IMA policy needs to support measuring only those keys linked to
a specific set of keyrings.
This patch defines a new IMA policy option namely "keyrings=" that
can be used to specify a set of keyrings. If this option is specified
in the policy for func=KEYRING_CHECK then only the keys linked to
the keyrings given in "keyrings=" option are measured.
If "keyrings=" option is not specified for func=KEYRING_CHECK then
all keys are measured.
Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
---
Documentation/ABI/testing/ima_policy | 10 +++++++++-
security/integrity/ima/ima_policy.c | 2 ++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 341df49b5ad1..be2874fa3928 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -25,7 +25,7 @@ Description:
lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
option: [[appraise_type=]] [template=] [permit_directio]
- [appraise_flag=]
+ [appraise_flag=] [keyrings=]
base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
@@ -43,6 +43,9 @@ Description:
appraise_flag:= [check_blacklist]
Currently, blacklist check is only for files signed with appended
signature.
+ keyrings:= list of keyrings
+ (eg, .builtin_trusted_keys|.ima). Only valid
+ when action is "measure" and func is KEYRING_CHECK.
template:= name of a defined IMA template type
(eg, ima-ng). Only valid when action is "measure".
pcr:= decimal value
@@ -119,3 +122,8 @@ Description:
all keys:
measure func=KEYRING_CHECK
+
+ Example of measure rule using KEYRING_CHECK to only measure
+ keys added to .builtin_trusted_keys or .ima keyring:
+
+ measure func=KEYRING_CHECK keyrings=.builtin_trusted_keys|.ima
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 9ca32ffaaa9d..a0f7ffa80736 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -34,6 +34,7 @@
#define IMA_EUID 0x0080
#define IMA_PCR 0x0100
#define IMA_FSNAME 0x0200
+#define IMA_KEYRINGS 0x0400
#define UNKNOWN 0
#define MEASURE 0x0001 /* same as IMA_MEASURE */
@@ -79,6 +80,7 @@ struct ima_rule_entry {
int type; /* audit type */
} lsm[MAX_LSM_RULES];
char *fsname;
+ char *keyrings; /* Measure keys added to these keyrings */
struct ima_template_desc *template;
};
--
2.17.1
The C maximum line length is 80 characters. The subject line is even
less than that (~50). The Subject line here could be "ima: add
support to limit measuring keys".
On Mon, 2019-11-11 at 11:32 -0800, Lakshmi Ramasubramanian wrote:
> IMA policy needs to support measuring only those keys linked to
> a specific set of keyrings.
Patch descriptions should be written in the imperative. For example,
"Limit measuring keys to those keys being loaded onto a specific
keyring."
>
> This patch defines a new IMA policy option namely "keyrings=" that
> can be used to specify a set of keyrings. If this option is specified
> in the policy for func=KEYRING_CHECK then only the keys linked to
> the keyrings given in "keyrings=" option are measured.
This description does not seem to match the code, which for some
reason isn't included in this patch, nor in 3/10. Please
combine/squash patches 2 & 3. Missing from the combined patch is the
keyring matching code in ima_match_rules().
>
> If "keyrings=" option is not specified for func=KEYRING_CHECK then
> all keys are measured.
The last sentence is unnecessary. Please remove.
>
> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
> ---
> Documentation/ABI/testing/ima_policy | 10 +++++++++-
> security/integrity/ima/ima_policy.c | 2 ++
> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
> index 341df49b5ad1..be2874fa3928 100644
> --- a/Documentation/ABI/testing/ima_policy
> +++ b/Documentation/ABI/testing/ima_policy
> @@ -25,7 +25,7 @@ Description:
> lsm: [[subj_user=] [subj_role=] [subj_type=]
> [obj_user=] [obj_role=] [obj_type=]]
> option: [[appraise_type=]] [template=] [permit_directio]
> - [appraise_flag=]
> + [appraise_flag=] [keyrings=]
> base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
> [FIRMWARE_CHECK]
> [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
> @@ -43,6 +43,9 @@ Description:
> appraise_flag:= [check_blacklist]
> Currently, blacklist check is only for files signed with appended
> signature.
> + keyrings:= list of keyrings
> + (eg, .builtin_trusted_keys|.ima). Only valid
> + when action is "measure" and func is KEYRING_CHECK.
