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authorPau Espin Pedrol <pespin@sysmocom.de>2020-10-19 16:38:25 +0200
committerlaforge <laforge@osmocom.org>2020-10-19 15:06:55 +0000
commit5ce54ba1e68ba2233f4d0cf94b12d6b4a3537399 (patch)
treed82f48732a151cb0646b476c298fa503d0430168
parentff5b59a821f3211f422b676e89b9c4508134c839 (diff)
Fix crash rx DeactPdpReq while waiting for DeactPdpAck after gtp side is freed
Scenario: 1- For an unknwon reason, sgsn sends DeletePdpCtxReq on GTP towards GGSN. 2- GGSN answers with Error Indication to that pdp ctx which calls gtp_freepdp() 3- gtp_freepdp() calls libgtp callback cb_delete_context() before freeing the pointer, in osmo-sgsn callback points to cb_delete_context(), which removes pctx->ggsn and tries to drop the pdp on the NS side by sending a DeactPdpReq. 4- While waiting for DeactPdpAck, the MS/PCU sends a DeactPdpReq, and code was unconditionalyl trying to release the gtp side without checking if it was alreay released, using pctx->ggsn==NULL and crashing. This is basically the same logic already in place in regular path gsm48_rx_gsm_deact_pdp_ack. Related: OS#4817 Change-Id: I02587a3dc812823d893fc00b904142b75fd190b9
-rw-r--r--src/sgsn/gprs_sm.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/src/sgsn/gprs_sm.c b/src/sgsn/gprs_sm.c
index f8019ab6..3bdad3bf 100644
--- a/src/sgsn/gprs_sm.c
+++ b/src/sgsn/gprs_sm.c
@@ -639,7 +639,11 @@ static int gsm48_rx_gsm_deact_pdp_req(struct sgsn_mm_ctx *mm, struct msgb *msg)
return _gsm48_tx_gsm_deact_pdp_acc(mm, transaction_id);
}
- return sgsn_delete_pdp_ctx(pdp);
+ if (pdp->ggsn)
+ return sgsn_delete_pdp_ctx(pdp);
+ /* GTP side already detached, freeing */
+ sgsn_pdp_ctx_free(pdp);
+ return 0;
}
/* 3GPP TS 24.008 ยง 9.5.9: Deactivate PDP Context Accept */