From 2494c088f0aacb50305b1c05a81ea64a28b21caf Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Mon, 9 Dec 2024 21:14:01 +0100
Subject: [PATCH] unix,win: handle nbufs=0 in uv_udp_try_send (#4641)

---
 src/unix/udp.c           | 3 ++-
 src/win/udp.c            | 3 ++-
 test/test-udp-try-send.c | 4 ++++
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/unix/udp.c b/src/unix/udp.c
index f6640fc7..c3e30314 100644
--- a/src/unix/udp.c
+++ b/src/unix/udp.c
@@ -793,7 +793,8 @@ int uv__udp_try_send(uv_udp_t* handle,
   struct msghdr h;
   ssize_t size;
 
-  assert(nbufs > 0);
+  if (nbufs < 1)
+    return UV_EINVAL;
 
   /* already sending a message */
   if (handle->send_queue_count != 0)
diff --git a/src/win/udp.c b/src/win/udp.c
index 5c8f6e1d..557b4e60 100644
--- a/src/win/udp.c
+++ b/src/win/udp.c
@@ -1101,7 +1101,8 @@ int uv__udp_try_send(uv_udp_t* handle,
   struct sockaddr_storage converted;
   int err;
 
-  assert(nbufs > 0);
+  if (nbufs < 1)
+    return UV_EINVAL;
 
   if (addr != NULL) {
     err = uv__convert_to_localhost_if_unspecified(addr, &converted);
diff --git a/test/test-udp-try-send.c b/test/test-udp-try-send.c
index 0c76fb1c..04246a82 100644
--- a/test/test-udp-try-send.c
+++ b/test/test-udp-try-send.c
@@ -101,6 +101,10 @@ TEST_IMPL(udp_try_send) {
   ASSERT_OK(r);
 
   buf = uv_buf_init(buffer, sizeof(buffer));
+
+  r = uv_udp_try_send(&client, &buf, 0, (const struct sockaddr*) &addr);
+  ASSERT_EQ(r, UV_EINVAL);
+
   r = uv_udp_try_send(&client, &buf, 1, (const struct sockaddr*) &addr);
   ASSERT_EQ(r, UV_EMSGSIZE);