1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Module taint unload tracking support
4 *
5 * Copyright (C) 2022 Aaron Tomlin
6 */
7
8 #include <linux/module.h>
9 #include <linux/string.h>
10 #include <linux/printk.h>
11 #include <linux/slab.h>
12 #include <linux/list.h>
13 #include <linux/debugfs.h>
14 #include <linux/rculist.h>
15 #include "internal.h"
16
17 static LIST_HEAD(unloaded_tainted_modules);
18 extern struct dentry *mod_debugfs_root;
19
try_add_tainted_module(struct module * mod)20 int try_add_tainted_module(struct module *mod)
21 {
22 struct mod_unload_taint *mod_taint;
23
24 if (!mod->taints)
25 goto out;
26
27 list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
28 lockdep_is_held(&module_mutex)) {
29 if (!strcmp(mod_taint->name, mod->name) &&
30 mod_taint->taints & mod->taints) {
31 mod_taint->count++;
32 goto out;
33 }
34 }
35
36 mod_taint = kmalloc(sizeof(*mod_taint), GFP_KERNEL);
37 if (unlikely(!mod_taint))
38 return -ENOMEM;
39 strscpy(mod_taint->name, mod->name, MODULE_NAME_LEN);
40 mod_taint->taints = mod->taints;
41 list_add_rcu(&mod_taint->list, &unloaded_tainted_modules);
42 mod_taint->count = 1;
43 out:
44 return 0;
45 }
46
print_unloaded_tainted_modules(void)47 void print_unloaded_tainted_modules(void)
48 {
49 struct mod_unload_taint *mod_taint;
50 char buf[MODULE_FLAGS_BUF_SIZE];
51
52 if (!list_empty(&unloaded_tainted_modules)) {
53 printk(KERN_DEFAULT "Unloaded tainted modules:");
54 list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules,
55 list) {
56 size_t l;
57
58 l = module_flags_taint(mod_taint->taints, buf);
59 buf[l++] = '\0';
60 pr_cont(" %s(%s):%llu", mod_taint->name, buf,
61 mod_taint->count);
62 }
63 }
64 }
65
66 #ifdef CONFIG_DEBUG_FS
unloaded_tainted_modules_seq_start(struct seq_file * m,loff_t * pos)67 static void *unloaded_tainted_modules_seq_start(struct seq_file *m, loff_t *pos)
68 __acquires(rcu)
69 {
70 rcu_read_lock();
71 return seq_list_start_rcu(&unloaded_tainted_modules, *pos);
72 }
73
unloaded_tainted_modules_seq_next(struct seq_file * m,void * p,loff_t * pos)74 static void *unloaded_tainted_modules_seq_next(struct seq_file *m, void *p, loff_t *pos)
75 {
76 return seq_list_next_rcu(p, &unloaded_tainted_modules, pos);
77 }
78
unloaded_tainted_modules_seq_stop(struct seq_file * m,void * p)79 static void unloaded_tainted_modules_seq_stop(struct seq_file *m, void *p)
80 __releases(rcu)
81 {
82 rcu_read_unlock();
83 }
84
unloaded_tainted_modules_seq_show(struct seq_file * m,void * p)85 static int unloaded_tainted_modules_seq_show(struct seq_file *m, void *p)
86 {
87 struct mod_unload_taint *mod_taint;
88 char buf[MODULE_FLAGS_BUF_SIZE];
89 size_t l;
90
91 mod_taint = list_entry(p, struct mod_unload_taint, list);
92 l = module_flags_taint(mod_taint->taints, buf);
93 buf[l++] = '\0';
94
95 seq_printf(m, "%s (%s) %llu", mod_taint->name, buf, mod_taint->count);
96 seq_puts(m, "\n");
97
98 return 0;
99 }
100
101 static const struct seq_operations unloaded_tainted_modules_seq_ops = {
102 .start = unloaded_tainted_modules_seq_start,
103 .next = unloaded_tainted_modules_seq_next,
104 .stop = unloaded_tainted_modules_seq_stop,
105 .show = unloaded_tainted_modules_seq_show,
106 };
107
unloaded_tainted_modules_open(struct inode * inode,struct file * file)108 static int unloaded_tainted_modules_open(struct inode *inode, struct file *file)
109 {
110 return seq_open(file, &unloaded_tainted_modules_seq_ops);
111 }
112
113 static const struct file_operations unloaded_tainted_modules_fops = {
114 .open = unloaded_tainted_modules_open,
115 .read = seq_read,
116 .llseek = seq_lseek,
117 .release = seq_release,
118 };
119
unloaded_tainted_modules_init(void)120 static int __init unloaded_tainted_modules_init(void)
121 {
122 debugfs_create_file("unloaded_tainted", 0444, mod_debugfs_root, NULL,
123 &unloaded_tainted_modules_fops);
124 return 0;
125 }
126 module_init(unloaded_tainted_modules_init);
127 #endif /* CONFIG_DEBUG_FS */
128