<p>Neels Hofmeyr has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/12156">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">gsm48_mi_to_string(): guard against zero length output buffer<br><br>All successful cases already return from the switch(), so simply handle all<br>errors below it by returning an empty string (if there is enough string<br>buffer).<br><br>Change-Id: I709ac3b9efb7b4258d8660715b10312e11b9b571<br>---<br>M src/gsm/gsm48.c<br>M tests/gsm0408/gsm0408_test.ok<br>2 files changed, 13 insertions(+), 12 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/56/12156/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/src/gsm/gsm48.c b/src/gsm/gsm48.c</span><br><span>index 3487ef7..7517c09 100644</span><br><span>--- a/src/gsm/gsm48.c</span><br><span>+++ b/src/gsm/gsm48.c</span><br><span>@@ -658,8 +658,6 @@</span><br><span>   mi_type = mi[0] & GSM_MI_TYPE_MASK;</span><br><span> </span><br><span>  switch (mi_type) {</span><br><span style="color: hsl(0, 100%, 40%);">-      case GSM_MI_TYPE_NONE:</span><br><span style="color: hsl(0, 100%, 40%);">-          break;</span><br><span>       case GSM_MI_TYPE_TMSI:</span><br><span>               /* Table 10.5.4.3, reverse generate_mid_from_tmsi */</span><br><span>                 if (mi_len == GSM48_TMSI_LEN && mi[0] == (0xf0 | GSM_MI_TYPE_TMSI)) {</span><br><span>@@ -679,12 +677,15 @@</span><br><span>                        return 0;</span><br><span>            else</span><br><span>                         return strlen(string) + 1;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span>         default:</span><br><span>             break;</span><br><span>       }</span><br><span style="color: hsl(0, 100%, 40%);">-       *str_cur++ = '\0';</span><br><span> </span><br><span style="color: hsl(0, 100%, 40%);">-  return str_cur - string;</span><br><span style="color: hsl(120, 100%, 40%);">+      if (str_len < 1)</span><br><span style="color: hsl(120, 100%, 40%);">+           return 0;</span><br><span style="color: hsl(120, 100%, 40%);">+     *string = '\0';</span><br><span style="color: hsl(120, 100%, 40%);">+       return 1;</span><br><span> }</span><br><span> </span><br><span> /*! Parse TS 04.08 Routing Area Identifier</span><br><span>diff --git a/tests/gsm0408/gsm0408_test.ok b/tests/gsm0408/gsm0408_test.ok</span><br><span>index 6e99f5b..d6579e5 100644</span><br><span>--- a/tests/gsm0408/gsm0408_test.ok</span><br><span>+++ b/tests/gsm0408/gsm0408_test.ok</span><br><span>@@ -72,8 +72,8 @@</span><br><span>     returned empty string</span><br><span> - MI type: TMSI</span><br><span>   - writing to zero-length string:</span><br><span style="color: hsl(0, 100%, 40%);">-    rc=1</span><br><span style="color: hsl(0, 100%, 40%);">-    ERROR: Wrote to invalid memory!</span><br><span style="color: hsl(120, 100%, 40%);">+    rc=0</span><br><span style="color: hsl(120, 100%, 40%);">+    nothing written</span><br><span>   - writing to 1-byte-length string:</span><br><span>     rc=1</span><br><span>     returned empty string</span><br><span>@@ -82,8 +82,8 @@</span><br><span>     returned empty string</span><br><span> - MI type: NONE</span><br><span>   - writing to zero-length string:</span><br><span style="color: hsl(0, 100%, 40%);">-    rc=1</span><br><span style="color: hsl(0, 100%, 40%);">-    ERROR: Wrote to invalid memory!</span><br><span style="color: hsl(120, 100%, 40%);">+    rc=0</span><br><span style="color: hsl(120, 100%, 40%);">+    nothing written</span><br><span>   - writing to 1-byte-length string:</span><br><span>     rc=1</span><br><span>     returned empty string</span><br><span>@@ -102,8 +102,8 @@</span><br><span>     returned empty string</span><br><span> - MI type: TMSI | GSM_MI_ODD</span><br><span>   - writing to zero-length string:</span><br><span style="color: hsl(0, 100%, 40%);">-    rc=1</span><br><span style="color: hsl(0, 100%, 40%);">-    ERROR: Wrote to invalid memory!</span><br><span style="color: hsl(120, 100%, 40%);">+    rc=0</span><br><span style="color: hsl(120, 100%, 40%);">+    nothing written</span><br><span>   - writing to 1-byte-length string:</span><br><span>     rc=1</span><br><span>     returned empty string</span><br><span>@@ -112,8 +112,8 @@</span><br><span>     returned empty string</span><br><span> - MI type: NONE | GSM_MI_ODD</span><br><span>   - writing to zero-length string:</span><br><span style="color: hsl(0, 100%, 40%);">-    rc=1</span><br><span style="color: hsl(0, 100%, 40%);">-    ERROR: Wrote to invalid memory!</span><br><span style="color: hsl(120, 100%, 40%);">+    rc=0</span><br><span style="color: hsl(120, 100%, 40%);">+    nothing written</span><br><span>   - writing to 1-byte-length string:</span><br><span>     rc=1</span><br><span>     returned empty string</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/12156">change 12156</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/12156"/><meta itemprop="name" content="View Change"/></div></div>

<div style="display:none"> Gerrit-Project: libosmocore </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>
<div style="display:none"> Gerrit-Change-Id: I709ac3b9efb7b4258d8660715b10312e11b9b571 </div>
<div style="display:none"> Gerrit-Change-Number: 12156 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: Neels Hofmeyr <nhofmeyr@sysmocom.de> </div>