Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-03-16 Thread Richard Guy Briggs 
On 14/03/16, Richard Guy Briggs wrote:
> On 14/02/28, Eric W. Biederman wrote:
> > 
> > While reading through 3.14-rc1 I found a pretty siginficant mishandling
> > of network namespaces in the recent audit changes.
> > 
> > In struct audit_netlink_list and audit_reply add a reference to the
> > network namespace of the caller and remove the userspace pid of the
> > caller.  This cleanly remembers the callers network namespace, and
> > removes a huge class of races and nasty failure modes that can occur
> > when attempting to relook up the callers network namespace from a pid_t
> > (including the caller's network namespace changing, pid wraparound, and
> > the pid simply not being present).
> > 
> > Signed-off-by: "Eric W. Biederman" 
> 
> Signed-off-by: Richard Guy Briggs 

Sorry for the noise, please change that sig to:

Signed-off-by: Richard Guy Briggs 

> > ---
> >  kernel/audit.c   |   10 ++
> >  kernel/audit.h   |2 +-
> >  kernel/auditfilter.c |3 ++-
> >  3 files changed, 9 insertions(+), 6 deletions(-)
> > 
> > diff --git a/kernel/audit.c b/kernel/audit.c
> > index 34c5a2310fbf..1e5756f16f6f 100644
> > --- a/kernel/audit.c
> > +++ b/kernel/audit.c
> > @@ -182,7 +182,7 @@ struct audit_buffer {
> >  
> >  struct audit_reply {
> > __u32 portid;
> > -   pid_t pid;
> > +   struct net *net;
> > struct sk_buff *skb;
> >  };
> >  
> > @@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
> >  {
> > struct audit_netlink_list *dest = _dest;
> > struct sk_buff *skb;
> > -   struct net *net = get_net_ns_by_pid(dest->pid);
> > +   struct net *net = dest->net;
> > struct audit_net *aunet = net_generic(net, audit_net_id);
> >  
> > /* wait for parent to finish and send an ACK */
> > @@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
> > while ((skb = __skb_dequeue(>q)) != NULL)
> > netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
> >  
> > +   put_net(net);
> > kfree(dest);
> >  
> > return 0;
> > @@ -543,7 +544,7 @@ out_kfree_skb:
> >  static int audit_send_reply_thread(void *arg)
> >  {
> > struct audit_reply *reply = (struct audit_reply *)arg;
> > -   struct net *net = get_net_ns_by_pid(reply->pid);
> > +   struct net *net = reply->net;
> > struct audit_net *aunet = net_generic(net, audit_net_id);
> >  
> > mutex_lock(_cmd_mutex);
> > @@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
> > /* Ignore failure. It'll only happen if the sender goes away,
> >because our timeout is set to infinite. */
> > netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
> > +   put_net(net);
> > kfree(reply);
> > return 0;
> >  }
> > @@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
> > type, int done,
> > if (!skb)
> > goto out;
> >  
> > +   reply->net = get_net(current->nsproxy->net_ns);
> > reply->portid = portid;
> > -   reply->pid = task_pid_vnr(current);
> > reply->skb = skb;
> >  
> > tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
> > diff --git a/kernel/audit.h b/kernel/audit.h
> > index 57cc64d67718..8df132214606 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -247,7 +247,7 @@ extern void audit_panic(const char 
> > *message);
> >  
> >  struct audit_netlink_list {
> > __u32 portid;
> > -   pid_t pid;
> > +   struct net *net;
> > struct sk_buff_head q;
> >  };
> >  
> > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> > index 14a78cca384e..a5e3d73d73e4 100644
> > --- a/kernel/auditfilter.c
> > +++ b/kernel/auditfilter.c
> > @@ -29,6 +29,7 @@
> >  #include 
> >  #include 
> >  #include 
> > +#include 
> >  #include "audit.h"
> >  
> >  /*
> > @@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
> > dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
> > if (!dest)
> > return -ENOMEM;
> > +   dest->net = get_net(current->nsproxy->net_ns);
> > dest->portid = portid;
> > -   dest->pid = task_pid_vnr(current);
> > skb_queue_head_init(>q);
> >  
> > mutex_lock(_filter_mutex);
> > -- 
> > 1.7.5.4
> > 
> 
> - RGB
> 
> --
> Richard Guy Briggs 
> Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, 
> Red Hat
> Remote, Ottawa, Canada
> Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545

