tty: vt: sanitize arguments of consw::con_clear()

In consw::con_clear():
* Height is always 1, so drop it.
* Offsets and width are always unsigned values, so re-type them as such.

This needs a new __fbcon_clear() in the fbcon code to still handle
height which might not be 1 when called internally.

Note that tests for negative count/width are left in place -- they are
taken care of in the next patches.

And document the hook.

Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-parisc@vger.kernel.org
Tested-by: Helge Deller <deller@gmx.de> # parisc STI console
Link: https://lore.kernel.org/r/20240122110401.7289-22-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 19 insertions, 13 deletions

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 939c5d893dfb..8a31a36483ea 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1235,8 +1235,8 @@ finished:
  *  restriction is simplicity & efficiency at the moment.
  */
 
-static void fbcon_clear(struct vc_data *vc, int sy, int sx, int height,
-			int width)
+static void __fbcon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
+			  unsigned int height, unsigned int width)
 {
 	struct fb_info *info = fbcon_info_from_console(vc->vc_num);
 	struct fbcon_ops *ops = info->fbcon_par;
@@ -1273,6 +1273,12 @@ static void fbcon_clear(struct vc_data *vc, int sy, int sx, int height,
 		ops->clear(vc, info, real_y(p, sy), sx, height, width);
 }
 
+static void fbcon_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
+			unsigned int width)
+{
+	__fbcon_clear(vc, sy, sx, 1, width);
+}
+
 static void fbcon_putcs(struct vc_data *vc, const unsigned short *s,
 			int count, int ypos, int xpos)
 {
@@ -1760,7 +1766,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 		case SCROLL_MOVE:
 			fbcon_redraw_blit(vc, info, p, t, b - t - count,
 				     count);
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							(b - count)),
@@ -1783,7 +1789,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 					    b - t - count, vc->vc_cols);
 			else
 				goto redraw_up;
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
 			break;
 
 		case SCROLL_PAN_REDRAW:
@@ -1801,7 +1807,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 							  vc->vc_rows - b, b);
 			} else
 				fbcon_redraw_move(vc, p, t + count, b - t - count, t);
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
 			break;
 
 		case SCROLL_PAN_MOVE:
@@ -1824,14 +1830,14 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 					    b - t - count, vc->vc_cols);
 			else
 				goto redraw_up;
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
 			break;
 
 		case SCROLL_REDRAW:
 		      redraw_up:
 			fbcon_redraw(vc, t, b - t - count,
 				     count * vc->vc_cols);
-			fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, b - count, 0, count, vc->vc_cols);
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							(b - count)),
@@ -1848,7 +1854,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 		case SCROLL_MOVE:
 			fbcon_redraw_blit(vc, info, p, b - 1, b - t - count,
 				     -count);
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, t, 0, count, vc->vc_cols);
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							t),
@@ -1871,7 +1877,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 					    b - t - count, vc->vc_cols);
 			else
 				goto redraw_down;
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, t, 0, count, vc->vc_cols);
 			break;
 
 		case SCROLL_PAN_MOVE:
@@ -1893,7 +1899,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 					    b - t - count, vc->vc_cols);
 			else
 				goto redraw_down;
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, t, 0, count, vc->vc_cols);
 			break;
 
 		case SCROLL_PAN_REDRAW:
@@ -1910,14 +1916,14 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
 					fbcon_redraw_move(vc, p, count, t, 0);
 			} else
 				fbcon_redraw_move(vc, p, t, b - t - count, t + count);
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, t, 0, count, vc->vc_cols);
 			break;
 
 		case SCROLL_REDRAW:
 		      redraw_down:
 			fbcon_redraw(vc, b - 1, b - t - count,
 				     -count * vc->vc_cols);
-			fbcon_clear(vc, t, 0, count, vc->vc_cols);
+			__fbcon_clear(vc, t, 0, count, vc->vc_cols);
 			scr_memsetw((unsigned short *) (vc->vc_origin +
 							vc->vc_size_row *
 							t),
@@ -2196,7 +2202,7 @@ static void fbcon_generic_blank(struct vc_data *vc, struct fb_info *info,
 
 		oldc = vc->vc_video_erase_char;
 		vc->vc_video_erase_char &= charmask;
-		fbcon_clear(vc, 0, 0, vc->vc_rows, vc->vc_cols);
+		__fbcon_clear(vc, 0, 0, vc->vc_rows, vc->vc_cols);
 		vc->vc_video_erase_char = oldc;
 	}
 }