Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-05 Thread Lorenzo Colitti 
On Fri, Feb 3, 2017 at 10:51 AM, Eric Dumazet  wrote:
> if (sk) {
> sk = sk_to_full_sk(sk);
> if (sk_fullsock(sk))
> return sk->sk_uid;
> }

Sure, though sk_to_full_sk is in inet_sock.h so I have to move some
core around. Options I see:

1. Move sk_to_full_sk from inet_sock.h to sock.h.
2. Move sock_net_uid to inet_sock.h.
3. Move sock_net_uid to sock.c and EXPORT_SYMBOL_GPL it.

Thoughts? #1 seems reasonable, since sk_fullsock is already in sock.h.
#2 would mean that we can't call sock_net_uid from non-inet code.
Currently the only code that accesses sk->sk_uid is inet code, but in
the future perhaps some of the code around the tree that calls
sock_i_uid could be migrated to use at sk->sk_uid instead.

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-03 Thread Daniel Borkmann 

On 02/03/2017 02:51 AM, Eric Dumazet wrote:

On Fri, 2017-02-03 at 10:18 +0900, Lorenzo Colitti wrote:

On Fri, Feb 3, 2017 at 9:31 AM, Eric Dumazet  wrote:

It should be safe to call sock_net_uid on any type of socket
(including NULL). sk_uid was added to struct sock in 86741ec25462
("net: core: Add a UID field to struct sock.")


But a request socket or a timewait socket do not have this field.

Daniel point is valid.


My bad. Yes.

It would definitely be useful to have the UID available in request
sockets, and perhaps timewait sockets as well. That could be done by
moving the UID to sock_common, or with something along the lines of:

  static inline kuid_t sock_net_uid(const struct net *net, const struct sock 
*sk)
  {
+   if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
+   sk = sk->__sk_common.skc_listener;
+   else if (sk && !sk_fullsock(sk))
+   sk = NULL;
+
 return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
  }

Any thoughts on which is better?


You could use

if (sk) {
 sk = sk_to_full_sk(sk);
 if (sk_fullsock(sk))
 return sk->sk_uid;
}


Yeah, if that moves into the sock_net_uid() helper, then you could
remove the sk && sk_fullsock(sk) ? sk : NULL tests from the current
sock_net_uid() call sites such as in tcp code. Maybe then also make
the sock_net_uid() as __always_inline, so that most of the callers
with sock_net_uid(net, NULL) are guaranteed to optimize away their
sk checks at compile time?

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Eric Dumazet 
On Fri, 2017-02-03 at 10:18 +0900, Lorenzo Colitti wrote:
> On Fri, Feb 3, 2017 at 9:31 AM, Eric Dumazet  wrote:
> >> It should be safe to call sock_net_uid on any type of socket
> >> (including NULL). sk_uid was added to struct sock in 86741ec25462
> >> ("net: core: Add a UID field to struct sock.")
> >
> > But a request socket or a timewait socket do not have this field.
> >
> > Daniel point is valid.
> 
> My bad. Yes.
> 
> It would definitely be useful to have the UID available in request
> sockets, and perhaps timewait sockets as well. That could be done by
> moving the UID to sock_common, or with something along the lines of:
> 
>  static inline kuid_t sock_net_uid(const struct net *net, const struct sock 
> *sk)
>  {
> +   if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
> +   sk = sk->__sk_common.skc_listener;
> +   else if (sk && !sk_fullsock(sk))
> +   sk = NULL;
> +
> return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
>  }
> 
> Any thoughts on which is better?

You could use

if (sk) {
sk = sk_to_full_sk(sk);
if (sk_fullsock(sk))
return sk->sk_uid;
}

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Lorenzo Colitti 
On Fri, Feb 3, 2017 at 9:31 AM, Eric Dumazet  wrote:
>> It should be safe to call sock_net_uid on any type of socket
>> (including NULL). sk_uid was added to struct sock in 86741ec25462
>> ("net: core: Add a UID field to struct sock.")
>
> But a request socket or a timewait socket do not have this field.
>
> Daniel point is valid.

My bad. Yes.

It would definitely be useful to have the UID available in request
sockets, and perhaps timewait sockets as well. That could be done by
moving the UID to sock_common, or with something along the lines of:

 static inline kuid_t sock_net_uid(const struct net *net, const struct sock *sk)
 {
+   if (sk && sk->sk_state == TCP_NEW_SYN_RECV)
+   sk = sk->__sk_common.skc_listener;
+   else if (sk && !sk_fullsock(sk))
+   sk = NULL;
+
return sk ? sk->sk_uid : make_kuid(net->user_ns, 0);
 }

Any thoughts on which is better?

