When update flowi6 daddr in fl6_update_dst() for srcrt, the used index of segments should be segments_left minus one per RFC8754 (section 4.3.1.1) S15 S16. Otherwise it may results in an out-of-bounds read.
Reported-by: syzbot+e8c028b62439eac42...@syzkaller.appspotmail.com Fixes: 0cb7498f234e ("seg6: fix SRH processing to comply with RFC8754") Signed-off-by: YueHaibing <yuehaib...@huawei.com> --- net/ipv6/exthdrs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c index 5a8bbcdcaf2b..f5304bf33ab1 100644 --- a/net/ipv6/exthdrs.c +++ b/net/ipv6/exthdrs.c @@ -1353,7 +1353,7 @@ struct in6_addr *fl6_update_dst(struct flowi6 *fl6, { struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; - fl6->daddr = srh->segments[srh->segments_left]; + fl6->daddr = srh->segments[srh->segments_left - 1]; break; } default: -- 2.17.1