[net-next,v3] net: ioctl: Use kernel memory on protocol ioctl callbacks

Commit Message

Breno Leitao May 25, 2023, 12:54 p.m. UTC

Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl callback.  This is not flexible, because it is hard to reuse these
functions without passing userspace buffers.

Change the "struct proto" ioctls to avoid touching userspace memory and
operate on kernel buffers, i.e., all protocol's ioctl callbacks is
adapted to operate on a kernel memory other than on userspace (so, no
more {put,get}_user() and friends being called in the ioctl callback).

This changes the "struct proto" ioctl format in the following way:

    int                     (*ioctl)(struct sock *sk, int cmd,
-                                        unsigned long arg);
+                                        int *karg);

So, the "karg" argument, which is passed to the ioctl callback, is a
pointer allocated to kernel space memory (inside a function wrapper).
This buffer (karg) may contain input argument (copied from userspace in
a prep function) and it might return a value/buffer, which is copied
back to userspace if necessary. There is not one-size-fits-all format
(that is I am using 'may' above), but basically, there are three type of
ioctls:

1) Do not read from userspace, returns a result to userspace
2) Read an input parameter from userspace, and does not return anything
  to userspace
3) Read an input from userspace, and return a buffer to userspace.

The default case (1) (where no input parameter is given, and an "int" is
returned to userspace) encompasses more than 90% of the cases, but there
are two other exceptions. Here is a list of exceptions:

* Protocol RAW:
   * cmd = SIOCGETVIFCNT:
     * input and output = struct sioc_vif_req
   * cmd = SIOCGETSGCNT
     * input and output = struct sioc_sg_req
   * Explanation: for the SIOCGETVIFCNT case, userspace passes the input
     argument, which is struct sioc_vif_req. Then the callback populates
     the struct, which is copied back to userspace.

* Protocol RAW6:
   * cmd = SIOCGETMIFCNT_IN6
     * input and output = struct sioc_mif_req6
   * cmd = SIOCGETSGCNT_IN6
     * input and output = struct sioc_sg_req6

* Protocol PHONET:
  * cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
     * input int (4 bytes)
  * Nothing is copied back to userspace.

For the exception cases, functions sock_sk_ioctl_inout() will
copy the userspace input, and copy it back to kernel space.

The wrapper that prepare the buffer and put the buffer back to user is
sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
calls sk_ioctl(), which will handle all cases.

Signed-off-by: Breno Leitao <[e-mail]>

---
V1 -> V2:
   * Rename mouthful functions to have saner names
   * Make functions statics and export sk_ioctl()
   * Allocate kernel structures at sk_ioctl()
V2 -> V3:
   * Move protocol specific logic to the protocol code (instead of
     keeping it on core code), and simplify sk_ioctl() by relaying
     on protocol code, for ioctl specifics.

---
 include/linux/mroute.h      | 20 ++++++++++--
 include/linux/mroute6.h     | 17 ++++++++--
 include/net/phonet/phonet.h | 19 +++++++++++
 include/net/sock.h          |  5 ++-
 include/net/tcp.h           |  2 +-
 include/net/udp.h           |  2 +-
 net/core/sock.c             | 63 ++++++++++++++++++++++++++++++++++++
 net/dccp/dccp.h             |  2 +-
 net/dccp/proto.c            | 12 +++----
 net/ieee802154/socket.c     | 15 ++++-----
 net/ipv4/af_inet.c          |  2 +-
 net/ipv4/ipmr.c             | 63 ++++++++++++++++++++++--------------
 net/ipv4/raw.c              | 16 +++++-----
 net/ipv4/tcp.c              |  5 +--
 net/ipv4/udp.c              | 12 +++----
 net/ipv6/af_inet6.c         |  2 +-
 net/ipv6/ip6mr.c            | 64 ++++++++++++++++++++++---------------
 net/ipv6/raw.c              | 16 +++++-----
 net/l2tp/l2tp_core.h        |  2 +-
 net/l2tp/l2tp_ip.c          |  9 +++---
 net/mptcp/protocol.c        | 11 +++----
 net/phonet/af_phonet.c      | 16 ++++++++++
 net/phonet/datagram.c       | 11 +++----
 net/phonet/pep.c            | 11 +++----
 net/phonet/socket.c         |  2 +-
 net/sctp/socket.c           |  8 ++---
 26 files changed, 278 insertions(+), 129 deletions(-)

Comments

Eric Dumazet May 25, 2023, 2:19 p.m. UTC | #1

On Thu, May 25, 2023 at 2:55 PM Breno Leitao <[e-mail]> wrote:
>
> Most of the ioctls to net protocols operates directly on userspace
> argument (arg). Usually doing get_user()/put_user() directly in the
> ioctl callback.  This is not flexible, because it is hard to reuse these
> functions without passing userspace buffers.
>
> Change the "struct proto" ioctls to avoid touching userspace memory and
> operate on kernel buffers, i.e., all protocol's ioctl callbacks is
> adapted to operate on a kernel memory other than on userspace (so, no
> more {put,get}_user() and friends being called in the ioctl callback).
>

 diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
> index 862f1719b523..93705d99f862 100644
> --- a/include/net/phonet/phonet.h
> +++ b/include/net/phonet/phonet.h
> @@ -109,4 +109,23 @@ void phonet_sysctl_exit(void);
>  int isi_register(void);
>  void isi_unregister(void);
>
> +#ifdef CONFIG_PHONET
> +int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
> +
> +static inline bool phonet_is_sk(struct sock *sk)
> +{
> +       return sk->sk_family == PF_PHONET && sk->sk_protocol == PN_PROTO_PHONET;
> +}
> +#else
> +static inline bool phonet_is_sk(struct sock *sk)
> +{
> +       return 0;
> +}
> +
> +static inline int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
> +{
> +       return 1;
> +}
> +#endif
> +
>

PHONET can be built as a module, so I guess the compiler would
complain if "CONFIG_PHONET=m" ???

Simon Horman May 25, 2023, 2:54 p.m. UTC | #2

On Thu, May 25, 2023 at 04:19:32PM +0200, Eric Dumazet wrote:
> On Thu, May 25, 2023 at 2:55 PM Breno Leitao <[e-mail]> wrote:
> >
> > Most of the ioctls to net protocols operates directly on userspace
> > argument (arg). Usually doing get_user()/put_user() directly in the
> > ioctl callback.  This is not flexible, because it is hard to reuse these
> > functions without passing userspace buffers.
> >
> > Change the "struct proto" ioctls to avoid touching userspace memory and
> > operate on kernel buffers, i.e., all protocol's ioctl callbacks is
> > adapted to operate on a kernel memory other than on userspace (so, no
> > more {put,get}_user() and friends being called in the ioctl callback).
> >
> 
>  diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
> > index 862f1719b523..93705d99f862 100644
> > --- a/include/net/phonet/phonet.h
> > +++ b/include/net/phonet/phonet.h
> > @@ -109,4 +109,23 @@ void phonet_sysctl_exit(void);
> >  int isi_register(void);
> >  void isi_unregister(void);
> >
> > +#ifdef CONFIG_PHONET
> > +int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
> > +
> > +static inline bool phonet_is_sk(struct sock *sk)
> > +{
> > +       return sk->sk_family == PF_PHONET && sk->sk_protocol == PN_PROTO_PHONET;
> > +}
> > +#else
> > +static inline bool phonet_is_sk(struct sock *sk)
> > +{
> > +       return 0;
> > +}
> > +
> > +static inline int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
> > +{
> > +       return 1;
> > +}
> > +#endif
> > +
> >
> 
> PHONET can be built as a module, so I guess the compiler would
> complain if "CONFIG_PHONET=m" ???

