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Commit b9a58de5 authored by Jan H. Schönherr's avatar Jan H. Schönherr Committed by Bartlomiej Zolnierkiewicz
Browse files

vgacon: Prevent faulty bootparams.screeninfo from causing harm 



If a zero for the number of colums or rows manages to slip through,
gotoxy() will underflow vc->vc_pos, causing the next action on the
referenced memory to end with a page fault.

Make the check in vgacon_startup() more pessimistic to prevent that.

Signed-off-by: default avatarJan H. Schönherr <jschoenh@amazon.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
parent 58ec01ce

drivers/video/console/vgacon.c

+2 −3
Original line number Diff line number Diff line
@@ -398,9 +398,8 @@ static const char *vgacon_startup(void) 
#endif

	}



	/* boot_params.screen_info initialized? */

	if ((screen_info.orig_video_mode  == 0) &&

	    (screen_info.orig_video_lines == 0) &&

	/* boot_params.screen_info reasonably initialized? */

	if ((screen_info.orig_video_lines == 0) ||

	    (screen_info.orig_video_cols  == 0))

		goto no_vga;