Date: Tue, 2 Mar 2021 12:56:39 GMT From: Michael Tuexen <tuexen@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: f7c20120c19b - stable/13 - sctp: avoid integer overflow when starting the HB timer Message-ID: <202103021256.122Cudnr052140@gitrepo.freebsd.org>
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The branch stable/13 has been updated by tuexen: URL: https://cgit.FreeBSD.org/src/commit/?id=f7c20120c19b6307536908a7f779be2832b133f3 commit f7c20120c19b6307536908a7f779be2832b133f3 Author: Michael Tuexen <tuexen@FreeBSD.org> AuthorDate: 2021-02-27 22:27:30 +0000 Commit: Michael Tuexen <tuexen@FreeBSD.org> CommitDate: 2021-03-02 12:33:01 +0000 sctp: avoid integer overflow when starting the HB timer MFC after: 3 days Reported by: syzbot+14b9d7c3c64208fae62f@syzkaller.appspotmail.com (cherry picked from commit 70e95f0b6917a8b8cd4a2a5f883f3e9753fc86d8) --- sys/netinet/sctputil.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/sys/netinet/sctputil.c b/sys/netinet/sctputil.c index 319344842d5f..7ddb4c3710df 100644 --- a/sys/netinet/sctputil.c +++ b/sys/netinet/sctputil.c @@ -2277,14 +2277,19 @@ sctp_timer_start(int t_type, struct sctp_inpcb *inp, struct sctp_tcb *stcb, } rndval = sctp_select_initial_TSN(&inp->sctp_ep); jitter = rndval % to_ticks; - if (jitter >= (to_ticks >> 1)) { - to_ticks = to_ticks + (jitter - (to_ticks >> 1)); + to_ticks >>= 1; + if (jitter < (UINT32_MAX - to_ticks)) { + to_ticks += jitter; } else { - to_ticks = to_ticks - jitter; + to_ticks = UINT32_MAX; } if (!(net->dest_state & SCTP_ADDR_UNCONFIRMED) && !(net->dest_state & SCTP_ADDR_PF)) { - to_ticks += net->heart_beat_delay; + if (net->heart_beat_delay < (UINT32_MAX - to_ticks)) { + to_ticks += net->heart_beat_delay; + } else { + to_ticks = UINT32_MAX; + } } /* * Now we must convert the to_ticks that are now in ms to
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