Yes, indeed it does.

David Ahern May 25, 2023, 3:03 p.m. UTC | #3

On 5/25/23 8:54 AM, Simon Horman wrote:
> On Thu, May 25, 2023 at 04:19:32PM +0200, Eric Dumazet wrote:
>> On Thu, May 25, 2023 at 2:55 PM Breno Leitao <[e-mail]> wrote:
>>>
>>> Most of the ioctls to net protocols operates directly on userspace
>>> argument (arg). Usually doing get_user()/put_user() directly in the
>>> ioctl callback.  This is not flexible, because it is hard to reuse these
>>> functions without passing userspace buffers.
>>>
>>> Change the "struct proto" ioctls to avoid touching userspace memory and
>>> operate on kernel buffers, i.e., all protocol's ioctl callbacks is
>>> adapted to operate on a kernel memory other than on userspace (so, no
>>> more {put,get}_user() and friends being called in the ioctl callback).
>>>
>>
>>  diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
>>> index 862f1719b523..93705d99f862 100644
>>> --- a/include/net/phonet/phonet.h
>>> +++ b/include/net/phonet/phonet.h
>>> @@ -109,4 +109,23 @@ void phonet_sysctl_exit(void);
>>>  int isi_register(void);
>>>  void isi_unregister(void);
>>>
>>> +#ifdef CONFIG_PHONET
>>> +int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
>>> +
>>> +static inline bool phonet_is_sk(struct sock *sk)
>>> +{
>>> +       return sk->sk_family == PF_PHONET && sk->sk_protocol == PN_PROTO_PHONET;
>>> +}
>>> +#else
>>> +static inline bool phonet_is_sk(struct sock *sk)
>>> +{
>>> +       return 0;
>>> +}
>>> +
>>> +static inline int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
>>> +{
>>> +       return 1;
>>> +}
>>> +#endif
>>> +
>>>
>>
>> PHONET can be built as a module, so I guess the compiler would
>> complain if "CONFIG_PHONET=m" ???
> 
> Yes, indeed it does.
> 

phonet_sk_ioctl is simple enough to make an inline in which case this
should go in include//linux/phonet.h.

Willem de Bruijn May 25, 2023, 3:05 p.m. UTC | #4

On Thu, May 25, 2023 at 8:55 AM Breno Leitao <[e-mail]> wrote:
>
> Most of the ioctls to net protocols operates directly on userspace
> argument (arg). Usually doing get_user()/put_user() directly in the
> ioctl callback.  This is not flexible, because it is hard to reuse these
> functions without passing userspace buffers.
>
> Change the "struct proto" ioctls to avoid touching userspace memory and
> operate on kernel buffers, i.e., all protocol's ioctl callbacks is
> adapted to operate on a kernel memory other than on userspace (so, no
> more {put,get}_user() and friends being called in the ioctl callback).
>
> This changes the "struct proto" ioctl format in the following way:
>
>     int                     (*ioctl)(struct sock *sk, int cmd,
> -                                        unsigned long arg);
> +                                        int *karg);
>
> So, the "karg" argument, which is passed to the ioctl callback, is a
> pointer allocated to kernel space memory (inside a function wrapper).
> This buffer (karg) may contain input argument (copied from userspace in
> a prep function) and it might return a value/buffer, which is copied
> back to userspace if necessary. There is not one-size-fits-all format
> (that is I am using 'may' above), but basically, there are three type of
> ioctls:
>
> 1) Do not read from userspace, returns a result to userspace
> 2) Read an input parameter from userspace, and does not return anything
>   to userspace
> 3) Read an input from userspace, and return a buffer to userspace.
>
> The default case (1) (where no input parameter is given, and an "int" is
> returned to userspace) encompasses more than 90% of the cases, but there
> are two other exceptions. Here is a list of exceptions:
>
> * Protocol RAW:
>    * cmd = SIOCGETVIFCNT:
>      * input and output = struct sioc_vif_req
>    * cmd = SIOCGETSGCNT
>      * input and output = struct sioc_sg_req
>    * Explanation: for the SIOCGETVIFCNT case, userspace passes the input
>      argument, which is struct sioc_vif_req. Then the callback populates
>      the struct, which is copied back to userspace.
>
> * Protocol RAW6:
>    * cmd = SIOCGETMIFCNT_IN6
>      * input and output = struct sioc_mif_req6
>    * cmd = SIOCGETSGCNT_IN6
>      * input and output = struct sioc_sg_req6
>
> * Protocol PHONET:
>   * cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
>      * input int (4 bytes)
>   * Nothing is copied back to userspace.
>
> For the exception cases, functions sock_sk_ioctl_inout() will
> copy the userspace input, and copy it back to kernel space.
>
> The wrapper that prepare the buffer and put the buffer back to user is
> sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
> calls sk_ioctl(), which will handle all cases.
>
> Signed-off-by: Breno Leitao <[e-mail]>

> +/* A wrapper around sock ioctls, which copies the data from userspace
> + * (depending on the protocol/ioctl), and copies back the result to userspace.
> + * The main motivation for this function is to pass kernel memory to the
> + * protocol ioctl callbacks, instead of userspace memory.
> + */
> +int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
> +{
> +       int rc = 1;
> +
> +       if (ipmr_is_sk(sk))
> +               rc = ipmr_sk_ioctl(sk, cmd, arg);
> +       else if (ip6mr_is_sk(sk))
> +               rc = ip6mr_sk_ioctl(sk, cmd, arg);
> +       else if (phonet_is_sk(sk))
> +               rc = phonet_sk_ioctl(sk, cmd, arg);

I don't understand what this buys us vs testing the sk_family,
sk_protocol and cmd here.

It introduces even deeper dependencies on the protocol specific
header files. And the CONFIG issues that result from that. And it
adds a bunch of wrappers that are only used once.

> @@ -1547,6 +1547,28 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval,
>         return ret;
>  }
>
> +/* Execute if this ioctl is a special mroute ioctl */
> +int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
> +{
> +       switch (cmd) {
> +       /* These userspace buffers will be consumed by ipmr_ioctl() */
> +       case SIOCGETVIFCNT: {
> +               struct sioc_vif_req buffer;
> +
> +               return sock_ioctl_inout(sk, cmd, arg, &buffer,
> +                                     sizeof(buffer));
> +               }

More importantly, if we go down the path of demultiplexing in protocol
independent code to call protocol specific handlers, then there there
is no need to have them call protocol independent helpers like
sock_ioct_inout again. Just call the protocol-specific ioctl handlers
directly?



