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* [PATCH] lkdtm: Use init_uts_ns.name instead of macros
@ 2021-09-01 23:34 Kees Cook
  2021-09-09 15:49 ` Kees Cook
  0 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2021-09-01 23:34 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Arnd Bergmann, linux-kernel, linux-hardening

Using generated/compile.h triggered a full LKDTM rebuild with every
build. Avoid this by using the exported strings instead.

Fixes: b8661450bc7f ("lkdtm: Add kernel version to failure hints")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/misc/lkdtm/core.c  | 10 ++++++++++
 drivers/misc/lkdtm/lkdtm.h | 28 +++++++++++++++++-----------
 2 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index 95b1c6800a22..fe6fd34b8caf 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -26,6 +26,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/debugfs.h>
+#include <linux/utsname.h>
 
 #define DEFAULT_COUNT 10
 
@@ -210,6 +211,8 @@ module_param(cpoint_count, int, 0644);
 MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
 				"crash point is to be hit to trigger action");
 
+/* For test debug reporting. */
+char *lkdtm_kernel_info;
 
 /* Return the crashtype number or NULL if the name is invalid */
 static const struct crashtype *find_crashtype(const char *name)
@@ -490,6 +493,11 @@ static int __init lkdtm_module_init(void)
 	crash_count = cpoint_count;
 #endif
 
+	/* Common initialization. */
+	lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)",
+				      init_uts_ns.name.release,
+				      init_uts_ns.name.machine);
+
 	/* Handle test-specific initialization. */
 	lkdtm_bugs_init(&recur_count);
 	lkdtm_perms_init();
@@ -538,6 +546,8 @@ static void __exit lkdtm_module_exit(void)
 	if (lkdtm_kprobe != NULL)
 		unregister_kprobe(lkdtm_kprobe);
 
+	kfree(lkdtm_kernel_info);
+
 	pr_info("Crash point unregistered\n");
 }
 
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index d7d64d9765eb..c212a253edde 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -5,17 +5,17 @@
 #define pr_fmt(fmt) "lkdtm: " fmt
 
 #include <linux/kernel.h>
-#include <generated/compile.h>
-#include <generated/utsrelease.h>
 
-#define LKDTM_KERNEL "kernel (" UTS_RELEASE " " UTS_MACHINE ")"
+extern char *lkdtm_kernel_info;
 
 #define pr_expected_config(kconfig)				\
 {								\
 	if (IS_ENABLED(kconfig)) 				\
-		pr_err("Unexpected! This " LKDTM_KERNEL " was built with " #kconfig "=y\n"); \
+		pr_err("Unexpected! This %s was built with " #kconfig "=y\n", \
+			lkdtm_kernel_info);			\
 	else							\
-		pr_warn("This is probably expected, since this " LKDTM_KERNEL " was built *without* " #kconfig "=y\n"); \
+		pr_warn("This is probably expected, since this %s was built *without* " #kconfig "=y\n", \
+			lkdtm_kernel_info);			\
 }
 
 #ifndef MODULE
@@ -25,24 +25,30 @@ int lkdtm_check_bool_cmdline(const char *param);
 	if (IS_ENABLED(kconfig)) {				\
 		switch (lkdtm_check_bool_cmdline(param)) {	\
 		case 0:						\
-			pr_warn("This is probably expected, since this " LKDTM_KERNEL " was built with " #kconfig "=y but booted with '" param "=N'\n"); \
+			pr_warn("This is probably expected, since this %s was built with " #kconfig "=y but booted with '" param "=N'\n", \
+				lkdtm_kernel_info);		\
 			break;					\
 		case 1:						\
-			pr_err("Unexpected! This " LKDTM_KERNEL " was built with " #kconfig "=y and booted with '" param "=Y'\n"); \
+			pr_err("Unexpected! This %s was built with " #kconfig "=y and booted with '" param "=Y'\n", \
+				lkdtm_kernel_info);		\
 			break;					\
 		default:					\
-			pr_err("Unexpected! This " LKDTM_KERNEL " was built with " #kconfig "=y (and booted without '" param "' specified)\n"); \
+			pr_err("Unexpected! This %s was built with " #kconfig "=y (and booted without '" param "' specified)\n", \
+				lkdtm_kernel_info);		\
 		}						\
 	} else {						\
 		switch (lkdtm_check_bool_cmdline(param)) {	\
 		case 0:						\
-			pr_warn("This is probably expected, as this " LKDTM_KERNEL " was built *without* " #kconfig "=y and booted with '" param "=N'\n"); \
+			pr_warn("This is probably expected, as this %s was built *without* " #kconfig "=y and booted with '" param "=N'\n", \
+				lkdtm_kernel_info);		\
 			break;					\
 		case 1:						\
-			pr_err("Unexpected! This " LKDTM_KERNEL " was built *without* " #kconfig "=y but booted with '" param "=Y'\n"); \
+			pr_err("Unexpected! This %s was built *without* " #kconfig "=y but booted with '" param "=Y'\n", \
+				lkdtm_kernel_info);		\
 			break;					\
 		default:					\
-			pr_err("This is probably expected, since this " LKDTM_KERNEL " was built *without* " #kconfig "=y (and booted without '" param "' specified)\n"); \
+			pr_err("This is probably expected, since this %s was built *without* " #kconfig "=y (and booted without '" param "' specified)\n", \
+				lkdtm_kernel_info);		\
 			break;					\
 		}						\
 	}							\
-- 
2.30.2


