Rooba
/
boinc
mirror of https://github.com/BOINC/boinc.git
1
0
Fork 0
Code Issues 1 Packages Projects Releases Wiki Activity

Update sandbox security documentation 

svn path=/trunk/boinc/; revision=13839
This commit is contained in:
Charlie Fenton 2007-10-12 05:11:04 +00:00
parent a1da761346
commit f32e42e1bb
2 changed files with 68 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
clientgui/mac/SetupSecurity.cpp
View File

@ -243,7 +243,7 @@ int SetBOINCAppOwnersGroupsAndPermissions(char *path) {
// chmod u=rsx,g=rx,o=rx "/Library/Screen Savers/BOINCSaver.saver/Contents/Resources/gfx_switcher"
// 04055 = S_ISUID | S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH
// setuid-on-execution, setgid-on-execution plus read and execute permission for user, group & others
// setuid-on-execution plus read and execute permission for user, group & others
err = DoPrivilegedExec(chmodPath, "u=rsx,g=rx,o=rx", fullpath, NULL, NULL, NULL);
if (err)
return err;

81
doc/sandbox.php
View File

@ -27,7 +27,8 @@ function prot($user, $group, $perm) {
$pp06640775 = prot('boinc_project', 'boinc_project', '0664 or 0775');
$mp2500 = prot('boinc_master', 'boinc_project', '0500+setgid');
$pp6551 = prot('boinc_project', 'boinc_project', '0551+setuid+setgid');
$rm4050 = prot('root', 'boinc_master', '0050+setuid');
$rm4055 = prot('root', 'boinc_master', '0055+setuid');
$mm0550 = prot('boinc_master', 'boinc_master', '0550');
$mm0440 = prot('boinc_master', 'boinc_master', '0440');
$mm0660 = prot('boinc_master', 'boinc_master', '0660');
@ -112,7 +113,7 @@ echo
))
)),
show_dir(1, 'switcher (directory)', $mm0550, array(
show_file('switcher (executable)', $pp6551),
show_file('switcher (executable)', $rm4050),
show_file('setprojectgrp (executable)', $mp2500)
)),
show_dir(1, 'locale', $mm0550, array(
@ -134,7 +135,10 @@ echo "<br><br>";
echo
show_dir(0, 'BOINC executables', $ua0555, array(
show_file('BOINC Manager', $mm2555),
show_file('BOINC Client', $mm6555)
show_file('BOINC Client', $mm6555),
show_dir(1, 'screensaver (directory)', $ua0555, array(
show_file('gfx_switcher (executable)', $rm4055)
)),
));
echo "
@ -148,16 +152,70 @@ set project and slot files and directories to group <b>boinc_project</b>.
<li>BOINC Client does not directly execute project applications.
It runs the helper application <i>switcher</i>,
passing the request in the argument list.
<i>switcher</i> runs setuid <b>boinc_project</b> and setgid
<b>boinc_project</b>,
<i>switcher</i> runs setuid <b>root</b> and immediately changes its real and
effective user ID and group ID to <b>boinc_project</b>,
so all project applications inherit user and group <b>boinc_project</b>.
This blocks project applications from accessing unauthorized files.
<li>In most cases, it is best to avoid running setuid <b>root</b> because
it can present a security risk. In this case, however, this is necessary to
<i>reduce</i> the risk because only the superuser can change the <i>real</i>
user and group of a process. This prevents a malicious or malfunctioning
application from reverting to the user and group who launched BOINC, since any
process can change its user and group back to the <i>real</i> user and
group IDs.
<li>BOINC's use of setuid <b>root</b> for the <i>switcher</i> application is
safe because:
<ul>
<li>The <i>switcher</i> application is inside the <i>switcher</i> directory.
This directory is accessible only by user and group <b>boinc_master</b>,
so that project applications cannot modify the <i>switcher</i>
application's permissions or code. This also prevents unauthorized users
from using <i>switcher</i> to damage or manipulate project files.
<li>The <i>switcher</i> application is readable and executable only by
group <b>boinc_master</b>; all other access is forbidden.
<li>When it is run, the <i>switcher</i> application immediately changes
its real and effective user ID and group ID to <b>boinc_project</b>, disabling
its superuser privileges.
</ul>
<li>BOINC Manager runs setgid to group <b>boinc_master</b>.
