<p>neels <strong>submitted</strong> this change.</p><p><a href="https://gerrit.osmocom.org/c/osmo-bsc/+/24676">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;">rewire build_encr_info() to return errors<br><br>In build_encr_info(), validate the algorithm and key presence and return<br>negative if errors are encountered.<br><br>At all callers, handle the error case.<br><br>An upcoming patch will add handling of Kc128 for A5/4 encryption and<br>also wants to return error codes. This is a preparation for that patch:<br>I7c458c8a7350f34ff79531b3c891e1b367614469<br><br>Notice that osmo-bsc does send the key along even if A5/0 is chosen,<br>this patch keeps that behavior unchanged.<br><br>Related: SYS#5324<br>Change-Id: I125d8aabceddd5b34cb98978cee9b6d2fc8fd0f2<br>---<br>M src/osmo-bsc/abis_rsl.c<br>1 file changed, 35 insertions(+), 4 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/src/osmo-bsc/abis_rsl.c b/src/osmo-bsc/abis_rsl.c</span><br><span>index 7525e31..c844f18 100644</span><br><span>--- a/src/osmo-bsc/abis_rsl.c</span><br><span>+++ b/src/osmo-bsc/abis_rsl.c</span><br><span>@@ -152,13 +152,36 @@</span><br><span> memset(out+len, 0x2b, GSM_MACBLOCK_LEN - len);</span><br><span> }</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-/* Chapter 9.3.7: Encryption Information */</span><br><span style="color: hsl(120, 100%, 40%);">+/* Chapter 9.3.7: Encryption Information</span><br><span style="color: hsl(120, 100%, 40%);">+ * Return negative on error, number of bytes written to 'out' on success.</span><br><span style="color: hsl(120, 100%, 40%);">+ * 'out' must provide room for 17 bytes. */</span><br><span> static int build_encr_info(uint8_t *out, struct gsm_lchan *lchan)</span><br><span> {</span><br><span> *out++ = lchan->encr.alg_id & 0xff;</span><br><span style="color: hsl(0, 100%, 40%);">- if (lchan->encr.key_len)</span><br><span style="color: hsl(0, 100%, 40%);">- memcpy(out, lchan->encr.key, lchan->encr.key_len);</span><br><span style="color: hsl(0, 100%, 40%);">- return lchan->encr.key_len + 1;</span><br><span style="color: hsl(120, 100%, 40%);">+ switch (lchan->encr.alg_id) {</span><br><span style="color: hsl(120, 100%, 40%);">+ case GSM0808_ALG_ID_A5_1:</span><br><span style="color: hsl(120, 100%, 40%);">+ case GSM0808_ALG_ID_A5_2:</span><br><span style="color: hsl(120, 100%, 40%);">+ case GSM0808_ALG_ID_A5_3:</span><br><span style="color: hsl(120, 100%, 40%);">+ if (!lchan->encr.key_len) {</span><br><span style="color: hsl(120, 100%, 40%);">+ LOG_LCHAN(lchan, LOGL_ERROR, "A5/%d encryption chosen, but missing Kc\n", lchan->encr.alg_id);</span><br><span style="color: hsl(120, 100%, 40%);">+ return -EINVAL;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span style="color: hsl(120, 100%, 40%);">+ /* fall through */</span><br><span style="color: hsl(120, 100%, 40%);">+ case GSM0808_ALG_ID_A5_0:</span><br><span style="color: hsl(120, 100%, 40%);">+ /* When A5/0 is chosen, no encryption is active, so technically, no key is needed. However, 3GPP TS</span><br><span style="color: hsl(120, 100%, 40%);">+ * 48.058 9.3.7 Encryption Information stays quite silent about presence or absence of a key for A5/0.</span><br><span style="color: hsl(120, 100%, 40%);">+ * The only thing specified is how to indicate the length of the key; the possibility that the key may</span><br><span style="color: hsl(120, 100%, 40%);">+ * be zero length is not explicitly mentioned. So it seems that we should always send the key along,</span><br><span style="color: hsl(120, 100%, 40%);">+ * even for A5/0. Currently our ttcn3 test suite does expect the key to be present also for A5/0, see</span><br><span style="color: hsl(120, 100%, 40%);">+ * f_cipher_mode() in bsc/MSC_ConnectionHandler.ttcn. */</span><br><span style="color: hsl(120, 100%, 40%);">+ if (lchan->encr.key_len)</span><br><span style="color: hsl(120, 100%, 40%);">+ memcpy(out, lchan->encr.key, lchan->encr.key_len);</span><br><span style="color: hsl(120, 100%, 40%);">+ return 1 + lchan->encr.key_len;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+ default:</span><br><span style="color: hsl(120, 100%, 40%);">+ LOG_LCHAN(lchan, LOGL_ERROR, "A5/%d encryption not supported\n", lchan->encr.alg_id);</span><br><span style="color: hsl(120, 100%, 40%);">+ return -EINVAL;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> }</span><br><span> </span><br><span> /* If the TLV contain an RSL Cause IE, return pointer to the cause value. If there is no Cause IE, return</span><br><span>@@ -595,6 +618,10 @@</span><br><span> rc = build_encr_info(encr_info, lchan);</span><br><span> if (rc > 0)</span><br><span> msgb_tlv_put(msg, RSL_IE_ENCR_INFO, rc, encr_info);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (rc < 0) {</span><br><span style="color: hsl(120, 100%, 40%);">+ msgb_free(msg);</span><br><span style="color: hsl(120, 100%, 40%);">+ return rc;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> }</span><br><span> </span><br><span> switch (act_type) {</span><br><span>@@ -688,6 +715,10 @@</span><br><span> rc = build_encr_info(encr_info, lchan);</span><br><span> if (rc > 0)</span><br><span> msgb_tlv_put(msg, RSL_IE_ENCR_INFO, rc, encr_info);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (rc < 0) {</span><br><span style="color: hsl(120, 100%, 40%);">+ msgb_free(msg);</span><br><span style="color: hsl(120, 100%, 40%);">+ return rc;</span><br><span style="color: hsl(120, 100%, 40%);">+ }</span><br><span> }</span><br><span> </span><br><span> if (gsm48_chan_mode_to_non_vamos(lchan->modify.ch_mode_rate.chan_mode) == GSM48_CMODE_SPEECH_AMR) {</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/c/osmo-bsc/+/24676">change 24676</a>. 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<div style="display:none"> Gerrit-Project: osmo-bsc </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-Change-Id: I125d8aabceddd5b34cb98978cee9b6d2fc8fd0f2 </div>
<div style="display:none"> Gerrit-Change-Number: 24676 </div>
<div style="display:none"> Gerrit-PatchSet: 2 </div>
<div style="display:none"> Gerrit-Owner: neels <nhofmeyr@sysmocom.de> </div>
<div style="display:none"> Gerrit-Reviewer: Jenkins Builder </div>
<div style="display:none"> Gerrit-Reviewer: dexter <pmaier@sysmocom.de> </div>
<div style="display:none"> Gerrit-Reviewer: fixeria <vyanitskiy@sysmocom.de> </div>
<div style="display:none"> Gerrit-Reviewer: laforge <laforge@osmocom.org> </div>
<div style="display:none"> Gerrit-Reviewer: neels <nhofmeyr@sysmocom.de> </div>
<div style="display:none"> Gerrit-Reviewer: pespin <pespin@sysmocom.de> </div>
<div style="display:none"> Gerrit-MessageType: merged </div>