> +       case SIOCGETSGCNT: {
> +               struct sioc_sg_req buffer;
> +
> +               return sock_ioctl_inout(sk, cmd, arg, &buffer,
> +                                     sizeof(buffer));
> +               }
> +       }
> +       /* return code > 0 means that the ioctl was not executed */
> +       return 1;
> +}

David Ahern May 25, 2023, 3:34 p.m. UTC | #5

On 5/25/23 9:05 AM, Willem de Bruijn wrote:
>> +/* A wrapper around sock ioctls, which copies the data from userspace
>> + * (depending on the protocol/ioctl), and copies back the result to userspace.
>> + * The main motivation for this function is to pass kernel memory to the
>> + * protocol ioctl callbacks, instead of userspace memory.
>> + */
>> +int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
>> +{
>> +       int rc = 1;
>> +
>> +       if (ipmr_is_sk(sk))
>> +               rc = ipmr_sk_ioctl(sk, cmd, arg);
>> +       else if (ip6mr_is_sk(sk))
>> +               rc = ip6mr_sk_ioctl(sk, cmd, arg);
>> +       else if (phonet_is_sk(sk))
>> +               rc = phonet_sk_ioctl(sk, cmd, arg);
> 
> I don't understand what this buys us vs testing the sk_family,
> sk_protocol and cmd here.

To keep protocol specific code out of core files is the reason I
suggested it.

> 
> It introduces even deeper dependencies on the protocol specific
> header files. And the CONFIG issues that result from that. And it
> adds a bunch of wrappers that are only used once.
>

Willem de Bruijn May 25, 2023, 4:06 p.m. UTC | #6

On Thu, May 25, 2023 at 11:34 AM David Ahern <[e-mail]> wrote:
>
> On 5/25/23 9:05 AM, Willem de Bruijn wrote:
> >> +/* A wrapper around sock ioctls, which copies the data from userspace
> >> + * (depending on the protocol/ioctl), and copies back the result to userspace.
> >> + * The main motivation for this function is to pass kernel memory to the
> >> + * protocol ioctl callbacks, instead of userspace memory.
> >> + */
> >> +int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
> >> +{
> >> +       int rc = 1;
> >> +
> >> +       if (ipmr_is_sk(sk))
> >> +               rc = ipmr_sk_ioctl(sk, cmd, arg);
> >> +       else if (ip6mr_is_sk(sk))
> >> +               rc = ip6mr_sk_ioctl(sk, cmd, arg);
> >> +       else if (phonet_is_sk(sk))
> >> +               rc = phonet_sk_ioctl(sk, cmd, arg);
> >
> > I don't understand what this buys us vs testing the sk_family,
> > sk_protocol and cmd here.
>
> To keep protocol specific code out of core files is the reason I
> suggested it.

I guess you object to demultiplexing based on per-family
protocol and ioctl cmd constants directly in this file?

That only requires including the smaller uapi headers.

But now net/core/sock.h now still has to add includes
linux/mroute.h, linux/mroute6.h and net/phonet/phonet.h.

Aside on phonet_is_sk, if we're keeping this: this should be
sk_is_phonet? Analogous to sk_is_tcp and such. And, it should suffice
to  demultiplex based on the protocol family, without testing the
type or protocol. The family is defined in protocol-independent header
linux/socket.h. The differences between
PN_PROTO_PHONET and PN_PROTO_PIPE should be handled inside the family
code. So I think it is cleaner just to open-coded as `if
(sk->sk_family == PF_PHONET)`

Breno Leitao May 26, 2023, 8:49 a.m. UTC | #7

On Thu, May 25, 2023 at 11:05:40AM -0400, Willem de Bruijn wrote:
> On Thu, May 25, 2023 at 8:55 AM Breno Leitao <[e-mail]> wrote:
> > @@ -1547,6 +1547,28 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval,
> >         return ret;
> >  }
> >
> > +/* Execute if this ioctl is a special mroute ioctl */
> > +int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
> > +{
> > +       switch (cmd) {
> > +       /* These userspace buffers will be consumed by ipmr_ioctl() */
> > +       case SIOCGETVIFCNT: {
> > +               struct sioc_vif_req buffer;
> > +
> > +               return sock_ioctl_inout(sk, cmd, arg, &buffer,
> > +                                     sizeof(buffer));
> > +               }
> 
> More importantly, if we go down the path of demultiplexing in protocol
> independent code to call protocol specific handlers, then there there
> is no need to have them call protocol independent helpers like
> sock_ioct_inout again. Just call the protocol-specific ioctl handlers
> directly?

That is what I was expecting, but, the code is exactly the same and I
kept it in the generic section. This is what this code needs to do:

 * Copy X byte from userspace
 * sk->sk_prot->ioctl()
 * Copy X bytes back to userspace

I tried to keep the code generic enough that it could be reused.
I can definitely push the same code to two different protocols, if you
prefer, no strong opinion.

Breno Leitao May 26, 2023, 9:08 a.m. UTC | #8

On Thu, May 25, 2023 at 12:06:00PM -0400, Willem de Bruijn wrote:
> On Thu, May 25, 2023 at 11:34 AM David Ahern <[e-mail]> wrote:
> > On 5/25/23 9:05 AM, Willem de Bruijn wrote:
> > > I don't understand what this buys us vs testing the sk_family,
> > > sk_protocol and cmd here.
> >
> > To keep protocol specific code out of core files is the reason I
> > suggested it.
> 
> I guess you object to demultiplexing based on per-family
> protocol and ioctl cmd constants directly in this file?
> 
> That only requires including the smaller uapi headers.
> 
> But now net/core/sock.h now still has to add includes
> linux/mroute.h, linux/mroute6.h and net/phonet/phonet.h.
> 
> Aside on phonet_is_sk, if we're keeping this: this should be
> sk_is_phonet? Analogous to sk_is_tcp and such. And, it should suffice
> to  demultiplex based on the protocol family, without testing the
> type or protocol. The family is defined in protocol-independent header
> linux/socket.h. The differences between
> PN_PROTO_PHONET and PN_PROTO_PIPE should be handled inside the family
> code. So I think it is cleaner just to open-coded as `if
> (sk->sk_family == PF_PHONET)`

Should we do the same for ipmr as well? Currently I am checking it
using:

	return sk->sk_type == SOCK_RAW && inet_sk(sk)->inet_num == IPPROTO_ICMPV6;

This is what ip{6}mr functions[1] are use to check if `sk` is using ip{6}mr.
If we just use `sk->family`, then I suppose that `sk_is_ip6mr` would be
something as coded below. Is this correct?

	static inline int sk_is_ip6mr(struct sock *sk)
	{
		return sk->sk_family == PF_INET6;
	}

Anyway, should we continue with the current (V3) approach, where we keep
the protocol code out of core files, or, should I come back to the
previous (V2) approach, where the protocol checks is coded directly in
the core file?

Thanks for the review!
[1] Link: https://github.com/torvalds/linux/blob/0d85b27b0cc6b5cf54567c5ad913a247a71583ce/net/ipv6/ip6mr.c#L1666