- RGB

--
Richard Guy Briggs 
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red 
Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-03-16 Thread Richard Guy Briggs 
On 14/02/28, Eric W. Biederman wrote:
> 
> While reading through 3.14-rc1 I found a pretty siginficant mishandling
> of network namespaces in the recent audit changes.
> 
> In struct audit_netlink_list and audit_reply add a reference to the
> network namespace of the caller and remove the userspace pid of the
> caller.  This cleanly remembers the callers network namespace, and
> removes a huge class of races and nasty failure modes that can occur
> when attempting to relook up the callers network namespace from a pid_t
> (including the caller's network namespace changing, pid wraparound, and
> the pid simply not being present).
> 
> Signed-off-by: "Eric W. Biederman" 

Signed-off-by: Richard Guy Briggs 

> ---
>  kernel/audit.c   |   10 ++
>  kernel/audit.h   |2 +-
>  kernel/auditfilter.c |3 ++-
>  3 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/audit.c b/kernel/audit.c
> index 34c5a2310fbf..1e5756f16f6f 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -182,7 +182,7 @@ struct audit_buffer {
>  
>  struct audit_reply {
>   __u32 portid;
> - pid_t pid;
> + struct net *net;
>   struct sk_buff *skb;
>  };
>  
> @@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
>  {
>   struct audit_netlink_list *dest = _dest;
>   struct sk_buff *skb;
> - struct net *net = get_net_ns_by_pid(dest->pid);
> + struct net *net = dest->net;
>   struct audit_net *aunet = net_generic(net, audit_net_id);
>  
>   /* wait for parent to finish and send an ACK */
> @@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
>   while ((skb = __skb_dequeue(>q)) != NULL)
>   netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
>  
> + put_net(net);
>   kfree(dest);
>  
>   return 0;
> @@ -543,7 +544,7 @@ out_kfree_skb:
>  static int audit_send_reply_thread(void *arg)
>  {
>   struct audit_reply *reply = (struct audit_reply *)arg;
> - struct net *net = get_net_ns_by_pid(reply->pid);
> + struct net *net = reply->net;
>   struct audit_net *aunet = net_generic(net, audit_net_id);
>  
>   mutex_lock(_cmd_mutex);
> @@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
>   /* Ignore failure. It'll only happen if the sender goes away,
>  because our timeout is set to infinite. */
>   netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
> + put_net(net);
>   kfree(reply);
>   return 0;
>  }
> @@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
> type, int done,
>   if (!skb)
>   goto out;
>  
> + reply->net = get_net(current->nsproxy->net_ns);
>   reply->portid = portid;
> - reply->pid = task_pid_vnr(current);
>   reply->skb = skb;
>  
>   tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
> diff --git a/kernel/audit.h b/kernel/audit.h
> index 57cc64d67718..8df132214606 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -247,7 +247,7 @@ extern void   audit_panic(const char 
> *message);
>  
>  struct audit_netlink_list {
>   __u32 portid;
> - pid_t pid;
> + struct net *net;
>   struct sk_buff_head q;
>  };
>  
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index 14a78cca384e..a5e3d73d73e4 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -29,6 +29,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include "audit.h"
>  
>  /*
> @@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
>   dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
>   if (!dest)
>   return -ENOMEM;
> + dest->net = get_net(current->nsproxy->net_ns);
>   dest->portid = portid;
> - dest->pid = task_pid_vnr(current);
>   skb_queue_head_init(>q);
>  
>   mutex_lock(_filter_mutex);
> -- 
> 1.7.5.4
> 

- RGB

--
Richard Guy Briggs 
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red 
Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-03-16 Thread Richard Guy Briggs 
On 14/02/28, Eric W. Biederman wrote:
 
 While reading through 3.14-rc1 I found a pretty siginficant mishandling
 of network namespaces in the recent audit changes.
 
 In struct audit_netlink_list and audit_reply add a reference to the
 network namespace of the caller and remove the userspace pid of the
 caller.  This cleanly remembers the callers network namespace, and
 removes a huge class of races and nasty failure modes that can occur
 when attempting to relook up the callers network namespace from a pid_t
 (including the caller's network namespace changing, pid wraparound, and
 the pid simply not being present).
 
