[PATCH] ima: add a new CONFIG for loading arch-specific policies

[PATCH] ima: add a new CONFIG for loading arch-specific policies

[Nayna Jain]

Every time a new architecture defines the IMA architecture specific
functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
include file needs to be updated. To avoid this "noise", this patch
defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
the different architectures to select it.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Philipp Rudo <prudo@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/Kconfig           | 2 +-
 arch/s390/Kconfig              | 1 +
 arch/x86/Kconfig               | 1 +
 include/linux/ima.h            | 3 +--
 security/integrity/ima/Kconfig | 9 +++++++++
 5 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 497b7d0b2d7e..b8ce1b995633 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -246,6 +246,7 @@ config PPC
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
 	select VIRT_TO_BUS			if !PPC64
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT	if PPC_SECURE_BOOT
 	#
 	# Please keep this list sorted alphabetically.
 	#
@@ -978,7 +979,6 @@ config PPC_SECURE_BOOT
 	prompt "Enable secure boot support"
 	bool
 	depends on PPC_POWERNV
-	depends on IMA_ARCH_POLICY
 	help
 	  Systems with firmware secure boot enabled need to define security
 	  policies to extend secure boot to the OS. This config allows a user
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 8abe77536d9d..90ff3633ade6 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -195,6 +195,7 @@ config S390
 	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
 	select SWIOTLB
 	select GENERIC_ALLOCATOR
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT
 
 
 config SCHED_OMIT_FRAME_POINTER
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index beea77046f9b..cafa66313fe2 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -230,6 +230,7 @@ config X86
 	select VIRT_TO_BUS
 	select X86_FEATURE_NAMES		if PROC_FS
 	select PROC_PID_ARCH_STATUS		if PROC_FS
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT	if EFI
 
 config INSTRUCTION_DECODER
 	def_bool y
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 1659217e9b60..aefe758f4466 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -30,8 +30,7 @@ extern void ima_kexec_cmdline(const void *buf, int size);
 extern void ima_add_kexec_buffer(struct kimage *image);
 #endif
 
-#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) \
-	|| defined(CONFIG_PPC_SECURE_BOOT)
+#ifdef CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT
 extern bool arch_ima_get_secureboot(void);
 extern const char * const *arch_get_ima_policy(void);
 #else
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 3f3ee4e2eb0d..d17972aa413a 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -327,3 +327,12 @@ config IMA_QUEUE_EARLY_BOOT_KEYS
 	depends on IMA_MEASURE_ASYMMETRIC_KEYS
 	depends on SYSTEM_TRUSTED_KEYRING
 	default y
+
+config IMA_SECURE_AND_OR_TRUSTED_BOOT
+	bool
+	depends on IMA
+	depends on IMA_ARCH_POLICY
+	default n
+	help
+	   This option is selected by architectures to enable secure and/or
+	   trusted boot based on IMA runtime policies.
-- 
2.18.1

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Lakshmi Ramasubramanian]

Hi Nayna,

> +
> +config IMA_SECURE_AND_OR_TRUSTED_BOOT
> +	bool
> +	depends on IMA
> +	depends on IMA_ARCH_POLICY
> +	default n
> +	help
> +	   This option is selected by architectures to enable secure and/or
> +	   trusted boot based on IMA runtime policies.
> 

Why is the default for this new config "n"?
Is there any reason to not turn on this config if both IMA and 
IMA_ARCH_POLICY are set to y?

thanks,
  -lakshmi

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Mimi Zohar]

On Wed, 2020-02-26 at 11:21 -0800, Lakshmi Ramasubramanian wrote:
> Hi Nayna,
> 
> > +
> > +config IMA_SECURE_AND_OR_TRUSTED_BOOT
> > +	bool
> > +	depends on IMA
> > +	depends on IMA_ARCH_POLICY
> > +	default n
> > +	help
> > +	   This option is selected by architectures to enable secure and/or
> > +	   trusted boot based on IMA runtime policies.
> > 
> 
> Why is the default for this new config "n"?
> Is there any reason to not turn on this config if both IMA and 
> IMA_ARCH_POLICY are set to y?

