On Wed, Aug 26, 2015 at 04:42:21PM -0400, Vlad Yasevich wrote:
> On 08/26/2015 04:35 PM, Xin Long wrote:
> > in sctp_process_asconf(), we get address parameter from the beginning of
> > the addip params. but we never check if it's really there. if the addr
> > param is not there, it still can pass sctp_verify_asconf(), then to be
> > handled by sctp_process_asconf(), it will not be safe.
> >
> > so add a code in sctp_verify_asconf() to check the address parameter is in
> > the beginning, or return false to send abort.
> >
> > v2->v3:
> > * put the check in the loop, add the check for multiple address parameters.
>
>
> Please split the multiple address detection from first address detection.
> They are 2 different bugs and each one deserves a separate commit and
> changelog.
See below, thx.
>
> Thanks
> -vlad
>
> > v1->v2:
> > * put the check behind the params' length verify.
> >
> > Signed-off-by: Xin Long <lucien....@gmail.com>
> > Signed-off-by: Vlad Yasevich <vyase...@redhat.com>
> > ---
> > net/sctp/sm_make_chunk.c | 14 ++++++++++++--
> > 1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
> > index 06320c8..4068fe1 100644
> > --- a/net/sctp/sm_make_chunk.c
> > +++ b/net/sctp/sm_make_chunk.c
> > @@ -3130,14 +3130,24 @@ bool sctp_verify_asconf(const struct
> > sctp_association *asoc,
> > case SCTP_PARAM_ERR_CAUSE:
> > break;
> > case SCTP_PARAM_IPV4_ADDRESS:
> > + if (addr_param_seen) {
> > + /* peer placed multiple address parameters into
> > + * the same asconf. reject it.
> > + */
> > + return false;
> > + }
> > if (length != sizeof(sctp_ipv4addr_param_t))
> > return false;
> > - addr_param_seen = true;
> > + if (param.v == addip->addip_hdr.params)
> > + addr_param_seen = true;
> > break;
I know I had suggested using addr_param_seen to check for multiple
occurrences, but now realized we can simplify this with something like:
+ if (param.v != addip->addip_hdr.params)
+ return false;
addr_param_seen = true;
Then the check against addr_param_seen is not needed and do both checks
at once.
Thanks,
Marcelo
> > case SCTP_PARAM_IPV6_ADDRESS:
> > + if (addr_param_seen)
> > + return false;
> > if (length != sizeof(sctp_ipv6addr_param_t))
> > return false;
> > - addr_param_seen = true;
> > + if (param.v == addip->addip_hdr.params)
> > + addr_param_seen = true;
> > break;
> > case SCTP_PARAM_ADD_IP:
> > case SCTP_PARAM_DEL_IP:
> >
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
