diff mbox series

[01/10] capability: introduce new capable flag CAP_OPT_NOAUDIT_ONDENY

Message ID 20240315113828.258005-1-cgzones@googlemail.com (mailing list archive)
State New, archived
Headers show
Series [01/10] capability: introduce new capable flag CAP_OPT_NOAUDIT_ONDENY | expand

Commit Message

Christian Göttsche March 15, 2024, 11:37 a.m. UTC
Introduce a new capable flag, CAP_OPT_NOAUDIT_ONDENY, to not generate
an audit event if the requested capability is not granted.  This will be
used in a new capable_any() functionality to reduce the number of
necessary capable calls.

Handle the flag accordingly in AppArmor and SELinux.

CC: linux-block@vger.kernel.org
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
---
v5:
   rename flag to CAP_OPT_NOAUDIT_ONDENY, suggested by Serge:
     https://lore.kernel.org/all/20230606190013.GA640488@mail.hallyn.com/
---
 include/linux/security.h       |  2 ++
 security/apparmor/capability.c |  8 +++++---
 security/selinux/hooks.c       | 14 ++++++++------
 3 files changed, 15 insertions(+), 9 deletions(-)

Comments

Serge E. Hallyn March 15, 2024, 7:59 p.m. UTC | #1
On Fri, Mar 15, 2024 at 12:37:22PM +0100, Christian Göttsche wrote:
> Introduce a new capable flag, CAP_OPT_NOAUDIT_ONDENY, to not generate
> an audit event if the requested capability is not granted.  This will be
> used in a new capable_any() functionality to reduce the number of
> necessary capable calls.
> 
> Handle the flag accordingly in AppArmor and SELinux.
> 
> CC: linux-block@vger.kernel.org
> Suggested-by: Paul Moore <paul@paul-moore.com>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>

Thanks.

Reviewed-by: Serge Hallyn <serge@hallyn.com>

> ---
> v5:
>    rename flag to CAP_OPT_NOAUDIT_ONDENY, suggested by Serge:
>      https://lore.kernel.org/all/20230606190013.GA640488@mail.hallyn.com/
> ---
>  include/linux/security.h       |  2 ++
>  security/apparmor/capability.c |  8 +++++---
>  security/selinux/hooks.c       | 14 ++++++++------
>  3 files changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 41a8f667bdfa..c60cae78ff8b 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -70,6 +70,8 @@ struct lsm_ctx;
>  #define CAP_OPT_NOAUDIT BIT(1)
>  /* If capable is being called by a setid function */
>  #define CAP_OPT_INSETID BIT(2)
> +/* If capable should audit the security request for authorized requests only */
> +#define CAP_OPT_NOAUDIT_ONDENY BIT(3)
>  
>  /* LSM Agnostic defines for security_sb_set_mnt_opts() flags */
>  #define SECURITY_LSM_NATIVE_LABELS	1
> diff --git a/security/apparmor/capability.c b/security/apparmor/capability.c
> index 9934df16c843..08c9c9a0fc19 100644
> --- a/security/apparmor/capability.c
> +++ b/security/apparmor/capability.c
> @@ -108,7 +108,8 @@ static int audit_caps(struct apparmor_audit_data *ad, struct aa_profile *profile
>   * profile_capable - test if profile allows use of capability @cap
>   * @profile: profile being enforced    (NOT NULL, NOT unconfined)
>   * @cap: capability to test if allowed
> - * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
> + * @opts: CAP_OPT_NOAUDIT/CAP_OPT_NOAUDIT_ONDENY bit determines whether audit
> + *	record is generated
>   * @ad: audit data (MAY BE NULL indicating no auditing)
>   *
>   * Returns: 0 if allowed else -EPERM
> @@ -126,7 +127,7 @@ static int profile_capable(struct aa_profile *profile, int cap,
>  	else
>  		error = -EPERM;
>  
> -	if (opts & CAP_OPT_NOAUDIT) {
> +	if ((opts & CAP_OPT_NOAUDIT) || ((opts & CAP_OPT_NOAUDIT_ONDENY) && error)) {
>  		if (!COMPLAIN_MODE(profile))
>  			return error;
>  		/* audit the cap request in complain mode but note that it
> @@ -143,7 +144,8 @@ static int profile_capable(struct aa_profile *profile, int cap,
>   * @subj_cred: cred we are testing capability against
>   * @label: label being tested for capability (NOT NULL)
>   * @cap: capability to be tested
> - * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
> + * @opts: CAP_OPT_NOAUDIT/CAP_OPT_NOAUDIT_ONDENY bit determines whether audit
> + *	record is generated
>   *
>   * Look up capability in profile capability set.
>   *
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3448454c82d0..1a2c7c1a89be 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -1624,7 +1624,7 @@ static int cred_has_capability(const struct cred *cred,
>  	u16 sclass;
>  	u32 sid = cred_sid(cred);
>  	u32 av = CAP_TO_MASK(cap);
> -	int rc;
> +	int rc, rc2;
>  
>  	ad.type = LSM_AUDIT_DATA_CAP;
>  	ad.u.cap = cap;
> @@ -1643,11 +1643,13 @@ static int cred_has_capability(const struct cred *cred,
>  	}
>  
>  	rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
> -	if (!(opts & CAP_OPT_NOAUDIT)) {
> -		int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
> -		if (rc2)
> -			return rc2;
> -	}
> +	if ((opts & CAP_OPT_NOAUDIT) || ((opts & CAP_OPT_NOAUDIT_ONDENY) && rc))
> +		return rc;
> +
> +	rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
> +	if (rc2)
> +		return rc2;
> +
>  	return rc;
>  }
>  
> -- 
> 2.43.0
> 
>
Paul Moore June 10, 2024, 8:56 p.m. UTC | #2
On Fri, Mar 15, 2024 at 7:38 AM Christian Göttsche
<cgzones@googlemail.com> wrote:
>
> Introduce a new capable flag, CAP_OPT_NOAUDIT_ONDENY, to not generate
> an audit event if the requested capability is not granted.  This will be
> used in a new capable_any() functionality to reduce the number of
> necessary capable calls.
>
> Handle the flag accordingly in AppArmor and SELinux.
>
> CC: linux-block@vger.kernel.org
> Suggested-by: Paul Moore <paul@paul-moore.com>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
> v5:
>    rename flag to CAP_OPT_NOAUDIT_ONDENY, suggested by Serge:
>      https://lore.kernel.org/all/20230606190013.GA640488@mail.hallyn.com/
> ---
>  include/linux/security.h       |  2 ++
>  security/apparmor/capability.c |  8 +++++---
>  security/selinux/hooks.c       | 14 ++++++++------
>  3 files changed, 15 insertions(+), 9 deletions(-)

