From bb0890b4cd7f8203e3aa99c6d0f062d6acdaad27 Mon Sep 17 00:00:00 2001
From: Peilin Ye <yepeilin.cs@gmail.com>
Date: Thu, 24 Sep 2020 09:40:53 -0400
Subject: [PATCH] fbdev, newport_con: Move FONT_EXTRA_WORDS macros into linux/font.h
Git-commit: bb0890b4cd7f8203e3aa99c6d0f062d6acdaad27
Patch-mainline: v5.9
References: CVE-2020-28915 bsc#1178886

drivers/video/console/newport_con.c is borrowing FONT_EXTRA_WORDS macros
from drivers/video/fbdev/core/fbcon.h. To keep things simple, move all
definitions into <linux/font.h>.

Since newport_con now uses four extra words, initialize the fourth word in
newport_set_font() properly.

Cc: stable@vger.kernel.org
Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/7fb8bc9b0abc676ada6b7ac0e0bd443499357267.1600953813.git.yepeilin.cs@gmail.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/video/console/fbcon.h        |    7 -------
 drivers/video/console/fbcon_rotate.c |    1 +
 drivers/video/console/newport_con.c  |    7 +------
 drivers/video/console/tileblit.c     |    1 +
 include/linux/font.h                 |    8 ++++++++
 5 files changed, 11 insertions(+), 13 deletions(-)

--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -33,12 +33,6 @@
 
 #define FONT_DATA ((unsigned char *)font_vga_8x16.data)
 
-/* borrowed from fbcon.c */
-#define REFCOUNT(fd)	(((int *)(fd))[-1])
-#define FNTSIZE(fd)	(((int *)(fd))[-2])
-#define FNTCHARCNT(fd)	(((int *)(fd))[-3])
-#define FONT_EXTRA_WORDS 3
-
 static unsigned char *font_data[MAX_NR_CONSOLES];
 
 static struct newport_regs *npregs;
@@ -519,6 +513,7 @@ static int newport_set_font(int unit, st
 	FNTSIZE(new_data) = size;
 	FNTCHARCNT(new_data) = op->charcount;
 	REFCOUNT(new_data) = 0;	/* usage counter */
+	FNTSUM(new_data) = 0;
 
 	p = new_data;
 	for (i = 0; i < op->charcount; i++) {
--- a/drivers/video/console/fbcon.h
+++ b/drivers/video/console/fbcon.h
@@ -151,13 +151,6 @@ static inline int attr_col_ec(int shift,
 #define attr_bgcol_ec(bgshift, vc, info) attr_col_ec(bgshift, vc, info, 0)
 #define attr_fgcol_ec(fgshift, vc, info) attr_col_ec(fgshift, vc, info, 1)
 
-/* Font */
-#define REFCOUNT(fd)	(((int *)(fd))[-1])
-#define FNTSIZE(fd)	(((int *)(fd))[-2])
-#define FNTCHARCNT(fd)	(((int *)(fd))[-3])
-#define FNTSUM(fd)	(((int *)(fd))[-4])
-#define FONT_EXTRA_WORDS 4
-
     /*
      *  Scroll Method
      */
--- a/drivers/video/console/fbcon_rotate.c
+++ b/drivers/video/console/fbcon_rotate.c
@@ -14,6 +14,7 @@
 #include <linux/fb.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
+#include <linux/font.h>
 #include <asm/types.h>
 #include "fbcon.h"
 #include "fbcon_rotate.h"
--- a/drivers/video/console/tileblit.c
+++ b/drivers/video/console/tileblit.c
@@ -13,6 +13,7 @@
 #include <linux/fb.h>
 #include <linux/vt_kern.h>
 #include <linux/console.h>
+#include <linux/font.h>
 #include <asm/types.h>
 #include "fbcon.h"
 
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -57,4 +57,12 @@ extern const struct font_desc *get_defau
 /* Max. length for the name of a predefined font */
 #define MAX_FONT_NAME	32
 
+/* Extra word getters */
+#define REFCOUNT(fd)	(((int *)(fd))[-1])
+#define FNTSIZE(fd)	(((int *)(fd))[-2])
+#define FNTCHARCNT(fd)	(((int *)(fd))[-3])
+#define FNTSUM(fd)	(((int *)(fd))[-4])
+
+#define FONT_EXTRA_WORDS 4
+
 #endif /* _VIDEO_FONT_H */