Good catch.  Having "IMA_SECURE_AND_OR_TRUSTED_BOOT" depend on
"IMA_ARCH_POLICY" doesn't make sense.  "IMA_ARCH_POLICY" needs to be
selected.

thanks,

Mimi

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Mimi Zohar]

On Wed, 2020-02-26 at 15:36 -0500, Mimi Zohar wrote:
> On Wed, 2020-02-26 at 11:21 -0800, Lakshmi Ramasubramanian wrote:
> > Hi Nayna,
> > 
> > > +
> > > +config IMA_SECURE_AND_OR_TRUSTED_BOOT
> > > +	bool
> > > +	depends on IMA
> > > +	depends on IMA_ARCH_POLICY
> > > +	default n
> > > +	help
> > > +	   This option is selected by architectures to enable secure and/or
> > > +	   trusted boot based on IMA runtime policies.
> > > 
> > 
> > Why is the default for this new config "n"?
> > Is there any reason to not turn on this config if both IMA and 
> > IMA_ARCH_POLICY are set to y?
> 
> Good catch.  Having "IMA_SECURE_AND_OR_TRUSTED_BOOT" depend on
> "IMA_ARCH_POLICY" doesn't make sense.  "IMA_ARCH_POLICY" needs to be
> selected.

After discussing this some more with Nayna, the new Kconfig indicates
that the architecture defines the arch_ima_get_secureboot() and
arch_get_ima_policy() functions, but doesn't automatically enable
IMA_ARCH_POLICY.  The decision to enable IMA_ARCH_POLICY is left up to
whoever is building the kernel.  The patch, at least this aspect of
it, is correct.

Mimi

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Mimi Zohar]

On Wed, 2020-02-26 at 14:10 -0500, Nayna Jain wrote:
> Every time a new architecture defines the IMA architecture specific
> functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
> include file needs to be updated. To avoid this "noise", this patch
> defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
> the different architectures to select it.
> 
> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Cc: Ard Biesheuvel <ardb@kernel.org>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Philipp Rudo <prudo@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  arch/powerpc/Kconfig           | 2 +-
>  arch/s390/Kconfig              | 1 +
>  arch/x86/Kconfig               | 1 +
>  include/linux/ima.h            | 3 +--
>  security/integrity/ima/Kconfig | 9 +++++++++
>  5 files changed, 13 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 497b7d0b2d7e..b8ce1b995633 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -246,6 +246,7 @@ config PPC
>  	select SYSCTL_EXCEPTION_TRACE
>  	select THREAD_INFO_IN_TASK
>  	select VIRT_TO_BUS			if !PPC64
> +	select IMA_SECURE_AND_OR_TRUSTED_BOOT	if PPC_SECURE_BOOT
>  	#
>  	# Please keep this list sorted alphabetically.
>  	#
> @@ -978,7 +979,6 @@ config PPC_SECURE_BOOT
>  	prompt "Enable secure boot support"
>  	bool
>  	depends on PPC_POWERNV
> -	depends on IMA_ARCH_POLICY
>  	help
>  	  Systems with firmware secure boot enabled need to define security
>  	  policies to extend secure boot to the OS. This config allows a user
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index 8abe77536d9d..90ff3633ade6 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -195,6 +195,7 @@ config S390
>  	select ARCH_HAS_FORCE_DMA_UNENCRYPTED
>  	select SWIOTLB
>  	select GENERIC_ALLOCATOR
> +	select IMA_SECURE_AND_OR_TRUSTED_BOOT
>  
>  
>  config SCHED_OMIT_FRAME_POINTER
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index beea77046f9b..cafa66313fe2 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -230,6 +230,7 @@ config X86
>  	select VIRT_TO_BUS
>  	select X86_FEATURE_NAMES		if PROC_FS
>  	select PROC_PID_ARCH_STATUS		if PROC_FS
> +	select IMA_SECURE_AND_OR_TRUSTED_BOOT	if EFI

Not everyone is interested in enabling IMA or requiring IMA runtime
policies.  With this patch, enabling IMA_ARCH_POLICY is therefore
still left up to the person building the kernel.  As a result, I'm
seeing the following warning, which is kind of cool.

WARNING: unmet direct dependencies detected for
IMA_SECURE_AND_OR_TRUSTED_BOOT
  Depends on [n]: INTEGRITY [=y] && IMA [=y] && IMA_ARCH_POLICY [=n]
  Selected by [y]:
  - X86 [=y] && EFI [=y]

Ard, Michael, Martin, just making sure this type of warning is
acceptable before upstreaming this patch.  I would appreciate your
tags.

thanks!