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] lkdtm: Use init_uts_ns.name instead of macros
  2021-09-01 23:34 [PATCH] lkdtm: Use init_uts_ns.name instead of macros Kees Cook
@ 2021-09-09 15:49 ` Kees Cook
  2021-09-09 16:02   ` Greg Kroah-Hartman
  0 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2021-09-09 15:49 UTC (permalink / raw)
  To: Greg Kroah-Hartman; +Cc: Arnd Bergmann, linux-kernel, linux-hardening

On Wed, Sep 01, 2021 at 04:34:06PM -0700, Kees Cook wrote:
> Using generated/compile.h triggered a full LKDTM rebuild with every
> build. Avoid this by using the exported strings instead.
> 
> Fixes: b8661450bc7f ("lkdtm: Add kernel version to failure hints")
> Signed-off-by: Kees Cook <keescook@chromium.org>

Hi Greg,

Your bot said "please wait, the merge window is open", but it'd be really
nice to get this into -rc1 to avoid annoying people doing rebuilds...

:)

-Kees

> ---
>  drivers/misc/lkdtm/core.c  | 10 ++++++++++
>  drivers/misc/lkdtm/lkdtm.h | 28 +++++++++++++++++-----------
>  2 files changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
> index 95b1c6800a22..fe6fd34b8caf 100644
> --- a/drivers/misc/lkdtm/core.c
> +++ b/drivers/misc/lkdtm/core.c
> @@ -26,6 +26,7 @@
>  #include <linux/init.h>
>  #include <linux/slab.h>
>  #include <linux/debugfs.h>
> +#include <linux/utsname.h>
>  
>  #define DEFAULT_COUNT 10
>  
> @@ -210,6 +211,8 @@ module_param(cpoint_count, int, 0644);
>  MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\
>  				"crash point is to be hit to trigger action");
>  
> +/* For test debug reporting. */
> +char *lkdtm_kernel_info;
>  
>  /* Return the crashtype number or NULL if the name is invalid */
>  static const struct crashtype *find_crashtype(const char *name)
> @@ -490,6 +493,11 @@ static int __init lkdtm_module_init(void)
>  	crash_count = cpoint_count;
>  #endif
>  
> +	/* Common initialization. */
> +	lkdtm_kernel_info = kasprintf(GFP_KERNEL, "kernel (%s %s)",
> +				      init_uts_ns.name.release,
> +				      init_uts_ns.name.machine);
> +
>  	/* Handle test-specific initialization. */
>  	lkdtm_bugs_init(&recur_count);
>  	lkdtm_perms_init();
> @@ -538,6 +546,8 @@ static void __exit lkdtm_module_exit(void)
>  	if (lkdtm_kprobe != NULL)
>  		unregister_kprobe(lkdtm_kprobe);
>  
> +	kfree(lkdtm_kernel_info);
> +
>  	pr_info("Crash point unregistered\n");
>  }
>  
> diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
> index d7d64d9765eb..c212a253edde 100644
> --- a/drivers/misc/lkdtm/lkdtm.h
> +++ b/drivers/misc/lkdtm/lkdtm.h
> @@ -5,17 +5,17 @@
>  #define pr_fmt(fmt) "lkdtm: " fmt
>  
>  #include <linux/kernel.h>
> -#include <generated/compile.h>
> -#include <generated/utsrelease.h>
>  
> -#define LKDTM_KERNEL "kernel (" UTS_RELEASE " " UTS_MACHINE ")"
> +extern char *lkdtm_kernel_info;
>  
>  #define pr_expected_config(kconfig)				\
>  {								\
>  	if (IS_ENABLED(kconfig)) 				\
> -		pr_err("Unexpected! This " LKDTM_KERNEL " was built with " #kconfig "=y\n"); \
> +		pr_err("Unexpected! This %s was built with " #kconfig "=y\n", \
> +			lkdtm_kernel_info);			\
>  	else							\
> -		pr_warn("This is probably expected, since this " LKDTM_KERNEL " was built *without* " #kconfig "=y\n"); \
> +		pr_warn("This is probably expected, since this %s was built *without* " #kconfig "=y\n", \
