kernel: filedesc: Ensure write() fd is correct

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

1 files changed, 4 insertions, 0 deletions

diff --git a/sys/kern/kern_filedesc.c b/sys/kern/kern_filedesc.c
index b95d123..7e65d77 100644
--- a/sys/kern/kern_filedesc.c
+++ b/sys/kern/kern_filedesc.c
@@ -242,6 +242,10 @@ write(int fd, const void *buf, size_t count)
     }
 
     desc = fd_from_fdnum(td, fd);
+    if (desc == NULL) {
+        return -EBADF;
+    }
+
     if (desc->oflag != O_WRONLY && desc->oflag != O_WRONLY) {
         ret = -EACCES;
         goto cleanup;