On 10/28/18 5:17 AM, Xin Long wrote: > 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 > Ack, good to know ty!