> +			lkdtm_kernel_info);			\
>  }
>  
>  #ifndef MODULE
> @@ -25,24 +25,30 @@ int lkdtm_check_bool_cmdline(const char *param);
>  	if (IS_ENABLED(kconfig)) {				\
>  		switch (lkdtm_check_bool_cmdline(param)) {	\
>  		case 0:						\
> -			pr_warn("This is probably expected, since this " LKDTM_KERNEL " was built with " #kconfig "=y but booted with '" param "=N'\n"); \
> +			pr_warn("This is probably expected, since this %s was built with " #kconfig "=y but booted with '" param "=N'\n", \
> +				lkdtm_kernel_info);		\
>  			break;					\
>  		case 1:						\
> -			pr_err("Unexpected! This " LKDTM_KERNEL " was built with " #kconfig "=y and booted with '" param "=Y'\n"); \
> +			pr_err("Unexpected! This %s was built with " #kconfig "=y and booted with '" param "=Y'\n", \
> +				lkdtm_kernel_info);		\
>  			break;					\
>  		default:					\
> -			pr_err("Unexpected! This " LKDTM_KERNEL " was built with " #kconfig "=y (and booted without '" param "' specified)\n"); \
> +			pr_err("Unexpected! This %s was built with " #kconfig "=y (and booted without '" param "' specified)\n", \
> +				lkdtm_kernel_info);		\
>  		}						\
>  	} else {						\
>  		switch (lkdtm_check_bool_cmdline(param)) {	\
>  		case 0:						\
> -			pr_warn("This is probably expected, as this " LKDTM_KERNEL " was built *without* " #kconfig "=y and booted with '" param "=N'\n"); \
> +			pr_warn("This is probably expected, as this %s was built *without* " #kconfig "=y and booted with '" param "=N'\n", \
> +				lkdtm_kernel_info);		\
>  			break;					\
>  		case 1:						\
> -			pr_err("Unexpected! This " LKDTM_KERNEL " was built *without* " #kconfig "=y but booted with '" param "=Y'\n"); \
> +			pr_err("Unexpected! This %s was built *without* " #kconfig "=y but booted with '" param "=Y'\n", \
> +				lkdtm_kernel_info);		\
>  			break;					\
>  		default:					\
> -			pr_err("This is probably expected, since this " LKDTM_KERNEL " was built *without* " #kconfig "=y (and booted without '" param "' specified)\n"); \
> +			pr_err("This is probably expected, since this %s was built *without* " #kconfig "=y (and booted without '" param "' specified)\n", \
> +				lkdtm_kernel_info);		\
>  			break;					\
>  		}						\
>  	}							\
> -- 
> 2.30.2
> 

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] lkdtm: Use init_uts_ns.name instead of macros
  2021-09-09 15:49 ` Kees Cook
@ 2021-09-09 16:02   ` Greg Kroah-Hartman
  2021-09-09 16:08     ` Mark Brown
  0 siblings, 1 reply; 6+ messages in thread
From: Greg Kroah-Hartman @ 2021-09-09 16:02 UTC (permalink / raw)
  To: Kees Cook; +Cc: Arnd Bergmann, linux-kernel, linux-hardening

On Thu, Sep 09, 2021 at 08:49:57AM -0700, Kees Cook wrote:
> On Wed, Sep 01, 2021 at 04:34:06PM -0700, Kees Cook wrote:
> > Using generated/compile.h triggered a full LKDTM rebuild with every
> > build. Avoid this by using the exported strings instead.
> > 
> > Fixes: b8661450bc7f ("lkdtm: Add kernel version to failure hints")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> 
> Hi Greg,
> 
> Your bot said "please wait, the merge window is open", but it'd be really
> nice to get this into -rc1 to avoid annoying people doing rebuilds...
> 
> :)

I'm not supposed to be adding new patches to my tree during this period
of time in the merge window.

