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      <base href="https://bugs.freedesktop.org/" />
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Unsecure/unreliable shared memory"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=90512">90512</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Unsecure/unreliable shared memory
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>cairo
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>major
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>general
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>chris@chris-wilson.co.uk
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>wbrana@gmail.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>cairo-bugs@cairographics.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Cairo is using shared memory using shmget with permissions 600 in following
files:
cairo-xlib-surface-shm.c
cairo-xcb-shm.c
cairo-xcb-connection.c
which
- is unsecure because other applications from same user can access that memory
using shmat and shmid from /proc/sysvipc/shm
- doesn't work if application is running as different non-root user from
Xserver

Cairo should use new functions with Xserver 1.15 and newer:

"In the 1.15 release of the X.org server[1] the MIT-SHM extension gains two
additional requests: 'X_ShmAttachFd' and 'X_ShmCreateSegment', to be able to
pass shared memory through file descriptors from client to server and from
server to client"</pre>
        </div>
      </p>
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