kernel: filedesc: Ensure 'fd' is valid during r/w

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 4 insertions, 0 deletions

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;