Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[Neil Horman]

On Thu, Apr 12, 2018 at 12:16:58AM +0800, Xin Long wrote:
> On Wed, Apr 11, 2018 at 10:59 PM, Marcelo Ricardo Leitner
>  wrote:
> > On Wed, Apr 11, 2018 at 10:36:07AM -0400, Neil Horman wrote:
> >> On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
> >> > pf->cmp_addr() is called before binding a v6 address to the sock. It
> >> > should not check ports, like in sctp_inet_cmp_addr.
> >> >
> >> > But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
> >> > sctp_v6_cmp_addr where it also compares the ports.
> >> >
> >> > This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
> >> > multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
> >> > lack the check for ports in sctp_v6_cmp_addr").
> >> >
> >> > This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
> >> > but do the proper check for both v6 addrs and v4mapped addrs.
> >> >
> >> > Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in 
> >> > sctp_v6_cmp_addr")
> >> > Reported-by: Jianwen Ji 
> >> > Signed-off-by: Xin Long 
> >> > ---
> >> >  net/sctp/ipv6.c | 27 ---
> >> >  1 file changed, 24 insertions(+), 3 deletions(-)
> >> >
> >> > diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> >> > index f1fc48e..be4b72c 100644
> >> > --- a/net/sctp/ipv6.c
> >> > +++ b/net/sctp/ipv6.c
> >> > @@ -846,8 +846,8 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
> >> > *addr1,
> >> >const union sctp_addr *addr2,
> >> >struct sctp_sock *opt)
> >> >  {
> >> > -   struct sctp_af *af1, *af2;
> >> > struct sock *sk = sctp_opt2sk(opt);
> >> > +   struct sctp_af *af1, *af2;
> >> >
> >> > af1 = sctp_get_af_specific(addr1->sa.sa_family);
> >> > af2 = sctp_get_af_specific(addr2->sa.sa_family);
> >> > @@ -863,10 +863,31 @@ static int sctp_inet6_cmp_addr(const union 
> >> > sctp_addr *addr1,
> >> > if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
> >> > return 1;
> >> >
> >> > -   if (addr1->sa.sa_family != addr2->sa.sa_family)
> >> > +   if (addr1->sa.sa_family != addr2->sa.sa_family) {
> >> > +   if (addr1->sa.sa_family == AF_INET &&
> >> > +   addr2->sa.sa_family == AF_INET6 &&
> >> > +   ipv6_addr_v4mapped(>v6.sin6_addr))
> >> > +   if (addr2->v6.sin6_addr.s6_addr32[3] ==
> >> > +   addr1->v4.sin_addr.s_addr)
> >> > +   return 1;
> >> > +   if (addr2->sa.sa_family == AF_INET &&
> >> > +   addr1->sa.sa_family == AF_INET6 &&
> >> > +   ipv6_addr_v4mapped(>v6.sin6_addr))
> >> > +   if (addr1->v6.sin6_addr.s6_addr32[3] ==
> >> > +   addr2->v4.sin_addr.s_addr)
> >> > +   return 1;
> >> > +   return 0;
> >> > +   }
> >> > +
> >> > +   if (!ipv6_addr_equal(>v6.sin6_addr, >v6.sin6_addr))
> >> > +   return 0;
> >> > +
> >> > +   if ((ipv6_addr_type(>v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) &&
> >> > +   addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
> >> > +   addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)
> >> > return 0;
> >> >
> >> > -   return af1->cmp_addr(addr1, addr2);
> >> > +   return 1;
> >> >  }
> >> >
> >> >  /* Verify that the provided sockaddr looks bindable.   Common 
> >> > verification,
> >> > --
> >> > 2.1.0
> >> >
> >> This looks correct to me, but is it worth duplicating the comparison code 
> >> like
> >> this from the cmp_addr function?  It might be more worthwhile to add a 
> >> flag to
> >> the cmp_addr method to direct weather it needs to check port values or not.
> >> That way you could continue to use the cmp_addr function here.
> >
> > Adding a flag into sctp_v6_cmp_addr will get us a terrible code to
> > read. It's already not one of the best looking part of it. Maybe
> > still duplicate part of it it, but at 'af' level? As in:
> > - af->cmp_addr
> > - af->cmp_addr_port
> >
> What do you think of:
> 
> static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
> const union sctp_addr *addr2)
> {
> return __sctp_v6_cmp_addr(addr1, addr2) &&
>addr1->v6.sin_port == addr2->v6.sin_port;
> }
> 
> (v6.sin_port and v4.sin_port have the same offset in union sctp_addr,
>  we've exploited this in many places in SCTP)
Yes, I'd be ok with that
Neil

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> 

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[David Miller]

From: Xin Long 
Date: Thu, 12 Apr 2018 00:16:58 +0800

> What do you think of:
> 
> static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
> const union sctp_addr *addr2)
> {
> return __sctp_v6_cmp_addr(addr1, addr2) &&
>addr1->v6.sin_port == addr2->v6.sin_port;
> }
> 
> (v6.sin_port and v4.sin_port have the same offset in union sctp_addr,
>  we've exploited this in many places in SCTP)

>From my perspective this is OK.

