On 10/27/18 10:20 PM, Tomas Bortoli 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 > --- > v2 - added forgot || > > net/sctp/socket.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/net/sctp/socket.c b/net/sctp/socket.c > index fc0386e8ff23..5290b8bd40c8 100644 > --- a/net/sctp/socket.c > +++ b/net/sctp/socket.c > @@ -7083,7 +7083,8 @@ 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)) > goto out; > > asoc = sctp_id2assoc(sk, params.sprstat_assoc_id); > @@ -7142,7 +7143,8 @@ 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)) > goto out; > > asoc = sctp_id2assoc(sk, params.sprstat_assoc_id); > I just realized we also have to check for less than 0 indexes..