 Signed-off-by: Eric W. Biederman ebied...@xmission.com

Signed-off-by: Richard Guy Briggs r...@tricolour.ca

 ---
  kernel/audit.c   |   10 ++
  kernel/audit.h   |2 +-
  kernel/auditfilter.c |3 ++-
  3 files changed, 9 insertions(+), 6 deletions(-)
 
 diff --git a/kernel/audit.c b/kernel/audit.c
 index 34c5a2310fbf..1e5756f16f6f 100644
 --- a/kernel/audit.c
 +++ b/kernel/audit.c
 @@ -182,7 +182,7 @@ struct audit_buffer {
  
  struct audit_reply {
   __u32 portid;
 - pid_t pid;
 + struct net *net;
   struct sk_buff *skb;
  };
  
 @@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
  {
   struct audit_netlink_list *dest = _dest;
   struct sk_buff *skb;
 - struct net *net = get_net_ns_by_pid(dest-pid);
 + struct net *net = dest-net;
   struct audit_net *aunet = net_generic(net, audit_net_id);
  
   /* wait for parent to finish and send an ACK */
 @@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
   while ((skb = __skb_dequeue(dest-q)) != NULL)
   netlink_unicast(aunet-nlsk, skb, dest-portid, 0);
  
 + put_net(net);
   kfree(dest);
  
   return 0;
 @@ -543,7 +544,7 @@ out_kfree_skb:
  static int audit_send_reply_thread(void *arg)
  {
   struct audit_reply *reply = (struct audit_reply *)arg;
 - struct net *net = get_net_ns_by_pid(reply-pid);
 + struct net *net = reply-net;
   struct audit_net *aunet = net_generic(net, audit_net_id);
  
   mutex_lock(audit_cmd_mutex);
 @@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
   /* Ignore failure. It'll only happen if the sender goes away,
  because our timeout is set to infinite. */
   netlink_unicast(aunet-nlsk , reply-skb, reply-portid, 0);
 + put_net(net);
   kfree(reply);
   return 0;
  }
 @@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
 type, int done,
   if (!skb)
   goto out;
  
 + reply-net = get_net(current-nsproxy-net_ns);
   reply-portid = portid;
 - reply-pid = task_pid_vnr(current);
   reply-skb = skb;
  
   tsk = kthread_run(audit_send_reply_thread, reply, audit_send_reply);
 diff --git a/kernel/audit.h b/kernel/audit.h
 index 57cc64d67718..8df132214606 100644
 --- a/kernel/audit.h
 +++ b/kernel/audit.h
 @@ -247,7 +247,7 @@ extern void   audit_panic(const char 
 *message);
  
  struct audit_netlink_list {
   __u32 portid;
 - pid_t pid;
 + struct net *net;
   struct sk_buff_head q;
  };
  
 diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
 index 14a78cca384e..a5e3d73d73e4 100644
 --- a/kernel/auditfilter.c
 +++ b/kernel/auditfilter.c
 @@ -29,6 +29,7 @@
  #include linux/sched.h
  #include linux/slab.h
  #include linux/security.h
 +#include net/net_namespace.h
  #include audit.h
  
  /*
 @@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
   dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
   if (!dest)
   return -ENOMEM;
 + dest-net = get_net(current-nsproxy-net_ns);
   dest-portid = portid;
 - dest-pid = task_pid_vnr(current);
   skb_queue_head_init(dest-q);
  
   mutex_lock(audit_filter_mutex);
 -- 
 1.7.5.4
 

- RGB

--
Richard Guy Briggs rbri...@redhat.com
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red 
Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-03-16 Thread Richard Guy Briggs 
On 14/03/16, Richard Guy Briggs wrote:
 On 14/02/28, Eric W. Biederman wrote:
  
  While reading through 3.14-rc1 I found a pretty siginficant mishandling
  of network namespaces in the recent audit changes.
  
  In struct audit_netlink_list and audit_reply add a reference to the
  network namespace of the caller and remove the userspace pid of the
  caller.  This cleanly remembers the callers network namespace, and
  removes a huge class of races and nasty failure modes that can occur
  when attempting to relook up the callers network namespace from a pid_t
  (including the caller's network namespace changing, pid wraparound, and
  the pid simply not being present).
  