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Eric Dumazet 
On Fri, 2017-02-03 at 09:00 +0900, Lorenzo Colitti wrote:
> On Fri, Feb 3, 2017 at 6:32 AM, Daniel Borkmann  wrote:
> >> +   sk = skb->sk;
> >> +   kuid = sock_net_uid(dev_net(skb->dev), sk);
> >
> >
> > Don't you need to test for fullsock? Do you mean something like below?
> 
> It should be safe to call sock_net_uid on any type of socket
> (including NULL). sk_uid was added to struct sock in 86741ec25462
> ("net: core: Add a UID field to struct sock.")

But a request socket or a timewait socket do not have this field.

Daniel point is valid.

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Daniel Borkmann 

On 02/03/2017 01:00 AM, Lorenzo Colitti wrote:

On Fri, Feb 3, 2017 at 6:32 AM, Daniel Borkmann  wrote:

+   sk = skb->sk;
+   kuid = sock_net_uid(dev_net(skb->dev), sk);


Don't you need to test for fullsock? Do you mean something like below?


It should be safe to call sock_net_uid on any type of socket
(including NULL). sk_uid was added to struct sock in 86741ec25462
("net: core: Add a UID field to struct sock.")


Hmm, maybe I'm missing something, but then shouldn't this sit in
struct sock_common for being 'safe'? F.e. struct inet_timewait_sock
wouldn't have it ...

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Lorenzo Colitti 
On Fri, Feb 3, 2017 at 6:32 AM, Daniel Borkmann  wrote:
>> +   sk = skb->sk;
>> +   kuid = sock_net_uid(dev_net(skb->dev), sk);
>
>
> Don't you need to test for fullsock? Do you mean something like below?

It should be safe to call sock_net_uid on any type of socket
(including NULL). sk_uid was added to struct sock in 86741ec25462
("net: core: Add a UID field to struct sock.")

Re: [PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Daniel Borkmann 

On 02/02/2017 09:59 PM, Chenbo Feng wrote:

From: Chenbo Feng 

Returns the owner uid of the socket inside a sk_buff. This is useful to
perform per-UID accounting of network traffic or per-UID packet
filtering.

Signed-off-by: Chenbo Feng 
---
  include/linux/bpf.h  |  1 +
  include/uapi/linux/bpf.h |  9 -
  net/core/filter.c| 19 +++
  3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3f2e0af28c6e..c775ca4678b7 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -350,6 +350,7 @@ extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
  extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
  extern const struct bpf_func_proto bpf_get_stackid_proto;
  extern const struct bpf_func_proto bpf_get_socket_cookie_proto;
+extern const struct bpf_func_proto bpf_get_socket_uid_proto;


Likewise, no need to add it here.


  /* Shared helpers among cBPF and eBPF. */
  void bpf_user_rnd_init_once(void);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 62ee5fab08e5..dad4dc7aca49 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -436,6 +436,12 @@ union bpf_attr {
   * @skb: pointer to skb
   * Return: 8 Bytes non-decreasing number on success or 0 if the socket
   * field is missing inside sk_buff
+ *
+ * u32 bpf_get_socket_uid(skb)
+ * Get the owner uid of the socket stored inside sk_buff.
+ * @skb: pointer to skb
+ * Return: uid of the socket owner on success or 0 if the socket pointer
+ * inside sk_buff is NULL
   */
  #define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -483,7 +489,8 @@ union bpf_attr {
FN(get_numa_node_id),   \
FN(skb_change_head),\
FN(xdp_adjust_head),\
-   FN(get_socket_cookie),
+   FN(get_socket_cookie),  \
+   FN(get_socket_uid),

  /* integer value in 'imm' field of BPF_CALL instruction selects which helper
   * function eBPF program intends to call
diff --git a/net/core/filter.c b/net/core/filter.c
index 913b14d3b484..bc36ed72551f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2610,6 +2610,23 @@ const struct bpf_func_proto bpf_get_socket_cookie_proto 
= {
.arg1_type  = ARG_PTR_TO_CTX,
  };

+BPF_CALL_1(bpf_get_socket_uid, struct sk_buff *, skb)
+{
+   struct sock *sk;
+   kuid_t kuid;


Nit: already init them above.


