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Commit a0127afb authored by Linus Torvalds's avatar Linus Torvalds
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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 

Pull security docs update from James Morris.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  security: Minor improvements to no_new_privs documentation
parents 332a2e12 c540521b

Documentation/prctl/no_new_privs.txt

+7 −0
Original line number Diff line number Diff line
@@ -25,6 +25,13 @@ bits will no longer change the uid or gid; file capabilities will not 
add to the permitted set, and LSMs will not relax constraints after

execve.



To set no_new_privs, use prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0).



Be careful, though: LSMs might also not tighten constraints on exec

in no_new_privs mode.  (This means that setting up a general-purpose

service launcher to set no_new_privs before execing daemons may

interfere with LSM-based sandboxing.)



Note that no_new_privs does not prevent privilege changes that do not

involve execve.  An appropriately privileged task can still call

setuid(2) and receive SCM_RIGHTS datagrams.

include/linux/prctl.h

+2 −0
Original line number Diff line number Diff line
@@ -141,6 +141,8 @@ 
 * Changing LSM security domain is considered a new privilege.  So, for example,

 * asking selinux for a specific new context (e.g. with runcon) will result

 * in execve returning -EPERM.

 *

 * See Documentation/prctl/no_new_privs.txt for more details.

 */

#define PR_SET_NO_NEW_PRIVS	38

#define PR_GET_NO_NEW_PRIVS	39