pdch: Fix null MS access gprs_rlcmac_pdch::rcv_control_ack
If bts_ms_by_tlli() at the start of the function fails, ms could be
NULL. As a result "ms->nacc" access at the end of the function would
crash.
Solution:
In the function, we get the related expected TBF from pdch_ulc, and we only
continue if a TBF is found. Since tbf objects are always expected to
have a GprsMs, simply gather it from there.
Change-Id: I666ed5d157f42e74956fa49fc9eea85d27e63d44
diff --git a/src/pdch.cpp b/src/pdch.cpp
index 8e0a24a..9321384 100644
--- a/src/pdch.cpp
+++ b/src/pdch.cpp
@@ -304,7 +304,7 @@
{
struct gprs_rlcmac_tbf *tbf, *new_tbf;
uint32_t tlli = packet->TLLI;
- GprsMs *ms = bts_ms_by_tlli(bts(), tlli, GSM_RESERVED_TMSI);
+ GprsMs *ms;
gprs_rlcmac_ul_tbf *ul_tbf;
enum pdch_ulc_tbf_poll_reason reason;
struct pdch_ulc_node *poll;
@@ -314,6 +314,7 @@
LOGPDCH(this, DRLCMAC, LOGL_NOTICE, "PACKET CONTROL ACK with "
"unknown FN=%u TLLI=0x%08x (TRX %d TS %d)\n",
fn, tlli, trx_no(), ts_no);
+ ms = bts_ms_by_tlli(bts(), tlli, GSM_RESERVED_TMSI);
if (ms)
LOGPDCH(this, DRLCMAC, LOGL_NOTICE, "PACKET CONTROL ACK with "
"unknown TBF corresponds to MS with IMSI %s, TA %d, "
@@ -332,6 +333,8 @@
tbf->n_reset(N3101);
tbf->update_ms(tlli, GPRS_RLCMAC_UL_TBF);
+ /* Gather MS from TBF, since it may be NULL or may have been merged during update_ms */
+ ms = tbf->ms();
LOGPTBF(tbf, LOGL_DEBUG, "FN=%" PRIu32 " Rx Packet Control Ack (reason=%s)\n",
fn, get_value_string(pdch_ulc_tbf_poll_reason_names, reason));
@@ -353,7 +356,7 @@
tbf->n_reset(N3105);
TBF_SET_ASS_STATE_DL(tbf, GPRS_RLCMAC_DL_ASS_NONE);
- new_tbf = tbf->ms() ? ms_dl_tbf(tbf->ms()) : NULL;
+ new_tbf = ms_dl_tbf(ms);
if (!new_tbf) {
LOGPDCH(this, DRLCMAC, LOGL_ERROR, "Got ACK, but DL "
"TBF is gone TLLI=0x%08x\n", tlli);
@@ -385,7 +388,7 @@
tbf->n_reset(N3105);
TBF_SET_ASS_STATE_UL(tbf, GPRS_RLCMAC_UL_ASS_NONE);
- new_tbf = tbf->ms() ? ms_ul_tbf(tbf->ms()) : NULL;
+ new_tbf = ms_ul_tbf(ms);
if (!new_tbf) {
LOGPDCH(this, DRLCMAC, LOGL_ERROR, "Got ACK, but UL "
"TBF is gone TLLI=0x%08x\n", tlli);