On Tue, Oct 25, 2016 at 02:27:39PM -0200, Marcelo Ricardo Leitner wrote: > Andrey Konovalov reported that KASAN detected that SCTP was using a slab > beyond the boundaries. It was caused because when handling out of the > blue packets in function sctp_sf_ootb() it was checking the chunk len > only after already processing the first chunk, validating only for the > 2nd and subsequent ones. > > The fix is to just move the check upwards so it's also validated for the > 1st chunk. > > Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> > --- > > Hi. Please consider this to -stable too. Thanks > > net/sctp/sm_statefuns.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c > index 026e3bca4a94bd34b418d5e6947f7182c1512358..8ec20a64a3f8055a0c3576627c5ec5dad7e99ca8 100644 > --- a/net/sctp/sm_statefuns.c > +++ b/net/sctp/sm_statefuns.c > @@ -3422,6 +3422,12 @@ sctp_disposition_t sctp_sf_ootb(struct net *net, > return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, > commands); > > + /* Report violation if chunk len overflows */ > + ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); > + if (ch_end > skb_tail_pointer(skb)) > + return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, > + commands); > + > /* Now that we know we at least have a chunk header, > * do things that are type appropriate. > */ > @@ -3453,12 +3459,6 @@ sctp_disposition_t sctp_sf_ootb(struct net *net, > } > } > > - /* Report violation if chunk len overflows */ > - ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); > - if (ch_end > skb_tail_pointer(skb)) > - return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, > - commands); > - > ch = (sctp_chunkhdr_t *) ch_end; > } while (ch_end < skb_tail_pointer(skb)); > > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