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[Xin Long]

On Wed, Apr 11, 2018 at 10:59 PM, Marcelo Ricardo Leitner
 wrote:
> On Wed, Apr 11, 2018 at 10:36:07AM -0400, Neil Horman wrote:
>> On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
>> > pf->cmp_addr() is called before binding a v6 address to the sock. It
>> > should not check ports, like in sctp_inet_cmp_addr.
>> >
>> > But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
>> > sctp_v6_cmp_addr where it also compares the ports.
>> >
>> > This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
>> > multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
>> > lack the check for ports in sctp_v6_cmp_addr").
>> >
>> > This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
>> > but do the proper check for both v6 addrs and v4mapped addrs.
>> >
>> > Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
>> > Reported-by: Jianwen Ji 
>> > Signed-off-by: Xin Long 
>> > ---
>> >  net/sctp/ipv6.c | 27 ---
>> >  1 file changed, 24 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
>> > index f1fc48e..be4b72c 100644
>> > --- a/net/sctp/ipv6.c
>> > +++ b/net/sctp/ipv6.c
>> > @@ -846,8 +846,8 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
>> > *addr1,
>> >const union sctp_addr *addr2,
>> >struct sctp_sock *opt)
>> >  {
>> > -   struct sctp_af *af1, *af2;
>> > struct sock *sk = sctp_opt2sk(opt);
>> > +   struct sctp_af *af1, *af2;
>> >
>> > af1 = sctp_get_af_specific(addr1->sa.sa_family);
>> > af2 = sctp_get_af_specific(addr2->sa.sa_family);
>> > @@ -863,10 +863,31 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
>> > *addr1,
>> > if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
>> > return 1;
>> >
>> > -   if (addr1->sa.sa_family != addr2->sa.sa_family)
>> > +   if (addr1->sa.sa_family != addr2->sa.sa_family) {
>> > +   if (addr1->sa.sa_family == AF_INET &&
>> > +   addr2->sa.sa_family == AF_INET6 &&
>> > +   ipv6_addr_v4mapped(>v6.sin6_addr))
>> > +   if (addr2->v6.sin6_addr.s6_addr32[3] ==
>> > +   addr1->v4.sin_addr.s_addr)
>> > +   return 1;
>> > +   if (addr2->sa.sa_family == AF_INET &&
>> > +   addr1->sa.sa_family == AF_INET6 &&
>> > +   ipv6_addr_v4mapped(>v6.sin6_addr))
>> > +   if (addr1->v6.sin6_addr.s6_addr32[3] ==
>> > +   addr2->v4.sin_addr.s_addr)
>> > +   return 1;
>> > +   return 0;
>> > +   }
>> > +
>> > +   if (!ipv6_addr_equal(>v6.sin6_addr, >v6.sin6_addr))
>> > +   return 0;
>> > +
>> > +   if ((ipv6_addr_type(>v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) &&
>> > +   addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
>> > +   addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)
>> > return 0;
>> >
>> > -   return af1->cmp_addr(addr1, addr2);
>> > +   return 1;
>> >  }
>> >
>> >  /* Verify that the provided sockaddr looks bindable.   Common 
>> > verification,
>> > --
>> > 2.1.0
>> >
>> This looks correct to me, but is it worth duplicating the comparison code 
>> like
>> this from the cmp_addr function?  It might be more worthwhile to add a flag 
>> to
>> the cmp_addr method to direct weather it needs to check port values or not.
>> That way you could continue to use the cmp_addr function here.
>
> Adding a flag into sctp_v6_cmp_addr will get us a terrible code to
> read. It's already not one of the best looking part of it. Maybe
> still duplicate part of it it, but at 'af' level? As in:
> - af->cmp_addr
> - af->cmp_addr_port
>
What do you think of:

static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
const union sctp_addr *addr2)
{
return __sctp_v6_cmp_addr(addr1, addr2) &&
   addr1->v6.sin_port == addr2->v6.sin_port;
}

(v6.sin_port and v4.sin_port have the same offset in union sctp_addr,
 we've exploited this in many places in SCTP)

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[Marcelo Ricardo Leitner]

