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(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(&mod_taint->list, &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(&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(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(&unloaded_tainted_modules, *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(p, &unloaded_tainted_modules, 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(mod_taint->taints, buf); 95 buf[l++] = '\0'; 96 97 seq_printf(m, "%s (%s) %llu", mod_taint->name, buf, mod_taint->count); 98 seq_puts(m, "\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("unloaded_tainted", 0444, mod_debugfs_root, NULL, 125 &unloaded_tainted_modules_fops); 126 return 0; 127 } 128 module_init(unloaded_tainted_modules_init); 129 #endif /* CONFIG_DEBUG_FS */ 130