From 3915e1c08e635f44b2d090cf80eb2a52e1fd5ebf Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Wed, 16 Jul 2025 18:02:04 -0400
Subject: kernel: filedesc: Ensure 'fd' is valid during r/w

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 sys/kern/kern_descrip.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index b5ff144..57beaf6 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -154,6 +154,10 @@ fd_rw(unsigned int fd, void *buf, size_t count, uint8_t write)
     struct sio_txn sio;
     scret_t retval = 0;
 
+    if (fd > PROC_MAX_FILEDES) {
+        return -EBADF;
+    }
+
     if (count > SSIZE_MAX) {
         retval = -EINVAL;
         goto done;
-- 
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