> template:= name of a defined IMA template type
> (eg, ima-ng). Only valid when action is "measure".
> pcr:= decimal value
> @@ -119,3 +122,8 @@ Description:
> all keys:
>
> measure func=KEYRING_CHECK
> +
> + Example of measure rule using KEYRING_CHECK to only measure
> + keys added to .builtin_trusted_keys or .ima keyring:
> +
> + measure func=KEYRING_CHECK keyrings=.builtin_trusted_keys|.ima
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index 9ca32ffaaa9d..a0f7ffa80736 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -34,6 +34,7 @@
> #define IMA_EUID 0x0080
> #define IMA_PCR 0x0100
> #define IMA_FSNAME 0x0200
> +#define IMA_KEYRINGS 0x0400
>
> #define UNKNOWN 0
> #define MEASURE 0x0001 /* same as IMA_MEASURE */
> @@ -79,6 +80,7 @@ struct ima_rule_entry {
> int type; /* audit type */
> } lsm[MAX_LSM_RULES];
> char *fsname;
> + char *keyrings; /* Measure keys added to these keyrings */
> struct ima_template_desc *template;
> };
>
On 11/12/2019 9:05 AM, Mimi Zohar wrote:
> The C maximum line length is 80 characters. The subject line is even
> less than that (~50). The Subject line here could be "ima: add
> support to limit measuring keys".
I'll update the subject line for the patches - limit to max 50 chars.
>
> On Mon, 2019-11-11 at 11:32 -0800, Lakshmi Ramasubramanian wrote:
>> IMA policy needs to support measuring only those keys linked to
>> a specific set of keyrings.
>
> Patch descriptions should be written in the imperative. For example,
> "Limit measuring keys to those keys being loaded onto a specific
> keyring."
Will update.
>
>>
>> This patch defines a new IMA policy option namely "keyrings=" that
>> can be used to specify a set of keyrings. If this option is specified
>> in the policy for func=KEYRING_CHECK then only the keys linked to
>> the keyrings given in "keyrings=" option are measured.
>
> This description does not seem to match the code, which for some
> reason isn't included in this patch, nor in 3/10. Please
> combine/squash patches 2 & 3. Missing from the combined patch is the
> keyring matching code in ima_match_rules().
This patch defines "keyrings=" option in the IMA policy and adds the
related field in ima_rule_entry struct.
The code for updating the new field in ima_rule_entry is in patch #4
[PATCH v5 04/10] IMA: Updated IMA policy functions to return keyrings
option read from the policy
I'll update the description for this patch (#2).
-lakshmi
On Tue, 2019-11-12 at 09:43 -0800, Lakshmi Ramasubramanian wrote:
> On 11/12/2019 9:05 AM, Mimi Zohar wrote:
>
> > The C maximum line length is 80 characters. The subject line is even
> > less than that (~50). The Subject line here could be "ima: add
> > support to limit measuring keys".
> I'll update the subject line for the patches - limit to max 50 chars.
>
> >
> > On Mon, 2019-11-11 at 11:32 -0800, Lakshmi Ramasubramanian wrote:
> >> IMA policy needs to support measuring only those keys linked to
> >> a specific set of keyrings.
> >
> > Patch descriptions should be written in the imperative. For example,
> > "Limit measuring keys to those keys being loaded onto a specific
> > keyring."
> Will update.
>
> >
> >>
> >> This patch defines a new IMA policy option namely "keyrings=" that
> >> can be used to specify a set of keyrings. If this option is specified
> >> in the policy for func=KEYRING_CHECK then only the keys linked to
> >> the keyrings given in "keyrings=" option are measured.
> >
> > This description does not seem to match the code, which for some
> > reason isn't included in this patch, nor in 3/10. Please
> > combine/squash patches 2 & 3. Missing from the combined patch is the
> > keyring matching code in ima_match_rules().
>
> This patch defines "keyrings=" option in the IMA policy and adds the
> related field in ima_rule_entry struct.
>
> The code for updating the new field in ima_rule_entry is in patch #4
> [PATCH v5 04/10] IMA: Updated IMA policy functions to return keyrings
> option read from the policy
That's the problem. The keyrings doesn't need to be returned, but
processed in ima_match_rules().
Mimi