Re: [PATCH V40 10/29] hibernate: Disable when the kernel is locked down

[Pavel Machek]

On Mon 2019-08-19 17:17:46, Matthew Garrett wrote:
> From: Josh Boyer 
> 
> There is currently no way to verify the resume image when returning
> from hibernate.  This might compromise the signed modules trust model,
> so until we can work with signed hibernate images we disable it when the
> kernel is locked down.
> 
> Signed-off-by: Josh Boyer 
> Signed-off-by: David Howells 
> Signed-off-by: Matthew Garrett 
> Reviewed-by: Kees Cook 
> Cc: r...@rjwysocki.net
> Cc: pa...@ucw.cz
> cc: linux...@vger.kernel.org
> Signed-off-by: James Morris 

Acked-by: Pavel Machek 

Pavel

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Re: [PATCH V40 10/29] hibernate: Disable when the kernel is locked down

[Rafael J. Wysocki]

On Tuesday, August 20, 2019 2:17:46 AM CEST Matthew Garrett wrote:
> From: Josh Boyer 
> 
> There is currently no way to verify the resume image when returning
> from hibernate.  This might compromise the signed modules trust model,
> so until we can work with signed hibernate images we disable it when the
> kernel is locked down.
> 
> Signed-off-by: Josh Boyer 
> Signed-off-by: David Howells 
> Signed-off-by: Matthew Garrett 
> Reviewed-by: Kees Cook 
> Cc: r...@rjwysocki.net
> Cc: pa...@ucw.cz
> cc: linux...@vger.kernel.org
> Signed-off-by: James Morris 

Acked-by: Rafael J. Wysocki 

> ---
>  include/linux/security.h | 1 +
>  kernel/power/hibernate.c | 3 ++-
>  security/lockdown/lockdown.c | 1 +
>  3 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/security.h b/include/linux/security.h
> index b607a8ac97fe..80ac7fb27aa9 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -106,6 +106,7 @@ enum lockdown_reason {
>   LOCKDOWN_MODULE_SIGNATURE,
>   LOCKDOWN_DEV_MEM,
>   LOCKDOWN_KEXEC,
> + LOCKDOWN_HIBERNATION,
>   LOCKDOWN_INTEGRITY_MAX,
>   LOCKDOWN_CONFIDENTIALITY_MAX,
>  };
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index cd7434e6000d..3c0a5a8170b0 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -30,6 +30,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  #include 
>  
>  #include "power.h"
> @@ -68,7 +69,7 @@ static const struct platform_hibernation_ops 
> *hibernation_ops;
>  
>  bool hibernation_available(void)
>  {
> - return (nohibernate == 0);
> + return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
>  }
>  
>  /**
> diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
> index aaf30ad351f9..3462f7edcaac 100644
> --- a/security/lockdown/lockdown.c
> +++ b/security/lockdown/lockdown.c
> @@ -21,6 +21,7 @@ static char 
> *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
>   [LOCKDOWN_MODULE_SIGNATURE] = "unsigned module loading",
>   [LOCKDOWN_DEV_MEM] = "/dev/mem,kmem,port",
>   [LOCKDOWN_KEXEC] = "kexec of unsigned images",
> + [LOCKDOWN_HIBERNATION] = "hibernation",
>   [LOCKDOWN_INTEGRITY_MAX] = "integrity",
>   [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
>  };
> 

[PATCH V40 10/29] hibernate: Disable when the kernel is locked down

[Matthew Garrett]

From: Josh Boyer 

There is currently no way to verify the resume image when returning
from hibernate.  This might compromise the signed modules trust model,
so until we can work with signed hibernate images we disable it when the
kernel is locked down.

Signed-off-by: Josh Boyer 
Signed-off-by: David Howells 
Signed-off-by: Matthew Garrett 
Reviewed-by: Kees Cook 
Cc: r...@rjwysocki.net
Cc: pa...@ucw.cz
cc: linux...@vger.kernel.org
Signed-off-by: James Morris 
---
 include/linux/security.h | 1 +
 kernel/power/hibernate.c | 3 ++-
 security/lockdown/lockdown.c | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index b607a8ac97fe..80ac7fb27aa9 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -106,6 +106,7 @@ enum lockdown_reason {
LOCKDOWN_MODULE_SIGNATURE,
LOCKDOWN_DEV_MEM,
LOCKDOWN_KEXEC,
+   LOCKDOWN_HIBERNATION,
LOCKDOWN_INTEGRITY_MAX,
LOCKDOWN_CONFIDENTIALITY_MAX,
 };
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index cd7434e6000d..3c0a5a8170b0 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -30,6 +30,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 
 #include "power.h"
@@ -68,7 +69,7 @@ static const struct platform_hibernation_ops *hibernation_ops;
 
 bool hibernation_available(void)
 {
-   return (nohibernate == 0);
+   return nohibernate == 0 && !security_locked_down(LOCKDOWN_HIBERNATION);
 }
 
 /**
diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c
index aaf30ad351f9..3462f7edcaac 100644
--- a/security/lockdown/lockdown.c
+++ b/security/lockdown/lockdown.c
@@ -21,6 +21,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] 
= {
[LOCKDOWN_MODULE_SIGNATURE] = "unsigned module loading",
[LOCKDOWN_DEV_MEM] = "/dev/mem,kmem,port",
[LOCKDOWN_KEXEC] = "kexec of unsigned images",
+   [LOCKDOWN_HIBERNATION] = "hibernation",
[LOCKDOWN_INTEGRITY_MAX] = "integrity",
[LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality",
 };
-- 
2.23.0.rc1.153.gdeed80330f-goog