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>
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index b4d8c36..7714d93 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -405,6 +405,12 @@
if (f->val > AUDIT_MAX_FIELD_COMPARE)
return -EINVAL;
break;
+ case AUDIT_EXE:
+ if (f->op != Audit_equal)
+ return -EINVAL;
+ if (entry->rule.listnr != AUDIT_FILTER_EXIT)
+ return -EINVAL;
+ break;
};
return 0;
}
@@ -419,6 +425,7 @@
size_t remain = datasz - sizeof(struct audit_rule_data);
int i;
char *str;
+ struct audit_fsnotify_mark *audit_mark;
entry = audit_to_entry_common(data);
if (IS_ERR(entry))
@@ -539,6 +546,24 @@
entry->rule.buflen += f->val;
entry->rule.filterkey = str;
break;
+ case AUDIT_EXE:
+ if (entry->rule.exe || f->val > PATH_MAX)
+ goto exit_free;
+ str = audit_unpack_string(&bufp, &remain, f->val);
+ if (IS_ERR(str)) {
+ err = PTR_ERR(str);
+ goto exit_free;
+ }
+ entry->rule.buflen += f->val;
+
+ audit_mark = audit_alloc_mark(&entry->rule, str, f->val);
+ if (IS_ERR(audit_mark)) {
+ kfree(str);
+ err = PTR_ERR(audit_mark);
+ goto exit_free;
+ }
+ entry->rule.exe = audit_mark;
+ break;
}
}
@@ -551,6 +576,8 @@
exit_free:
if (entry->rule.tree)
audit_put_tree(entry->rule.tree); /* that's the temporary one */
+ if (entry->rule.exe)
+ audit_remove_mark(entry->rule.exe); /* that's the template one */
audit_free_rule(entry);
return ERR_PTR(err);
}
@@ -615,6 +642,10 @@
data->buflen += data->values[i] =
audit_pack_string(&bufp, krule->filterkey);
break;
+ case AUDIT_EXE:
+ data->buflen += data->values[i] =
+ audit_pack_string(&bufp, audit_mark_path(krule->exe));
+ break;
case AUDIT_LOGINUID_SET:
if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
data->fields[i] = AUDIT_LOGINUID;
@@ -678,6 +709,12 @@
if (strcmp(a->filterkey, b->filterkey))
return 1;
break;
+ case AUDIT_EXE:
+ /* both paths exist based on above type compare */
+ if (strcmp(audit_mark_path(a->exe),
+ audit_mark_path(b->exe)))
+ return 1;
+ break;
case AUDIT_UID:
case AUDIT_EUID:
case AUDIT_SUID:
@@ -799,8 +836,14 @@
err = -ENOMEM;
else
new->filterkey = fk;
+ break;
+ case AUDIT_EXE:
+ err = audit_dupe_exe(new, old);
+ break;
}
if (err) {
+ if (new->exe)
+ audit_remove_mark(new->exe);
audit_free_rule(entry);
return ERR_PTR(err);
}
@@ -963,6 +1006,9 @@
if (e->rule.tree)
audit_remove_tree_rule(&e->rule);
+ if (e->rule.exe)
+ audit_remove_mark_rule(&e->rule);
+
#ifdef CONFIG_AUDITSYSCALL
if (!dont_count)
audit_n_rules--;
@@ -1067,8 +1113,11 @@
WARN_ON(1);
}
- if (err || type == AUDIT_DEL_RULE)
+ if (err || type == AUDIT_DEL_RULE) {
+ if (entry->rule.exe)
+ audit_remove_mark(entry->rule.exe);
audit_free_rule(entry);
+ }
return err;
}
@@ -1360,6 +1409,8 @@
return 0;
nentry = audit_dupe_rule(r);
+ if (entry->rule.exe)
+ audit_remove_mark(entry->rule.exe);
if (IS_ERR(nentry)) {
/* save the first error encountered for the
* return value */