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Commit 669e0a51 authored by Adam Borowski's avatar Adam Borowski Committed by Greg Kroah-Hartman
Browse files

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: default avatarAdam Borowski <kilobyte@angband.pl>
Signed-off-by: default avatarGreg 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];