From 6cdff09c0d70f780a738dbd3d87deb3b13ec8446 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Mon, 25 Dec 2023 20:42:58 -0500 Subject: [PATCH] gntdev: Handle errors from suword32() in gntdev_alloc_gref() Try to copy out output values before handling errors, and check that we did so successfully. In particular, it doesn't seem sensible to ignore errors here, otherwise userspace won't have any way to refer to the allocations. This is in preparation for annotating copyin() and related functions with __result_use_check. Reviewed by: royger MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D43145 --- sys/dev/xen/gntdev/gntdev.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/sys/dev/xen/gntdev/gntdev.c b/sys/dev/xen/gntdev/gntdev.c index a9b69ba1605e..4530feb1c76d 100644 --- a/sys/dev/xen/gntdev/gntdev.c +++ b/sys/dev/xen/gntdev/gntdev.c @@ -383,6 +383,13 @@ gntdev_alloc_gref(struct ioctl_gntdev_alloc_gref *arg) } } + /* Copy the output values. */ + arg->index = file_offset; + for (i = 0; error == 0 && i < arg->count; i++) { + if (suword32(&arg->gref_ids[i], grefs[i].gref_id) != 0) + error = EFAULT; + } + if (error != 0) { /* * If target domain maps the gref (by guessing the gref-id), @@ -401,11 +408,6 @@ gntdev_alloc_gref(struct ioctl_gntdev_alloc_gref *arg) return (error); } - /* Copy the output values. */ - arg->index = file_offset; - for (i = 0; i < arg->count; i++) - suword32(&arg->gref_ids[i], grefs[i].gref_id); - /* Modify the per user private data. */ mtx_lock(&priv_user->user_data_lock); for (i = 0; i < arg->count; i++)