From 777be2e734b95ab9982a20c22f134d004a78c961 Mon Sep 17 00:00:00 2001 From: Max Date: Wed, 1 Mar 2017 18:16:44 +0100 Subject: Check for proper lapdm_datalink entity Previously lapdm_datalink->entity->mode was dereferenced without checking if correct entity is present. This might lead to segfault. Check it explicitly before dereferencing, log error and gracefully return if necessary. Change-Id: I0361e3731e86712b415a370cab1128d611988f56 Related: OS#1898 --- src/gsm/lapdm.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/gsm/lapdm.c b/src/gsm/lapdm.c index fa7769b2..1fdf311c 100644 --- a/src/gsm/lapdm.c +++ b/src/gsm/lapdm.c @@ -852,10 +852,16 @@ static int rslms_rx_rll_udata_req(struct msgb *msg, struct lapdm_datalink *dl) struct abis_rsl_rll_hdr *rllh = msgb_l2(msg); uint8_t chan_nr = rllh->chan_nr; uint8_t link_id = rllh->link_id; - int ui_bts = (le->mode == LAPDM_MODE_BTS && (link_id & 0x40)); uint8_t sapi = link_id & 7; struct tlv_parsed tv; - int length; + int length, ui_bts; + + if (!le) { + LOGP(DLLAPD, LOGL_ERROR, "lapdm_datalink without entity error\n"); + msgb_free(msg); + return -EMLINK; + } + ui_bts = (le->mode == LAPDM_MODE_BTS && (link_id & 0x40)); /* check if the layer3 message length exceeds N201 */ -- cgit v1.2.3