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gbproxy: Check whether gbproxy_update_link_state_after() deletes the link_info 

In case the link_info is deleted we have to stop handling the stored messages
inside link_info. Not doing so can lead to invalid memory being accessed.

Change-Id: Ieb8503e9e94e7a5ac450ad8aa1713ec4f21cdea5
Ticket: OW#3049
Sponsored-by: On-Waves ehf
This commit is contained in:
Daniel Willmann 2016-11-07 17:54:29 +01:00 committed by Harald Welte
parent 58273f4b88
commit beade314d0
3 changed files with 27 additions and 13 deletions
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2
openbsc/include/openbsc/gb_proxy.h
View File

@ -208,7 +208,7 @@ struct gbproxy_link_info *gbproxy_update_link_state_ul(
struct gbproxy_link_info *gbproxy_update_link_state_dl(
struct gbproxy_peer *peer, time_t now,
struct gprs_gb_parse_context *parse_ctx);
void gbproxy_update_link_state_after(
int gbproxy_update_link_state_after(
struct gbproxy_peer *peer, struct gbproxy_link_info *link_info,
time_t now, struct gprs_gb_parse_context *parse_ctx);
int gbproxy_remove_stale_link_infos(struct gbproxy_peer *peer, time_t now);

22
openbsc/src/gprs/gb_proxy.c
View File

@ -318,7 +318,7 @@ static void gbproxy_reset_imsi_acquisition(struct gbproxy_link_info* link_info)
link_info->vu_gen_tx_bss = GBPROXY_INIT_VU_GEN_TX;
}
static void gbproxy_flush_stored_messages(struct gbproxy_peer *peer,
static int gbproxy_flush_stored_messages(struct gbproxy_peer *peer,
struct msgb *msg,
time_t now,
struct gbproxy_link_info* link_info,
@ -349,8 +349,13 @@ static void gbproxy_flush_stored_messages(struct gbproxy_peer *peer,
peer, link_info, &len_change,
&tmp_parse_ctx);
gbproxy_update_link_state_after(peer, link_info, now,
&tmp_parse_ctx);
rc = gbproxy_update_link_state_after(peer, link_info, now,
&tmp_parse_ctx);
if (rc == 1) {
LOGP(DLLC, LOGL_NOTICE, "link_info deleted while flushing stored messages\n");
msgb_free(stored_msg);
return -1;
}
rc = gbprox_relay2sgsn(peer->cfg, stored_msg,
msgb_bvci(msg), link_info->sgsn_nsei);
@ -364,6 +369,8 @@ static void gbproxy_flush_stored_messages(struct gbproxy_peer *peer,
parse_ctx->llc_msg_name : "BSSGP");
msgb_free(stored_msg);
}
return 0;
}
static int gbproxy_gsm48_to_peer(struct gbproxy_peer *peer,
@ -465,9 +472,12 @@ static int gbproxy_imsi_acquisition(struct gbproxy_peer *peer,
gsm48_hdr_pdisc(parse_ctx->g48_hdr) == GSM48_PDISC_MM_GPRS &&
gsm48_hdr_msg_type(parse_ctx->g48_hdr) == GSM48_MT_GMM_ID_RESP;
/* The IMSI is now available */
gbproxy_flush_stored_messages(peer, msg, now, link_info,
parse_ctx);
/* The IMSI is now available. If flushing the messages fails,
* then link_info has been deleted and we should return
* immediately. */
if (gbproxy_flush_stored_messages(peer, msg, now, link_info,
parse_ctx) < 0)
return 0;
gbproxy_reset_imsi_acquisition(link_info);

16
openbsc/src/gprs/gb_proxy_tlli.c
View File

@ -348,18 +348,18 @@ static void gbproxy_touch_link_info(struct gbproxy_peer *peer,
gbproxy_attach_link_info(peer, now, link_info);
}
static void gbproxy_unregister_link_info(struct gbproxy_peer *peer,
static int gbproxy_unregister_link_info(struct gbproxy_peer *peer,
struct gbproxy_link_info *link_info)
{
if (!link_info)
return;
return 1;
if (link_info->tlli.ptmsi == GSM_RESERVED_TMSI && !link_info->imsi_len) {
LOGP(DGPRS, LOGL_INFO,
"Removing TLLI %08x from list (P-TMSI or IMSI are not set)\n",
link_info->tlli.current);
gbproxy_delete_link_info(peer, link_info);
return;
return 1;
}
link_info->tlli.current = 0;
@ -371,7 +371,7 @@ static void gbproxy_unregister_link_info(struct gbproxy_peer *peer,
gbproxy_reset_link(link_info);
return;
return 0;
}
int gbproxy_imsi_matches(struct gbproxy_config *cfg,
@ -668,12 +668,13 @@ struct gbproxy_link_info *gbproxy_update_link_state_dl(
return link_info;
}
void gbproxy_update_link_state_after(
int gbproxy_update_link_state_after(
struct gbproxy_peer *peer,
struct gbproxy_link_info *link_info,
time_t now,
struct gprs_gb_parse_context *parse_ctx)
{
int rc = 0;
if (parse_ctx->invalidate_tlli && link_info) {
int keep_info =
peer->cfg->keep_link_infos == GBPROX_KEEP_ALWAYS ||
@ -684,11 +685,12 @@ void gbproxy_update_link_state_after(
if (keep_info) {
LOGP(DGPRS, LOGL_INFO, "Unregistering TLLI %08x\n",
link_info->tlli.current);
gbproxy_unregister_link_info(peer, link_info);
rc = gbproxy_unregister_link_info(peer, link_info);
} else {
LOGP(DGPRS, LOGL_INFO, "Removing TLLI %08x from list\n",
link_info->tlli.current);
gbproxy_delete_link_info(peer, link_info);
rc = 1;
}
} else if (parse_ctx->to_bss && parse_ctx->tlli_enc &&
parse_ctx->new_ptmsi_enc && link_info) {
@ -714,6 +716,8 @@ void gbproxy_update_link_state_after(
}
gbproxy_remove_stale_link_infos(peer, now);
return rc;
}