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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: 0ed5269f9e ("net/sched: add tunnel option support to act_tunnel_key")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
alistair/sunxi64-5.4-dsi
Xin Long 2019-11-18 17:39:34 +08:00 committed by David S. Miller
parent 1fc1657775
commit 4f0e97d070
1 changed files with 4 additions and 0 deletions
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4
net/sched/act_tunnel_key.c
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@ -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;