Merge tag 'tty-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are a few small TTY/Serial/vt fixes for 5.9-rc3

  Included in here are:
   - qcom serial fixes
   - vt ioctl and core bugfixes
   - pl011 serial driver fixes
   - 8250 serial driver fixes
   - other misc serial driver fixes

  and for good measure:
   - fbcon fix for syzbot found problem.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: serial: imx: add dependence and build for earlycon
  serial: samsung: Removes the IRQ not found warning
  serial: 8250: change lock order in serial8250_do_startup()
  serial: stm32: avoid kernel warning on absence of optional IRQ
  serial: pl011: Fix oops on -EPROBE_DEFER
  serial: pl011: Don't leak amba_ports entry on driver register error
  serial: 8250_exar: Fix number of ports for Commtech PCIe cards
  tty: serial: qcom_geni_serial: Drop __init from qcom_geni_console_setup
  serial: qcom_geni_serial: Fix recent kdb hang
  vt_ioctl: change VT_RESIZEX ioctl to check for error return from vc_resize()
  fbcon: prevent user font height or width change from causing potential out-of-bounds access
  vt: defer kfree() of vc_screenbuf in vc_do_resize()

2 files changed, 14 insertions, 3 deletions

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index d8b9363b81c1..19cd4a4b1939 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1201,7 +1201,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	unsigned int old_rows, old_row_size, first_copied_row;
 	unsigned int new_cols, new_rows, new_row_size, new_screen_size;
 	unsigned int user;
-	unsigned short *newscreen;
+	unsigned short *oldscreen, *newscreen;
 	struct uni_screen *new_uniscr = NULL;
 
 	WARN_CONSOLE_UNLOCKED();
@@ -1299,10 +1299,11 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	if (new_scr_end > new_origin)
 		scr_memsetw((void *)new_origin, vc->vc_video_erase_char,
 			    new_scr_end - new_origin);
-	kfree(vc->vc_screenbuf);
+	oldscreen = vc->vc_screenbuf;
 	vc->vc_screenbuf = newscreen;
 	vc->vc_screenbuf_size = new_screen_size;
 	set_origin(vc);
+	kfree(oldscreen);
 
 	/* do part of a reset_terminal() */
 	vc->vc_top = 0;
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index 91c301775047..a4e520bdd521 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -806,12 +806,22 @@ static int vt_resizex(struct vc_data *vc, struct vt_consize __user *cs)
 		console_lock();
 		vcp = vc_cons[i].d;
 		if (vcp) {
+			int ret;
+			int save_scan_lines = vcp->vc_scan_lines;
+			int save_font_height = vcp->vc_font.height;
+
 			if (v.v_vlin)
 				vcp->vc_scan_lines = v.v_vlin;
 			if (v.v_clin)
 				vcp->vc_font.height = v.v_clin;
 			vcp->vc_resize_user = 1;
-			vc_resize(vcp, v.v_cols, v.v_rows);
+			ret = vc_resize(vcp, v.v_cols, v.v_rows);
+			if (ret) {
+				vcp->vc_scan_lines = save_scan_lines;
+				vcp->vc_font.height = save_font_height;
+				console_unlock();
+				return ret;
+			}
 		}
 		console_unlock();
 	}