[PATCH 4.4 097/113] VT_RESIZEX: get rid of field-by-field copyin

Greg Kroah-Hartman
2020-02-27T13:44:31Z

From: Al Viro <viro@zeniv.linux.org.uk>

[ Upstream commit 1b3bce4d6bf839304a90951b4b25a5863533bf2a ]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/vt/vt_ioctl.c | 68 ++++++++++++++++-----------------------
1 file changed, 27 insertions(+), 41 deletions(-)

diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index a86bc7afb3b28..a1e5c408c931b 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -850,58 +850,44 @@ int vt_ioctl(struct tty_struct *tty,

case VT_RESIZEX:
{
- struct vt_consize __user *vtconsize = up;
- ushort ll,cc,vlin,clin,vcol,ccol;
+ struct vt_consize v;
if (!perm)
return -EPERM;
- if (!access_ok(VERIFY_READ, vtconsize,
- sizeof(struct vt_consize))) {
- ret = -EFAULT;
- break;
- }
+ if (copy_from_user(&v, up, sizeof(struct vt_consize)))
+ return -EFAULT;
/* FIXME: Should check the copies properly */
- __get_user(ll, &vtconsize->v_rows);
- __get_user(cc, &vtconsize->v_cols);
- __get_user(vlin, &vtconsize->v_vlin);
- __get_user(clin, &vtconsize->v_clin);
- __get_user(vcol, &vtconsize->v_vcol);
- __get_user(ccol, &vtconsize->v_ccol);
- vlin = vlin ? vlin : vc->vc_scan_lines;
- if (clin) {
- if (ll) {
- if (ll != vlin/clin) {
- /* Parameters don't add up */
- ret = -EINVAL;
- break;
- }
- } else
- ll = vlin/clin;
+ if (!v.v_vlin)
+ v.v_vlin = vc->vc_scan_lines;
+ if (v.v_clin) {
+ int rows = v.v_vlin/v.v_clin;
+ if (v.v_rows != rows) {
+ if (v.v_rows) /* Parameters don't add up */
+ return -EINVAL;
+ v.v_rows = rows;
+ }
}
- if (vcol && ccol) {
- if (cc) {
- if (cc != vcol/ccol) {
- ret = -EINVAL;
- break;
- }
- } else
- cc = vcol/ccol;
+ if (v.v_vcol && v.v_ccol) {
+ int cols = v.v_vcol/v.v_ccol;
+ if (v.v_cols != cols) {
+ if (v.v_cols)
+ return -EINVAL;
+ v.v_cols = cols;
+ }
}

- if (clin > 32) {
- ret = -EINVAL;
- break;
- }
-
+ if (v.v_clin > 32)
+ return -EINVAL;
+
for (i = 0; i < MAX_NR_CONSOLES; i++) {
if (!vc_cons[i].d)
continue;
console_lock();
- if (vlin)
- vc_cons[i].d->vc_scan_lines = vlin;
- if (clin)
- vc_cons[i].d->vc_font.height = clin;
+ if (v.v_vlin)
+ vc_cons[i].d->vc_scan_lines = v.v_vlin;
+ if (v.v_clin)
+ vc_cons[i].d->vc_font.height = v.v_clin;
vc_cons[i].d->vc_resize_user = 1;
- vc_resize(vc_cons[i].d, cc, ll);
+ vc_resize(vc_cons[i].d, v.v_cols, v.v_rows);
console_unlock();
}
break;
--
2.20.1