Willem de Bruijn May 26, 2023, 2:09 p.m. UTC | #9

On Fri, May 26, 2023 at 5:08 AM Breno Leitao <[e-mail]> wrote:
>
> On Thu, May 25, 2023 at 12:06:00PM -0400, Willem de Bruijn wrote:
> > On Thu, May 25, 2023 at 11:34 AM David Ahern <[e-mail]> wrote:
> > > On 5/25/23 9:05 AM, Willem de Bruijn wrote:
> > > > I don't understand what this buys us vs testing the sk_family,
> > > > sk_protocol and cmd here.
> > >
> > > To keep protocol specific code out of core files is the reason I
> > > suggested it.
> >
> > I guess you object to demultiplexing based on per-family
> > protocol and ioctl cmd constants directly in this file?
> >
> > That only requires including the smaller uapi headers.
> >
> > But now net/core/sock.h now still has to add includes
> > linux/mroute.h, linux/mroute6.h and net/phonet/phonet.h.
> >
> > Aside on phonet_is_sk, if we're keeping this: this should be
> > sk_is_phonet? Analogous to sk_is_tcp and such. And, it should suffice
> > to  demultiplex based on the protocol family, without testing the
> > type or protocol. The family is defined in protocol-independent header
> > linux/socket.h. The differences between
> > PN_PROTO_PHONET and PN_PROTO_PIPE should be handled inside the family
> > code. So I think it is cleaner just to open-coded as `if
> > (sk->sk_family == PF_PHONET)`
>
> Should we do the same for ipmr as well? Currently I am checking it
> using:
>
>         return sk->sk_type == SOCK_RAW && inet_sk(sk)->inet_num == IPPROTO_ICMPV6;
>
> This is what ip{6}mr functions[1] are use to check if `sk` is using ip{6}mr.
> If we just use `sk->family`, then I suppose that `sk_is_ip6mr` would be
> something as coded below. Is this correct?
>
>         static inline int sk_is_ip6mr(struct sock *sk)
>         {
>                 return sk->sk_family == PF_INET6;
>         }

Actually, for multicast routing, the protocol check is required.

> Anyway, should we continue with the current (V3) approach, where we keep
> the protocol code out of core files, or, should I come back to the
> previous (V2) approach, where the protocol checks is coded directly in
> the core file?

David expressed preference for the current approach. So let's stay with that.

kernel test robot May 28, 2023, 6:05 p.m. UTC | #10

Hi Breno,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Breno-Leitao/net-ioctl-Use-kernel-memory-on-protocol-ioctl-callbacks/20230525-205741
base:   net-next/main
patch link:    https://lore.kernel.org/r/20230525125503.400797-1-leitao%40debian.org
patch subject: [PATCH net-next v3] net: ioctl: Use kernel memory on protocol ioctl callbacks
config: i386-randconfig-i061-20230525 (https://download.01.org/0day-ci/archive/20230529/[e-mail]/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
        mkdir -p ~/bin
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/dbeb44f8503d11da0219fc6ef8a56c28cfde1511
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Breno-Leitao/net-ioctl-Use-kernel-memory-on-protocol-ioctl-callbacks/20230525-205741
        git checkout dbeb44f8503d11da0219fc6ef8a56c28cfde1511
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash net/phonet/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <[e-mail]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/

All errors (new ones prefixed by >>):

>> net/phonet/af_phonet.c:43:5: error: redefinition of 'phonet_sk_ioctl'
   int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
       ^
   include/net/phonet/phonet.h:125:19: note: previous definition is here
   static inline int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
                     ^
   1 error generated.


vim +/phonet_sk_ioctl +43 net/phonet/af_phonet.c

    42	
  > 43	int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
    44	{
    45		int karg;
    46	
    47		switch (cmd) {
    48		case SIOCPNADDRESOURCE:
    49		case SIOCPNDELRESOURCE:
    50			if (get_user(karg, (int __user *)arg))
    51				return -EFAULT;
    52	
    53			return sk->sk_prot->ioctl(sk, cmd, &karg);
    54		}
    55		/* A positive return value means that the ioctl was not processed */
    56		return 1;
    57	}
    58

Patch

diff --git a/include/linux/mroute.h b/include/linux/mroute.h
index 80b8400ab8b2..28a9d629f7d9 100644
--- a/include/linux/mroute.h
+++ b/include/linux/mroute.h
@@ -16,12 +16,18 @@  static inline int ip_mroute_opt(int opt)
 	return opt >= MRT_BASE && opt <= MRT_MAX;
 }
 
+static inline int ipmr_is_sk(struct sock *sk)
+{
+	return sk->sk_type == SOCK_RAW && inet_sk(sk)->inet_num == IPPROTO_IGMP;
+}
+
 int ip_mroute_setsockopt(struct sock *, int, sockptr_t, unsigned int);
 int ip_mroute_getsockopt(struct sock *, int, sockptr_t, sockptr_t);
-int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg);
+int ipmr_ioctl(struct sock *sk, int cmd, void *arg);
 int ipmr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
 int ip_mr_init(void);
 bool ipmr_rule_default(const struct fib_rule *rule);
+int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
 #else
 static inline int ip_mroute_setsockopt(struct sock *sock, int optname,
 				       sockptr_t optval, unsigned int optlen)
@@ -35,7 +41,7 @@  static inline int ip_mroute_getsockopt(struct sock *sk, int optname,
 	return -ENOPROTOOPT;
 }
 
-static inline int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
+static inline int ipmr_ioctl(struct sock *sk, int cmd, void *arg)
 {
 	return -ENOIOCTLCMD;
 }
@@ -50,10 +56,20 @@  static inline int ip_mroute_opt(int opt)
 	return 0;
 }
 
+static inline int ipmr_is_sk(struct sock *sk)
+{
+	return 0;
+}
+
 static inline bool ipmr_rule_default(const struct fib_rule *rule)
 {
 	return true;
 }
+
+static inline int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	return 1;
+}
 #endif
 
 #define VIFF_STATIC 0x8000
diff --git a/include/linux/mroute6.h b/include/linux/mroute6.h
index 8f2b307fb124..99f9b05b1341 100644
--- a/include/linux/mroute6.h
+++ b/include/linux/mroute6.h
@@ -29,7 +29,7 @@  struct sock;
 extern int ip6_mroute_setsockopt(struct sock *, int, sockptr_t, unsigned int);
 extern int ip6_mroute_getsockopt(struct sock *, int, sockptr_t, sockptr_t);
 extern int ip6_mr_input(struct sk_buff *skb);
-extern int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg);
+extern int ip6mr_ioctl(struct sock *sk, int cmd, void *arg);
 extern int ip6mr_compat_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
 extern int ip6_mr_init(void);
 extern void ip6_mr_cleanup(void);
@@ -48,7 +48,7 @@  int ip6_mroute_getsockopt(struct sock *sock,
 }
 
 static inline
-int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
+int ip6mr_ioctl(struct sock *sk, int cmd, void *arg)
 {
 	return -ENOIOCTLCMD;
 }
@@ -100,6 +100,11 @@  extern int ip6mr_get_route(struct net *net, struct sk_buff *skb,
 #ifdef CONFIG_IPV6_MROUTE
 bool mroute6_is_socket(struct net *net, struct sk_buff *skb);
 extern int ip6mr_sk_done(struct sock *sk);
+int ip6mr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
+static inline int ip6mr_is_sk(struct sock *sk)
+{
+	return sk->sk_type == SOCK_RAW && inet_sk(sk)->inet_num == IPPROTO_ICMPV6;
+}
 #else
 static inline bool mroute6_is_socket(struct net *net, struct sk_buff *skb)
 {
@@ -109,5 +114,13 @@  static inline int ip6mr_sk_done(struct sock *sk)
 {
 	return 0;
 }
+static inline int ip6mr_is_sk(struct sock *sk)
+{
+	return 0;
+}
+static inline int ip6mr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	return 1;
+}
 #endif
 #endif
diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
index 862f1719b523..93705d99f862 100644
--- a/include/net/phonet/phonet.h
+++ b/include/net/phonet/phonet.h
@@ -109,4 +109,23 @@  void phonet_sysctl_exit(void);
 int isi_register(void);
 void isi_unregister(void);
 