It can access all files in group <b>boinc_master</b>.
It runs as the user who launched it,
which is necessary for a number of GUI features to work correctly.
Although this means that BOINC Manager cannot modify files
created by project applications, there is no need for it to do so.
<li>Starting with BOINC version 6.0, project science applications use a
separate companion application to display graphics. These graphics
applications are launched by the BOINC Manager when the user clicks on
the <i>Show Graphics</i> button. Running the graphics application
with the BOINC Manager's user and group would be a security risk, so
BOINC Manager uses the <i>switcher</i> application to launch them as
user and group <b>boinc_project</b>.
<li>The screensaver also can run the graphics applications. The Macintosh
screensaver is launched by the operating system, so it runs as the
currently logged in user and group. Since running the science projects' graphics applications
with this user and group would be a security risk, the screensaver has
its own embedded helper application <i>gfx_switcher</i> which it uses to
launch the graphics applications.
Like the <i>switcher</i> application, <i>gfx_switcher</i> runs setuid
<b>root</b> and immediately changes its real and effective user ID and
group ID to <b>boinc_project</b>
<li>The BOINC screensaver's use of setuid <b>root</b> for the
<i>gfx_switcher</i> application is safe because:
<ul>
<li>When it is run, the <i>gfx_switcher</i> application immediately changes
its real and effective user ID and group ID to <b>boinc_project</b>, disabling
its superuser privileges.
<li>The <i>gfx_switcher</i> application has very limited functionality. It
accepts only two commands as its first argument:.
<ul>
<li><i>launch_gfx</i>: the second argument is the slot number. It looks for
a soft-link named <b>graphics_app</b> in the specified slot directory and launches
the referenced graphics application.
<li><i>kill_gfx</i>: the second argument is the process ID. It kills the
application with the process ID; since it is running as user and group
<b>boinc_project</b>, it can affect only processes belonging to that user.
</ul>
</ul>
<li>BOINC Manager and BOINC Client set their umasks to 002,
which is inherited by all child applications.
The default permissions for all files and directories they create prevent
@ -166,11 +224,6 @@ Because files are world-readable, BOINC Client can read files written by project
Third-party add-ons can also read BOINC data files.
<li>Non-admin users cannot directly modify BOINC or project files.
They can modify these files only by running the BOINC Manager and Client.
<li>The <i>switcher</i> application is inside the <i>switcher</i> directory.
This directory is accessible only by user and group <b>boinc_master</b>,
so that project applications cannot modify the <i>switcher</i>
application's permissions or code. This also prevents unauthorized users
from using <i>switcher</i> to damage project files.
<li>Users with admin access are members of groups <b>boinc_master</b>
and <b>boinc_project</b> so that they do have
direct access to all BOINC and project files
@ -185,10 +238,10 @@ Attach to Project, Detach from Project, Reset Project, Abort Task,
Abort Transfer, Update Account Manager.
If an unauthorized user requests these functions,
the Manager requires password authentication.
<li>On Macintosh computers, the actual directory structure
of the BOINC Manager application bundle is more complex
than implied by the box <i>BOINC executables</i> in the BOINC
tree diagram shown above.
<li>On Macintosh computers, the actual directory structures
of the BOINC Manager application bundle and the screensaver bundle are
more complex than implied by the box <i>BOINC executables</i> in the
BOINC tree diagram shown above.
<li>Some Macintosh system administrators may wish to limit which users
can perform BOINC Manager functions (Activity Menu, etc.).
This can be done by moving BOINC Manager out of the