Re: [PATCH net 3/4] sctp: don't treat an I-FORWARD-TSN as an association reset

[Tim Budding]

On Sun, 25 Oct 2026 12:08:48 +0000, netdev-bot+sashiko@xxxxxxxxxx wrote:
> [Severity: Medium]
> With this call gone, sctp_intl_skip() now sends
> SCTP_PARTIAL_DELIVERY_ABORTED for an I-FORWARD-TSN at the leading edge.
> Is the pdapi_seq it reports still the message that was being partially
> delivered?

[...]

> Could sctp_intl_skip() pass sin->mid_uo (unordered) or sin->mid
> (ordered) to sctp_intl_stream_abort_pd() for the notification, and
> keep using the skip MID for the flush and sctp_mid_skip()?

Thanks, this is a real bug. sctp_intl_skip() has always reported the
skip entry's MID, which is the largest MID skipped on that stream, so
for an I-FORWARD-TSN below the leading edge pdapi_seq could already be
wrong when more than one message on the stream was skipped. For
unordered streams it was wrong whenever the abort was reported at all,
as the old check only fired when the skip MID was larger than the one
being delivered. This patch removes the path that happened to report
the right MID at the leading edge, so it now shows up there too.

v2 will add a patch before this one that does that: report sin->mid_uo
/ sin->mid in the notification and keep the skip MID for the flush and
sctp_mid_skip(). The selftest will check pdapi_seq for an I-FORWARD-TSN
below the leading edge that skips two messages on the stream being
partially delivered.