Acked-by: Paul Moore <paul@paul-moore.com>
John Johansen June 10, 2024, 9:12 p.m. UTC | #3
On 3/15/24 04:37, Christian Göttsche wrote:
> Introduce a new capable flag, CAP_OPT_NOAUDIT_ONDENY, to not generate
> an audit event if the requested capability is not granted.  This will be
> used in a new capable_any() functionality to reduce the number of
> necessary capable calls.
> 
> Handle the flag accordingly in AppArmor and SELinux.
> 
> CC: linux-block@vger.kernel.org
> Suggested-by: Paul Moore <paul@paul-moore.com>
> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: John Johansen <john.johansen@canonical.com>

> ---
> v5:
>     rename flag to CAP_OPT_NOAUDIT_ONDENY, suggested by Serge:
>       https://lore.kernel.org/all/20230606190013.GA640488@mail.hallyn.com/
> ---
>   include/linux/security.h       |  2 ++
>   security/apparmor/capability.c |  8 +++++---
>   security/selinux/hooks.c       | 14 ++++++++------
>   3 files changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 41a8f667bdfa..c60cae78ff8b 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -70,6 +70,8 @@ struct lsm_ctx;
>   #define CAP_OPT_NOAUDIT BIT(1)
>   /* If capable is being called by a setid function */
>   #define CAP_OPT_INSETID BIT(2)
> +/* If capable should audit the security request for authorized requests only */
> +#define CAP_OPT_NOAUDIT_ONDENY BIT(3)
>   
>   /* LSM Agnostic defines for security_sb_set_mnt_opts() flags */
>   #define SECURITY_LSM_NATIVE_LABELS	1
> diff --git a/security/apparmor/capability.c b/security/apparmor/capability.c
> index 9934df16c843..08c9c9a0fc19 100644
> --- a/security/apparmor/capability.c
> +++ b/security/apparmor/capability.c
> @@ -108,7 +108,8 @@ static int audit_caps(struct apparmor_audit_data *ad, struct aa_profile *profile
>    * profile_capable - test if profile allows use of capability @cap
>    * @profile: profile being enforced    (NOT NULL, NOT unconfined)
>    * @cap: capability to test if allowed
> - * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
> + * @opts: CAP_OPT_NOAUDIT/CAP_OPT_NOAUDIT_ONDENY bit determines whether audit
> + *	record is generated
>    * @ad: audit data (MAY BE NULL indicating no auditing)
>    *
>    * Returns: 0 if allowed else -EPERM
> @@ -126,7 +127,7 @@ static int profile_capable(struct aa_profile *profile, int cap,
>   	else
>   		error = -EPERM;
>   
> -	if (opts & CAP_OPT_NOAUDIT) {
> +	if ((opts & CAP_OPT_NOAUDIT) || ((opts & CAP_OPT_NOAUDIT_ONDENY) && error)) {
>   		if (!COMPLAIN_MODE(profile))
>   			return error;
>   		/* audit the cap request in complain mode but note that it
> @@ -143,7 +144,8 @@ static int profile_capable(struct aa_profile *profile, int cap,
>    * @subj_cred: cred we are testing capability against
>    * @label: label being tested for capability (NOT NULL)
>    * @cap: capability to be tested
> - * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
> + * @opts: CAP_OPT_NOAUDIT/CAP_OPT_NOAUDIT_ONDENY bit determines whether audit
> + *	record is generated
>    *
>    * Look up capability in profile capability set.
>    *
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 3448454c82d0..1a2c7c1a89be 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -1624,7 +1624,7 @@ static int cred_has_capability(const struct cred *cred,
>   	u16 sclass;
>   	u32 sid = cred_sid(cred);
>   	u32 av = CAP_TO_MASK(cap);
> -	int rc;
> +	int rc, rc2;
>   
>   	ad.type = LSM_AUDIT_DATA_CAP;
>   	ad.u.cap = cap;
> @@ -1643,11 +1643,13 @@ static int cred_has_capability(const struct cred *cred,
>   	}
>   
>   	rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
> -	if (!(opts & CAP_OPT_NOAUDIT)) {
> -		int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
> -		if (rc2)
> -			return rc2;
> -	}
> +	if ((opts & CAP_OPT_NOAUDIT) || ((opts & CAP_OPT_NOAUDIT_ONDENY) && rc))
> +		return rc;
> +
> +	rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
> +	if (rc2)
> +		return rc2;
> +
>   	return rc;
>   }
>
diff mbox series

