<p>pespin <strong>merged</strong> this change.</p><p><a href="https://gerrit.osmocom.org/c/osmo-ggsn/+/13608">View Change</a></p><div style="white-space:pre-wrap">Approvals:
Jenkins Builder: Verified
fixeria: Looks good to me, approved
</div><pre style="font-family: monospace,monospace; white-space: pre-wrap;">ggsn: Add minimalistic PAP support<br><br>Some modems are configured to use PAP as an additional authentication<br>mechanism beyond the GSM authentication that's part of GMM. Let's<br>handle such PAP authentication requests by simply acknowledging them<br>all, without actually checking any credentials database.<br><br>This is the most sane thing we can do for now, without adding external<br>requirements / interfaces like radius servers or the like.<br><br>Closes: OS#3914<br>Change-Id: I81875f30f9f1497199253497f84718510747f731<br>---<br>M ggsn/ggsn.c<br>1 file changed, 86 insertions(+), 1 deletion(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c</span><br><span>index c559923..e95471a 100644</span><br><span>--- a/ggsn/ggsn.c</span><br><span>+++ b/ggsn/ggsn.c</span><br><span>@@ -1,7 +1,7 @@</span><br><span> /*</span><br><span> * OsmoGGSN - Gateway GPRS Support Node</span><br><span> * Copyright (C) 2002, 2003, 2004 Mondru AB.</span><br><span style="color: hsl(0, 100%, 40%);">- * Copyright (C) 2017 by Harald Welte <laforge@gnumonks.org></span><br><span style="color: hsl(120, 100%, 40%);">+ * Copyright (C) 2017-2019 by Harald Welte <laforge@gnumonks.org></span><br><span> *</span><br><span> * The contents of this file may be used under the terms of the GNU</span><br><span> * General Public License Version 2, provided that the above copyright</span><br><span>@@ -47,6 +47,7 @@</span><br><span> #include <osmocom/core/stats.h></span><br><span> #include <osmocom/core/rate_ctr.h></span><br><span> #include <osmocom/core/timer.h></span><br><span style="color: hsl(120, 100%, 40%);">+#include <osmocom/core/utils.h></span><br><span> #include <osmocom/ctrl/control_if.h></span><br><span> #include <osmocom/ctrl/control_cmd.h></span><br><span> #include <osmocom/ctrl/control_vty.h></span><br><span>@@ -499,6 +500,87 @@</span><br><span> return NULL;</span><br><span> }</span><br><span> </span><br><span style="color: hsl(120, 100%, 40%);">+/* RFC 1334, section 3.2. Packet Format */</span><br><span style="color: hsl(120, 100%, 40%);">+struct pap_element {</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t code;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t id;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint16_t len; /* length including header */</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t data[0];</span><br><span style="color: hsl(120, 100%, 40%);">+} __attribute__((packed));</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+enum pap_code {</span><br><span style="color: hsl(120, 100%, 40%);">+ PAP_CODE_AUTH_REQ = 1,</span><br><span style="color: hsl(120, 100%, 40%);">+ PAP_CODE_AUTH_ACK = 2,</span><br><span style="color: hsl(120, 100%, 40%);">+ PAP_CODE_AUTH_NAK = 3,</span><br><span style="color: hsl(120, 100%, 40%);">+};</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+static const char *pap_welcome = "Welcome to OsmoGGSN " PACKAGE_VERSION;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+/* Handle PAP protocol according to RFC 1334 */</span><br><span style="color: hsl(120, 100%, 40%);">+static void process_pco_element_pap(const struct pco_element *pco_in, struct msgb *resp,</span><br><span style="color: hsl(120, 100%, 40%);">+ const struct apn_ctx *apn, struct pdp_t *pdp)</span><br><span style="color: hsl(120, 100%, 40%);">+{</span><br><span style="color: hsl(120, 100%, 40%);">+ const struct pap_element *pap_in = (const struct pap_element *) pco_in->data;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint16_t pap_in_len;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t peer_id_len;</span><br><span style="color: hsl(120, 100%, 40%);">+ const uint8_t *peer_id;</span><br><span style="color: hsl(120, 100%, 40%);">+ unsigned int pap_welcome_len;</span><br><span style="color: hsl(120, 100%, 40%);">+ uint8_t pap_out_size;</span><br><span style="color: hsl(120, 100%, 40%);">+ struct pap_element *pap_out;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pco_in->length < sizeof(struct pap_element))</span><br><span style="color: hsl(120, 100%, 40%);">+ goto ret_broken;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_in_len = osmo_load16be(&pap_in->len);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pco_in->length < pap_in_len)</span><br><span style="color: hsl(120, 100%, 40%);">+ goto ret_broken;</span><br><span style="color: hsl(120, 100%, 40%);">+ /* "pco_in->length > pap_in_len" is allowed: RFC1334 2.2 states:</span><br><span style="color: hsl(120, 100%, 40%);">+ "Octets outside the range of the Length field should be treated as</span><br><span style="color: hsl(120, 100%, 40%);">+ Data Link Layer padding and should be ignored on reception."