+#ifdef CONFIG_PHONET
+int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
+
+static inline bool phonet_is_sk(struct sock *sk)
+{
+	return sk->sk_family == PF_PHONET && sk->sk_protocol == PN_PROTO_PHONET;
+}
+#else
+static inline bool phonet_is_sk(struct sock *sk)
+{
+	return 0;
+}
+
+static inline int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	return 1;
+}
+#endif
+
 #endif
diff --git a/include/net/sock.h b/include/net/sock.h
index 656ea89f60ff..0f4876fc1ff6 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1246,7 +1246,7 @@  struct proto {
 					  bool kern);
 
 	int			(*ioctl)(struct sock *sk, int cmd,
-					 unsigned long arg);
+					 int *karg);
 	int			(*init)(struct sock *sk);
 	void			(*destroy)(struct sock *sk);
 	void			(*shutdown)(struct sock *sk, int how);
@@ -2961,6 +2961,9 @@  int sock_get_timeout(long timeo, void *optval, bool old_timeval);
 int sock_copy_user_timeval(struct __kernel_sock_timeval *tv,
 			   sockptr_t optval, int optlen, bool old_timeval);
 
+int sock_ioctl_inout(struct sock *sk, unsigned int cmd,
+		     void __user *arg, void *karg, size_t size);
+int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg);
 static inline bool sk_is_readable(struct sock *sk)
 {
 	if (sk->sk_prot->sock_is_readable)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 04a31643cda3..f784fa49d95d 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -342,7 +342,7 @@  void tcp_release_cb(struct sock *sk);
 void tcp_wfree(struct sk_buff *skb);
 void tcp_write_timer_handler(struct sock *sk);
 void tcp_delack_timer_handler(struct sock *sk);
-int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg);
+int tcp_ioctl(struct sock *sk, int cmd, int *karg);
 int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb);
 void tcp_rcv_established(struct sock *sk, struct sk_buff *skb);
 void tcp_rcv_space_adjust(struct sock *sk);
diff --git a/include/net/udp.h b/include/net/udp.h
index de4b528522bb..9ff5bce33aa0 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -283,7 +283,7 @@  void udp_flush_pending_frames(struct sock *sk);
 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 int udp_rcv(struct sk_buff *skb);
-int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
+int udp_ioctl(struct sock *sk, int cmd, int *karg);
 int udp_init_sock(struct sock *sk);
 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
 int __udp_disconnect(struct sock *sk, int flags);
diff --git a/net/core/sock.c b/net/core/sock.c
index 5440e67bcfe3..06f987f2356b 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -114,6 +114,8 @@ 
 #include <linux/memcontrol.h>
 #include <linux/prefetch.h>
 #include <linux/compat.h>
+#include <linux/mroute.h>
+#include <linux/mroute6.h>
 
 #include <linux/uaccess.h>
 
@@ -138,6 +140,7 @@ 
 
 #include <net/tcp.h>
 #include <net/busy_poll.h>
+#include <net/phonet/phonet.h>
 
 #include <linux/ethtool.h>
 
@@ -4106,3 +4109,63 @@  int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len)
 	return sk->sk_prot->bind_add(sk, addr, addr_len);
 }
 EXPORT_SYMBOL(sock_bind_add);
+
+/* Copy 'size' bytes from userspace and return `size` back to userspace */
+int sock_ioctl_inout(struct sock *sk, unsigned int cmd,
+		     void __user *arg, void *karg, size_t size)
+{
+	int ret;
+
+	if (copy_from_user(karg, arg, size))
+		return -EFAULT;
+
+	ret = sk->sk_prot->ioctl(sk, cmd, karg);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(arg, karg, size))
+		return -EFAULT;
+
+	return 0;
+}
+EXPORT_SYMBOL(sock_ioctl_inout);
+
+/* This is the most common ioctl prep function, where the result (4 bytes) is
+ * copied back to userspace if the ioctl() returns successfully. No input is
+ * copied from userspace as input argument.
+ */
+static int sock_ioctl_out(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	int ret, karg = 0;
+
+	ret = sk->sk_prot->ioctl(sk, cmd, &karg);
+	if (ret)
+		return ret;
+
+	return put_user(karg, (int __user *)arg);
+}
+
+/* A wrapper around sock ioctls, which copies the data from userspace
+ * (depending on the protocol/ioctl), and copies back the result to userspace.
+ * The main motivation for this function is to pass kernel memory to the
+ * protocol ioctl callbacks, instead of userspace memory.
+ */
+int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	int rc = 1;
+
+	if (ipmr_is_sk(sk))
+		rc = ipmr_sk_ioctl(sk, cmd, arg);
+	else if (ip6mr_is_sk(sk))
+		rc = ip6mr_sk_ioctl(sk, cmd, arg);
+	else if (phonet_is_sk(sk))
+		rc = phonet_sk_ioctl(sk, cmd, arg);
+
+	/* If ioctl was processed, returns its value */
+	if (rc <= 0)
+		return rc;
+
+	/* Otherwise call the default handler */
+	return sock_ioctl_out(sk, cmd, arg);
+}
+EXPORT_SYMBOL(sk_ioctl);
diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 9ddc3a9e89e4..1f748ed1279d 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -292,7 +292,7 @@  int dccp_getsockopt(struct sock *sk, int level, int optname,
 		    char __user *optval, int __user *optlen);
 int dccp_setsockopt(struct sock *sk, int level, int optname,
 		    sockptr_t optval, unsigned int optlen);
-int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg);
+int dccp_ioctl(struct sock *sk, int cmd, int *karg);
 int dccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
 int dccp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags,
 		 int *addr_len);
diff --git a/net/dccp/proto.c b/net/dccp/proto.c
index a06b5641287a..9fc3ba4f62de 100644
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -359,7 +359,7 @@  __poll_t dccp_poll(struct file *file, struct socket *sock,
 
 EXPORT_SYMBOL_GPL(dccp_poll);
 
-int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+int dccp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	int rc = -ENOTCONN;
 
@@ -370,17 +370,17 @@  int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 
 	switch (cmd) {
 	case SIOCOUTQ: {
-		int amount = sk_wmem_alloc_get(sk);
+		*karg = sk_wmem_alloc_get(sk);
 		/* Using sk_wmem_alloc here because sk_wmem_queued is not used by DCCP and
 		 * always 0, comparably to UDP.
 		 */
 
-		rc = put_user(amount, (int __user *)arg);
+		rc = 0;
 	}
 		break;
 	case SIOCINQ: {
 		struct sk_buff *skb;
-		unsigned long amount = 0;
+		*karg = 0;
 
 		skb = skb_peek(&sk->sk_receive_queue);
 		if (skb != NULL) {
@@ -388,9 +388,9 @@  int dccp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 			 * We will only return the amount of this packet since
 			 * that is all that will be read.
 			 */
-			amount = skb->len;
+			*karg = skb->len;
 		}
-		rc = put_user(amount, (int __user *)arg);
+		rc = 0;
 	}
 		break;
 	default:
diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c
index 1fa2fe041ec0..9c124705120d 100644
--- a/net/ieee802154/socket.c
+++ b/net/ieee802154/socket.c
@@ -162,7 +162,7 @@  static int ieee802154_sock_ioctl(struct socket *sock, unsigned int cmd,
 	default:
 		if (!sk->sk_prot->ioctl)
 			return -ENOIOCTLCMD;
-		return sk->sk_prot->ioctl(sk, cmd, arg);
+		return sk_ioctl(sk, cmd, (void __user *)arg);
 	}
 }
 
