47cc75aa92
This ensures that no module record/or entry is added to the
unloaded_tainted_modules list if it does not carry a taint.
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Fixes: 99bd995655 ("module: Introduce module unload taint tracking")
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
133 lines
3.2 KiB
C
133 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Module taint unload tracking support
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*
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* Copyright (C) 2022 Aaron Tomlin
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*/
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/printk.h>
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <linux/debugfs.h>
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#include <linux/rculist.h>
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#include "internal.h"
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static LIST_HEAD(unloaded_tainted_modules);
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int try_add_tainted_module(struct module *mod)
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{
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struct mod_unload_taint *mod_taint;
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module_assert_mutex_or_preempt();
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if (!mod->taints)
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goto out;
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list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
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lockdep_is_held(&module_mutex)) {
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if (!strcmp(mod_taint->name, mod->name) &&
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mod_taint->taints & mod->taints) {
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mod_taint->count++;
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goto out;
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}
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}
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mod_taint = kmalloc(sizeof(*mod_taint), GFP_KERNEL);
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if (unlikely(!mod_taint))
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return -ENOMEM;
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strscpy(mod_taint->name, mod->name, MODULE_NAME_LEN);
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mod_taint->taints = mod->taints;
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list_add_rcu(&mod_taint->list, &unloaded_tainted_modules);
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mod_taint->count = 1;
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out:
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return 0;
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}
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void print_unloaded_tainted_modules(void)
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{
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struct mod_unload_taint *mod_taint;
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char buf[MODULE_FLAGS_BUF_SIZE];
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if (!list_empty(&unloaded_tainted_modules)) {
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printk(KERN_DEFAULT "Unloaded tainted modules:");
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list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules,
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list) {
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size_t l;
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l = module_flags_taint(mod_taint->taints, buf);
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buf[l++] = '\0';
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pr_cont(" %s(%s):%llu", mod_taint->name, buf,
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mod_taint->count);
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}
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}
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}
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#ifdef CONFIG_DEBUG_FS
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static void *unloaded_tainted_modules_seq_start(struct seq_file *m, loff_t *pos)
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__acquires(rcu)
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{
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rcu_read_lock();
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return seq_list_start_rcu(&unloaded_tainted_modules, *pos);
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}
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static void *unloaded_tainted_modules_seq_next(struct seq_file *m, void *p, loff_t *pos)
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{
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return seq_list_next_rcu(p, &unloaded_tainted_modules, pos);
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}
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static void unloaded_tainted_modules_seq_stop(struct seq_file *m, void *p)
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__releases(rcu)
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{
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rcu_read_unlock();
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}
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static int unloaded_tainted_modules_seq_show(struct seq_file *m, void *p)
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{
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struct mod_unload_taint *mod_taint;
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char buf[MODULE_FLAGS_BUF_SIZE];
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size_t l;
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mod_taint = list_entry(p, struct mod_unload_taint, list);
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l = module_flags_taint(mod_taint->taints, buf);
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buf[l++] = '\0';
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seq_printf(m, "%s (%s) %llu", mod_taint->name, buf, mod_taint->count);
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seq_puts(m, "\n");
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return 0;
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}
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static const struct seq_operations unloaded_tainted_modules_seq_ops = {
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.start = unloaded_tainted_modules_seq_start,
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.next = unloaded_tainted_modules_seq_next,
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.stop = unloaded_tainted_modules_seq_stop,
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.show = unloaded_tainted_modules_seq_show,
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};
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static int unloaded_tainted_modules_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &unloaded_tainted_modules_seq_ops);
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}
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static const struct file_operations unloaded_tainted_modules_fops = {
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.open = unloaded_tainted_modules_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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static int __init unloaded_tainted_modules_init(void)
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{
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struct dentry *dir;
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dir = debugfs_create_dir("modules", NULL);
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debugfs_create_file("unloaded_tainted", 0444, dir, NULL,
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&unloaded_tainted_modules_fops);
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return 0;
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}
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module_init(unloaded_tainted_modules_init);
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#endif /* CONFIG_DEBUG_FS */
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