From 065c997f5bc18c03ccdd8566a05b274c7c060407 Mon Sep 17 00:00:00 2001
From: shivanayak <shivanayak@gmail.com>
Date: Tue, 10 Mar 2026 13:51:35 +0530
Subject: [PATCH] fish: fix fd leak and undefined behavior on fdopen failure in
 rc_listen (#320)

Add missing NULL check after fdopen in both rc_listen and rc_remote.
In rc_listen, fdopen failure on a valid fd indicates something
fundamentally broken, so abort. In rc_remote, return an error to
the caller.

Co-authored-by: Claude <nor@anthropic.com>
---
 fish/rc.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fish/rc.c b/fish/rc.c
index 056610633..0f4ca9b72 100644
--- a/fish/rc.c
+++ b/fish/rc.c
@@ -277,6 +277,11 @@ rc_listen (void)
       receive_stdout (s);
 
       fp = fdopen (s, "r+");
+      if (fp == NULL) {
+        perror ("fdopen");
+        close (s);
+        abort ();
+      }
       xdrstdio_create (&xdr, fp, XDR_DECODE);
 
       if (!xdr_guestfish_hello (&xdr, &hello)) {
@@ -393,6 +398,11 @@ rc_remote (int pid, const char *cmd, size_t argc, char *argv[],
 
   /* Send the greeting. */
   fp = fdopen (sock, "r+");
+  if (fp == NULL) {
+    perror ("fdopen");
+    close (sock);
+    return -1;
+  }
   xdrstdio_create (&xdr, fp, XDR_ENCODE);
 
   if (!xdr_guestfish_hello (&xdr, &hello)) {