@@ -531,22 +531,21 @@  static int dgram_bind(struct sock *sk, struct sockaddr *uaddr, int len)
 	return err;
 }
 
-static int dgram_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int dgram_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	switch (cmd) {
 	case SIOCOUTQ:
 	{
-		int amount = sk_wmem_alloc_get(sk);
+		*karg = sk_wmem_alloc_get(sk);
 
-		return put_user(amount, (int __user *)arg);
+		return 0;
 	}
 
 	case SIOCINQ:
 	{
 		struct sk_buff *skb;
-		unsigned long amount;
 
-		amount = 0;
+		*karg = 0;
 		spin_lock_bh(&sk->sk_receive_queue.lock);
 		skb = skb_peek(&sk->sk_receive_queue);
 		if (skb) {
@@ -554,10 +553,10 @@  static int dgram_ioctl(struct sock *sk, int cmd, unsigned long arg)
 			 * of this packet since that is all
 			 * that will be read.
 			 */
-			amount = skb->len - ieee802154_hdr_length(skb);
+			*karg = skb->len - ieee802154_hdr_length(skb);
 		}
 		spin_unlock_bh(&sk->sk_receive_queue.lock);
-		return put_user(amount, (int __user *)arg);
+		return 0;
 	}
 	}
 
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index c4aab3aacbd8..be2ae13511da 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -978,7 +978,7 @@  int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		break;
 	default:
 		if (sk->sk_prot->ioctl)
-			err = sk->sk_prot->ioctl(sk, cmd, arg);
+			err = sk_ioctl(sk, cmd, (void __user *)arg);
 		else
 			err = -ENOIOCTLCMD;
 		break;
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index eec1f6df80d8..3f0c6d602fb7 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1547,6 +1547,28 @@  int ip_mroute_setsockopt(struct sock *sk, int optname, sockptr_t optval,
 	return ret;
 }
 
+/* Execute if this ioctl is a special mroute ioctl */
+int ipmr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	switch (cmd) {
+	/* These userspace buffers will be consumed by ipmr_ioctl() */
+	case SIOCGETVIFCNT: {
+		struct sioc_vif_req buffer;
+
+		return sock_ioctl_inout(sk, cmd, arg, &buffer,
+				      sizeof(buffer));
+		}
+	case SIOCGETSGCNT: {
+		struct sioc_sg_req buffer;
+
+		return sock_ioctl_inout(sk, cmd, arg, &buffer,
+				      sizeof(buffer));
+		}
+	}
+	/* return code > 0 means that the ioctl was not executed */
+	return 1;
+}
+
 /* Getsock opt support for the multicast routing system. */
 int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
 			 sockptr_t optlen)
@@ -1593,13 +1615,13 @@  int ip_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
 }
 
 /* The IP multicast ioctl support routines. */
-int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
+int ipmr_ioctl(struct sock *sk, int cmd, void *arg)
 {
-	struct sioc_sg_req sr;
-	struct sioc_vif_req vr;
 	struct vif_device *vif;
 	struct mfc_cache *c;
 	struct net *net = sock_net(sk);
+	struct sioc_vif_req *vr;
+	struct sioc_sg_req *sr;
 	struct mr_table *mrt;
 
 	mrt = ipmr_get_table(net, raw_sk(sk)->ipmr_table ? : RT_TABLE_DEFAULT);
@@ -1608,40 +1630,33 @@  int ipmr_ioctl(struct sock *sk, int cmd, void __user *arg)
 
 	switch (cmd) {
 	case SIOCGETVIFCNT:
-		if (copy_from_user(&vr, arg, sizeof(vr)))
-			return -EFAULT;
-		if (vr.vifi >= mrt->maxvif)
+		vr = (struct sioc_vif_req *)arg;
+		if (vr->vifi >= mrt->maxvif)
 			return -EINVAL;
-		vr.vifi = array_index_nospec(vr.vifi, mrt->maxvif);
+		vr->vifi = array_index_nospec(vr->vifi, mrt->maxvif);
 		rcu_read_lock();
-		vif = &mrt->vif_table[vr.vifi];
-		if (VIF_EXISTS(mrt, vr.vifi)) {
-			vr.icount = READ_ONCE(vif->pkt_in);
-			vr.ocount = READ_ONCE(vif->pkt_out);
-			vr.ibytes = READ_ONCE(vif->bytes_in);
-			vr.obytes = READ_ONCE(vif->bytes_out);
+		vif = &mrt->vif_table[vr->vifi];
+		if (VIF_EXISTS(mrt, vr->vifi)) {
+			vr->icount = READ_ONCE(vif->pkt_in);
+			vr->ocount = READ_ONCE(vif->pkt_out);
+			vr->ibytes = READ_ONCE(vif->bytes_in);
+			vr->obytes = READ_ONCE(vif->bytes_out);
 			rcu_read_unlock();
 
-			if (copy_to_user(arg, &vr, sizeof(vr)))
-				return -EFAULT;
 			return 0;
 		}
 		rcu_read_unlock();
 		return -EADDRNOTAVAIL;
 	case SIOCGETSGCNT:
-		if (copy_from_user(&sr, arg, sizeof(sr)))
-			return -EFAULT;
+		sr = (struct sioc_sg_req *)arg;
 
 		rcu_read_lock();
-		c = ipmr_cache_find(mrt, sr.src.s_addr, sr.grp.s_addr);
+		c = ipmr_cache_find(mrt, sr->src.s_addr, sr->grp.s_addr);
 		if (c) {
-			sr.pktcnt = c->_c.mfc_un.res.pkt;
-			sr.bytecnt = c->_c.mfc_un.res.bytes;
-			sr.wrong_if = c->_c.mfc_un.res.wrong_if;
+			sr->pktcnt = c->_c.mfc_un.res.pkt;
+			sr->bytecnt = c->_c.mfc_un.res.bytes;
+			sr->wrong_if = c->_c.mfc_un.res.wrong_if;
 			rcu_read_unlock();
-
-			if (copy_to_user(arg, &sr, sizeof(sr)))
-				return -EFAULT;
 			return 0;
 		}
 		rcu_read_unlock();
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index ff712bf2a98d..e394f02380b6 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -855,29 +855,29 @@  static int raw_getsockopt(struct sock *sk, int level, int optname,
 	return do_raw_getsockopt(sk, level, optname, optval, optlen);
 }
 
-static int raw_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int raw_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	switch (cmd) {
 	case SIOCOUTQ: {
-		int amount = sk_wmem_alloc_get(sk);
-
-		return put_user(amount, (int __user *)arg);
+		*karg = sk_wmem_alloc_get(sk);
+		return 0;
 	}
 	case SIOCINQ: {
 		struct sk_buff *skb;
-		int amount = 0;
 
 		spin_lock_bh(&sk->sk_receive_queue.lock);
 		skb = skb_peek(&sk->sk_receive_queue);
 		if (skb)
-			amount = skb->len;
+			*karg = skb->len;
+		else
+			*karg = 0;
 		spin_unlock_bh(&sk->sk_receive_queue.lock);
-		return put_user(amount, (int __user *)arg);
+		return 0;
 	}
 
 	default:
 #ifdef CONFIG_IP_MROUTE
-		return ipmr_ioctl(sk, cmd, (void __user *)arg);
+		return ipmr_ioctl(sk, cmd, karg);
 #else
 		return -ENOIOCTLCMD;
 #endif
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4d6392c16b7a..8ff2c3784aab 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -599,7 +599,7 @@  __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
 }
 EXPORT_SYMBOL(tcp_poll);
 
