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osmo-bts-{sysmo,lc15,oc2g}: fix segfault in ph_tch_req() 

ph_tch_req() is a recursive function and conditionally calls itself at
the very bottom.  The recursive call happens iff all of the following
conditions are met:

* DTXd is enabled,
* AMR codec is in use,
* DTX DL AMR FSM state is recursive.

The problem is that ph_tch_req() may pull sizeof(*lsap) from the given
msgb twice: during the initial and the recursive calls.  The second
attempt to pull sizeof(*lsap) causes the process to abort, because
the remaining room is less than it's attempting to pull.

AFAICT, doing msgb_pull() is not really necessary, given that
l1sap_tch_rts_ind() thankfully does set msg->l2h before pushing
the lsap header in front of the actual frame.

Update osmo-bts-sysmo and its copy-pasted siblings, which are likely
affected too, except osmo-bts-octphy which does not do the recursion.

Change-Id: Ib349b74a9e4bd48c902286f872d3b0e9a068256c
Related: OS#5925
This commit is contained in:
Vadim Yanitskiy 2023-03-21 05:42:02 +07:00 committed by fixeria
parent dbd70bca75
commit e464ef6524
4 changed files with 4 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/osmo-bts-lc15/l1_if.c
View File

@ -508,7 +508,6 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
/* create new message and fill data */
if (msg) {
msgb_pull(msg, sizeof(*l1sap));
/* create new message */
nmsg = l1p_msgb_alloc();
if (!nmsg)
@ -517,7 +516,7 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
rc = l1if_tch_encode(lchan,
l1p->u.phDataReq.msgUnitParam.u8Buffer,
&l1p->u.phDataReq.msgUnitParam.u8Size,
msg->data, msg->len, u32Fn, use_cache,
msgb_l2(msg), msgb_l2len(msg), u32Fn, use_cache,
l1sap->u.tch.marker);
if (rc < 0) {
/* no data encoded for L1: smth will be generated below */

3
src/osmo-bts-oc2g/l1_if.c
View File

@ -561,7 +561,6 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
/* create new message and fill data */
if (msg) {
msgb_pull(msg, sizeof(*l1sap));
/* create new message */
nmsg = l1p_msgb_alloc();
if (!nmsg)
@ -570,7 +569,7 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
rc = l1if_tch_encode(lchan,
l1p->u.phDataReq.msgUnitParam.u8Buffer,
&l1p->u.phDataReq.msgUnitParam.u8Size,
msg->data, msg->len, u32Fn, use_cache,
msgb_l2(msg), msgb_l2len(msg), u32Fn, use_cache,
l1sap->u.tch.marker);
if (rc < 0) {
/* no data encoded for L1: smth will be generated below */

3
src/osmo-bts-octphy/l1_if.c
View File

@ -593,7 +593,6 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
return -ENOMEM;
}
msgb_pull(msg, sizeof(*l1sap));
tOCTVC1_GSM_MSG_TRX_REQUEST_LOGICAL_CHANNEL_DATA_CMD *data_req =
(tOCTVC1_GSM_MSG_TRX_REQUEST_LOGICAL_CHANNEL_DATA_CMD *)
msgb_put(nmsg, sizeof(*data_req));
@ -615,7 +614,7 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
&data_req->Data.ulPayloadType,
data_req->Data.abyDataContent,
&data_req->Data.ulDataLength,
msg->data, msg->len);
msgb_l2(msg), msgb_l2len(msg));
mOCTVC1_GSM_MSG_TRX_REQUEST_LOGICAL_CHANNEL_DATA_CMD_SWAP(data_req);
} else {

3
src/osmo-bts-sysmo/l1_if.c
View File

@ -505,7 +505,6 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
/* create new message and fill data */
if (msg) {
msgb_pull(msg, sizeof(*l1sap));
/* create new message */
nmsg = l1p_msgb_alloc();
if (!nmsg)
@ -514,7 +513,7 @@ static int ph_tch_req(struct gsm_bts_trx *trx, struct msgb *msg,
rc = l1if_tch_encode(lchan,
l1p->u.phDataReq.msgUnitParam.u8Buffer,
&l1p->u.phDataReq.msgUnitParam.u8Size,
msg->data, msg->len, u32Fn, use_cache,
msgb_l2(msg), msgb_l2len(msg), u32Fn, use_cache,
l1sap->u.tch.marker);
if (rc < 0) {
/* no data encoded for L1: smth will be generated below */