Mimi

>  
>  config INSTRUCTION_DECODER
>  	def_bool y
> diff --git a/include/linux/ima.h b/include/linux/ima.h
> index 1659217e9b60..aefe758f4466 100644
> --- a/include/linux/ima.h
> +++ b/include/linux/ima.h
> @@ -30,8 +30,7 @@ extern void ima_kexec_cmdline(const void *buf, int size);
>  extern void ima_add_kexec_buffer(struct kimage *image);
>  #endif
>  
> -#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) \
> -	|| defined(CONFIG_PPC_SECURE_BOOT)
> +#ifdef CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT
>  extern bool arch_ima_get_secureboot(void);
>  extern const char * const *arch_get_ima_policy(void);
>  #else
> diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> index 3f3ee4e2eb0d..d17972aa413a 100644
> --- a/security/integrity/ima/Kconfig
> +++ b/security/integrity/ima/Kconfig
> @@ -327,3 +327,12 @@ config IMA_QUEUE_EARLY_BOOT_KEYS
>  	depends on IMA_MEASURE_ASYMMETRIC_KEYS
>  	depends on SYSTEM_TRUSTED_KEYRING
>  	default y
> +
> +config IMA_SECURE_AND_OR_TRUSTED_BOOT
> +	bool
> +	depends on IMA
> +	depends on IMA_ARCH_POLICY
> +	default n
> +	help
> +	   This option is selected by architectures to enable secure and/or
> +	   trusted boot based on IMA runtime policies.

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Ard Biesheuvel]

On Mon, 2 Mar 2020 at 15:48, Mimi Zohar <zohar@linux.ibm.com> wrote:
>
> On Wed, 2020-02-26 at 14:10 -0500, Nayna Jain wrote:
> > Every time a new architecture defines the IMA architecture specific
> > functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
> > include file needs to be updated. To avoid this "noise", this patch
> > defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
> > the different architectures to select it.
> >
> > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> > Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> > Cc: Ard Biesheuvel <ardb@kernel.org>
> > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> > Cc: Philipp Rudo <prudo@linux.ibm.com>
> > Cc: Michael Ellerman <mpe@ellerman.id.au>
> > ---
> >  arch/powerpc/Kconfig           | 2 +-
> >  arch/s390/Kconfig              | 1 +
> >  arch/x86/Kconfig               | 1 +
> >  include/linux/ima.h            | 3 +--
> >  security/integrity/ima/Kconfig | 9 +++++++++
> >  5 files changed, 13 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index 497b7d0b2d7e..b8ce1b995633 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -246,6 +246,7 @@ config PPC
> >       select SYSCTL_EXCEPTION_TRACE
> >       select THREAD_INFO_IN_TASK
> >       select VIRT_TO_BUS                      if !PPC64
> > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if PPC_SECURE_BOOT
> >       #
> >       # Please keep this list sorted alphabetically.
> >       #
> > @@ -978,7 +979,6 @@ config PPC_SECURE_BOOT
> >       prompt "Enable secure boot support"
> >       bool
> >       depends on PPC_POWERNV
> > -     depends on IMA_ARCH_POLICY
> >       help
> >         Systems with firmware secure boot enabled need to define security
> >         policies to extend secure boot to the OS. This config allows a user
> > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> > index 8abe77536d9d..90ff3633ade6 100644
> > --- a/arch/s390/Kconfig
> > +++ b/arch/s390/Kconfig
> > @@ -195,6 +195,7 @@ config S390
> >       select ARCH_HAS_FORCE_DMA_UNENCRYPTED
> >       select SWIOTLB
> >       select GENERIC_ALLOCATOR
> > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT
> >
> >
> >  config SCHED_OMIT_FRAME_POINTER
> > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > index beea77046f9b..cafa66313fe2 100644
> > --- a/arch/x86/Kconfig
> > +++ b/arch/x86/Kconfig
> > @@ -230,6 +230,7 @@ config X86
> >       select VIRT_TO_BUS
> >       select X86_FEATURE_NAMES                if PROC_FS
> >       select PROC_PID_ARCH_STATUS             if PROC_FS
> > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI
>
> Not everyone is interested in enabling IMA or requiring IMA runtime
> policies.  With this patch, enabling IMA_ARCH_POLICY is therefore
> still left up to the person building the kernel.  As a result, I'm
> seeing the following warning, which is kind of cool.
>
> WARNING: unmet direct dependencies detected for
> IMA_SECURE_AND_OR_TRUSTED_BOOT
>   Depends on [n]: INTEGRITY [=y] && IMA [=y] && IMA_ARCH_POLICY [=n]
>   Selected by [y]:
>   - X86 [=y] && EFI [=y]
>
> Ard, Michael, Martin, just making sure this type of warning is
> acceptable before upstreaming this patch.  I would appreciate your
> tags.
>

Ehm, no, warnings like these are not really acceptable. It means there
is an inconsistency in the way the Kconfig dependencies are defined.

