On Sun, Oct 28, 2018 at 5:54 AM Tomas Bortoli <tomasbortoli@xxxxxxxxx> wrote: > > It is possible to perform out-of-bound reads on > sctp_getsockopt_pr_streamstatus() and on > sctp_getsockopt_pr_assocstatus() by passing from userspace a > sprstat_policy that overflows the abandoned_sent/abandoned_unsent > fixed length arrays. The over-read data are directly copied/leaked > to userspace. > > Signed-off-by: Tomas Bortoli <tomasbortoli@xxxxxxxxx> > Reported-by: syzbot+5da0d0a72a9e7d791748@xxxxxxxxxxxxxxxxxxxxxxxxx > --- > net/sctp/socket.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index fc0386e8ff23..14dce5d95817 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -7083,7 +7083,9 @@ static int sctp_getsockopt_pr_assocstatus(struct sock *sk, int len, > } > > policy = params.sprstat_policy; > - if (!policy || (policy & ~(SCTP_PR_SCTP_MASK | SCTP_PR_SCTP_ALL))) > + if (!policy || (policy & ~(SCTP_PR_SCTP_MASK | SCTP_PR_SCTP_ALL)) || > + __SCTP_PR_INDEX(policy) > SCTP_PR_INDEX(MAX) || > + __SCTP_PR_INDEX(policy) < 0) > goto out; > > asoc = sctp_id2assoc(sk, params.sprstat_assoc_id); > @@ -7142,7 +7144,9 @@ static int sctp_getsockopt_pr_streamstatus(struct sock *sk, int len, > } > > policy = params.sprstat_policy; > - if (!policy || (policy & ~(SCTP_PR_SCTP_MASK | SCTP_PR_SCTP_ALL))) > + if (!policy || (policy & ~(SCTP_PR_SCTP_MASK | SCTP_PR_SCTP_ALL)) || > + __SCTP_PR_INDEX(policy) > SCTP_PR_INDEX(MAX) || > + __SCTP_PR_INDEX(policy) < 0) > goto out; This is not the correct fix. See https://lkml.org/lkml/2018/10/27/136
