jolly has uploaded this change for review. ( https://gerrit.osmocom.org/c/osmo-bts/+/35082?usp=email )

Change subject: LAPDm: Reject (release) establishment on DCC0, SAPI 0 without L3 payload ......................................................................

LAPDm: Reject (release) establishment on DCC0, SAPI 0 without L3 payload

Related: OS#5971 Change-Id: I6819b51a876b8743c2d4a04165b7900723a1631c --- M src/common/rsl.c 1 file changed, 24 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/osmo-bts refs/changes/82/35082/1

diff --git a/src/common/rsl.c b/src/common/rsl.c index deeb255..705eef7 100644 --- a/src/common/rsl.c +++ b/src/common/rsl.c @@ -3831,6 +3831,20 @@ msg->trx = lchan->ts->trx; msg->lchan = lchan;

+ /* Reject L2 establishment on main DCCH, SAPI 0 without contention resolution. */ + if (rh->msg_type == RSL_MT_EST_IND) { + const struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); + + /* no L3 payload && main signaling channel && SAPI 0 */ + if (msgb_l2len(msg) == sizeof(*rllh) && (rllh->link_id & 0xc7) == 0x00) { + LOGPLCHAN(lchan, DRSL, LOGL_ERROR, "RLL establishment without contention resolution.\n"); + /* Release normally, re-use the msgb. */ + rh->msg_type = RSL_MT_REL_REQ; + msgb_tv_put(msg, RSL_IE_RELEASE_MODE, RSL_REL_NORMAL); + return rsl_rx_rll(lchan->ts->trx, msg); + } + } + /* If this is a Measurement Report, then we simply ignore it, * because it has already been processed in l1sap_ph_data_ind(). */ if (rslms_is_meas_rep(msg)) {