On Tue, Sep 10, 2019 at 9:19 PM David Laight <David.Laight@xxxxxxxxxx> wrote:
>
> From: Xin Long
> > Sent: 09 September 2019 08:57
> > Section 7.2 of rfc7829: "Peer Address Thresholds (SCTP_PEER_ADDR_THLDS)
> > Socket Option" extends 'struct sctp_paddrthlds' with 'spt_pathcpthld'
> > added to allow a user to change ps_retrans per sock/asoc/transport, as
> > other 2 paddrthlds: pf_retrans, pathmaxrxt.
> >
> > Note that ps_retrans is not allowed to be greater than pf_retrans.
> >
> > Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> > ---
> > include/uapi/linux/sctp.h | 1 +
> > net/sctp/socket.c | 10 ++++++++++
> > 2 files changed, 11 insertions(+)
> >
> > diff --git a/include/uapi/linux/sctp.h b/include/uapi/linux/sctp.h
> > index a15cc28..dfd81e1 100644
> > --- a/include/uapi/linux/sctp.h
> > +++ b/include/uapi/linux/sctp.h
> > @@ -1069,6 +1069,7 @@ struct sctp_paddrthlds {
> > struct sockaddr_storage spt_address;
> > __u16 spt_pathmaxrxt;
> > __u16 spt_pathpfthld;
> > + __u16 spt_pathcpthld;
> > };
> >
> > /*
> > diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> > index 5e2098b..5b9774d 100644
> > --- a/net/sctp/socket.c
> > +++ b/net/sctp/socket.c
> > @@ -3954,6 +3954,9 @@ static int sctp_setsockopt_paddr_thresholds(struct sock *sk,
>
> This code does:
> if (optlen < sizeof(struct sctp_paddrthlds))
> return -EINVAL;
here will become:
if (optlen >= sizeof(struct sctp_paddrthlds)) {
optlen = sizeof(struct sctp_paddrthlds);
} else if (optlen >= ALIGN(offsetof(struct sctp_paddrthlds,
spt_pathcpthld), 4))
optlen = ALIGN(offsetof(struct sctp_paddrthlds,
spt_pathcpthld), 4);
val.spt_pathcpthld = 0xffff;
else {
return -EINVAL;
}
if (copy_from_user(&val, (struct sctp_paddrthlds __user *)optval,
optlen))
return -EFAULT;
in sctp_getsockopt_paddr_thresholds():
if (len >= sizeof(struct sctp_paddrthlds))
len = sizeof(struct sctp_paddrthlds);
else if (len >= ALIGN(offsetof(struct sctp_paddrthlds,
spt_pathcpthld), 4))
len = ALIGN(offsetof(struct sctp_paddrthlds,
spt_pathcpthld), 4);
else
return -EINVAL;
if (copy_from_user(&val, (struct sctp_paddrthlds __user *)optval, len))
return -EFAULT;
>
> So adding an extra field breaks existing application binaries
> that use this option.
>
> I've not checked the other patches or similar fubar.
>
> David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>
