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