[v2,7/8] x86/vsyscall: Add __ro_after_init to global variables
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Message ID a386925835e49d319e70c4d7404b1f6c3c2e3702.1561610354.git.luto@kernel.org
State New
Headers show
Series
  • [v2,1/8] x86/vsyscall: Remove the vsyscall=native documentation
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Commit Message

Andy Lutomirski June 27, 2019, 4:45 a.m. UTC
The vDSO is only configurable by command-line options, so make its
global variables __ro_after_init.  This seems highly unlikely to
ever stop an exploit, but I think it's nice anyway.

Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Kees Cook June 27, 2019, 5:30 p.m. UTC | #1
On Wed, Jun 26, 2019 at 09:45:08PM -0700, Andy Lutomirski wrote:
> The vDSO is only configurable by command-line options, so make its
> global variables __ro_after_init.  This seems highly unlikely to
> ever stop an exploit, but I think it's nice anyway.
> 
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
> index 9c58ab807aeb..07003f3f1bfc 100644
> --- a/arch/x86/entry/vsyscall/vsyscall_64.c
> +++ b/arch/x86/entry/vsyscall/vsyscall_64.c
> @@ -42,7 +42,7 @@
>  #define CREATE_TRACE_POINTS
>  #include "vsyscall_trace.h"
>  
> -static enum { EMULATE, XONLY, NONE } vsyscall_mode =
> +static enum { EMULATE, XONLY, NONE } vsyscall_mode __ro_after_init =
>  #ifdef CONFIG_LEGACY_VSYSCALL_NONE
>  	NONE;
>  #elif defined(CONFIG_LEGACY_VSYSCALL_XONLY)
> @@ -305,7 +305,7 @@ static const char *gate_vma_name(struct vm_area_struct *vma)
>  static const struct vm_operations_struct gate_vma_ops = {
>  	.name = gate_vma_name,
>  };
> -static struct vm_area_struct gate_vma = {
> +static struct vm_area_struct gate_vma __ro_after_init = {
>  	.vm_start	= VSYSCALL_ADDR,
>  	.vm_end		= VSYSCALL_ADDR + PAGE_SIZE,
>  	.vm_page_prot	= PAGE_READONLY_EXEC,
> -- 
> 2.21.0
>

Patch
diff mbox series

diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 9c58ab807aeb..07003f3f1bfc 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -42,7 +42,7 @@ 
 #define CREATE_TRACE_POINTS
 #include "vsyscall_trace.h"
 
-static enum { EMULATE, XONLY, NONE } vsyscall_mode =
+static enum { EMULATE, XONLY, NONE } vsyscall_mode __ro_after_init =
 #ifdef CONFIG_LEGACY_VSYSCALL_NONE
 	NONE;
 #elif defined(CONFIG_LEGACY_VSYSCALL_XONLY)
@@ -305,7 +305,7 @@  static const char *gate_vma_name(struct vm_area_struct *vma)
 static const struct vm_operations_struct gate_vma_ops = {
 	.name = gate_vma_name,
 };
-static struct vm_area_struct gate_vma = {
+static struct vm_area_struct gate_vma __ro_after_init = {
 	.vm_start	= VSYSCALL_ADDR,
 	.vm_end		= VSYSCALL_ADDR + PAGE_SIZE,
 	.vm_page_prot	= PAGE_READONLY_EXEC,