[PATCH 4.9 17/39] net/sched: act_simple: fix parsing of TCA_DEF_DATA

Greg Kroah-Hartman
2018-06-24T15:54:07Z

From: Davide Caratti <dcaratti@redhat.com>

[ 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@redhat.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -55,22 +55,22 @@ 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);
}

@@ -89,7 +89,6 @@ 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;
@@ -112,8 +111,6 @@ static int tcf_simp_init(struct net *net
return -EINVAL;
}

- defdata = nla_data(tb[TCA_DEF_DATA]);
-
if (!exists) {
ret = tcf_hash_create(tn, parm->index, est, a,
&act_simp_ops, bind, false);
@@ -121,7 +118,7 @@ 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;
@@ -135,7 +132,7 @@ 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)