-int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+int tcp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	int answ;
@@ -641,7 +641,8 @@  int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 		return -ENOIOCTLCMD;
 	}
 
-	return put_user(answ, (int __user *)arg);
+	*karg = answ;
+	return 0;
 }
 EXPORT_SYMBOL(tcp_ioctl);
 
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index aa32afd871ee..8b83a67cf852 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1720,21 +1720,19 @@  static int first_packet_length(struct sock *sk)
  *	IOCTL requests applicable to the UDP protocol
  */
 
-int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+int udp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	switch (cmd) {
 	case SIOCOUTQ:
 	{
-		int amount = sk_wmem_alloc_get(sk);
-
-		return put_user(amount, (int __user *)arg);
+		*karg = sk_wmem_alloc_get(sk);
+		return 0;
 	}
 
 	case SIOCINQ:
 	{
-		int amount = max_t(int, 0, first_packet_length(sk));
-
-		return put_user(amount, (int __user *)arg);
+		*karg = max_t(int, 0, first_packet_length(sk));
+		return 0;
 	}
 
 	default:
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 2bbf13216a3d..001ba5a17af9 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -579,7 +579,7 @@  int inet6_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 		prot = READ_ONCE(sk->sk_prot);
 		if (!prot->ioctl)
 			return -ENOIOCTLCMD;
-		return prot->ioctl(sk, cmd, arg);
+		return sk_ioctl(sk, cmd, (void __user *)arg);
 	}
 	/*NOTREACHED*/
 	return 0;
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 51cf37abd142..084e57191ba0 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1589,6 +1589,27 @@  static int ip6mr_sk_init(struct mr_table *mrt, struct sock *sk)
 	return err;
 }
 
+int ip6mr_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	switch (cmd) {
+	/* These userspace buffers will be consumed by ip6mr_ioctl() */
+	case SIOCGETMIFCNT_IN6: {
+		struct sioc_mif_req6 buffer;
+
+		return sock_ioctl_inout(sk, cmd, arg, &buffer,
+				      sizeof(buffer));
+		}
+	case SIOCGETSGCNT_IN6: {
+		struct sioc_mif_req6 buffer;
+
+		return sock_ioctl_inout(sk, cmd, arg, &buffer,
+				      sizeof(buffer));
+		}
+	}
+
+	return 1;
+}
+
 int ip6mr_sk_done(struct sock *sk)
 {
 	struct net *net = sock_net(sk);
@@ -1879,11 +1900,10 @@  int ip6_mroute_getsockopt(struct sock *sk, int optname, sockptr_t optval,
 /*
  *	The IP multicast ioctl support routines.
  */
-
-int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
+int ip6mr_ioctl(struct sock *sk, int cmd, void *arg)
 {
-	struct sioc_sg_req6 sr;
-	struct sioc_mif_req6 vr;
+	struct sioc_sg_req6 *sr;
+	struct sioc_mif_req6 *vr;
 	struct vif_device *vif;
 	struct mfc6_cache *c;
 	struct net *net = sock_net(sk);
@@ -1895,40 +1915,32 @@  int ip6mr_ioctl(struct sock *sk, int cmd, void __user *arg)
 
 	switch (cmd) {
 	case SIOCGETMIFCNT_IN6:
-		if (copy_from_user(&vr, arg, sizeof(vr)))
-			return -EFAULT;
-		if (vr.mifi >= mrt->maxvif)
+		vr = (struct sioc_mif_req6 *)arg;
+		if (vr->mifi >= mrt->maxvif)
 			return -EINVAL;
-		vr.mifi = array_index_nospec(vr.mifi, mrt->maxvif);
+		vr->mifi = array_index_nospec(vr->mifi, mrt->maxvif);
 		rcu_read_lock();
-		vif = &mrt->vif_table[vr.mifi];
-		if (VIF_EXISTS(mrt, vr.mifi)) {
-			vr.icount = READ_ONCE(vif->pkt_in);
-			vr.ocount = READ_ONCE(vif->pkt_out);
-			vr.ibytes = READ_ONCE(vif->bytes_in);
-			vr.obytes = READ_ONCE(vif->bytes_out);
+		vif = &mrt->vif_table[vr->mifi];
+		if (VIF_EXISTS(mrt, vr->mifi)) {
+			vr->icount = READ_ONCE(vif->pkt_in);
+			vr->ocount = READ_ONCE(vif->pkt_out);
+			vr->ibytes = READ_ONCE(vif->bytes_in);
+			vr->obytes = READ_ONCE(vif->bytes_out);
 			rcu_read_unlock();
-
-			if (copy_to_user(arg, &vr, sizeof(vr)))
-				return -EFAULT;
 			return 0;
 		}
 		rcu_read_unlock();
 		return -EADDRNOTAVAIL;
 	case SIOCGETSGCNT_IN6:
-		if (copy_from_user(&sr, arg, sizeof(sr)))
-			return -EFAULT;
+		sr = (struct sioc_sg_req6 *)arg;
 
 		rcu_read_lock();
-		c = ip6mr_cache_find(mrt, &sr.src.sin6_addr, &sr.grp.sin6_addr);
+		c = ip6mr_cache_find(mrt, &sr->src.sin6_addr, &sr->grp.sin6_addr);
 		if (c) {
-			sr.pktcnt = c->_c.mfc_un.res.pkt;
-			sr.bytecnt = c->_c.mfc_un.res.bytes;
-			sr.wrong_if = c->_c.mfc_un.res.wrong_if;
+			sr->pktcnt = c->_c.mfc_un.res.pkt;
+			sr->bytecnt = c->_c.mfc_un.res.bytes;
+			sr->wrong_if = c->_c.mfc_un.res.wrong_if;
 			rcu_read_unlock();
-
-			if (copy_to_user(arg, &sr, sizeof(sr)))
-				return -EFAULT;
 			return 0;
 		}
 		rcu_read_unlock();
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 7d0adb612bdd..51d4f2d7c596 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -1117,29 +1117,29 @@  static int rawv6_getsockopt(struct sock *sk, int level, int optname,
 	return do_rawv6_getsockopt(sk, level, optname, optval, optlen);
 }
 
-static int rawv6_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int rawv6_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	switch (cmd) {
 	case SIOCOUTQ: {
-		int amount = sk_wmem_alloc_get(sk);
-
-		return put_user(amount, (int __user *)arg);
+		*karg = sk_wmem_alloc_get(sk);
+		return 0;
 	}
 	case SIOCINQ: {
 		struct sk_buff *skb;
-		int amount = 0;
 
 		spin_lock_bh(&sk->sk_receive_queue.lock);
 		skb = skb_peek(&sk->sk_receive_queue);
 		if (skb)
-			amount = skb->len;
+			*karg = skb->len;
+		else
+			*karg = 0;
 		spin_unlock_bh(&sk->sk_receive_queue.lock);
-		return put_user(amount, (int __user *)arg);
+		return 0;
 	}
 
 	default:
 #ifdef CONFIG_IPV6_MROUTE
-		return ip6mr_ioctl(sk, cmd, (void __user *)arg);
+		return ip6mr_ioctl(sk, cmd, karg);
 #else
 		return -ENOIOCTLCMD;
 #endif
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index a88e070b431d..91ebf0a3f499 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -272,7 +272,7 @@  int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops
 void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
 