</span><br><span style="color: hsl(120, 100%, 40%);">+ */</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ switch (pap_in->code) {</span><br><span style="color: hsl(120, 100%, 40%);">+ case PAP_CODE_AUTH_REQ:</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pap_in_len < sizeof(struct pap_element) + 1)</span><br><span style="color: hsl(120, 100%, 40%);">+ goto ret_broken_auth;</span><br><span style="color: hsl(120, 100%, 40%);">+ peer_id_len = pap_in->data[0];</span><br><span style="color: hsl(120, 100%, 40%);">+ if (pap_in_len < sizeof(struct pap_element) + 1 + peer_id_len)</span><br><span style="color: hsl(120, 100%, 40%);">+ goto ret_broken_auth;</span><br><span style="color: hsl(120, 100%, 40%);">+ peer_id = &pap_in->data[1];</span><br><span style="color: hsl(120, 100%, 40%);">+ LOGPPDP(LOGL_DEBUG, pdp, "PCO PAP PeerId = %s, ACKing\n",</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_quote_str((const char *)peer_id, peer_id_len));</span><br><span style="color: hsl(120, 100%, 40%);">+ /* Password-Length + Password following here, but we don't care */</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ /* Prepare response, we ACK all of them: */</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_welcome_len = strlen(pap_welcome);</span><br><span style="color: hsl(120, 100%, 40%);">+ /* +1: Length field of pap_welcome Message */</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_out_size = sizeof(struct pap_element) + 1 + pap_welcome_len;</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_out = alloca(pap_out_size);</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_out->code = PAP_CODE_AUTH_ACK;</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_out->id = pap_in->id;</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_out->len = htons(pap_out_size);</span><br><span style="color: hsl(120, 100%, 40%);">+ pap_out->data[0] = pap_welcome_len;</span><br><span style="color: hsl(120, 100%, 40%);">+ memcpy(pap_out->data+1, pap_welcome, pap_welcome_len);</span><br><span style="color: hsl(120, 100%, 40%);">+ msgb_t16lv_put(resp, PCO_P_PAP, pap_out_size, (uint8_t *) pap_out);</span><br><span style="color: hsl(120, 100%, 40%);">+ break;</span><br><span style="color: hsl(120, 100%, 40%);">+ case PAP_CODE_AUTH_ACK:</span><br><span style="color: hsl(120, 100%, 40%);">+ case PAP_CODE_AUTH_NAK:</span><br><span style="color: hsl(120, 100%, 40%);">+ default:</span><br><span style="color: hsl(120, 100%, 40%);">+ LOGPPDP(LOGL_NOTICE, pdp, "Unsupported PAP PCO Code %u, ignoring\n", pap_in->code);</span><br><span style="color: hsl(120, 100%, 40%);">+ break;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+ return;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ret_broken_auth:</span><br><span style="color: hsl(120, 100%, 40%);">+ LOGPPDP(LOGL_NOTICE, pdp, "Invalid PAP AuthenticateReq: %s, ignoring\n",</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_hexdump_nospc((const uint8_t *)pco_in, pco_in->length));</span><br><span style="color: hsl(120, 100%, 40%);">+ return;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ret_broken:</span><br><span style="color: hsl(120, 100%, 40%);">+ LOGPPDP(LOGL_NOTICE, pdp, "Invalid PAP PCO Length: %s, ignoring\n",</span><br><span style="color: hsl(120, 100%, 40%);">+ osmo_hexdump_nospc((const uint8_t *)pco_in, pco_in->length));</span><br><span style="color: hsl(120, 100%, 40%);">+}</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span> static void process_pco_element_ipcp(const struct pco_element *pco_elem, struct msgb *resp,</span><br><span> const struct apn_ctx *apn, struct pdp_t *pdp)</span><br><span> {</span><br><span>@@ -580,6 +662,9 @@</span><br><span> const struct apn_ctx *apn, struct pdp_t *pdp)</span><br><span> {</span><br><span> switch (ntohs(pco_elem->protocol_id)) {</span><br><span style="color: hsl(120, 100%, 40%);">+ case PCO_P_PAP:</span><br><span style="color: hsl(120, 100%, 40%);">+ process_pco_element_pap(pco_elem, resp, apn, pdp);</span><br><span style="color: hsl(120, 100%, 40%);">+ break;</span><br><span> case PCO_P_IPCP:</span><br><span> process_pco_element_ipcp(pco_elem, resp, apn, pdp);</span><br><span> break;</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-ggsn/+/13608">change 13608</a>. To unsubscribe, or for help writing mail filters, visit <a href="https://gerrit.osmocom.org/settings">settings</a>.</p><div itemscope itemtype="http://schema.org/EmailMessage"><div itemscope itemprop="action" itemtype="http://schema.org/ViewAction"><link itemprop="url" href="https://gerrit.osmocom.org/c/osmo-ggsn/+/13608"/><meta itemprop="name" content="View Change"/></div></div>
<div style="display:none"> Gerrit-Project: osmo-ggsn </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I81875f30f9f1497199253497f84718510747f731 </div>
<div style="display:none"> Gerrit-Change-Number: 13608 </div>
<div style="display:none"> Gerrit-PatchSet: 6 </div>
<div style="display:none"> Gerrit-Owner: laforge <laforge@gnumonks.org> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder </div>
<div style="display:none"> Gerrit-Reviewer: fixeria <axilirator@gmail.com> </div>
<div style="display:none"> Gerrit-Reviewer: laforge <laforge@gnumonks.org> </div>
<div style="display:none"> Gerrit-Reviewer: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-CC: msuraev <suraev@alumni.ntnu.no> </div>
<div style="display:none"> Gerrit-MessageType: merged </div>