  Signed-off-by: Eric W. Biederman ebied...@xmission.com
 
 Signed-off-by: Richard Guy Briggs r...@tricolour.ca

Sorry for the noise, please change that sig to:

Signed-off-by: Richard Guy Briggs r...@redhat.com

  ---
   kernel/audit.c   |   10 ++
   kernel/audit.h   |2 +-
   kernel/auditfilter.c |3 ++-
   3 files changed, 9 insertions(+), 6 deletions(-)
  
  diff --git a/kernel/audit.c b/kernel/audit.c
  index 34c5a2310fbf..1e5756f16f6f 100644
  --- a/kernel/audit.c
  +++ b/kernel/audit.c
  @@ -182,7 +182,7 @@ struct audit_buffer {
   
   struct audit_reply {
  __u32 portid;
  -   pid_t pid;
  +   struct net *net;
  struct sk_buff *skb;
   };
   
  @@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
   {
  struct audit_netlink_list *dest = _dest;
  struct sk_buff *skb;
  -   struct net *net = get_net_ns_by_pid(dest-pid);
  +   struct net *net = dest-net;
  struct audit_net *aunet = net_generic(net, audit_net_id);
   
  /* wait for parent to finish and send an ACK */
  @@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
  while ((skb = __skb_dequeue(dest-q)) != NULL)
  netlink_unicast(aunet-nlsk, skb, dest-portid, 0);
   
  +   put_net(net);
  kfree(dest);
   
  return 0;
  @@ -543,7 +544,7 @@ out_kfree_skb:
   static int audit_send_reply_thread(void *arg)
   {
  struct audit_reply *reply = (struct audit_reply *)arg;
  -   struct net *net = get_net_ns_by_pid(reply-pid);
  +   struct net *net = reply-net;
  struct audit_net *aunet = net_generic(net, audit_net_id);
   
  mutex_lock(audit_cmd_mutex);
  @@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
  /* Ignore failure. It'll only happen if the sender goes away,
 because our timeout is set to infinite. */
  netlink_unicast(aunet-nlsk , reply-skb, reply-portid, 0);
  +   put_net(net);
  kfree(reply);
  return 0;
   }
  @@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
  type, int done,
  if (!skb)
  goto out;
   
  +   reply-net = get_net(current-nsproxy-net_ns);
  reply-portid = portid;
  -   reply-pid = task_pid_vnr(current);
  reply-skb = skb;
   
  tsk = kthread_run(audit_send_reply_thread, reply, audit_send_reply);
  diff --git a/kernel/audit.h b/kernel/audit.h
  index 57cc64d67718..8df132214606 100644
  --- a/kernel/audit.h
  +++ b/kernel/audit.h
  @@ -247,7 +247,7 @@ extern void audit_panic(const char 
  *message);
   
   struct audit_netlink_list {
  __u32 portid;
  -   pid_t pid;
  +   struct net *net;
  struct sk_buff_head q;
   };
   
  diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
  index 14a78cca384e..a5e3d73d73e4 100644
  --- a/kernel/auditfilter.c
  +++ b/kernel/auditfilter.c
  @@ -29,6 +29,7 @@
   #include linux/sched.h
   #include linux/slab.h
   #include linux/security.h
  +#include net/net_namespace.h
   #include audit.h
   
   /*
  @@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
  dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
  if (!dest)
  return -ENOMEM;
  +   dest-net = get_net(current-nsproxy-net_ns);
  dest-portid = portid;
  -   dest-pid = task_pid_vnr(current);
  skb_queue_head_init(dest-q);
   
  mutex_lock(audit_filter_mutex);
  -- 
  1.7.5.4
  
 
 - RGB
 
 --
 Richard Guy Briggs rbri...@redhat.com
 Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, 
 Red Hat
 Remote, Ottawa, Canada
 Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545

- RGB

--
Richard Guy Briggs rbri...@redhat.com
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red 
Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28 Thread Eric W. Biederman 
Richard Guy Briggs  writes:

> On 14/02/28, Eric W. Biederman wrote:
>> While reading through 3.14-rc1 I found a pretty siginficant mishandling
>> of network namespaces in the recent audit changes.
>> 
>> In struct audit_netlink_list and audit_reply add a reference to the
>> network namespace of the caller and remove the userspace pid of the
>> caller.  This cleanly remembers the callers network namespace, and
>> removes a huge class of races and nasty failure modes that can occur
>> when attempting to relook up the callers network namespace from a pid_t
>> (including the caller's network namespace changing, pid wraparound, and
>> the pid simply not being present).
>
> Ok, so I see that avoiding pid_t in struct audit_reply and struct
> audit_netlink_list is necessary.  Why not switch to struct pid?
>
> How does this patch solve a caller's network namespace changing?

