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gprs_ns2: check if persistent nsei or nsvc exists when creating dynamic NSE 

When receiving a NS Reset over an unknown NSVC the NS code would create
a dynamic NSE. If the NSEI or NSVCI is already configured to a
persistant NSE/NSVC the packet should be ignored.

Related: SYS#5208
Change-Id: I855911e7d364f2e5b08ea05857747aa63fcf1cd3
This commit is contained in:
Alexander Couzens 2021-01-04 19:07:05 +01:00
parent 89a00f352d
commit 05ac4e52b9
1 changed files with 34 additions and 4 deletions
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38
src/gb/gprs_ns2.c
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@ -861,18 +861,49 @@ enum gprs_ns2_cs ns2_create_vc(struct gprs_ns2_vc_bind *bind,
return GPRS_NS2_CS_REJECTED;
}
/* find or create NSE */
nsei = tlvp_val16be(&tp, NS_IE_NSEI);
nsvci = tlvp_val16be(&tp, NS_IE_VCI);
/* find or create NSE */
nse = gprs_ns2_nse_by_nsei(bind->nsi, nsei);
if (!nse) {
if (!bind->nsi->create_nse) {
/* only create nse for udp & ipaccess */
if (bind->ll != GPRS_NS2_LL_UDP || dialect != NS2_DIALECT_IPACCESS)
return GPRS_NS2_CS_SKIPPED;
if (!bind->nsi->create_nse || !bind->accept_ipaccess)
return GPRS_NS2_CS_SKIPPED;
}
nse = gprs_ns2_create_nse(bind->nsi, nsei, bind->ll, dialect);
if (!nse) {
LOGP(DLNS, LOGL_ERROR, "Failed to create NSE(%05u)\n", nsei);
return GPRS_NS2_CS_ERROR;
}
} else {
/* nsei already known */
if (nse->ll != bind->ll) {
LOGP(DLNS, LOGL_ERROR, "Received NS-RESET NS-VCI(%05u) with wrong linklayer(%s) for already known NSE(%05u/%s)\n",
nsei, gprs_ns2_lltype_str(bind->ll), nse->nsei, gprs_ns2_lltype_str(nse->ll));
return GPRS_NS2_CS_SKIPPED;
}
}
nsvc = gprs_ns2_nsvc_by_nsvci(bind->nsi, nsvci);
if (nsvc) {
if (nsvc->persistent) {
LOGP(DLNS, LOGL_ERROR, "Received NS-RESET for a persistent NSE(%05u) NS-VCI(%05u) over wrong connection.\n",
nsei, nsvci);
return GPRS_NS2_CS_SKIPPED;
}
/* destroy old dynamic nsvc */
gprs_ns2_free_nsvc(nsvc);
}
/* do nse persistent check late to be more precise on the error message */
if (nse->persistent) {
LOGP(DLNS, LOGL_ERROR, "Received NS-RESET for a persistent NSE(%05u) but the unknown NS-VCI(%05u)\n",
nsei, nsvci);
return GPRS_NS2_CS_SKIPPED;
}
vc_mode = gprs_ns2_dialect_to_vc_mode(dialect);
@ -880,7 +911,6 @@ enum gprs_ns2_cs ns2_create_vc(struct gprs_ns2_vc_bind *bind,
if (!nsvc)
return GPRS_NS2_CS_SKIPPED;
nsvci = tlvp_val16be(&tp, NS_IE_VCI);
nsvc->nsvci = nsvci;
nsvc->nsvci_is_valid = true;