+   sk = skb->sk;
+   kuid = sock_net_uid(dev_net(skb->dev), sk);


Don't you need to test for fullsock? Do you mean something like below?

struct sock *sk = skb->sk;
kuid_t kuid = sock_net_uid(net, sk && sk_fullsock(sk) ?
   sk : NULL);


+   return (u32)kuid.val;
+}
+
+const struct bpf_func_proto bpf_get_socket_uid_proto = {


static ...


+   .func   = bpf_get_socket_uid,
+   .gpl_only   = false,
+   .ret_type   = RET_INTEGER,
+   .arg1_type  = ARG_PTR_TO_CTX,
+};
+
  static const struct bpf_func_proto *
  sk_filter_func_proto(enum bpf_func_id func_id)
  {
@@ -2635,6 +2652,8 @@ sk_filter_func_proto(enum bpf_func_id func_id)
return bpf_get_trace_printk_proto();
case BPF_FUNC_get_socket_cookie:
return _get_socket_cookie_proto;
+   case BPF_FUNC_get_socket_uid:
+   return _get_socket_uid_proto;
default:
return NULL;
}

[PATCH net-next 2/2] Add a eBPF helper function to retrieve socket uid

2017-02-02 Thread Chenbo Feng 
From: Chenbo Feng 

Returns the owner uid of the socket inside a sk_buff. This is useful to
perform per-UID accounting of network traffic or per-UID packet
filtering.

Signed-off-by: Chenbo Feng 
---
 include/linux/bpf.h  |  1 +
 include/uapi/linux/bpf.h |  9 -
 net/core/filter.c| 19 +++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 3f2e0af28c6e..c775ca4678b7 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -350,6 +350,7 @@ extern const struct bpf_func_proto bpf_skb_vlan_push_proto;
 extern const struct bpf_func_proto bpf_skb_vlan_pop_proto;
 extern const struct bpf_func_proto bpf_get_stackid_proto;
 extern const struct bpf_func_proto bpf_get_socket_cookie_proto;
+extern const struct bpf_func_proto bpf_get_socket_uid_proto;
 
 /* Shared helpers among cBPF and eBPF. */
 void bpf_user_rnd_init_once(void);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 62ee5fab08e5..dad4dc7aca49 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -436,6 +436,12 @@ union bpf_attr {
  * @skb: pointer to skb
  * Return: 8 Bytes non-decreasing number on success or 0 if the socket
  * field is missing inside sk_buff
+ *
+ * u32 bpf_get_socket_uid(skb)
+ * Get the owner uid of the socket stored inside sk_buff.
+ * @skb: pointer to skb
+ * Return: uid of the socket owner on success or 0 if the socket pointer
+ * inside sk_buff is NULL
  */
 #define __BPF_FUNC_MAPPER(FN)  \
FN(unspec), \
@@ -483,7 +489,8 @@ union bpf_attr {
FN(get_numa_node_id),   \
FN(skb_change_head),\
FN(xdp_adjust_head),\
-   FN(get_socket_cookie),
+   FN(get_socket_cookie),  \
+   FN(get_socket_uid),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call
diff --git a/net/core/filter.c b/net/core/filter.c
index 913b14d3b484..bc36ed72551f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2610,6 +2610,23 @@ const struct bpf_func_proto bpf_get_socket_cookie_proto 
= {
.arg1_type  = ARG_PTR_TO_CTX,
 };
 
+BPF_CALL_1(bpf_get_socket_uid, struct sk_buff *, skb)
+{
+   struct sock *sk;
+   kuid_t kuid;
+
+   sk = skb->sk;
+   kuid = sock_net_uid(dev_net(skb->dev), sk);
+   return (u32)kuid.val;
+}
+
+const struct bpf_func_proto bpf_get_socket_uid_proto = {
+   .func   = bpf_get_socket_uid,
+   .gpl_only   = false,
+   .ret_type   = RET_INTEGER,
+   .arg1_type  = ARG_PTR_TO_CTX,
+};
+
 static const struct bpf_func_proto *
 sk_filter_func_proto(enum bpf_func_id func_id)
 {
@@ -2635,6 +2652,8 @@ sk_filter_func_proto(enum bpf_func_id func_id)
return bpf_get_trace_printk_proto();
case BPF_FUNC_get_socket_cookie:
return _get_socket_cookie_proto;
+   case BPF_FUNC_get_socket_uid:
+   return _get_socket_uid_proto;
default:
return NULL;
}
-- 
2.11.0.483.g087da7b7c-goog