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 | |
20 | int try_add_tainted_module(struct module *mod) |
21 | { |
22 | struct mod_unload_taint *mod_taint; |
23 | |
24 | module_assert_mutex_or_preempt(); |
25 | |
26 | if (!mod->taints) |
27 | goto out; |
28 | |
29 | list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list, |
30 | lockdep_is_held(&module_mutex)) { |
31 | if (!strcmp(mod_taint->name, mod->name) && |
32 | mod_taint->taints & mod->taints) { |
33 | mod_taint->count++; |
34 | goto out; |
35 | } |
36 | } |
37 | |
38 | mod_taint = kmalloc(size: sizeof(*mod_taint), GFP_KERNEL); |
39 | if (unlikely(!mod_taint)) |
40 | return -ENOMEM; |
41 | strscpy(mod_taint->name, mod->name, MODULE_NAME_LEN); |
42 | mod_taint->taints = mod->taints; |
43 | list_add_rcu(new: &mod_taint->list, head: &unloaded_tainted_modules); |
44 | mod_taint->count = 1; |
45 | out: |
46 | return 0; |
47 | } |
48 | |
49 | void print_unloaded_tainted_modules(void) |
50 | { |
51 | struct mod_unload_taint *mod_taint; |
52 | char buf[MODULE_FLAGS_BUF_SIZE]; |
53 | |
54 | if (!list_empty(head: &unloaded_tainted_modules)) { |
55 | printk(KERN_DEFAULT "Unloaded tainted modules:" ); |
56 | list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, |
57 | list) { |
58 | size_t l; |
59 | |
60 | l = module_flags_taint(taints: mod_taint->taints, buf); |
61 | buf[l++] = '\0'; |
62 | pr_cont(" %s(%s):%llu" , mod_taint->name, buf, |
63 | mod_taint->count); |
64 | } |
65 | } |
66 | } |
67 | |
68 | #ifdef CONFIG_DEBUG_FS |
69 | static void *unloaded_tainted_modules_seq_start(struct seq_file *m, loff_t *pos) |
70 | __acquires(rcu) |
71 | { |
72 | rcu_read_lock(); |
73 | return seq_list_start_rcu(head: &unloaded_tainted_modules, pos: *pos); |
74 | } |
75 | |
76 | static void *unloaded_tainted_modules_seq_next(struct seq_file *m, void *p, loff_t *pos) |
77 | { |
78 | return seq_list_next_rcu(v: p, head: &unloaded_tainted_modules, ppos: pos); |
79 | } |
80 | |
81 | static void unloaded_tainted_modules_seq_stop(struct seq_file *m, void *p) |
82 | __releases(rcu) |
83 | { |
84 | rcu_read_unlock(); |
85 | } |
86 | |
87 | static int unloaded_tainted_modules_seq_show(struct seq_file *m, void *p) |
88 | { |
89 | struct mod_unload_taint *mod_taint; |
90 | char buf[MODULE_FLAGS_BUF_SIZE]; |
91 | size_t l; |
92 | |
93 | mod_taint = list_entry(p, struct mod_unload_taint, list); |
94 | l = module_flags_taint(taints: mod_taint->taints, buf); |
95 | buf[l++] = '\0'; |
96 | |
97 | seq_printf(m, fmt: "%s (%s) %llu" , mod_taint->name, buf, mod_taint->count); |
98 | seq_puts(m, s: "\n" ); |
99 | |
100 | return 0; |
101 | } |
102 | |
103 | static const struct seq_operations unloaded_tainted_modules_seq_ops = { |
104 | .start = unloaded_tainted_modules_seq_start, |
105 | .next = unloaded_tainted_modules_seq_next, |
106 | .stop = unloaded_tainted_modules_seq_stop, |
107 | .show = unloaded_tainted_modules_seq_show, |
108 | }; |
109 | |
110 | static int unloaded_tainted_modules_open(struct inode *inode, struct file *file) |
111 | { |
112 | return seq_open(file, &unloaded_tainted_modules_seq_ops); |
113 | } |
114 | |
115 | static const struct file_operations unloaded_tainted_modules_fops = { |
116 | .open = unloaded_tainted_modules_open, |
117 | .read = seq_read, |
118 | .llseek = seq_lseek, |
119 | .release = seq_release, |
120 | }; |
121 | |
122 | static int __init unloaded_tainted_modules_init(void) |
123 | { |
124 | debugfs_create_file(name: "unloaded_tainted" , mode: 0444, parent: mod_debugfs_root, NULL, |
125 | fops: &unloaded_tainted_modules_fops); |
126 | return 0; |
127 | } |
128 | module_init(unloaded_tainted_modules_init); |
129 | #endif /* CONFIG_DEBUG_FS */ |
130 | |