This solves the callers network namespace changing or the caller going
away entirely (a much more serious concern) because we capture the
network namespace at the time of the request when the caller is in the
kernel.  I would have simply captured the socket we want to reply on but
there did not appear to be a good way to do that.

Reading through it again capturing current->nsproxy->net_ns is striclty
wrong.  We should be capturing sock_net(NETLINK_CB(skb).sk).  The
network namespace of the requesting socket.  That handles even weird
cases of passing file descriptors between processes in different network
namespaces.  (An incremental patch to change to code to selct the
network namespace of the requesting socket to follow in a moment).

Still what my patch implements today at least means we won't oops the
kernel if the audit process exits early, and causes get_net_ns_by_pid
to return NULL.


This whole code path is so crazy because what we really should be doing
is sending the packets in nonblocking mode and just dropping packets
if the receiving socket does not have enough socket buvffers.

Eric
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Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28 Thread Richard Guy Briggs 
On 14/02/28, Eric W. Biederman wrote:
> While reading through 3.14-rc1 I found a pretty siginficant mishandling
> of network namespaces in the recent audit changes.
> 
> In struct audit_netlink_list and audit_reply add a reference to the
> network namespace of the caller and remove the userspace pid of the
> caller.  This cleanly remembers the callers network namespace, and
> removes a huge class of races and nasty failure modes that can occur
> when attempting to relook up the callers network namespace from a pid_t
> (including the caller's network namespace changing, pid wraparound, and
> the pid simply not being present).

Ok, so I see that avoiding pid_t in struct audit_reply and struct
audit_netlink_list is necessary.  Why not switch to struct pid?

How does this patch solve a caller's network namespace changing?

> Signed-off-by: "Eric W. Biederman" 
> ---
>  kernel/audit.c   |   10 ++
>  kernel/audit.h   |2 +-
>  kernel/auditfilter.c |3 ++-
>  3 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/kernel/audit.c b/kernel/audit.c
> index 34c5a2310fbf..1e5756f16f6f 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -182,7 +182,7 @@ struct audit_buffer {
>  
>  struct audit_reply {
>   __u32 portid;
> - pid_t pid;
> + struct net *net;
>   struct sk_buff *skb;
>  };
>  
> @@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
>  {
>   struct audit_netlink_list *dest = _dest;
>   struct sk_buff *skb;
> - struct net *net = get_net_ns_by_pid(dest->pid);
> + struct net *net = dest->net;
>   struct audit_net *aunet = net_generic(net, audit_net_id);
>  
>   /* wait for parent to finish and send an ACK */
> @@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
>   while ((skb = __skb_dequeue(>q)) != NULL)
>   netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
>  
> + put_net(net);
>   kfree(dest);
>  
>   return 0;
> @@ -543,7 +544,7 @@ out_kfree_skb:
>  static int audit_send_reply_thread(void *arg)
>  {
>   struct audit_reply *reply = (struct audit_reply *)arg;
> - struct net *net = get_net_ns_by_pid(reply->pid);
> + struct net *net = reply->net;
>   struct audit_net *aunet = net_generic(net, audit_net_id);
>  
>   mutex_lock(_cmd_mutex);
> @@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
>   /* Ignore failure. It'll only happen if the sender goes away,
>  because our timeout is set to infinite. */
>   netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
> + put_net(net);
>   kfree(reply);
>   return 0;
>  }
> @@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
> type, int done,
>   if (!skb)
>   goto out;
>  
> + reply->net = get_net(current->nsproxy->net_ns);
>   reply->portid = portid;
> - reply->pid = task_pid_vnr(current);
>   reply->skb = skb;
>  
>   tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
> diff --git a/kernel/audit.h b/kernel/audit.h
> index 57cc64d67718..8df132214606 100644
> --- a/kernel/audit.h
> +++ b/kernel/audit.h
> @@ -247,7 +247,7 @@ extern void   audit_panic(const char 
> *message);
>  
>  struct audit_netlink_list {
>   __u32 portid;
> - pid_t pid;
> + struct net *net;
>   struct sk_buff_head q;
>  };
>  
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index 14a78cca384e..a5e3d73d73e4 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -29,6 +29,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include "audit.h"
>  
>  /*
> @@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
>   dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
>   if (!dest)
>   return -ENOMEM;
> + dest->net = get_net(current->nsproxy->net_ns);
>   dest->portid = portid;
> - dest->pid = task_pid_vnr(current);
>   skb_queue_head_init(>q);
>  
>   mutex_lock(_filter_mutex);
> -- 
> 1.7.5.4
> 

- RGB

--
Richard Guy Briggs 
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red 
Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28 Thread Eric W. Biederman 

While reading through 3.14-rc1 I found a pretty siginficant mishandling
of network namespaces in the recent audit changes.

