From 818c7b769a4f7d3c8fecc4cf491f4e22ef816eba Mon Sep 17 00:00:00 2001 From: David Jones Date: Fri, 11 Oct 2024 09:49:17 -0600 Subject: [PATCH] uncompress: Avoid reading an extra byte When reading the next code in a stream, avoid reading an extra byte if we're going to throw it away. When there's no more bits to extract from the stream, bits will be 0 and we'll mask the read byte with 0 anyway. At worst, this will avoid reading one past the end of gbuf array (which is not possible in well formed streams). PR: 127912 Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D47041 --- usr.bin/compress/zopen.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/usr.bin/compress/zopen.c b/usr.bin/compress/zopen.c index be66358884c..cb7e6e9eb10 100644 --- a/usr.bin/compress/zopen.c +++ b/usr.bin/compress/zopen.c @@ -620,7 +620,8 @@ getcode(struct s_zstate *zs) } /* High order bits. */ - gcode |= (*bp & rmask[bits]) << r_off; + if (bits > 0) + gcode |= (*bp & rmask[bits]) << r_off; roffset += n_bits; return (gcode);