4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davide Caratti <dcaratti@xxxxxxxxxx> [ Upstream commit 8d499533e0bc02d44283dbdab03142b599b8ba16 ] use nla_strlcpy() to avoid copying data beyond the length of TCA_DEF_DATA netlink attribute, in case it is less than SIMP_MAX_DATA and it does not end with '\0' character. v2: fix errors in the commit message, thanks Hangbin Liu Fixes: fa1b1cff3d06 ("net_cls_act: Make act_simple use of netlink policy.") Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx> Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/act_simple.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) --- a/net/sched/act_simple.c +++ b/net/sched/act_simple.c @@ -53,22 +53,22 @@ static void tcf_simp_release(struct tc_a kfree(d->tcfd_defdata); } -static int alloc_defdata(struct tcf_defact *d, char *defdata) +static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata) { d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL); if (unlikely(!d->tcfd_defdata)) return -ENOMEM; - strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); + nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); return 0; } -static void reset_policy(struct tcf_defact *d, char *defdata, +static void reset_policy(struct tcf_defact *d, const struct nlattr *defdata, struct tc_defact *p) { spin_lock_bh(&d->tcf_lock); d->tcf_action = p->action; memset(d->tcfd_defdata, 0, SIMP_MAX_DATA); - strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); + nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA); spin_unlock_bh(&d->tcf_lock); } @@ -87,7 +87,6 @@ static int tcf_simp_init(struct net *net struct tcf_defact *d; bool exists = false; int ret = 0, err; - char *defdata; if (nla == NULL) return -EINVAL; @@ -110,8 +109,6 @@ static int tcf_simp_init(struct net *net return -EINVAL; } - defdata = nla_data(tb[TCA_DEF_DATA]); - if (!exists) { ret = tcf_idr_create(tn, parm->index, est, a, &act_simp_ops, bind, false); @@ -119,7 +116,7 @@ static int tcf_simp_init(struct net *net return ret; d = to_defact(*a); - ret = alloc_defdata(d, defdata); + ret = alloc_defdata(d, tb[TCA_DEF_DATA]); if (ret < 0) { tcf_idr_release(*a, bind); return ret; @@ -133,7 +130,7 @@ static int tcf_simp_init(struct net *net if (!ovr) return -EEXIST; - reset_policy(d, defdata, parm); + reset_policy(d, tb[TCA_DEF_DATA], parm); } if (ret == ACT_P_CREATED)