Does this help:

  select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI && IMA_ARCH_POLICY

?


>
> >
> >  config INSTRUCTION_DECODER
> >       def_bool y
> > diff --git a/include/linux/ima.h b/include/linux/ima.h
> > index 1659217e9b60..aefe758f4466 100644
> > --- a/include/linux/ima.h
> > +++ b/include/linux/ima.h
> > @@ -30,8 +30,7 @@ extern void ima_kexec_cmdline(const void *buf, int size);
> >  extern void ima_add_kexec_buffer(struct kimage *image);
> >  #endif
> >
> > -#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) \
> > -     || defined(CONFIG_PPC_SECURE_BOOT)
> > +#ifdef CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT
> >  extern bool arch_ima_get_secureboot(void);
> >  extern const char * const *arch_get_ima_policy(void);
> >  #else
> > diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> > index 3f3ee4e2eb0d..d17972aa413a 100644
> > --- a/security/integrity/ima/Kconfig
> > +++ b/security/integrity/ima/Kconfig
> > @@ -327,3 +327,12 @@ config IMA_QUEUE_EARLY_BOOT_KEYS
> >       depends on IMA_MEASURE_ASYMMETRIC_KEYS
> >       depends on SYSTEM_TRUSTED_KEYRING
> >       default y
> > +
> > +config IMA_SECURE_AND_OR_TRUSTED_BOOT
> > +     bool
> > +     depends on IMA
> > +     depends on IMA_ARCH_POLICY
> > +     default n
> > +     help
> > +        This option is selected by architectures to enable secure and/or
> > +        trusted boot based on IMA runtime policies.
>
>
>
>

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Mimi Zohar]

On Mon, 2020-03-02 at 15:52 +0100, Ard Biesheuvel wrote:
> On Mon, 2 Mar 2020 at 15:48, Mimi Zohar <zohar@linux.ibm.com> wrote:
> >
> > On Wed, 2020-02-26 at 14:10 -0500, Nayna Jain wrote:
> > > Every time a new architecture defines the IMA architecture specific
> > > functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
> > > include file needs to be updated. To avoid this "noise", this patch
> > > defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
> > > the different architectures to select it.
> > >
> > > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
> > > Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> > > Cc: Ard Biesheuvel <ardb@kernel.org>
> > > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> > > Cc: Philipp Rudo <prudo@linux.ibm.com>
> > > Cc: Michael Ellerman <mpe@ellerman.id.au>
> > > ---
> > >  arch/powerpc/Kconfig           | 2 +-
> > >  arch/s390/Kconfig              | 1 +
> > >  arch/x86/Kconfig               | 1 +
> > >  include/linux/ima.h            | 3 +--
> > >  security/integrity/ima/Kconfig | 9 +++++++++
> > >  5 files changed, 13 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > > index 497b7d0b2d7e..b8ce1b995633 100644
> > > --- a/arch/powerpc/Kconfig
> > > +++ b/arch/powerpc/Kconfig
> > > @@ -246,6 +246,7 @@ config PPC
> > >       select SYSCTL_EXCEPTION_TRACE
> > >       select THREAD_INFO_IN_TASK
> > >       select VIRT_TO_BUS                      if !PPC64
> > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if PPC_SECURE_BOOT
> > >       #
> > >       # Please keep this list sorted alphabetically.
> > >       #
> > > @@ -978,7 +979,6 @@ config PPC_SECURE_BOOT
> > >       prompt "Enable secure boot support"
> > >       bool
> > >       depends on PPC_POWERNV
> > > -     depends on IMA_ARCH_POLICY
> > >       help
> > >         Systems with firmware secure boot enabled need to define security
> > >         policies to extend secure boot to the OS. This config allows a user
> > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> > > index 8abe77536d9d..90ff3633ade6 100644
> > > --- a/arch/s390/Kconfig
> > > +++ b/arch/s390/Kconfig
> > > @@ -195,6 +195,7 @@ config S390
> > >       select ARCH_HAS_FORCE_DMA_UNENCRYPTED
> > >       select SWIOTLB
> > >       select GENERIC_ALLOCATOR
> > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT
> > >
> > >
> > >  config SCHED_OMIT_FRAME_POINTER
> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > > index beea77046f9b..cafa66313fe2 100644
> > > --- a/arch/x86/Kconfig
> > > +++ b/arch/x86/Kconfig
> > > @@ -230,6 +230,7 @@ config X86
> > >       select VIRT_TO_BUS
> > >       select X86_FEATURE_NAMES                if PROC_FS
> > >       select PROC_PID_ARCH_STATUS             if PROC_FS
> > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI
> >
> > Not everyone is interested in enabling IMA or requiring IMA runtime
> > policies.  With this patch, enabling IMA_ARCH_POLICY is therefore
> > still left up to the person building the kernel.  As a result, I'm
> > seeing the following warning, which is kind of cool.
> >
> > WARNING: unmet direct dependencies detected for
> > IMA_SECURE_AND_OR_TRUSTED_BOOT
> >   Depends on [n]: INTEGRITY [=y] && IMA [=y] && IMA_ARCH_POLICY [=n]
> >   Selected by [y]:
> >   - X86 [=y] && EFI [=y]
> >
> > Ard, Michael, Martin, just making sure this type of warning is
> > acceptable before upstreaming this patch.  I would appreciate your
> > tags.
> >
> 
> Ehm, no, warnings like these are not really acceptable. It means there
> is an inconsistency in the way the Kconfig dependencies are defined.
> 
> Does this help:
> 
>   select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI && IMA_ARCH_POLICY
> 
> ?

