neels has uploaded this change for review.
fix rare segfault in MGCP client handling
Add missing conn->assignment.created_ci_for_msc to
gscon_forget_mgw_endpoint_ci().
Before this patch, when assignment.created_ci_for_msc lingers after a
DLCX, it can cause a use-after-free on assignment_reset(). Possible
scenario is rx BSSMAP Clear Cmd during ongoing Assignment.
In assignment_reset(), locally cache the ci pointer, because
gscon_forget_mgw_endpoint_ci() now NULLs created_ci_for_msc.
Related: OS#5572
Change-Id: If89610020f47fd6517081dd11b83911b043bd0f1
---
M src/osmo-bsc/assignment_fsm.c
M src/osmo-bsc/bsc_subscr_conn_fsm.c
2 files changed, 8 insertions(+), 2 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmo-bsc refs/changes/10/28210/1
diff --git a/src/osmo-bsc/assignment_fsm.c b/src/osmo-bsc/assignment_fsm.c
index 7deca65..a0d008d 100644
--- a/src/osmo-bsc/assignment_fsm.c
+++ b/src/osmo-bsc/assignment_fsm.c
@@ -128,10 +128,13 @@
}
if (conn->assignment.created_ci_for_msc) {
- gscon_forget_mgw_endpoint_ci(conn, conn->assignment.created_ci_for_msc);
+ /* Store ci pointer locally, because gscon_forget_mgw_endpoint_ci() NULLs
+ * conn->assignment.created_ci_for_msc. */
+ struct osmo_mgcpc_ep_ci *ci = conn->assignment.created_ci_for_msc;
+ gscon_forget_mgw_endpoint_ci(conn, ci);
/* If this is the last endpoint released, the mgw_endpoint_fsm will terminate and tell
* the gscon about it. */
- osmo_mgcpc_ep_ci_dlcx(conn->assignment.created_ci_for_msc);
+ osmo_mgcpc_ep_ci_dlcx(ci);
}
conn->assignment = (struct assignment_fsm_data){
diff --git a/src/osmo-bsc/bsc_subscr_conn_fsm.c b/src/osmo-bsc/bsc_subscr_conn_fsm.c
index 54d3975..9af28c7 100644
--- a/src/osmo-bsc/bsc_subscr_conn_fsm.c
+++ b/src/osmo-bsc/bsc_subscr_conn_fsm.c
@@ -955,6 +955,9 @@
if (conn->user_plane.mgw_endpoint_ci_msc == ci)
conn->user_plane.mgw_endpoint_ci_msc = NULL;
+
+ if (conn->assignment.created_ci_for_msc == ci)
+ conn->assignment.created_ci_for_msc = NULL;
}
static void gscon_fsm_allstate(struct osmo_fsm_inst *fi, uint32_t event, void *data)
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