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Commit 871bdea6 authored by Michael Gehring's avatar Michael Gehring Committed by Greg Kroah-Hartman
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tty/vt: handle bad user buffer in {G,P}IO_CMAP ioctl 



set_get_cmap() ignored the result of {get,put}_user(), causing ioctl(vt,
{G,P}IO_CMAP, 0xdeadbeef) to silently fail.

Another side effect of this: calling the PIO_CMAP ioctl with an invalid
buffer would zero the default colormap and the palette for all vts (all
colors set to black).

Leave the default colormap intact and return -EFAULT when
reading/writing to the userspace buffer fails.

Signed-off-by: default avatarMichael Gehring <mg@ebfe.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ef4f9d4f

drivers/tty/vt/vt.c

+32 −36
Original line number Diff line number Diff line
@@ -3893,25 +3893,28 @@ static void set_palette(struct vc_data *vc) 
		vc->vc_sw->con_set_palette(vc, color_table);

}



static int set_get_cmap(unsigned char __user *arg, int set)

/*

 * Load palette into the DAC registers. arg points to a colour

 * map, 3 bytes per colour, 16 colours, range from 0 to 255.

 */



int con_set_cmap(unsigned char __user *arg)

{

	int i, j, k;

	unsigned char colormap[3*16];



    WARN_CONSOLE_UNLOCKED();

	if (copy_from_user(colormap, arg, sizeof(colormap)))

		return -EFAULT;



    for (i = 0; i < 16; i++)

	if (set) {

	    get_user(default_red[i], arg++);

	    get_user(default_grn[i], arg++);

	    get_user(default_blu[i], arg++);

	} else {

	    put_user(default_red[i], arg++);

	    put_user(default_grn[i], arg++);

	    put_user(default_blu[i], arg++);

	console_lock();

	for (i = k = 0; i < 16; i++) {

		default_red[i] = colormap[k++];

		default_grn[i] = colormap[k++];

		default_blu[i] = colormap[k++];

	}

    if (set) {

	for (i = 0; i < MAX_NR_CONSOLES; i++)

	    if (vc_cons_allocated(i)) {

	for (i = 0; i < MAX_NR_CONSOLES; i++) {

		if (!vc_cons_allocated(i))

			continue;

		for (j = k = 0; j < 16; j++) {

			vc_cons[i].d->vc_palette[k++] = default_red[j];

			vc_cons[i].d->vc_palette[k++] = default_grn[j];
@@ -3919,35 +3922,28 @@ static int set_get_cmap(unsigned char __user *arg, int set) 
		}

		set_palette(vc_cons[i].d);

	}

    }

    return 0;

}



/*

 * Load palette into the DAC registers. arg points to a colour

 * map, 3 bytes per colour, 16 colours, range from 0 to 255.

 */



int con_set_cmap(unsigned char __user *arg)

{

	int rc;



	console_lock();

	rc = set_get_cmap (arg,1);

	console_unlock();



	return rc;

	return 0;

}



int con_get_cmap(unsigned char __user *arg)

{

	int rc;

	int i, k;

	unsigned char colormap[3*16];



	console_lock();

	rc = set_get_cmap (arg,0);

	for (i = k = 0; i < 16; i++) {

		colormap[k++] = default_red[i];

		colormap[k++] = default_grn[i];

		colormap[k++] = default_blu[i];

	}

	console_unlock();



	return rc;

	if (copy_to_user(arg, colormap, sizeof(colormap)))

		return -EFAULT;



	return 0;

}



void reset_palette(struct vc_data *vc)