On Wed, Apr 11, 2018 at 10:36:07AM -0400, Neil Horman wrote:
> On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
> > pf->cmp_addr() is called before binding a v6 address to the sock. It
> > should not check ports, like in sctp_inet_cmp_addr.
> >
> > But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
> > sctp_v6_cmp_addr where it also compares the ports.
> >
> > This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
> > multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
> > lack the check for ports in sctp_v6_cmp_addr").
> >
> > This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
> > but do the proper check for both v6 addrs and v4mapped addrs.
> >
> > Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
> > Reported-by: Jianwen Ji 
> > Signed-off-by: Xin Long 
> > ---
> >  net/sctp/ipv6.c | 27 ---
> >  1 file changed, 24 insertions(+), 3 deletions(-)
> >
> > diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> > index f1fc48e..be4b72c 100644
> > --- a/net/sctp/ipv6.c
> > +++ b/net/sctp/ipv6.c
> > @@ -846,8 +846,8 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
> > *addr1,
> >const union sctp_addr *addr2,
> >struct sctp_sock *opt)
> >  {
> > -   struct sctp_af *af1, *af2;
> > struct sock *sk = sctp_opt2sk(opt);
> > +   struct sctp_af *af1, *af2;
> >
> > af1 = sctp_get_af_specific(addr1->sa.sa_family);
> > af2 = sctp_get_af_specific(addr2->sa.sa_family);
> > @@ -863,10 +863,31 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
> > *addr1,
> > if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
> > return 1;
> >
> > -   if (addr1->sa.sa_family != addr2->sa.sa_family)
> > +   if (addr1->sa.sa_family != addr2->sa.sa_family) {
> > +   if (addr1->sa.sa_family == AF_INET &&
> > +   addr2->sa.sa_family == AF_INET6 &&
> > +   ipv6_addr_v4mapped(>v6.sin6_addr))
> > +   if (addr2->v6.sin6_addr.s6_addr32[3] ==
> > +   addr1->v4.sin_addr.s_addr)
> > +   return 1;
> > +   if (addr2->sa.sa_family == AF_INET &&
> > +   addr1->sa.sa_family == AF_INET6 &&
> > +   ipv6_addr_v4mapped(>v6.sin6_addr))
> > +   if (addr1->v6.sin6_addr.s6_addr32[3] ==
> > +   addr2->v4.sin_addr.s_addr)
> > +   return 1;
> > +   return 0;
> > +   }
> > +
> > +   if (!ipv6_addr_equal(>v6.sin6_addr, >v6.sin6_addr))
> > +   return 0;
> > +
> > +   if ((ipv6_addr_type(>v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) &&
> > +   addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
> > +   addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)
> > return 0;
> >
> > -   return af1->cmp_addr(addr1, addr2);
> > +   return 1;
> >  }
> >
> >  /* Verify that the provided sockaddr looks bindable.   Common verification,
> > --
> > 2.1.0
> >
> This looks correct to me, but is it worth duplicating the comparison code like
> this from the cmp_addr function?  It might be more worthwhile to add a flag to
> the cmp_addr method to direct weather it needs to check port values or not.
> That way you could continue to use the cmp_addr function here.

Adding a flag into sctp_v6_cmp_addr will get us a terrible code to
read. It's already not one of the best looking part of it. Maybe
still duplicate part of it it, but at 'af' level? As in:
- af->cmp_addr
- af->cmp_addr_port

  Marcelo

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[David Miller]

From: Xin Long 
Date: Wed, 11 Apr 2018 20:58:05 +0800

> @@ -863,10 +863,31 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
> *addr1,
>   if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
>   return 1;
>  
> - if (addr1->sa.sa_family != addr2->sa.sa_family)
> + if (addr1->sa.sa_family != addr2->sa.sa_family) {
> + if (addr1->sa.sa_family == AF_INET &&
> + addr2->sa.sa_family == AF_INET6 &&
> + ipv6_addr_v4mapped(>v6.sin6_addr))
> + if (addr2->v6.sin6_addr.s6_addr32[3] ==
> + addr1->v4.sin_addr.s_addr)
> + return 1;
> + if (addr2->sa.sa_family == AF_INET &&
> + addr1->sa.sa_family == AF_INET6 &&
> + ipv6_addr_v4mapped(>v6.sin6_addr))
> + if (addr1->v6.sin6_addr.s6_addr32[3] ==
> + addr2->v4.sin_addr.s_addr)
> + return 1;
> + return 0;
> + }
> +
> + if (!ipv6_addr_equal(>v6.sin6_addr, >v6.sin6_addr))
> + return 0;
> +
> + if ((ipv6_addr_type(>v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) &&
> + addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
> + addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)
>   return 0;
>  
> - return af1->cmp_addr(addr1, addr2);
> + return 1;
>  }

I agree with Neil that we should try to avoid the code duplication here
somehow.

