audit: implement audit by executable

This adds the ability audit the actions of a not-yet-running process.

This patch implements the ability to filter on the executable path.  Instead of
just hard coding the ino and dev of the executable we care about at the moment
the rule is inserted into the kernel, use the new audit_fsnotify
infrastructure to manage this dynamically.  This means that if the filename
does not yet exist but the containing directory does, or if the inode in
question is unlinked and creat'd (aka updated) the rule will just continue to
work.  If the containing directory is moved or deleted or the filesystem is
unmounted, the rule is deleted automatically.  A future enhancement would be to
have the rule survive across directory disruptions.

This is a heavily modified version of a patch originally submitted by Eric
Paris with some ideas from Peter Moody.

Cc: Peter Moody <peter@hda3.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
[PM: minor whitespace clean to satisfy ./scripts/checkpatch]
Signed-off-by: Paul Moore <pmoore@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
index 645c6884cee5..27ef8dcf7cd8 100644
--- a/kernel/audit_watch.c
+++ b/kernel/audit_watch.c
@@ -312,6 +312,8 @@ static void audit_update_watch(struct audit_parent *parent,
 				list_replace(&oentry->rule.list,
 					     &nentry->rule.list);
 			}
+			if (oentry->rule.exe)
+				audit_remove_mark(oentry->rule.exe);
 
 			audit_watch_log_rule_change(r, owatch, "updated_rules");
 
@@ -342,6 +344,8 @@ static void audit_remove_parent_watches(struct audit_parent *parent)
 		list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
 			e = container_of(r, struct audit_entry, rule);
 			audit_watch_log_rule_change(r, w, "remove_rule");
+			if (e->rule.exe)
+				audit_remove_mark(e->rule.exe);
 			list_del(&r->rlist);
 			list_del(&r->list);
 			list_del_rcu(&e->list);
@@ -514,3 +518,30 @@ static int __init audit_watch_init(void)
 	return 0;
 }
 device_initcall(audit_watch_init);
+
+int audit_dupe_exe(struct audit_krule *new, struct audit_krule *old)
+{
+	struct audit_fsnotify_mark *audit_mark;
+	char *pathname;
+
+	pathname = kstrdup(audit_mark_path(old->exe), GFP_KERNEL);
+	if (!pathname)
+		return -ENOMEM;
+
+	audit_mark = audit_alloc_mark(new, pathname, strlen(pathname));
+	if (IS_ERR(audit_mark)) {
+		kfree(pathname);
+		return PTR_ERR(audit_mark);
+	}
+	new->exe = audit_mark;
+
+	return 0;
+}
+
+int audit_exe_compare(struct task_struct *tsk, struct audit_fsnotify_mark *mark)
+{
+	unsigned long ino = tsk->mm->exe_file->f_inode->i_ino;
+	dev_t dev = tsk->mm->exe_file->f_inode->i_sb->s_dev;
+
+	return audit_mark_compare(mark, ino, dev);
+}