[PATCH] arm: ftrace: work with CONFIG_DEBUG_SET_MODULE_RONX

[PATCH] arm: ftrace: work with CONFIG_DEBUG_SET_MODULE_RONX

[Rabin Vincent]

Make ftrace work with CONFIG_DEBUG_SET_MODULE_RONX by making module text
writable around the place where ftrace does its work, like it is done on
x86 in the patch which introduced CONFIG_DEBUG_SET_MODULE_RONX,
84e1c6bb38eb ("x86: Add RO/NX protection for loadable kernel modules").

Signed-off-by: Rabin Vincent <rabin@rab.in>
---
 arch/arm/kernel/ftrace.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index 34e5664..70ce654 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -14,6 +14,7 @@
 
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
+#include <linux/module.h>
 
 #include <asm/cacheflush.h>
 #include <asm/opcodes.h>
@@ -63,6 +64,18 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
 }
 #endif
 
+int ftrace_arch_code_modify_prepare(void)
+{
+	set_all_modules_text_rw();
+	return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+	set_all_modules_text_ro();
+	return 0;
+}
+
 static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
 {
 	return arm_gen_branch_link(pc, addr);
-- 
1.9.1

Re: [PATCH] arm: ftrace: work with CONFIG_DEBUG_SET_MODULE_RONX

[Laura Abbott]

On 4/2/2014 3:10 PM, Rabin Vincent wrote:
> Make ftrace work with CONFIG_DEBUG_SET_MODULE_RONX by making module text
> writable around the place where ftrace does its work, like it is done on
> x86 in the patch which introduced CONFIG_DEBUG_SET_MODULE_RONX,
> 84e1c6bb38eb ("x86: Add RO/NX protection for loadable kernel modules").
> 
> Signed-off-by: Rabin Vincent <rabin@rab.in>
> ---
>  arch/arm/kernel/ftrace.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
> index 34e5664..70ce654 100644
> --- a/arch/arm/kernel/ftrace.c
> +++ b/arch/arm/kernel/ftrace.c
> @@ -14,6 +14,7 @@
>  
>  #include <linux/ftrace.h>
>  #include <linux/uaccess.h>
> +#include <linux/module.h>
>  
>  #include <asm/cacheflush.h>
>  #include <asm/opcodes.h>
> @@ -63,6 +64,18 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
>  }
>  #endif
>  
> +int ftrace_arch_code_modify_prepare(void)
> +{
> +	set_all_modules_text_rw();
> +	return 0;
> +}
> +
> +int ftrace_arch_code_modify_post_process(void)
> +{
> +	set_all_modules_text_ro();
> +	return 0;
> +}
> +
>  static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
>  {
>  	return arm_gen_branch_link(pc, addr);
> 

I think Mitch tested this on our internal targets. I'll let him reply with his Tested-by

Laura

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation

Re: [PATCH] arm: ftrace: work with CONFIG_DEBUG_SET_MODULE_RONX

[Mitchel Humpherys]

On Wed, Apr 02 2014 at 06:04:29 PM, Laura Abbott <lauraa@codeaurora.org> wrote:
> I think Mitch tested this on our internal targets. I'll let him reply with his Tested-by
>
> Laura

Indeed:

Tested-by: Mitchel Humpherys <mitchelh@codeaurora.org>

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Re: [PATCH] arm: ftrace: work with CONFIG_DEBUG_SET_MODULE_RONX

[Kees Cook]

On Wed, Apr 2, 2014 at 3:10 PM, Rabin Vincent <rabin@rab.in> wrote:
> Make ftrace work with CONFIG_DEBUG_SET_MODULE_RONX by making module text
> writable around the place where ftrace does its work, like it is done on
> x86 in the patch which introduced CONFIG_DEBUG_SET_MODULE_RONX,
> 84e1c6bb38eb ("x86: Add RO/NX protection for loadable kernel modules").
>
> Signed-off-by: Rabin Vincent <rabin@rab.in>

This works for me as well. Thanks!

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

-Kees

> ---
>  arch/arm/kernel/ftrace.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
> index 34e5664..70ce654 100644
> --- a/arch/arm/kernel/ftrace.c
> +++ b/arch/arm/kernel/ftrace.c
> @@ -14,6 +14,7 @@
>
>  #include <linux/ftrace.h>
>  #include <linux/uaccess.h>
> +#include <linux/module.h>
>
>  #include <asm/cacheflush.h>
>  #include <asm/opcodes.h>
> @@ -63,6 +64,18 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
>  }
>  #endif
>
> +int ftrace_arch_code_modify_prepare(void)
> +{
> +       set_all_modules_text_rw();
> +       return 0;
> +}
> +
> +int ftrace_arch_code_modify_post_process(void)
> +{
> +       set_all_modules_text_ro();
> +       return 0;
> +}
> +
>  static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
>  {
>         return arm_gen_branch_link(pc, addr);
> --
> 1.9.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel



-- 
Kees Cook
Chrome OS Security