In struct audit_netlink_list and audit_reply add a reference to the
network namespace of the caller and remove the userspace pid of the
caller.  This cleanly remembers the callers network namespace, and
removes a huge class of races and nasty failure modes that can occur
when attempting to relook up the callers network namespace from a pid_t
(including the caller's network namespace changing, pid wraparound, and
the pid simply not being present).

Signed-off-by: "Eric W. Biederman" 
---
 kernel/audit.c   |   10 ++
 kernel/audit.h   |2 +-
 kernel/auditfilter.c |3 ++-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 34c5a2310fbf..1e5756f16f6f 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -182,7 +182,7 @@ struct audit_buffer {
 
 struct audit_reply {
__u32 portid;
-   pid_t pid;
+   struct net *net;
struct sk_buff *skb;
 };
 
@@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
 {
struct audit_netlink_list *dest = _dest;
struct sk_buff *skb;
-   struct net *net = get_net_ns_by_pid(dest->pid);
+   struct net *net = dest->net;
struct audit_net *aunet = net_generic(net, audit_net_id);
 
/* wait for parent to finish and send an ACK */
@@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
while ((skb = __skb_dequeue(>q)) != NULL)
netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
 
+   put_net(net);
kfree(dest);
 
return 0;
@@ -543,7 +544,7 @@ out_kfree_skb:
 static int audit_send_reply_thread(void *arg)
 {
struct audit_reply *reply = (struct audit_reply *)arg;
-   struct net *net = get_net_ns_by_pid(reply->pid);
+   struct net *net = reply->net;
struct audit_net *aunet = net_generic(net, audit_net_id);
 
mutex_lock(_cmd_mutex);
@@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
/* Ignore failure. It'll only happen if the sender goes away,
   because our timeout is set to infinite. */
netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
+   put_net(net);
kfree(reply);
return 0;
 }
@@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
type, int done,
if (!skb)
goto out;
 
+   reply->net = get_net(current->nsproxy->net_ns);
reply->portid = portid;
-   reply->pid = task_pid_vnr(current);
reply->skb = skb;
 
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
diff --git a/kernel/audit.h b/kernel/audit.h
index 57cc64d67718..8df132214606 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -247,7 +247,7 @@ extern void audit_panic(const char *message);
 
 struct audit_netlink_list {
__u32 portid;
-   pid_t pid;
+   struct net *net;
struct sk_buff_head q;
 };
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 14a78cca384e..a5e3d73d73e4 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -29,6 +29,7 @@
 #include 
 #include 
 #include 
+#include 
 #include "audit.h"
 
 /*
@@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
if (!dest)
return -ENOMEM;
+   dest->net = get_net(current->nsproxy->net_ns);
dest->portid = portid;
-   dest->pid = task_pid_vnr(current);
skb_queue_head_init(>q);
 
mutex_lock(_filter_mutex);
-- 
1.7.5.4

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[PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28 Thread Eric W. Biederman 

While reading through 3.14-rc1 I found a pretty siginficant mishandling
of network namespaces in the recent audit changes.

In struct audit_netlink_list and audit_reply add a reference to the
network namespace of the caller and remove the userspace pid of the
caller.  This cleanly remembers the callers network namespace, and
removes a huge class of races and nasty failure modes that can occur
when attempting to relook up the callers network namespace from a pid_t
(including the caller's network namespace changing, pid wraparound, and
the pid simply not being present).

