mirror of
https://github.com/dynup/kpatch
synced 2024-12-23 13:42:09 +00:00
65810a47d0
Allow the user to atomically replace all existing modules with a new "kpatch replace" command. This provides a safe way to do atomic upgrades for cumulative patch module updates.
132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
/*
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* Copyright (C) 2013-2014 Josh Poimboeuf <jpoimboe@redhat.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA,
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* 02110-1301, USA.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/printk.h>
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#include <linux/slab.h>
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#include "kpatch.h"
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#include "kpatch-patch.h"
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static bool replace;
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module_param(replace, bool, S_IRUGO);
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MODULE_PARM_DESC(replace, "replace all previously loaded patch modules");
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extern char __kpatch_patches, __kpatch_patches_end;
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static struct kpatch_module kpmod;
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static struct kobject *patch_kobj;
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static ssize_t patch_enabled_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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return sprintf(buf, "%d\n", kpmod.enabled);
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}
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static ssize_t patch_enabled_store(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf,
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size_t count)
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{
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int ret;
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unsigned long val;
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/* only disabling is supported */
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if (!kpmod.enabled)
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return -EINVAL;
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ret = kstrtoul(buf, 10, &val);
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if (ret)
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return ret;
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val = !!val;
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/* only disabling is supported */
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if (val)
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return -EINVAL;
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ret = kpatch_unregister(&kpmod);
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if (ret)
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return ret;
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return count;
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}
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static struct kobj_attribute patch_enabled_attr =
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__ATTR(enabled, 0644, patch_enabled_show, patch_enabled_store);
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static int __init patch_init(void)
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{
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struct kpatch_patch *patches;
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int i, ret;
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patches = (struct kpatch_patch *)&__kpatch_patches;
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kpmod.mod = THIS_MODULE;
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kpmod.num_funcs = (&__kpatch_patches_end - &__kpatch_patches) /
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sizeof(*patches);
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kpmod.funcs = kmalloc(kpmod.num_funcs * sizeof(struct kpatch_func),
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GFP_KERNEL);
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if (!kpmod.funcs)
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return -ENOMEM;
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for (i = 0; i < kpmod.num_funcs; i++) {
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kpmod.funcs[i].old_addr = patches[i].old_addr;
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kpmod.funcs[i].old_size = patches[i].old_size;
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kpmod.funcs[i].new_addr = patches[i].new_addr;
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kpmod.funcs[i].new_size = patches[i].new_size;
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}
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patch_kobj = kobject_create_and_add(THIS_MODULE->name,
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kpatch_patches_kobj);
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if (!patch_kobj) {
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ret = -ENOMEM;
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goto err_free;
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}
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ret = sysfs_create_file(patch_kobj, &patch_enabled_attr.attr);
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if (ret)
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goto err_put;
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ret = kpatch_register(&kpmod, replace);
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if (ret)
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goto err_sysfs;
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return 0;
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err_sysfs:
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sysfs_remove_file(patch_kobj, &patch_enabled_attr.attr);
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err_put:
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kobject_put(patch_kobj);
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err_free:
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kfree(kpmod.funcs);
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return ret;
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}
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static void __exit patch_exit(void)
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{
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WARN_ON(kpmod.enabled);
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sysfs_remove_file(patch_kobj, &patch_enabled_attr.attr);
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kobject_put(patch_kobj);
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kfree(kpmod.funcs);
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}
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module_init(patch_init);
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module_exit(patch_exit);
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MODULE_LICENSE("GPL");
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