1 files changed, 64 insertions, 16 deletions

diff --git a/lib/socketpair.c b/lib/socketpair.c
index 0f8798f08..b94c9843e 100644
--- a/lib/socketpair.c
+++ b/lib/socketpair.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 2019 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -65,7 +65,7 @@ int Curl_socketpair(int domain, int type, int protocol,
   union {
     struct sockaddr_in inaddr;
     struct sockaddr addr;
-  } a, a2;
+  } a;
   curl_socket_t listener;
   curl_socklen_t addrlen = sizeof(a.inaddr);
   int reuse = 1;
@@ -85,9 +85,22 @@ int Curl_socketpair(int domain, int type, int protocol,
 
   socks[0] = socks[1] = CURL_SOCKET_BAD;
 
+#if defined(WIN32) || defined(__CYGWIN__)
+  /* don't set SO_REUSEADDR on Windows */
+  (void)reuse;
+#ifdef SO_EXCLUSIVEADDRUSE
+  {
+    int exclusive = 1;
+    if(setsockopt(listener, SOL_SOCKET, SO_EXCLUSIVEADDRUSE,
+                  (char *)&exclusive, (curl_socklen_t)sizeof(exclusive)) == -1)
+      goto error;
+  }
+#endif
+#else
   if(setsockopt(listener, SOL_SOCKET, SO_REUSEADDR,
                 (char *)&reuse, (curl_socklen_t)sizeof(reuse)) == -1)
     goto error;
+#endif
   if(bind(listener, &a.addr, sizeof(a.inaddr)) == -1)
     goto error;
   if(getsockname(listener, &a.addr, &addrlen) == -1 ||
@@ -107,24 +120,59 @@ int Curl_socketpair(int domain, int type, int protocol,
   pfd[0].fd = listener;
   pfd[0].events = POLLIN;
   pfd[0].revents = 0;
-  (void)Curl_poll(pfd, 1, 10*1000); /* 10 seconds */
+  (void)Curl_poll(pfd, 1, 1000); /* one second */
   socks[1] = accept(listener, NULL, NULL);
   if(socks[1] == CURL_SOCKET_BAD)
     goto error;
+  else {
+    struct curltime check;
+    struct curltime start = Curl_now();
+    char *p = (char *)&check;
+    size_t s = sizeof(check);
 
-  /* verify that nothing else connected */
-  addrlen = sizeof(a.inaddr);
-  if(getsockname(socks[0], &a.addr, &addrlen) == -1 ||
-     addrlen < (int)sizeof(a.inaddr))
-    goto error;
-  addrlen = sizeof(a2.inaddr);
-  if(getpeername(socks[1], &a2.addr, &addrlen) == -1 ||
-     addrlen < (int)sizeof(a2.inaddr))
-    goto error;
-  if(a.inaddr.sin_family != a2.inaddr.sin_family ||
-     a.inaddr.sin_addr.s_addr != a2.inaddr.sin_addr.s_addr ||
-     a.inaddr.sin_port != a2.inaddr.sin_port)
-    goto error;
+    /* write data to the socket */
+    swrite(socks[0], &start, sizeof(start));
+    /* verify that we read the correct data */
+    do {
+      ssize_t nread;
+
+      pfd[0].fd = socks[1];
+      pfd[0].events = POLLIN;
+      pfd[0].revents = 0;
+      (void)Curl_poll(pfd, 1, 1000); /* one second */
+
+      nread = sread(socks[1], p, s);
+      if(nread == -1) {
+        int sockerr = SOCKERRNO;
+        /* Don't block forever */
+        if(Curl_timediff(Curl_now(), start) > (60 * 1000))
+          goto error;
+        if(
+#ifdef WSAEWOULDBLOCK
+          /* This is how Windows does it */
+          (WSAEWOULDBLOCK == sockerr)
+#else
+          /* errno may be EWOULDBLOCK or on some systems EAGAIN when it
+             returned due to its inability to send off data without
+             blocking. We therefore treat both error codes the same here */
+          (EWOULDBLOCK == sockerr) || (EAGAIN == sockerr) ||
+          (EINTR == sockerr) || (EINPROGRESS == sockerr)
+#endif
+          ) {
+          continue;
+        }
+        goto error;
+      }
+      s -= nread;
+      if(s) {
+        p += nread;
+        continue;
+      }
+      if(memcmp(&start, &check, sizeof(check)))
+        goto error;
+      break;
+    } while(1);
+  }
 
   sclose(listener);
   return 0;