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 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 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 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 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 79 static void unloaded_tainted_modules_seq_stop(struct seq_file *m, void *p) 80 __releases(rcu) 81 { 82 rcu_read_unlock(); 83 } 84 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 }; 107 108 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 }; 119 120 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