb cb) {
+  if (buflen > 0x7FFFFFFFu)
+    return UV_E2BIG;
+
+  if (flags != 0)
+    return UV_EINVAL;
+
+  if (cb == NULL)
+    return uv__random(buf, buflen);
+
+  uv__req_init(loop, req, UV_RANDOM);
+  req->loop = loop;
+  req->status = 0;
+  req->cb = cb;
+  req->buf = buf;
+  req->buflen = buflen;
+
+  uv__work_submit(loop,
+                  &req->work_req,
+                  UV__WORK_CPU,
+                  uv__random_work,
+                  uv__random_done);
+
+  return 0;
+}