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Currently, only the initial module that tainted the kernel is recorded e.g. when an out-of-tree module is loaded. The purpose of this patch is to allow the kernel to maintain a record of each unloaded module that taints the kernel. So, in addition to displaying a list of linked modules (see print_modules()) e.g. in the event of a detected bad page, unloaded modules that carried a taint/or taints are displayed too. A tainted module unload count is maintained. The number of tracked modules is not fixed. This feature is disabled by default. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
62 lines
1.4 KiB
C
62 lines
1.4 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/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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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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