[refpolicy] [patch 1/1] sudo: Fixes for sudo, handle /var/db/sudo

[dwalsh@redhat.com (Daniel J Walsh)]

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On 02/19/2011 12:08 AM, Guido Trentalancia wrote:
> Hello Miroslav !
> 
> On Fri, 18/02/2011 at 17.15 +0000, Miroslav Grepl wrote:
>> http://mgrepl.fedorapeople.org/F15/admin_sudo.patch
>>
>>      * Allow sudo to send signals to any domains the user could have 
>> transitioned to.
>>      * Handle /var/db/sudo
>>      * Allow users to run executables in /tmp or ~/
> 
> To the best of my knowledge, the first part of the last change is
> something really bad from a security point of view. 
> 
> System administrators put much effort to avoid that (such as
> mounting /tmp with noexec, nosuid options) !
> 
> A legitimate user does not need to store his/her executables in /tmp, as
> he/she has at least its own home directory available for that (and if
> he/she cannot write there, then he/she is probably over quota).
> 
> /tmp just "potentially provides storage space for malicious
> executables" (quoted from paragraph 2.2.1.3 of NSA public document
> "Guide to the Secure Configuration of Red Hat Enterprise Linux 5"
> Revision 4, but any decent web search engine would easily provide you
> with tons of pages relative to the cries of those whom have allowed that
> sort of thing to happen on their systems).
> 
> Regards,
> 
> Guido
> 
> _______________________________________________
> refpolicy mailing list
> refpolicy at oss.tresys.com
> http://oss.tresys.com/mailman/listinfo/refpolicy

+	userdom_domtrans_user_tmp($1_sudo_t, $3)

Says to run user_tmp_t files as staff_t, Which is the equivalent of if
the staff_t had executed the file directly.

I guess if execution of homedir/tmp dir was turned off this could be
seen as a priv escalation.

staff_t is not allowed to execute user_tmp_t, but it can if it goes
through sudo.
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