Module Name: src
Committed By: maxv
Date: Tue Nov 14 10:15:40 UTC 2017
Modified Files:
src/sys/arch/amd64/conf: Makefile.amd64 kern.ldscript.kaslr
Log Message:
Split each kernel section into sub-blocks of approximately 2MB. The newly
created sections are named .origname.i, for example:
.text -> { .text .text.0 .text.1 .text.2 .text.3 .text.4 }
Each section is randomized independently by the prekern - and in a random
order obviously. As a result we can get intertwined mappings, of the type:
+-------+-----------+------+---------+-----------+-------+-------+------+-
| text1 | NOTMAPPED | bss0 | rodata1 | NOTMAPPED | data2 | text3 | bss1 |
+-------+-----------+------+---------+-----------+-------+-------+------+-
---------+-
rodata0 | ...
---------+-
The CTF section is dropped completely, because (a) when split it becomes
enormous for some reason (that I don't quite understand, verily), and (b)
the kernel expects only one CTF and can't handle several of them.
To generate a diff of this commit:
cvs rdiff -u -r1.62 -r1.63 src/sys/arch/amd64/conf/Makefile.amd64
cvs rdiff -u -r1.2 -r1.3 src/sys/arch/amd64/conf/kern.ldscript.kaslr
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/amd64/conf/Makefile.amd64
diff -u src/sys/arch/amd64/conf/Makefile.amd64:1.62 src/sys/arch/amd64/conf/Makefile.amd64:1.63
--- src/sys/arch/amd64/conf/Makefile.amd64:1.62 Tue Nov 14 09:56:26 2017
+++ src/sys/arch/amd64/conf/Makefile.amd64 Tue Nov 14 10:15:40 2017
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile.amd64,v 1.62 2017/11/14 09:56:26 maxv Exp $
+# $NetBSD: Makefile.amd64,v 1.63 2017/11/14 10:15:40 maxv Exp $
# Makefile for NetBSD
#
@@ -62,7 +62,7 @@ KERN_AS= library
##
TEXTADDR?= 0xffffffff80200000
.if defined(KASLR)
-EXTRA_LINKFLAGS= -r -d
+EXTRA_LINKFLAGS= --split-by-file=0x200000 -r -d
KERNLDSCRIPT?= ${AMD64}/conf/kern.ldscript.kaslr
.else
EXTRA_LINKFLAGS= -z max-page-size=0x200000
Index: src/sys/arch/amd64/conf/kern.ldscript.kaslr
diff -u src/sys/arch/amd64/conf/kern.ldscript.kaslr:1.2 src/sys/arch/amd64/conf/kern.ldscript.kaslr:1.3
--- src/sys/arch/amd64/conf/kern.ldscript.kaslr:1.2 Mon Nov 13 20:01:48 2017
+++ src/sys/arch/amd64/conf/kern.ldscript.kaslr Tue Nov 14 10:15:40 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: kern.ldscript.kaslr,v 1.2 2017/11/13 20:01:48 maxv Exp $ */
+/* $NetBSD: kern.ldscript.kaslr,v 1.3 2017/11/14 10:15:40 maxv Exp $ */
#include "assym.h"
@@ -57,4 +57,10 @@ SECTIONS
{
KEEP(*(.note.netbsd.ident));
}
+
+ /DISCARD/ :
+ {
+ *(.SUNW_ctf)
+ *(.SUNW_ctf.*)
+ }
}