Signed-off-by: Eric W. Biederman ebied...@xmission.com
---
 kernel/audit.c   |   10 ++
 kernel/audit.h   |2 +-
 kernel/auditfilter.c |3 ++-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 34c5a2310fbf..1e5756f16f6f 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -182,7 +182,7 @@ struct audit_buffer {
 
 struct audit_reply {
__u32 portid;
-   pid_t pid;
+   struct net *net;
struct sk_buff *skb;
 };
 
@@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
 {
struct audit_netlink_list *dest = _dest;
struct sk_buff *skb;
-   struct net *net = get_net_ns_by_pid(dest-pid);
+   struct net *net = dest-net;
struct audit_net *aunet = net_generic(net, audit_net_id);
 
/* wait for parent to finish and send an ACK */
@@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
while ((skb = __skb_dequeue(dest-q)) != NULL)
netlink_unicast(aunet-nlsk, skb, dest-portid, 0);
 
+   put_net(net);
kfree(dest);
 
return 0;
@@ -543,7 +544,7 @@ out_kfree_skb:
 static int audit_send_reply_thread(void *arg)
 {
struct audit_reply *reply = (struct audit_reply *)arg;
-   struct net *net = get_net_ns_by_pid(reply-pid);
+   struct net *net = reply-net;
struct audit_net *aunet = net_generic(net, audit_net_id);
 
mutex_lock(audit_cmd_mutex);
@@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
/* Ignore failure. It'll only happen if the sender goes away,
   because our timeout is set to infinite. */
netlink_unicast(aunet-nlsk , reply-skb, reply-portid, 0);
+   put_net(net);
kfree(reply);
return 0;
 }
@@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
type, int done,
if (!skb)
goto out;
 
+   reply-net = get_net(current-nsproxy-net_ns);
reply-portid = portid;
-   reply-pid = task_pid_vnr(current);
reply-skb = skb;
 
tsk = kthread_run(audit_send_reply_thread, reply, audit_send_reply);
diff --git a/kernel/audit.h b/kernel/audit.h
index 57cc64d67718..8df132214606 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -247,7 +247,7 @@ extern void audit_panic(const char *message);
 
 struct audit_netlink_list {
__u32 portid;
-   pid_t pid;
+   struct net *net;
struct sk_buff_head q;
 };
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 14a78cca384e..a5e3d73d73e4 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -29,6 +29,7 @@
 #include linux/sched.h
 #include linux/slab.h
 #include linux/security.h
+#include net/net_namespace.h
 #include audit.h
 
 /*
@@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
if (!dest)
return -ENOMEM;
+   dest-net = get_net(current-nsproxy-net_ns);
dest-portid = portid;
-   dest-pid = task_pid_vnr(current);
skb_queue_head_init(dest-q);
 
mutex_lock(audit_filter_mutex);
-- 
1.7.5.4

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Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28 Thread Richard Guy Briggs 
On 14/02/28, Eric W. Biederman wrote:
 While reading through 3.14-rc1 I found a pretty siginficant mishandling
 of network namespaces in the recent audit changes.
 
 In struct audit_netlink_list and audit_reply add a reference to the
 network namespace of the caller and remove the userspace pid of the
 caller.  This cleanly remembers the callers network namespace, and
 removes a huge class of races and nasty failure modes that can occur
 when attempting to relook up the callers network namespace from a pid_t
 (including the caller's network namespace changing, pid wraparound, and
 the pid simply not being present).

Ok, so I see that avoiding pid_t in struct audit_reply and struct
audit_netlink_list is necessary.  Why not switch to struct pid?

How does this patch solve a caller's network namespace changing?

 Signed-off-by: Eric W. Biederman ebied...@xmission.com
 ---
  kernel/audit.c   |   10 ++
  kernel/audit.h   |2 +-
  kernel/auditfilter.c |3 ++-
  3 files changed, 9 insertions(+), 6 deletions(-)
 
 diff --git a/kernel/audit.c b/kernel/audit.c
 index 34c5a2310fbf..1e5756f16f6f 100644
 --- a/kernel/audit.c
 +++ b/kernel/audit.c
 @@ -182,7 +182,7 @@ struct audit_buffer {
  
  struct audit_reply {
   __u32 portid;
 - pid_t pid;
 + struct net *net;
   struct sk_buff *skb;
  };
  
 @@ -500,7 +500,7 @@ int audit_send_list(void *_dest)
  {
   struct audit_netlink_list *dest = _dest;
   struct sk_buff *skb;
 - struct net *net = get_net_ns_by_pid(dest-pid);
 + struct net *net = dest-net;
   struct audit_net *aunet = net_generic(net, audit_net_id);
  
   /* wait for parent to finish and send an ACK */
 @@ -510,6 +510,7 @@ int audit_send_list(void *_dest)
   while ((skb = __skb_dequeue(dest-q)) != NULL)
   netlink_unicast(aunet-nlsk, skb, dest-portid, 0);
  
