[PATCH] integrity/ima: Provide Kconfig option for ima-modsig template

'ima-modsig' was not in the list of selectable templates in Kconfig.
The missing Kconfig options were added to support the ima-modsig
template as default template.

Signed-off-by: Michael Weiß <redacted>
---
 security/integrity/ima/Kconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 12e9250c1bec..32b9325f49bf 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig

@@ -78,6 +78,8 @@ choice
 		bool "ima-ng (default)"
 	config IMA_SIG_TEMPLATE
 		bool "ima-sig"
+	config IMA_MODSIG_TEMPLATE
+		bool "ima-modsig"
 endchoice
 
 config IMA_DEFAULT_TEMPLATE

@@ -86,6 +88,7 @@ config IMA_DEFAULT_TEMPLATE
 	default "ima" if IMA_TEMPLATE
 	default "ima-ng" if IMA_NG_TEMPLATE
 	default "ima-sig" if IMA_SIG_TEMPLATE
+	default "ima-modsig" if IMA_MODSIG_TEMPLATE
 
 choice
 	prompt "Default integrity hash algorithm"

-- 
2.20.1

Hi Michael,

On Mon, 2021-02-15 at 11:23 +0100, Michael Weiß wrote:

'ima-modsig' was not in the list of selectable templates in Kconfig.
The missing Kconfig options were added to support the ima-modsig
template as default template.

Signed-off-by: Michael Weiß <redacted>

Since 'ima-modsig' is only needed for appended signatures (e.g. kexec
kernel image on powerpc, kernel modules) a per policy rule "template="
option was defined.  There's also the 'ima_template=' boot command line
option.   Between these two options, I didn't see the need for making
it a build time default option.  Do you?

The patch itself looks good. 

thanks,

Mimi

Hi Mimi,

On Mon, 2021-02-15 at 08:26 -0500, Mimi Zohar wrote:

Hi Michael,

On Mon, 2021-02-15 at 11:23 +0100, Michael Weiß wrote:

quoted

'ima-modsig' was not in the list of selectable templates in Kconfig.
The missing Kconfig options were added to support the ima-modsig
template as default template.

Signed-off-by: Michael Weiß <redacted>

Since 'ima-modsig' is only needed for appended signatures (e.g. kexec
kernel image on powerpc, kernel modules) a per policy rule "template="
option was defined.  There's also the 'ima_template=' boot command line
option.   Between these two options, I didn't see the need for making
it a build time default option.  Do you?

The use-case I had in mind was a simple measured boot,
no user-space applications, only to measure already signed modules
which are already signed by modsig
using a single policy line:

measure func=MODULE_CHECK

I thought for this purpose, we could just compile in the default
template to be modsig but it wasn't
selectable.

I have overlooked the policy rule "template=",
In the above use-case, it also just works to set the policy:

measure func=MODULE_CHECK template=ima-modsig

So, your are right maybe that is not necessary.

Regards,
Michael
 

The patch itself looks good. 

thanks,

Mimi

quoted

---
 security/integrity/ima/Kconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 12e9250c1bec..32b9325f49bf 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig

@@ -78,6 +78,8 @@ choice
 		bool "ima-ng (default)"
 	config IMA_SIG_TEMPLATE
 		bool "ima-sig"
+	config IMA_MODSIG_TEMPLATE
+		bool "ima-modsig"
 endchoice
 
 config IMA_DEFAULT_TEMPLATE

@@ -86,6 +88,7 @@ config IMA_DEFAULT_TEMPLATE
 	default "ima" if IMA_TEMPLATE
 	default "ima-ng" if IMA_NG_TEMPLATE
 	default "ima-sig" if IMA_SIG_TEMPLATE
+	default "ima-modsig" if IMA_MODSIG_TEMPLATE
 
 choice
 	prompt "Default integrity hash algorithm"