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Map the rodata segment independently on amd64, and remove the W permission 

on it.
This commit is contained in:
maxv 2016-05-12 07:21:18 +00:00
parent a23ebbfe56
commit a819d82371
2 changed files with 20 additions and 15 deletions
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31
sys/arch/amd64/amd64/locore.S
View File

@ -1,4 +1,4 @@
/* $NetBSD: locore.S,v 1.87 2016/05/12 06:45:16 maxv Exp $ */ /* $NetBSD: locore.S,v 1.88 2016/05/12 07:21:18 maxv Exp $ */
/* /*
* Copyright-o-rama! * Copyright-o-rama!
@ -564,6 +564,8 @@ no_NOX:
* *
* (PROC0 STK + L4 + L3 + L2 + L1) is later referred to as BOOTSTRAP TABLES. * (PROC0 STK + L4 + L3 + L2 + L1) is later referred to as BOOTSTRAP TABLES.
* *
* Important note: the kernel segments are properly 4k-aligned
* (see kern.ldscript), so there's no need to enforce alignment.
*/ */
/* Find end of kernel image; brings us on (1). */ /* Find end of kernel image; brings us on (1). */
@ -616,16 +618,16 @@ no_NOX:
shrl $(PGSHIFT-3),%ecx /* ((n >> PGSHIFT) << 3) for # PDEs */ shrl $(PGSHIFT-3),%ecx /* ((n >> PGSHIFT) << 3) for # PDEs */
addl %ecx,%ebx addl %ecx,%ebx
/* /* Map the kernel text RX. */
* Compute &__rodata_start - KERNBASE. This can't be > 4G, or we can't movl $RELOC(__rodata_start),%ecx
* deal with it anyway, since we can't load it in 32 bit mode. So use subl %eax,%ecx
* the bottom 32 bits. shrl $PGSHIFT,%ecx
*/ orl $(PG_V|PG_KR),%eax
movl $RELOC(__rodata_start),%edx fillkpt
andl $~PGOFSET,%edx
/* Map the kernel text read-only. */ /* Map the kernel rodata ROX. */
movl %edx,%ecx movl $RELOC(__rodata_start),%eax
movl $RELOC(__data_start),%ecx
subl %eax,%ecx subl %eax,%ecx
shrl $PGSHIFT,%ecx shrl $PGSHIFT,%ecx
orl $(PG_V|PG_KR),%eax orl $(PG_V|PG_KR),%eax
@ -639,11 +641,12 @@ no_NOX:
* +--------+----------+-------------------+------------------+ * +--------+----------+-------------------+------------------+
* We just map everything from < to > with RWX rights. * We just map everything from < to > with RWX rights.
*/ */
leal (PG_V|PG_KW)(%edx),%eax movl $RELOC(__data_start),%eax
movl $TABLESIZE,%ecx movl %esi,%ecx /* start of BOOTSTRAP TABLES */
addl %esi,%ecx /* end of tables */ addl $TABLESIZE,%ecx /* end of BOOTSTRAP TABLES */
subl %edx,%ecx /* subtract end of text */ subl %eax,%ecx /* subtract start of DATA */
shrl $PGSHIFT,%ecx shrl $PGSHIFT,%ecx
orl $(PG_V|PG_KW),%eax
fillkpt fillkpt
/* We are on (4). Map ISA I/O mem (later atdevbase) RWX. */ /* We are on (4). Map ISA I/O mem (later atdevbase) RWX. */

4
sys/arch/amd64/conf/kern.ldscript
View File

@ -1,4 +1,4 @@
/* $NetBSD: kern.ldscript,v 1.19 2016/05/12 06:45:16 maxv Exp $ */ /* $NetBSD: kern.ldscript,v 1.20 2016/05/12 07:21:18 maxv Exp $ */
#include "assym.h" #include "assym.h"
@ -36,6 +36,8 @@ SECTIONS
*(.rodata.*) *(.rodata.*)
} }
. = ALIGN(__PAGE_SIZE);
__data_start = . ; __data_start = . ;
.data : .data :
{ {