Yes, that's fine for x86.  Michael, Martin, do you want something
similar or would you prefer actually selecting IMA_ARCH_POLICY?

Mimi

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Heiko Carstens]

On Mon, Mar 02, 2020 at 09:56:58AM -0500, Mimi Zohar wrote:
> On Mon, 2020-03-02 at 15:52 +0100, Ard Biesheuvel wrote:
> > On Mon, 2 Mar 2020 at 15:48, Mimi Zohar <zohar@linux.ibm.com> wrote:
> > > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> > > > index beea77046f9b..cafa66313fe2 100644
> > > > --- a/arch/x86/Kconfig
> > > > +++ b/arch/x86/Kconfig
> > > > @@ -230,6 +230,7 @@ config X86
> > > >       select VIRT_TO_BUS
> > > >       select X86_FEATURE_NAMES                if PROC_FS
> > > >       select PROC_PID_ARCH_STATUS             if PROC_FS
> > > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI
> > >
> > > Not everyone is interested in enabling IMA or requiring IMA runtime
> > > policies.  With this patch, enabling IMA_ARCH_POLICY is therefore
> > > still left up to the person building the kernel.  As a result, I'm
> > > seeing the following warning, which is kind of cool.
> > >
> > > WARNING: unmet direct dependencies detected for
> > > IMA_SECURE_AND_OR_TRUSTED_BOOT
> > >   Depends on [n]: INTEGRITY [=y] && IMA [=y] && IMA_ARCH_POLICY [=n]
> > >   Selected by [y]:
> > >   - X86 [=y] && EFI [=y]
> > >
> > > Ard, Michael, Martin, just making sure this type of warning is
> > > acceptable before upstreaming this patch.  I would appreciate your
> > > tags.
> > >
> > 
> > Ehm, no, warnings like these are not really acceptable. It means there
> > is an inconsistency in the way the Kconfig dependencies are defined.
> > 
> > Does this help:
> > 
> >   select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI && IMA_ARCH_POLICY
> > 
> > ?
> 
> Yes, that's fine for x86.  Michael, Martin, do you want something
> similar or would you prefer actually selecting IMA_ARCH_POLICY?

For s390 something like

	select IMA_SECURE_AND_OR_TRUSTED_BOOT if IMA_ARCH_POLICY

should be fine.

Thanks,
Heiko

Re: [PATCH] ima: add a new CONFIG for loading arch-specific policies

[Michael Ellerman]

