From 4f0e97d070984d487df027f163e52bb72d1713d8 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Mon, 18 Nov 2019 17:39:34 +0800 Subject: net: sched: ensure opts_len <= IP_TUNNEL_OPTS_MAX in act_tunnel_key info->options_len is 'u8' type, and when opts_len with a value > IP_TUNNEL_OPTS_MAX, 'info->options_len = opts_len' will cast int to u8 and set a wrong value to info->options_len. Kernel crashed in my test when doing: # opts="0102:80:00800022" # for i in {1..99}; do opts="$opts,0102:80:00800022"; done # ip link add name geneve0 type geneve dstport 0 external # tc qdisc add dev eth0 ingress # tc filter add dev eth0 protocol ip parent ffff: \ flower indev eth0 ip_proto udp action tunnel_key \ set src_ip 10.0.99.192 dst_ip 10.0.99.193 \ dst_port 6081 id 11 geneve_opts $opts \ action mirred egress redirect dev geneve0 So we should do the similar check as cls_flower does, return error when opts_len > IP_TUNNEL_OPTS_MAX in tunnel_key_copy_opts(). Fixes: 0ed5269f9e41 ("net/sched: add tunnel option support to act_tunnel_key") Signed-off-by: Xin Long Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- net/sched/act_tunnel_key.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'net/sched/act_tunnel_key.c') diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c index 2f83a79f76aa..d55669e14741 100644 --- a/net/sched/act_tunnel_key.c +++ b/net/sched/act_tunnel_key.c @@ -135,6 +135,10 @@ static int tunnel_key_copy_opts(const struct nlattr *nla, u8 *dst, if (opt_len < 0) return opt_len; opts_len += opt_len; + if (opts_len > IP_TUNNEL_OPTS_MAX) { + NL_SET_ERR_MSG(extack, "Tunnel options exceeds max size"); + return -EINVAL; + } if (dst) { dst_len -= opt_len; dst += opt_len; -- cgit v1.2.3-59-g8ed1b