[PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Thomas Graf]

Wrap several common instances of:
	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);

Signed-off-by: Thomas Graf <tgraf@suug.ch>
---
 include/net/netlink.h  | 10 ++++++++++
 net/sched/act_bpf.c    |  4 +---
 net/sched/cls_bpf.c    |  4 +---
 net/wireless/nl80211.c |  3 +--
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/net/netlink.h b/include/net/netlink.h
index 254a0fc..a34f53a 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -1191,6 +1191,16 @@ static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
 }
 
 /**
+ * nla_memdup - duplicate attribute memory (kmemdup)
+ * @src: netlink attribute to duplicate from
+ * @gfp: GFP mask
+ */
+static inline void *nla_memdup(const struct nlattr *src, gfp_t gfp)
+{
+	return kmemdup(nla_data(src), nla_len(src), gfp);
+}
+
+/**
  * nla_nest_start - Start a new level of nested attributes
  * @skb: socket buffer to add attributes to
  * @attrtype: attribute type of container
diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 1d39600..9ff06cf 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -226,9 +226,7 @@ static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
 		return PTR_ERR(fp);
 
 	if (tb[TCA_ACT_BPF_NAME]) {
-		name = kmemdup(nla_data(tb[TCA_ACT_BPF_NAME]),
-			       nla_len(tb[TCA_ACT_BPF_NAME]),
-			       GFP_KERNEL);
+		name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL);
 		if (!name) {
 			bpf_prog_put(fp);
 			return -ENOMEM;
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index bb1d5a4..52dc85a 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -369,9 +369,7 @@ static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 		return PTR_ERR(fp);
 
 	if (tb[TCA_BPF_NAME]) {
-		name = kmemdup(nla_data(tb[TCA_BPF_NAME]),
-			       nla_len(tb[TCA_BPF_NAME]),
-			       GFP_KERNEL);
+		name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
 		if (!name) {
 			bpf_prog_put(fp);
 			return -ENOMEM;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index c510810..7bfe1e0 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -10638,8 +10638,7 @@ static int handle_nan_filter(struct nlattr *attr_filter,
 
 	i = 0;
 	nla_for_each_nested(attr, attr_filter, rem) {
-		filter[i].filter = kmemdup(nla_data(attr), nla_len(attr),
-					   GFP_KERNEL);
+		filter[i].filter = nla_memdup(attr, GFP_KERNEL);
 		filter[i].len = nla_len(attr);
 		i++;
 	}
-- 
2.7.4

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Johannes Berg]

On Wed, 2016-10-26 at 10:53 +0200, Thomas Graf wrote:
> Wrap several common instances of:
> 	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);

Makes sense

Acked-by: Johannes Berg <johannes@sipsolutions.net>

johannes

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Johannes Berg]

On Wed, 2016-10-26 at 10:53 +0200, Thomas Graf wrote:
> Wrap several common instances of:
> 	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);

Makes sense

Acked-by: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>

johannes

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Daniel Borkmann]

On 10/26/2016 10:53 AM, Thomas Graf wrote:
> Wrap several common instances of:
> 	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);
>
> Signed-off-by: Thomas Graf <tgraf@suug.ch>

Thanks!

Acked-by: Daniel Borkmann <daniel@iogearbox.net>

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Johannes Berg]

>  /**
> + * nla_memdup - duplicate attribute memory (kmemdup)
> + * @src: netlink attribute to duplicate from
> + * @gfp: GFP mask

Actually, is there any point in passing a GFP mask? None of the current
users need it, and it seems fairly unlikely to be needed since this is
typically used on the netlink input path, where you surely shouldn't
need GFP_ATOMIC or so?

johannes

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Johannes Berg]

>  /**
> + * nla_memdup - duplicate attribute memory (kmemdup)
> + * @src: netlink attribute to duplicate from
> + * @gfp: GFP mask

Actually, is there any point in passing a GFP mask? None of the current
users need it, and it seems fairly unlikely to be needed since this is
typically used on the netlink input path, where you surely shouldn't
need GFP_ATOMIC or so?

johannes

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Thomas Graf]

On 10/26/16 at 10:59am, Johannes Berg wrote:
> 
> >  /**
> > + * nla_memdup - duplicate attribute memory (kmemdup)
> > + * @src: netlink attribute to duplicate from
> > + * @gfp: GFP mask
> 
> Actually, is there any point in passing a GFP mask? None of the current
> users need it, and it seems fairly unlikely to be needed since this is
> typically used on the netlink input path, where you surely shouldn't
> need GFP_ATOMIC or so?

I'm fine either way. I didn't want to make assumptions which need
later changes. It's not hurting either and the function prototype
is very small.

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Johannes Berg]

On Wed, 2016-10-26 at 11:52 +0200, Thomas Graf wrote:
> On 10/26/16 at 10:59am, Johannes Berg wrote:
> > 
> > 
> > > 
> > >  /**
> > > + * nla_memdup - duplicate attribute memory (kmemdup)
> > > + * @src: netlink attribute to duplicate from
> > > + * @gfp: GFP mask
> > 
> > Actually, is there any point in passing a GFP mask? None of the
> > current
> > users need it, and it seems fairly unlikely to be needed since this
> > is
> > typically used on the netlink input path, where you surely
> > shouldn't
> > need GFP_ATOMIC or so?
> 
> I'm fine either way. I didn't want to make assumptions which need
> later changes. It's not hurting either and the function prototype
> is very small.

Yeah, I don't really care much - just wondered.

johannes

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[Johannes Berg]

On Wed, 2016-10-26 at 11:52 +0200, Thomas Graf wrote:
> On 10/26/16 at 10:59am, Johannes Berg wrote:
> > 
> > 
> > > 
> > >  /**
> > > + * nla_memdup - duplicate attribute memory (kmemdup)
> > > + * @src: netlink attribute to duplicate from
> > > + * @gfp: GFP mask
> > 
> > Actually, is there any point in passing a GFP mask? None of the
> > current
> > users need it, and it seems fairly unlikely to be needed since this
> > is
> > typically used on the netlink input path, where you surely
> > shouldn't
> > need GFP_ATOMIC or so?
> 
> I'm fine either way. I didn't want to make assumptions which need
> later changes. It's not hurting either and the function prototype
> is very small.

Yeah, I don't really care much - just wondered.

johannes

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[David Miller]

From: Thomas Graf <tgraf@suug.ch>
Date: Wed, 26 Oct 2016 10:53:16 +0200

> Wrap several common instances of:
> 	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);
> 
> Signed-off-by: Thomas Graf <tgraf@suug.ch>

Applied.

Re: [PATCH net-next] netlink: Add nla_memdup() to wrap kmemdup() use on nlattr

[David Miller]

From: Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>
Date: Wed, 26 Oct 2016 10:53:16 +0200

> Wrap several common instances of:
> 	kmemdup(nla_data(attr), nla_len(attr), GFP_KERNEL);
> 
> Signed-off-by: Thomas Graf <tgraf-G/eBtMaohhA@public.gmane.org>

Applied.