Mimi Zohar <zohar@linux.ibm.com> writes:
> On Mon, 2020-03-02 at 15:52 +0100, Ard Biesheuvel wrote:
>> On Mon, 2 Mar 2020 at 15:48, Mimi Zohar <zohar@linux.ibm.com> wrote:
>> >
>> > On Wed, 2020-02-26 at 14:10 -0500, Nayna Jain wrote:
>> > > Every time a new architecture defines the IMA architecture specific
>> > > functions - arch_ima_get_secureboot() and arch_ima_get_policy(), the IMA
>> > > include file needs to be updated. To avoid this "noise", this patch
>> > > defines a new IMA Kconfig IMA_SECURE_AND_OR_TRUSTED_BOOT option, allowing
>> > > the different architectures to select it.
>> > >
>> > > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
>> > > Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
>> > > Cc: Ard Biesheuvel <ardb@kernel.org>
>> > > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
>> > > Cc: Philipp Rudo <prudo@linux.ibm.com>
>> > > Cc: Michael Ellerman <mpe@ellerman.id.au>
>> > > ---
>> > >  arch/powerpc/Kconfig           | 2 +-
>> > >  arch/s390/Kconfig              | 1 +
>> > >  arch/x86/Kconfig               | 1 +
>> > >  include/linux/ima.h            | 3 +--
>> > >  security/integrity/ima/Kconfig | 9 +++++++++
>> > >  5 files changed, 13 insertions(+), 3 deletions(-)
>> > >
>> > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> > > index 497b7d0b2d7e..b8ce1b995633 100644
>> > > --- a/arch/powerpc/Kconfig
>> > > +++ b/arch/powerpc/Kconfig
>> > > @@ -246,6 +246,7 @@ config PPC
>> > >       select SYSCTL_EXCEPTION_TRACE
>> > >       select THREAD_INFO_IN_TASK
>> > >       select VIRT_TO_BUS                      if !PPC64
>> > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if PPC_SECURE_BOOT
>> > >       #
>> > >       # Please keep this list sorted alphabetically.
>> > >       #
>> > > @@ -978,7 +979,6 @@ config PPC_SECURE_BOOT
>> > >       prompt "Enable secure boot support"
>> > >       bool
>> > >       depends on PPC_POWERNV
>> > > -     depends on IMA_ARCH_POLICY
>> > >       help
>> > >         Systems with firmware secure boot enabled need to define security
>> > >         policies to extend secure boot to the OS. This config allows a user
>> > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
>> > > index 8abe77536d9d..90ff3633ade6 100644
>> > > --- a/arch/s390/Kconfig
>> > > +++ b/arch/s390/Kconfig
>> > > @@ -195,6 +195,7 @@ config S390
>> > >       select ARCH_HAS_FORCE_DMA_UNENCRYPTED
>> > >       select SWIOTLB
>> > >       select GENERIC_ALLOCATOR
>> > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT
>> > >
>> > >
>> > >  config SCHED_OMIT_FRAME_POINTER
>> > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> > > index beea77046f9b..cafa66313fe2 100644
>> > > --- a/arch/x86/Kconfig
>> > > +++ b/arch/x86/Kconfig
>> > > @@ -230,6 +230,7 @@ config X86
>> > >       select VIRT_TO_BUS
>> > >       select X86_FEATURE_NAMES                if PROC_FS
>> > >       select PROC_PID_ARCH_STATUS             if PROC_FS
>> > > +     select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI
>> >
>> > Not everyone is interested in enabling IMA or requiring IMA runtime
>> > policies.  With this patch, enabling IMA_ARCH_POLICY is therefore
>> > still left up to the person building the kernel.  As a result, I'm
>> > seeing the following warning, which is kind of cool.
>> >
>> > WARNING: unmet direct dependencies detected for
>> > IMA_SECURE_AND_OR_TRUSTED_BOOT
>> >   Depends on [n]: INTEGRITY [=y] && IMA [=y] && IMA_ARCH_POLICY [=n]
>> >   Selected by [y]:
>> >   - X86 [=y] && EFI [=y]
>> >
>> > Ard, Michael, Martin, just making sure this type of warning is
>> > acceptable before upstreaming this patch.  I would appreciate your
>> > tags.
>> >
>> 
>> Ehm, no, warnings like these are not really acceptable. It means there
>> is an inconsistency in the way the Kconfig dependencies are defined.
>> 
>> Does this help:
>> 
>>   select IMA_SECURE_AND_OR_TRUSTED_BOOT   if EFI && IMA_ARCH_POLICY
>> 
>> ?
>
> Yes, that's fine for x86.  Michael, Martin, do you want something
> similar or would you prefer actually selecting IMA_ARCH_POLICY?

For powerpc this should be all we need:

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 497b7d0b2d7e..a5cfde432983 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -976,12 +976,13 @@ config PPC_MEM_KEYS
 
 config PPC_SECURE_BOOT
 	prompt "Enable secure boot support"
 	bool
 	depends on PPC_POWERNV
 	depends on IMA_ARCH_POLICY
+	select IMA_SECURE_AND_OR_TRUSTED_BOOT
 	help
 	  Systems with firmware secure boot enabled need to define security
 	  policies to extend secure boot to the OS. This config allows a user
 	  to enable OS secure boot on systems that have firmware support for
 	  it. If in doubt say N.
 

cheers