Although we risk gcc emitting two copies of the function if we do
something like:

__sctp_v6_cmp_addr(addr1, addr2, check_ports)
{
}

sctp_v6_cmp_addr(addr, addr2)
{
return __sctp_v6_cmp_addr(addr1, addr2, true);
}

and invoke __sctp_v6_cmp_addr(addr1, addr2, true) from sctp_inet6_cmp_addr().

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[Marcelo Ricardo Leitner]

On Wed, Apr 11, 2018 at 11:42:41AM -0300, Marcelo Ricardo Leitner wrote:
> On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
> > pf->cmp_addr() is called before binding a v6 address to the sock. It
> > should not check ports, like in sctp_inet_cmp_addr.
> >
> > But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
> > sctp_v6_cmp_addr where it also compares the ports.
> >
> > This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
> > multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
> > lack the check for ports in sctp_v6_cmp_addr").
> >
> > This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
> > but do the proper check for both v6 addrs and v4mapped addrs.
> >
> > Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
> > Reported-by: Jianwen Ji 
> > Signed-off-by: Xin Long 
>
> Acked-by: Marcelo Ricardo Leitner 

Sorry, I take this back.

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[Marcelo Ricardo Leitner]

On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
> pf->cmp_addr() is called before binding a v6 address to the sock. It
> should not check ports, like in sctp_inet_cmp_addr.
>
> But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
> sctp_v6_cmp_addr where it also compares the ports.
>
> This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
> multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
> lack the check for ports in sctp_v6_cmp_addr").
>
> This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
> but do the proper check for both v6 addrs and v4mapped addrs.
>
> Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
> Reported-by: Jianwen Ji 
> Signed-off-by: Xin Long 

Acked-by: Marcelo Ricardo Leitner 

Re: [PATCH net] sctp: do not check port in sctp_inet6_cmp_addr

[Neil Horman]

On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
> pf->cmp_addr() is called before binding a v6 address to the sock. It
> should not check ports, like in sctp_inet_cmp_addr.
> 
> But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
> sctp_v6_cmp_addr where it also compares the ports.
> 
> This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
> multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
> lack the check for ports in sctp_v6_cmp_addr").
> 
> This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
> but do the proper check for both v6 addrs and v4mapped addrs.
> 
> Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
> Reported-by: Jianwen Ji 
> Signed-off-by: Xin Long 
> ---
>  net/sctp/ipv6.c | 27 ---
>  1 file changed, 24 insertions(+), 3 deletions(-)
> 
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index f1fc48e..be4b72c 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -846,8 +846,8 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
> *addr1,
>  const union sctp_addr *addr2,
>  struct sctp_sock *opt)
>  {
> - struct sctp_af *af1, *af2;
>   struct sock *sk = sctp_opt2sk(opt);
> + struct sctp_af *af1, *af2;
>  
>   af1 = sctp_get_af_specific(addr1->sa.sa_family);
>   af2 = sctp_get_af_specific(addr2->sa.sa_family);
> @@ -863,10 +863,31 @@ static int sctp_inet6_cmp_addr(const union sctp_addr 
> *addr1,
>   if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
>   return 1;
>  
> - if (addr1->sa.sa_family != addr2->sa.sa_family)
> + if (addr1->sa.sa_family != addr2->sa.sa_family) {
> + if (addr1->sa.sa_family == AF_INET &&
> + addr2->sa.sa_family == AF_INET6 &&
> + ipv6_addr_v4mapped(>v6.sin6_addr))
> + if (addr2->v6.sin6_addr.s6_addr32[3] ==
> + addr1->v4.sin_addr.s_addr)
> + return 1;
> + if (addr2->sa.sa_family == AF_INET &&
> + addr1->sa.sa_family == AF_INET6 &&
> + ipv6_addr_v4mapped(>v6.sin6_addr))
> + if (addr1->v6.sin6_addr.s6_addr32[3] ==
> + addr2->v4.sin_addr.s_addr)
> + return 1;
> + return 0;
> + }
> +
> + if (!ipv6_addr_equal(>v6.sin6_addr, >v6.sin6_addr))
> + return 0;
> +
> + if ((ipv6_addr_type(>v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) &&
> + addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
> + addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)
>   return 0;
>  
> - return af1->cmp_addr(addr1, addr2);
> + return 1;
>  }
>  
>  /* Verify that the provided sockaddr looks bindable.   Common verification,
> -- 
> 2.1.0
> 
This looks correct to me, but is it worth duplicating the comparison code like
this from the cmp_addr function?  It might be more worthwhile to add a flag to
the cmp_addr method to direct weather it needs to check port values or not.
That way you could continue to use the cmp_addr function here.

Neil

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