linux-kernel - Re: [PATCH] add return value checking of get_user() in set_vesa

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20061121173115.6d258a5a.akpm@osdl.org>
Date:	Tue, 21 Nov 2006 17:31:15 -0800
From:	Andrew Morton <akpm@...l.org>
To:	Yoichi Yuasa <yoichi_yuasa@...peaks.co.jp>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] add return value checking of get_user() in
 set_vesa_blanking()

On Tue, 21 Nov 2006 14:15:28 +0900
Yoichi Yuasa <yoichi_yuasa@...peaks.co.jp> wrote:

> Hi,
> 
> This patch has added return value checking of get_user() in set_vesa_blanking().
> 
> Yoichi
> 
> Signed-off-by: Yoichi Yuasa <yoichi_yuasa@...peaks.co.jp>
>  
> diff -pruN -X generic/Documentation/dontdiff generic-orig/drivers/char/vt.c generic/drivers/char/vt.c
> --- generic-orig/drivers/char/vt.c	2006-11-21 10:23:39.409667250 +0900
> +++ generic/drivers/char/vt.c	2006-11-21 10:11:48.037209250 +0900
> @@ -3318,9 +3318,10 @@ postcore_initcall(vtconsole_class_init);
>  
>  static void set_vesa_blanking(char __user *p)
>  {
> -    unsigned int mode;
> -    get_user(mode, p + 1);
> -    vesa_blank_mode = (mode < 4) ? mode : 0;
> +	unsigned int mode;
> +
> +	if (!get_user(mode, p + 1))
> +		vesa_blank_mode = (mode < 4) ? mode : 0;
>  }
>  
>  void do_blank_screen(int entering_gfx)

How about we go all the way?

diff -puN drivers/char/vt.c~add-return-value-checking-of-get_user-in drivers/char/vt.c
--- a/drivers/char/vt.c~add-return-value-checking-of-get_user-in
+++ a/drivers/char/vt.c
@@ -152,7 +152,7 @@ static void gotoxy(struct vc_data *vc, i
 static void save_cur(struct vc_data *vc);
 static void reset_terminal(struct vc_data *vc, int do_clear);
 static void con_flush_chars(struct tty_struct *tty);
-static void set_vesa_blanking(char __user *p);
+static int set_vesa_blanking(char __user *p);
 static void set_cursor(struct vc_data *vc);
 static void hide_cursor(struct vc_data *vc);
 static void console_callback(void *ignored);
@@ -2369,7 +2369,7 @@ int tioclinux(struct tty_struct *tty, un
 			ret = __put_user(data, p);
 			break;
 		case TIOCL_SETVESABLANK:
-			set_vesa_blanking(p);
+			ret = set_vesa_blanking(p);
 			break;
 		case TIOCL_GETKMSGREDIRECT:
 			data = kmsg_redirect;
@@ -3315,9 +3315,13 @@ postcore_initcall(vtconsole_class_init);
 
 static void set_vesa_blanking(char __user *p)
 {
-    unsigned int mode;
-    get_user(mode, p + 1);
-    vesa_blank_mode = (mode < 4) ? mode : 0;
+	unsigned int mode;
+
+	if (get_user(mode, p + 1))
+		return -EFAULT;
+
+	vesa_blank_mode = (mode < 4) ? mode : 0;
+	return 0;
 }
 
 void do_blank_screen(int entering_gfx)
_

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/