[MPTCP] Re: Fwd: [martineau:kbuild-mptcp 22/38] subflow.c:undefined reference to `__crypto_memneq'

[MPTCP] Re: Fwd: [martineau:kbuild-mptcp 22/38] subflow.c:undefined reference to `__crypto_memneq'

[Paolo Abeni]

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On Fri, 2020-01-17 at 16:27 -0800, Mat Martineau wrote:
> On Sat, 18 Jan 2020, Florian Westphal wrote:
> 
> > ----- Forwarded message from kbuild test robot <lkp(a)intel.com> -----
> > 
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/martineau/linux.git kbuild-mptcp
> > head:   c4ccdd8177fb3d8123dd294ae93ee2dac1f43f32
> > commit: ccd5b6ef8fd4b37a7721231a55482523b07d7ef9 [22/38] mptcp: Add handling of incoming MP_JOIN requests
> > config: xtensa-common_defconfig (attached as .config)
> > compiler: xtensa-linux-gcc (GCC) 7.5.0
> > reproduce:
> >        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >        chmod +x ~/bin/make.cross
> >        git checkout ccd5b6ef8fd4b37a7721231a55482523b07d7ef9
> >        # save the attached .config to linux build tree
> >        GCC_VERSION=7.5.0 make.cross ARCH=xtensa
> > 
> > If you fix the issue, kindly add following tag
> > Reported-by: kbuild test robot <lkp(a)intel.com>
> > 
> > All errors (new ones prefixed by >>):
> > 
> >   net/mptcp/subflow.o: In function `subflow_ulp_release':
> > > > subflow.c:(.text+0x41c): undefined reference to `__crypto_memneq'
> >   net/mptcp/subflow.o: In function `subflow_syn_recv_sock':
> >   subflow.c:(.text+0x53a): undefined reference to `__crypto_memneq'
> > 
> > Hmpf.  The .config has CONFIG_CRYPTO=n and then the symbol doesn't
> > exist.
> > 
> > So we have two choices:
> > - select CRYPTO from Kconfig
> > - use plain memcmp as before (might reveal info about key though)
> > - copypaste a similar function into mptcp.
> > 
> > What do you think?
> 
> I prefer selecting CRYPTO over copy/paste. 

I agree with 'select CRYPTO=y'

/P

[MPTCP] Re: Fwd: [martineau:kbuild-mptcp 22/38] subflow.c:undefined reference to `__crypto_memneq'

[Matthieu Baerts]

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Hi Florian,

On 20/01/2020 17:20, Florian Westphal wrote:
> Matthieu Baerts <matthieu.baerts(a)tessares.net> wrote:
>>>> I prefer selecting CRYPTO over copy/paste.
>>>
>>> I agree with 'select CRYPTO=y'
>>
>> Me too.
>>
>> Florian: do you ask the question because you think we can have issues or
>> comments from net maintainers when forcing the selection of CRYPTO for
>> MPTCP?
> 
> I think its fine, tcpmd5 and ipsec select it too.

Good point, thank you for your reply.
Many are doing that, e.g. in net: bluetooth, ceph, mac80211, mac802154, 
rxrpc, sctp, tipc, tls, xfrm.

>> Do we plan to do this modification in "mptcp: Add handling of incoming
>> MP_JOIN requests" commit (part 3) or before (part 2, when starting using
>> functions from CRYPTO, e.g. "mptcp: Add key generation and token tree")?
> 
> I'm currently travelling so I can't comment which commit makes the most
> sense.  It should be added when the first crypto functions are used, I
> think.

Here is what I saw:

- "mptcp: Add key generation and token tree" commit introduces crypto.c 
but it only uses functions from lib/: sha_init(), sha_transform()

- "mptcp: move from sha1 (v0) to sha256 (v1)" commit is using sha256 
primitives from include/crypto/sha.h, e.g. sha256_init() instead of 
function from crypto module. Paolo already added CRYPTO_LIB_SHA256 (and 
not CRYPTO_SHA256).

- "mptcp: Add handling of incoming MP_JOIN requests" commit is using 
"crypto_memneq" which needs CRYPTO.

So if I'm not mistaken, we need CRYPTO only for part 3.

Please tell me if I miss something :)

Cheers,
Matt
-- 
Matthieu Baerts | R&D Engineer
matthieu.baerts(a)tessares.net
Tessares SA | Hybrid Access Solutions
www.tessares.net
1 Avenue Jean Monnet, 1348 Louvain-la-Neuve, Belgium

[MPTCP] Re: Fwd: [martineau:kbuild-mptcp 22/38] subflow.c:undefined reference to `__crypto_memneq'

[Florian Westphal]

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Matthieu Baerts <matthieu.baerts(a)tessares.net> wrote:
> > > I prefer selecting CRYPTO over copy/paste.
> > 
> > I agree with 'select CRYPTO=y'
> 
> Me too.
> 
> Florian: do you ask the question because you think we can have issues or
> comments from net maintainers when forcing the selection of CRYPTO for
> MPTCP?

I think its fine, tcpmd5 and ipsec select it too.

