<p>Pau Espin Pedrol has uploaded this change for <strong>review</strong>.</p><p><a href="https://gerrit.osmocom.org/9749">View Change</a></p><pre style="font-family: monospace,monospace; white-space: pre-wrap;">bsc-nat: Avoid heap-use-after-free on USSD conn lost<br><br>When ussd_read_cb calls bsc_nat_ussd_destroy the osmo_fd struct is<br>freed, so we need to indicate to osmo_wqueue_bfd_cb that it should not<br>continue using the fd pointer after we return.<br><br>Fixes following AddressSanitizer report:<br><0015> osmo-bsc_nat/bsc_ussd.c:273 USSD Connection on 13 with IP: 1.2.3.4<br><0015> osmo-bsc_nat/bsc_ussd.c:132 USSD Connection was lost.<br>=================================================================<br>==18118==ERROR: AddressSanitizer: heap-use-after-free on address 0x61200047c4b4 at pc 0x7ffff6067540 bp 0x7fffffffe170 sp 0x7fffffffe168<br>READ of size 4 at 0x61200047c4b4 thread T0<br>    #0 0x7ffff606753f in osmo_wqueue_bfd_cb libosmocore/src/write_queue.c:65<br>    #1 0x7ffff605206b in osmo_fd_disp_fds libosmocore/src/select.c:217<br>    #2 0x7ffff6052305 in osmo_select_main libosmocore/src/select.c:257<br>    #3 0x421dfa in main osmo-bsc_nat/bsc_nat.c:1718<br>    #4 0x7ffff47ffb44 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x21b44)<br>    #5 0x406438 (/bin/osmo-bsc_nat+0x406438)<br><br>Change-Id: I35854c43524714d07f31d71c775ac1cd0a57d22e<br>---<br>M openbsc/src/osmo-bsc_nat/bsc_ussd.c<br>1 file changed, 7 insertions(+), 4 deletions(-)<br><br></pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;">git pull ssh://gerrit.osmocom.org:29418/openbsc refs/changes/49/9749/1</pre><pre style="font-family: monospace,monospace; white-space: pre-wrap;"><span>diff --git a/openbsc/src/osmo-bsc_nat/bsc_ussd.c b/openbsc/src/osmo-bsc_nat/bsc_ussd.c</span><br><span>index 0ba6327..ee0b085 100644</span><br><span>--- a/openbsc/src/osmo-bsc_nat/bsc_ussd.c</span><br><span>+++ b/openbsc/src/osmo-bsc_nat/bsc_ussd.c</span><br><span>@@ -126,12 +126,11 @@</span><br><span>        int ret;</span><br><span> </span><br><span>         ret = ipa_msg_recv_buffered(bfd->fd, &msg, &conn->pending_msg);</span><br><span style="color: hsl(120, 100%, 40%);">+ if (ret == -EAGAIN)</span><br><span style="color: hsl(120, 100%, 40%);">+           return 0;</span><br><span>    if (ret <= 0) {</span><br><span style="color: hsl(0, 100%, 40%);">-              if (ret == -EAGAIN)</span><br><span style="color: hsl(0, 100%, 40%);">-                     return 0;</span><br><span>            LOGP(DNAT, LOGL_ERROR, "USSD Connection was lost.\n");</span><br><span style="color: hsl(0, 100%, 40%);">-                bsc_nat_ussd_destroy(conn);</span><br><span style="color: hsl(0, 100%, 40%);">-             return -1;</span><br><span style="color: hsl(120, 100%, 40%);">+            goto close_fd;</span><br><span>       }</span><br><span> </span><br><span>        LOGP(DNAT, LOGL_NOTICE, "MSG from USSD: %s proto: %d\n",</span><br><span>@@ -168,6 +167,10 @@</span><br><span>    }</span><br><span> </span><br><span>        return 0;</span><br><span style="color: hsl(120, 100%, 40%);">+</span><br><span style="color: hsl(120, 100%, 40%);">+close_fd:</span><br><span style="color: hsl(120, 100%, 40%);">+        bsc_nat_ussd_destroy(conn);</span><br><span style="color: hsl(120, 100%, 40%);">+   return -EBADF;</span><br><span> }</span><br><span> </span><br><span> static void ussd_auth_cb(void *_data)</span><br><span></span><br></pre><p>To view, visit <a href="https://gerrit.osmocom.org/9749">change 9749</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/9749"/><meta itemprop="name" content="View Change"/></div></div>

<div style="display:none"> Gerrit-Project: openbsc </div>
<div style="display:none"> Gerrit-Branch: master </div>
<div style="display:none"> Gerrit-MessageType: newchange </div>
<div style="display:none"> Gerrit-Change-Id: I35854c43524714d07f31d71c775ac1cd0a57d22e </div>
<div style="display:none"> Gerrit-Change-Number: 9749 </div>
<div style="display:none"> Gerrit-PatchSet: 1 </div>
<div style="display:none"> Gerrit-Owner: Pau Espin Pedrol <pespin@sysmocom.de> </div>