The attribute TCA_PEDIT_PARMS_EX is not be included in pedit_policy and
one malicious user could fake a TCA_PEDIT_PARMS_EX whose length is
smaller than the intended sizeof(struct tc_pedit). Hence, the
dereference in tcf_pedit_init() could access dirty heap data.
static int tcf_pedit_init(...)
{
// ...
pattr = tb[TCA_PEDIT_PARMS]; // TCA_PEDIT_PARMS is included
if (!pattr)
pattr = tb[TCA_PEDIT_PARMS_EX]; // but this is not
// ...
parm = nla_data(pattr);
index = parm->index; // parm is able to be smaller than 4 bytes
// and this dereference gets dirty skb_buff
// data created in netlink_sendmsg
}
This commit adds TCA_PEDIT_PARMS_EX length in pedit_policy which avoid
the above case, just like the TCA_PEDIT_PARMS.
Fixes: 71d0ed7079df ("net/act_pedit: Support using offset relative to the conventional network headers")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Link: https://lore.kernel.org/r/20230703110842.590282-1-linma@zju.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
30c45b5361