 + put_net(net);
   kfree(dest);
  
   return 0;
 @@ -543,7 +544,7 @@ out_kfree_skb:
  static int audit_send_reply_thread(void *arg)
  {
   struct audit_reply *reply = (struct audit_reply *)arg;
 - struct net *net = get_net_ns_by_pid(reply-pid);
 + struct net *net = reply-net;
   struct audit_net *aunet = net_generic(net, audit_net_id);
  
   mutex_lock(audit_cmd_mutex);
 @@ -552,6 +553,7 @@ static int audit_send_reply_thread(void *arg)
   /* Ignore failure. It'll only happen if the sender goes away,
  because our timeout is set to infinite. */
   netlink_unicast(aunet-nlsk , reply-skb, reply-portid, 0);
 + put_net(net);
   kfree(reply);
   return 0;
  }
 @@ -583,8 +585,8 @@ static void audit_send_reply(__u32 portid, int seq, int 
 type, int done,
   if (!skb)
   goto out;
  
 + reply-net = get_net(current-nsproxy-net_ns);
   reply-portid = portid;
 - reply-pid = task_pid_vnr(current);
   reply-skb = skb;
  
   tsk = kthread_run(audit_send_reply_thread, reply, audit_send_reply);
 diff --git a/kernel/audit.h b/kernel/audit.h
 index 57cc64d67718..8df132214606 100644
 --- a/kernel/audit.h
 +++ b/kernel/audit.h
 @@ -247,7 +247,7 @@ extern void   audit_panic(const char 
 *message);
  
  struct audit_netlink_list {
   __u32 portid;
 - pid_t pid;
 + struct net *net;
   struct sk_buff_head q;
  };
  
 diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
 index 14a78cca384e..a5e3d73d73e4 100644
 --- a/kernel/auditfilter.c
 +++ b/kernel/auditfilter.c
 @@ -29,6 +29,7 @@
  #include linux/sched.h
  #include linux/slab.h
  #include linux/security.h
 +#include net/net_namespace.h
  #include audit.h
  
  /*
 @@ -1083,8 +1084,8 @@ int audit_list_rules_send(__u32 portid, int seq)
   dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
   if (!dest)
   return -ENOMEM;
 + dest-net = get_net(current-nsproxy-net_ns);
   dest-portid = portid;
 - dest-pid = task_pid_vnr(current);
   skb_queue_head_init(dest-q);
  
   mutex_lock(audit_filter_mutex);
 -- 
 1.7.5.4
 

- RGB

--
Richard Guy Briggs rbri...@redhat.com
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red 
Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [PATCH] audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28 Thread Eric W. Biederman 
Richard Guy Briggs r...@redhat.com writes:

 On 14/02/28, Eric W. Biederman wrote:
 While reading through 3.14-rc1 I found a pretty siginficant mishandling
 of network namespaces in the recent audit changes.
 
 In struct audit_netlink_list and audit_reply add a reference to the
 network namespace of the caller and remove the userspace pid of the
 caller.  This cleanly remembers the callers network namespace, and
 removes a huge class of races and nasty failure modes that can occur
 when attempting to relook up the callers network namespace from a pid_t
 (including the caller's network namespace changing, pid wraparound, and
 the pid simply not being present).

 Ok, so I see that avoiding pid_t in struct audit_reply and struct
 audit_netlink_list is necessary.  Why not switch to struct pid?

 How does this patch solve a caller's network namespace changing?

This solves the callers network namespace changing or the caller going
away entirely (a much more serious concern) because we capture the
network namespace at the time of the request when the caller is in the
kernel.  I would have simply captured the socket we want to reply on but
there did not appear to be a good way to do that.

Reading through it again capturing current-nsproxy-net_ns is striclty
wrong.  We should be capturing sock_net(NETLINK_CB(skb).sk).  The
network namespace of the requesting socket.  That handles even weird
cases of passing file descriptors between processes in different network
namespaces.  (An incremental patch to change to code to selct the
network namespace of the requesting socket to follow in a moment).

Still what my patch implements today at least means we won't oops the
kernel if the audit process exits early, and causes get_net_ns_by_pid
to return NULL.


This whole code path is so crazy because what we really should be doing
is sending the packets in nonblocking mode and just dropping packets
if the receiving socket does not have enough socket buvffers.

Eric
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