 /* IOCTL helper for IP encap modules. */
-int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
+int l2tp_ioctl(struct sock *sk, int cmd, int *karg);
 
 /* Extract the tunnel structure from a socket's sk_user_data pointer,
  * validating the tunnel magic feather.
diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 41a74fc84ca1..2b795c1064f5 100644
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -562,19 +562,18 @@  static int l2tp_ip_recvmsg(struct sock *sk, struct msghdr *msg,
 	return err ? err : copied;
 }
 
-int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+int l2tp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	struct sk_buff *skb;
-	int amount;
 
 	switch (cmd) {
 	case SIOCOUTQ:
-		amount = sk_wmem_alloc_get(sk);
+		*karg = sk_wmem_alloc_get(sk);
 		break;
 	case SIOCINQ:
 		spin_lock_bh(&sk->sk_receive_queue.lock);
 		skb = skb_peek(&sk->sk_receive_queue);
-		amount = skb ? skb->len : 0;
+		*karg = skb ? skb->len : 0;
 		spin_unlock_bh(&sk->sk_receive_queue.lock);
 		break;
 
@@ -582,7 +581,7 @@  int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 		return -ENOIOCTLCMD;
 	}
 
-	return put_user(amount, (int __user *)arg);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(l2tp_ioctl);
 
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 08dc53f56bc2..abcdd7cf54b3 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3545,11 +3545,10 @@  static int mptcp_ioctl_outq(const struct mptcp_sock *msk, u64 v)
 	return (int)delta;
 }
 
-static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int mptcp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	bool slow;
-	int answ;
 
 	switch (cmd) {
 	case SIOCINQ:
@@ -3558,24 +3557,24 @@  static int mptcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 
 		lock_sock(sk);
 		__mptcp_move_skbs(msk);
-		answ = mptcp_inq_hint(sk);
+		*karg = mptcp_inq_hint(sk);
 		release_sock(sk);
 		break;
 	case SIOCOUTQ:
 		slow = lock_sock_fast(sk);
-		answ = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
+		*karg = mptcp_ioctl_outq(msk, READ_ONCE(msk->snd_una));
 		unlock_sock_fast(sk, slow);
 		break;
 	case SIOCOUTQNSD:
 		slow = lock_sock_fast(sk);
-		answ = mptcp_ioctl_outq(msk, msk->snd_nxt);
+		*karg = mptcp_ioctl_outq(msk, msk->snd_nxt);
 		unlock_sock_fast(sk, slow);
 		break;
 	default:
 		return -ENOIOCTLCMD;
 	}
 
-	return put_user(answ, (int __user *)arg);
+	return 0;
 }
 
 static void mptcp_subflow_early_fallback(struct mptcp_sock *msk,
diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index 2b582da1e88c..857f422b4a38 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -40,6 +40,22 @@  static const struct phonet_protocol *phonet_proto_get(unsigned int protocol)
 	return pp;
 }
 
+int phonet_sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg)
+{
+	int karg;
+
+	switch (cmd) {
+	case SIOCPNADDRESOURCE:
+	case SIOCPNDELRESOURCE:
+		if (get_user(karg, (int __user *)arg))
+			return -EFAULT;
+
+		return sk->sk_prot->ioctl(sk, cmd, &karg);
+	}
+	/* A positive return value means that the ioctl was not processed */
+	return 1;
+}
+
 static inline void phonet_proto_put(const struct phonet_protocol *pp)
 {
 	module_put(pp->prot->owner);
diff --git a/net/phonet/datagram.c b/net/phonet/datagram.c
index ff5f49ab236e..3aa50dc7535b 100644
--- a/net/phonet/datagram.c
+++ b/net/phonet/datagram.c
@@ -28,24 +28,21 @@  static void pn_sock_close(struct sock *sk, long timeout)
 	sk_common_release(sk);
 }
 
-static int pn_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int pn_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	struct sk_buff *skb;
-	int answ;
 
 	switch (cmd) {
 	case SIOCINQ:
 		lock_sock(sk);
 		skb = skb_peek(&sk->sk_receive_queue);
-		answ = skb ? skb->len : 0;
+		*karg = skb ? skb->len : 0;
 		release_sock(sk);
-		return put_user(answ, (int __user *)arg);
+		return 0;
 
 	case SIOCPNADDRESOURCE:
 	case SIOCPNDELRESOURCE: {
-			u32 res;
-			if (get_user(res, (u32 __user *)arg))
-				return -EFAULT;
+			u32 res = *karg;
 			if (res >= 256)
 				return -EINVAL;
 			if (cmd == SIOCPNADDRESOURCE)
diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index 83ea13a50690..faba31f2eff2 100644
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -917,10 +917,9 @@  static int pep_sock_enable(struct sock *sk, struct sockaddr *addr, int len)
 	return 0;
 }
 
-static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int pep_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	struct pep_sock *pn = pep_sk(sk);
-	int answ;
 	int ret = -ENOIOCTLCMD;
 
 	switch (cmd) {
@@ -933,13 +932,13 @@  static int pep_ioctl(struct sock *sk, int cmd, unsigned long arg)
 		lock_sock(sk);
 		if (sock_flag(sk, SOCK_URGINLINE) &&
 		    !skb_queue_empty(&pn->ctrlreq_queue))
-			answ = skb_peek(&pn->ctrlreq_queue)->len;
+			*karg = skb_peek(&pn->ctrlreq_queue)->len;
 		else if (!skb_queue_empty(&sk->sk_receive_queue))
-			answ = skb_peek(&sk->sk_receive_queue)->len;
+			*karg = skb_peek(&sk->sk_receive_queue)->len;
 		else
-			answ = 0;
+			*karg = 0;
 		release_sock(sk);
-		ret = put_user(answ, (int __user *)arg);
+		ret = 0;
 		break;
 
 	case SIOCPNENABLEPIPE:
diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index 71e2caf6ab85..967f9b4dc026 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -387,7 +387,7 @@  static int pn_socket_ioctl(struct socket *sock, unsigned int cmd,
 		return put_user(handle, (__u16 __user *)arg);
 	}
 
-	return sk->sk_prot->ioctl(sk, cmd, arg);
+	return sk_ioctl(sk, cmd, (void __user *)arg);
 }
 
 static int pn_socket_listen(struct socket *sock, int backlog)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index cda8c2874691..3acd6e223cd4 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4895,7 +4895,7 @@  static struct sock *sctp_accept(struct sock *sk, int flags, int *err, bool kern)
 }
 
 /* The SCTP ioctl handler. */
-static int sctp_ioctl(struct sock *sk, int cmd, unsigned long arg)
+static int sctp_ioctl(struct sock *sk, int cmd, int *karg)
 {
 	int rc = -ENOTCONN;
 
@@ -4911,7 +4911,7 @@  static int sctp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 	switch (cmd) {
 	case SIOCINQ: {
 		struct sk_buff *skb;
-		unsigned int amount = 0;
+		*karg = 0;
 
 		skb = skb_peek(&sk->sk_receive_queue);
 		if (skb != NULL) {
@@ -4919,9 +4919,9 @@  static int sctp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 			 * We will only return the amount of this packet since
 			 * that is all that will be read.
 			 */
-			amount = skb->len;
+			*karg = skb->len;
 		}
-		rc = put_user(amount, (int __user *)arg);
+		rc = 0;
 		break;
 	}
 	default: