audit: allow not equal op for audit by executable

Current implementation of auditing by executable name only implements
the 'equal' operator. This patch extends it to also support the 'not
equal' operator.

See: https://github.com/linux-audit/audit-kernel/issues/53

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

2 files changed, 3 insertions, 1 deletions

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index d7a807e81451..a0c5a3ec6e60 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -426,7 +426,7 @@ static int audit_field_valid(struct audit_entry *entry, struct audit_field *f)
                         return -EINVAL;
                 break;
         case AUDIT_EXE:
-                if (f->op != Audit_equal)
+                if (f->op != Audit_not_equal && f->op != Audit_equal)
                         return -EINVAL;
                 if (entry->rule.listnr != AUDIT_FILTER_EXIT)
                         return -EINVAL;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4e0a4ac803db..479c031ec54c 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -471,6 +471,8 @@ static int audit_filter_rules(struct task_struct *tsk,
                         break;
                 case AUDIT_EXE:
                         result = audit_exe_compare(tsk, rule->exe);
+                        if (f->op == Audit_not_equal)
+                                result = !result;
                         break;
                 case AUDIT_UID:
                         result = audit_uid_comparator(cred->uid, f->op, f->uid);