[PATCH 3.16 129/366] net/sched: act_simple: fix parsing of TCA_DEF_DATA

[Ben Hutchings]

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Davide Caratti <dcara...@redhat.com>

commit 8d499533e0bc02d44283dbdab03142b599b8ba16 upstream.

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 <dcara...@redhat.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -52,22 +52,22 @@ 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);
 }
 
@@ -83,7 +83,6 @@ static int tcf_simp_init(struct net *net
        struct nlattr *tb[TCA_DEF_MAX + 1];
        struct tc_defact *parm;
        struct tcf_defact *d;
-       char *defdata;
        int ret = 0, err;
 
        if (nla == NULL)
@@ -100,7 +99,6 @@ static int tcf_simp_init(struct net *net
                return -EINVAL;
 
        parm = nla_data(tb[TCA_DEF_PARMS]);
-       defdata = nla_data(tb[TCA_DEF_DATA]);
 
        if (!tcf_hash_check(parm->index, a, bind)) {
                ret = tcf_hash_create(parm->index, est, a, sizeof(*d), bind);
@@ -108,7 +106,7 @@ 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_hash_cleanup(a, est);
                        return ret;
@@ -124,7 +122,7 @@ 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)