svn commit: r344593 - head/lib/libc/sys

[Konstantin Belousov]

Author: kib
Date: Tue Feb 26 17:41:41 2019
New Revision: 344593
URL: https://svnweb.freebsd.org/changeset/base/344593

Log:
  procctl(2): document ASLR knobs.
  
  Reviewed by:	0mp
  Sponsored by:	The FreeBSD Foundation
  Differential revision:	https://reviews.freebsd.org/D19308

Modified:
  head/lib/libc/sys/procctl.2

Modified: head/lib/libc/sys/procctl.2
==============================================================================
--- head/lib/libc/sys/procctl.2	Tue Feb 26 17:35:06 2019	(r344592)
+++ head/lib/libc/sys/procctl.2	Tue Feb 26 17:41:41 2019	(r344593)
@@ -72,6 +72,46 @@ The control request to perform is specified by the
 argument.
 The following commands are supported:
 .Bl -tag -width PROC_TRAPCAP_STATUS
+.It Dv PROC_ASLR_CTL
+Controls the Address Space Layout Randomization (ASLR) in the program
+images created
+by
+.Xr execve 2
+in the specified process or its descendants that did not changed
+the control nor modified it by other means.
+The
+.Va arg
+parameter must point to the integer variable holding one of the following
+values:
+.Bl -tag -width PROC_ASLR_FORCE_DISABLE
+.It Dv PROC_ASLR_FORCE_ENABLE
+Request that ASLR is enabled after execution, even if it is disabled
+system-wide.
+The image flag and set-uid might prevent ASLR enablement still.
+.It Dv PROC_ASLR_FORCE_DISABLE
+Request that ASLR is disabled after execution.
+Same notes as for
+.Dv PROC_ASKR_FORCE_ENABLE
+apply.
+.It Dv PROC_ASLR_NOFORCE
+Use system-wide configured policy for ASLR.
+.El
+.It Dv PROC_ASLR_STATUS
+Returns the current status of ASLR enablement for the target process.
+The
+.Va arg
+parameter must point to the integer variable, where one of the
+following values is written:
+.Bl -tag -width PROC_ASLR_FORCE_DISABLE
+.It Dv PROC_ASLR_FORCE_ENABLE
+.It Dv PROC_ASLR_FORCE_DISABLE
+.It Dv PROC_ASLR_NOFORCE
+.El
+.Pp
+If the currently executed image in the process itself has ASLR enabled,
+the
+.Dv PROC_ASLR_ACTIVE
+flag is or-ed with the value listed above.
 .It Dv PROC_SPROTECT
 Set process protection state.
 This is used to mark a process as protected from being killed if the system
@@ -543,11 +583,16 @@ The
 .Fn procctl
 function appeared in
 .Fx 10.0 .
+.Pp
 The reaper facility is based on a similar feature of Linux and
 DragonflyBSD, and first appeared in
 .Fx 10.2 .
+.Pp
 The
 .Dv PROC_PDEATHSIG_CTL
 facility is based on the prctl(PR_SET_PDEATHSIG, ...) feature of Linux,
 and first appeared in
 .Fx 11.2 .
+.Pp
+The ASLR support was added to system for the checklists compliance in
+.Fx 13.0 .