Patch

diff --git a/include/linux/security.h b/include/linux/security.h
index 41a8f667bdfa..c60cae78ff8b 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -70,6 +70,8 @@  struct lsm_ctx;
 #define CAP_OPT_NOAUDIT BIT(1)
 /* If capable is being called by a setid function */
 #define CAP_OPT_INSETID BIT(2)
+/* If capable should audit the security request for authorized requests only */
+#define CAP_OPT_NOAUDIT_ONDENY BIT(3)
 
 /* LSM Agnostic defines for security_sb_set_mnt_opts() flags */
 #define SECURITY_LSM_NATIVE_LABELS	1
diff --git a/security/apparmor/capability.c b/security/apparmor/capability.c
index 9934df16c843..08c9c9a0fc19 100644
--- a/security/apparmor/capability.c
+++ b/security/apparmor/capability.c
@@ -108,7 +108,8 @@  static int audit_caps(struct apparmor_audit_data *ad, struct aa_profile *profile
  * profile_capable - test if profile allows use of capability @cap
  * @profile: profile being enforced    (NOT NULL, NOT unconfined)
  * @cap: capability to test if allowed
- * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
+ * @opts: CAP_OPT_NOAUDIT/CAP_OPT_NOAUDIT_ONDENY bit determines whether audit
+ *	record is generated
  * @ad: audit data (MAY BE NULL indicating no auditing)
  *
  * Returns: 0 if allowed else -EPERM
@@ -126,7 +127,7 @@  static int profile_capable(struct aa_profile *profile, int cap,
 	else
 		error = -EPERM;
 
-	if (opts & CAP_OPT_NOAUDIT) {
+	if ((opts & CAP_OPT_NOAUDIT) || ((opts & CAP_OPT_NOAUDIT_ONDENY) && error)) {
 		if (!COMPLAIN_MODE(profile))
 			return error;
 		/* audit the cap request in complain mode but note that it
@@ -143,7 +144,8 @@  static int profile_capable(struct aa_profile *profile, int cap,
  * @subj_cred: cred we are testing capability against
  * @label: label being tested for capability (NOT NULL)
  * @cap: capability to be tested
- * @opts: CAP_OPT_NOAUDIT bit determines whether audit record is generated
+ * @opts: CAP_OPT_NOAUDIT/CAP_OPT_NOAUDIT_ONDENY bit determines whether audit
+ *	record is generated
  *
  * Look up capability in profile capability set.
  *
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 3448454c82d0..1a2c7c1a89be 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1624,7 +1624,7 @@  static int cred_has_capability(const struct cred *cred,
 	u16 sclass;
 	u32 sid = cred_sid(cred);
 	u32 av = CAP_TO_MASK(cap);
-	int rc;
+	int rc, rc2;
 
 	ad.type = LSM_AUDIT_DATA_CAP;
 	ad.u.cap = cap;
@@ -1643,11 +1643,13 @@  static int cred_has_capability(const struct cred *cred,
 	}
 
 	rc = avc_has_perm_noaudit(sid, sid, sclass, av, 0, &avd);
-	if (!(opts & CAP_OPT_NOAUDIT)) {
-		int rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
-		if (rc2)
-			return rc2;
-	}
+	if ((opts & CAP_OPT_NOAUDIT) || ((opts & CAP_OPT_NOAUDIT_ONDENY) && rc))
+		return rc;
+
+	rc2 = avc_audit(sid, sid, sclass, av, &avd, rc, &ad);
+	if (rc2)
+		return rc2;
+
 	return rc;
 }