> Do we plan to do this modification in "mptcp: Add handling of incoming
> MP_JOIN requests" commit (part 3) or before (part 2, when starting using
> functions from CRYPTO, e.g. "mptcp: Add key generation and token tree")?

I'm currently travelling so I can't comment which commit makes the most
sense.  It should be added when the first crypto functions are used, I
think.

[MPTCP] Re: Fwd: [martineau:kbuild-mptcp 22/38] subflow.c:undefined reference to `__crypto_memneq'

[Matthieu Baerts]

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Hi Florian, Mat, Paolo,

On 19/01/2020 15:07, Paolo Abeni wrote:
> On Fri, 2020-01-17 at 16:27 -0800, Mat Martineau wrote:
>> On Sat, 18 Jan 2020, Florian Westphal wrote:
>>
>>> ----- Forwarded message from kbuild test robot <lkp(a)intel.com> -----
>>>
>>> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/martineau/linux.git kbuild-mptcp
>>> head:   c4ccdd8177fb3d8123dd294ae93ee2dac1f43f32
>>> commit: ccd5b6ef8fd4b37a7721231a55482523b07d7ef9 [22/38] mptcp: Add handling of incoming MP_JOIN requests
>>> config: xtensa-common_defconfig (attached as .config)
>>> compiler: xtensa-linux-gcc (GCC) 7.5.0
>>> reproduce:
>>>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>>         chmod +x ~/bin/make.cross
>>>         git checkout ccd5b6ef8fd4b37a7721231a55482523b07d7ef9
>>>         # save the attached .config to linux build tree
>>>         GCC_VERSION=7.5.0 make.cross ARCH=xtensa
>>>
>>> If you fix the issue, kindly add following tag
>>> Reported-by: kbuild test robot <lkp(a)intel.com>
>>>
>>> All errors (new ones prefixed by >>):
>>>
>>>    net/mptcp/subflow.o: In function `subflow_ulp_release':
>>>>> subflow.c:(.text+0x41c): undefined reference to `__crypto_memneq'
>>>    net/mptcp/subflow.o: In function `subflow_syn_recv_sock':
>>>    subflow.c:(.text+0x53a): undefined reference to `__crypto_memneq'
>>>
>>> Hmpf.  The .config has CONFIG_CRYPTO=n and then the symbol doesn't
>>> exist.
>>>
>>> So we have two choices:
>>> - select CRYPTO from Kconfig
>>> - use plain memcmp as before (might reveal info about key though)
>>> - copypaste a similar function into mptcp.
>>>
>>> What do you think?
>>
>> I prefer selecting CRYPTO over copy/paste.
> 
> I agree with 'select CRYPTO=y'

Me too.

Florian: do you ask the question because you think we can have issues or 
comments from net maintainers when forcing the selection of CRYPTO for 
MPTCP?

Do we plan to do this modification in "mptcp: Add handling of incoming 
MP_JOIN requests" commit (part 3) or before (part 2, when starting using 
functions from CRYPTO, e.g. "mptcp: Add key generation and token tree")?

Cheers,
Matt
-- 
Matthieu Baerts | R&D Engineer
matthieu.baerts(a)tessares.net
Tessares SA | Hybrid Access Solutions
www.tessares.net
1 Avenue Jean Monnet, 1348 Louvain-la-Neuve, Belgium

[MPTCP] Re: Fwd: [martineau:kbuild-mptcp 22/38] subflow.c:undefined reference to `__crypto_memneq'

[Mat Martineau]

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On Sat, 18 Jan 2020, Florian Westphal wrote:

> ----- Forwarded message from kbuild test robot <lkp(a)intel.com> -----
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/martineau/linux.git kbuild-mptcp
> head:   c4ccdd8177fb3d8123dd294ae93ee2dac1f43f32
> commit: ccd5b6ef8fd4b37a7721231a55482523b07d7ef9 [22/38] mptcp: Add handling of incoming MP_JOIN requests
> config: xtensa-common_defconfig (attached as .config)
> compiler: xtensa-linux-gcc (GCC) 7.5.0
> reproduce:
>        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>        chmod +x ~/bin/make.cross
>        git checkout ccd5b6ef8fd4b37a7721231a55482523b07d7ef9
>        # save the attached .config to linux build tree
>        GCC_VERSION=7.5.0 make.cross ARCH=xtensa
>
> If you fix the issue, kindly add following tag
> Reported-by: kbuild test robot <lkp(a)intel.com>
>
> All errors (new ones prefixed by >>):
>
>   net/mptcp/subflow.o: In function `subflow_ulp_release':
>>> subflow.c:(.text+0x41c): undefined reference to `__crypto_memneq'
>   net/mptcp/subflow.o: In function `subflow_syn_recv_sock':
>   subflow.c:(.text+0x53a): undefined reference to `__crypto_memneq'
>
> Hmpf.  The .config has CONFIG_CRYPTO=n and then the symbol doesn't
> exist.
>
> So we have two choices:
> - select CRYPTO from Kconfig
> - use plain memcmp as before (might reveal info about key though)
> - copypaste a similar function into mptcp.
>
> What do you think?

I prefer selecting CRYPTO over copy/paste. Plain memcmp does not seem 
suitable.

--
Mat Martineau
Intel