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162 lines
3.8 KiB
162 lines
3.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// Copyright (C) 2019 SUSE |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/printk.h> |
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#include <linux/livepatch.h> |
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#define CONSOLE_LOGLEVEL_STATE 1 |
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/* Version 1 does not support migration. */ |
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#define CONSOLE_LOGLEVEL_STATE_VERSION 1 |
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static const char *const module_state[] = { |
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[MODULE_STATE_LIVE] = "[MODULE_STATE_LIVE] Normal state", |
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[MODULE_STATE_COMING] = "[MODULE_STATE_COMING] Full formed, running module_init", |
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[MODULE_STATE_GOING] = "[MODULE_STATE_GOING] Going away", |
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[MODULE_STATE_UNFORMED] = "[MODULE_STATE_UNFORMED] Still setting it up", |
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}; |
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static void callback_info(const char *callback, struct klp_object *obj) |
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{ |
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if (obj->mod) |
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pr_info("%s: %s -> %s\n", callback, obj->mod->name, |
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module_state[obj->mod->state]); |
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else |
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pr_info("%s: vmlinux\n", callback); |
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} |
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static struct klp_patch patch; |
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static int allocate_loglevel_state(void) |
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{ |
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struct klp_state *loglevel_state; |
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); |
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if (!loglevel_state) |
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return -EINVAL; |
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loglevel_state->data = kzalloc(sizeof(console_loglevel), GFP_KERNEL); |
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if (!loglevel_state->data) |
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return -ENOMEM; |
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pr_info("%s: allocating space to store console_loglevel\n", |
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__func__); |
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return 0; |
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} |
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static void fix_console_loglevel(void) |
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{ |
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struct klp_state *loglevel_state; |
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); |
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if (!loglevel_state) |
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return; |
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pr_info("%s: fixing console_loglevel\n", __func__); |
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*(int *)loglevel_state->data = console_loglevel; |
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console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; |
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} |
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static void restore_console_loglevel(void) |
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{ |
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struct klp_state *loglevel_state; |
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); |
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if (!loglevel_state) |
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return; |
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pr_info("%s: restoring console_loglevel\n", __func__); |
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console_loglevel = *(int *)loglevel_state->data; |
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} |
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static void free_loglevel_state(void) |
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{ |
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struct klp_state *loglevel_state; |
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loglevel_state = klp_get_state(&patch, CONSOLE_LOGLEVEL_STATE); |
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if (!loglevel_state) |
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return; |
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pr_info("%s: freeing space for the stored console_loglevel\n", |
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__func__); |
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kfree(loglevel_state->data); |
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} |
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/* Executed on object patching (ie, patch enablement) */ |
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static int pre_patch_callback(struct klp_object *obj) |
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{ |
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callback_info(__func__, obj); |
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return allocate_loglevel_state(); |
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} |
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/* Executed on object unpatching (ie, patch disablement) */ |
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static void post_patch_callback(struct klp_object *obj) |
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{ |
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callback_info(__func__, obj); |
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fix_console_loglevel(); |
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} |
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/* Executed on object unpatching (ie, patch disablement) */ |
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static void pre_unpatch_callback(struct klp_object *obj) |
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{ |
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callback_info(__func__, obj); |
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restore_console_loglevel(); |
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} |
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/* Executed on object unpatching (ie, patch disablement) */ |
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static void post_unpatch_callback(struct klp_object *obj) |
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{ |
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callback_info(__func__, obj); |
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free_loglevel_state(); |
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} |
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static struct klp_func no_funcs[] = { |
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{} |
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}; |
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static struct klp_object objs[] = { |
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{ |
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.name = NULL, /* vmlinux */ |
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.funcs = no_funcs, |
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.callbacks = { |
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.pre_patch = pre_patch_callback, |
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.post_patch = post_patch_callback, |
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.pre_unpatch = pre_unpatch_callback, |
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.post_unpatch = post_unpatch_callback, |
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}, |
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}, { } |
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}; |
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static struct klp_state states[] = { |
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{ |
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.id = CONSOLE_LOGLEVEL_STATE, |
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.version = CONSOLE_LOGLEVEL_STATE_VERSION, |
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}, { } |
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}; |
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static struct klp_patch patch = { |
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.mod = THIS_MODULE, |
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.objs = objs, |
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.states = states, |
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.replace = true, |
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}; |
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static int test_klp_callbacks_demo_init(void) |
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{ |
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return klp_enable_patch(&patch); |
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} |
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static void test_klp_callbacks_demo_exit(void) |
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{ |
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} |
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module_init(test_klp_callbacks_demo_init); |
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module_exit(test_klp_callbacks_demo_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_INFO(livepatch, "Y"); |
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MODULE_AUTHOR("Petr Mladek <[email protected]>"); |
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MODULE_DESCRIPTION("Livepatch test: system state modification");
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