kernel/module/tracking.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Module taint unload tracking support
0004  *
0005  * Copyright (C) 2022 Aaron Tomlin
0006  */
0007
0008 #include <linux/module.h>
0009 #include <linux/string.h>
0010 #include <linux/printk.h>
0011 #include <linux/slab.h>
0012 #include <linux/list.h>
0013 #include <linux/rculist.h>
0014 #include "internal.h"
0015
0016 static LIST_HEAD(unloaded_tainted_modules);
0017
0018 int try_add_tainted_module(struct module *mod)
0019 {
0020     struct mod_unload_taint *mod_taint;
0021
0022     module_assert_mutex_or_preempt();
0023
0024     list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
0025                 lockdep_is_held(&module_mutex)) {
0026         if (!strcmp(mod_taint->name, mod->name) &&
0027             mod_taint->taints & mod->taints) {
0028             mod_taint->count++;
0029             goto out;
0030         }
0031     }
0032
0033     mod_taint = kmalloc(sizeof(*mod_taint), GFP_KERNEL);
0034     if (unlikely(!mod_taint))
0035         return -ENOMEM;
0036     strscpy(mod_taint->name, mod->name, MODULE_NAME_LEN);
0037     mod_taint->taints = mod->taints;
0038     list_add_rcu(&mod_taint->list, &unloaded_tainted_modules);
0039     mod_taint->count = 1;
0040 out:
0041     return 0;
0042 }
0043
0044 void print_unloaded_tainted_modules(void)
0045 {
0046     struct mod_unload_taint *mod_taint;
0047     char buf[MODULE_FLAGS_BUF_SIZE];
0048
0049     if (!list_empty(&unloaded_tainted_modules)) {
0050         printk(KERN_DEFAULT "Unloaded tainted modules:");
0051         list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules,
0052                     list) {
0053             size_t l;
0054
0055             l = module_flags_taint(mod_taint->taints, buf);
0056             buf[l++] = '\0';
0057             pr_cont(" %s(%s):%llu", mod_taint->name, buf,
0058                 mod_taint->count);
0059         }
0060     }
0061 }