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Commit 21b85c31 authored by Eric Paris's avatar Eric Paris
Browse files

audit: audit feature to set loginuid immutable 



This adds a new 'audit_feature' bit which allows userspace to set it
such that the loginuid is absolutely immutable, even if you have
CAP_AUDIT_CONTROL.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Signed-off-by: default avatarRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
parent d040e5af

include/uapi/linux/audit.h

+2 −1
Original line number Diff line number Diff line
@@ -387,7 +387,8 @@ struct audit_features { 
};



#define AUDIT_FEATURE_ONLY_UNSET_LOGINUID	0

#define AUDIT_LAST_FEATURE			AUDIT_FEATURE_ONLY_UNSET_LOGINUID

#define AUDIT_FEATURE_LOGINUID_IMMUTABLE	1

#define AUDIT_LAST_FEATURE			AUDIT_FEATURE_LOGINUID_IMMUTABLE



#define audit_feature_valid(x)		((x) >= 0 && (x) <= AUDIT_LAST_FEATURE)

#define AUDIT_FEATURE_TO_MASK(x)	(1 << ((x) & 31)) /* mask for __u32 */

kernel/audit.c

+2 −1
Original line number Diff line number Diff line
@@ -144,8 +144,9 @@ static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION, 
				   .features = 0,

				   .lock = 0,};



static char *audit_feature_names[1] = {

static char *audit_feature_names[2] = {

	"only_unset_loginuid",

	"loginuid_immutable",

};

kernel/auditsc.c

+3 −0
Original line number Diff line number Diff line
@@ -1971,6 +1971,9 @@ static int audit_set_loginuid_perm(kuid_t loginuid) 
	/* if we are unset, we don't need privs */

	if (!audit_loginuid_set(current))

		return 0;

	/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/

	if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))

		return -EPERM;

	/* it is set, you need permission */

	if (!capable(CAP_AUDIT_CONTROL))

		return -EPERM;