I can't see a rebuild locally here without this patch attached, so how
much of a problem is it right now?

And isn't -rc2 ok?

thanks,

greg k-h

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] lkdtm: Use init_uts_ns.name instead of macros
  2021-09-09 16:02   ` Greg Kroah-Hartman
@ 2021-09-09 16:08     ` Mark Brown
  2021-09-09 17:26       ` Kees Cook
  0 siblings, 1 reply; 6+ messages in thread
From: Mark Brown @ 2021-09-09 16:08 UTC (permalink / raw)
  To: Greg Kroah-Hartman
  Cc: Kees Cook, Arnd Bergmann, linux-kernel, linux-hardening

[-- Attachment #1: Type: text/plain, Size: 359 bytes --]

On Thu, Sep 09, 2021 at 06:02:09PM +0200, Greg Kroah-Hartman wrote:

> I can't see a rebuild locally here without this patch attached, so how
> much of a problem is it right now?

It's triggering for me all the time here FWIW.

> And isn't -rc2 ok?

Lots of trees base off -rc1 so unless people change their workflow to
merge up -rc2 it'll impact submitters.

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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] lkdtm: Use init_uts_ns.name instead of macros
  2021-09-09 16:08     ` Mark Brown
@ 2021-09-09 17:26       ` Kees Cook
  2021-09-10 15:10         ` Greg Kroah-Hartman
  0 siblings, 1 reply; 6+ messages in thread
From: Kees Cook @ 2021-09-09 17:26 UTC (permalink / raw)
  To: Mark Brown
  Cc: Greg Kroah-Hartman, Arnd Bergmann, linux-kernel, linux-hardening

On Thu, Sep 09, 2021 at 05:08:59PM +0100, Mark Brown wrote:
> On Thu, Sep 09, 2021 at 06:02:09PM +0200, Greg Kroah-Hartman wrote:
> 
> > I can't see a rebuild locally here without this patch attached, so how
> > much of a problem is it right now?
> 
> It's triggering for me all the time here FWIW.

Right, if you have CONFIG_LKDTM!=n it'll show up (e.g. with an
all*config build).

> > And isn't -rc2 ok?
> 
> Lots of trees base off -rc1 so unless people change their workflow to
> merge up -rc2 it'll impact submitters.

Right, that's why I was suggesting it.

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH] lkdtm: Use init_uts_ns.name instead of macros
  2021-09-09 17:26       ` Kees Cook
@ 2021-09-10 15:10         ` Greg Kroah-Hartman
  0 siblings, 0 replies; 6+ messages in thread
From: Greg Kroah-Hartman @ 2021-09-10 15:10 UTC (permalink / raw)
  To: Kees Cook; +Cc: Mark Brown, Arnd Bergmann, linux-kernel, linux-hardening

On Thu, Sep 09, 2021 at 10:26:18AM -0700, Kees Cook wrote:
> On Thu, Sep 09, 2021 at 05:08:59PM +0100, Mark Brown wrote:
> > On Thu, Sep 09, 2021 at 06:02:09PM +0200, Greg Kroah-Hartman wrote:
> > 
> > > I can't see a rebuild locally here without this patch attached, so how
> > > much of a problem is it right now?
> > 
> > It's triggering for me all the time here FWIW.
> 
> Right, if you have CONFIG_LKDTM!=n it'll show up (e.g. with an
> all*config build).
> 
> > > And isn't -rc2 ok?
> > 
> > Lots of trees base off -rc1 so unless people change their workflow to
> > merge up -rc2 it'll impact submitters.
> 
> Right, that's why I was suggesting it.

Ok, let me run it through 0-day right now and see if anything blows
up...

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-09-10 15:10 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-01 23:34 [PATCH] lkdtm: Use init_uts_ns.name instead of macros Kees Cook
2021-09-09 15:49 ` Kees Cook
2021-09-09 16:02   ` Greg Kroah-Hartman
2021-09-09 16:08     ` Mark Brown
2021-09-09 17:26       ` Kees Cook
2021-09-10 15:10         ` Greg Kroah-Hartman

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