Commit 669e0a51 authored Sep 15, 2016 by Adam Borowski Committed by Greg Kroah-Hartman Sep 22, 2016

vt: Fix a read-past-array in vc_t416_color().



This makes it show up on UBSAN:
perl -e 'for (0..15) {my @x=("0")x$_;push @x,qw(38 2 64 128 192 4);printf
"\e[%smAfter %d zeroes.\e[0m\n", join(";",@x[0..($_+5<15?$_+5:15)]), $_}'

Seems harmless: if you can programmatically read attributes of a vt
character (/dev/vcsa*), multiple probes can obtain parts of vt_mode then
lowest byte (5th on 64-bit big-endian) of a pointer.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d2ec3f77

drivers/tty/vt/vt.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1316,7 +1316,7 @@ static int vc_t416_color(struct vc_data *vc, int i,
		/* 256 colours -- ubiquitous */
		i++;
		rgb_from_256(vc->vc_par[i], &c);
		} else if (vc->vc_par[i] == 2 && i <= vc->vc_npar + 3) {
		} else if (vc->vc_par[i] == 2 && i + 3 <= vc->vc_npar) {
		/* 24 bit -- extremely rare */
		c.r = vc->vc_par[i + 1];
		c.g = vc->vc_par[i + 2];

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