mirror of
https://github.com/dynup/kpatch
synced 2024-12-14 09:24:33 +00:00
21fc274448
This adds dynamic linking support for the patch modules. It is the first step toward supporting patching module code and relocatable kernels. Rela entries that reference non-included local and non-exported global symbols are converted to "dynrelas". These dynrelas are relocations that are done by the core module, not the kernel module linker. This allows the core module to apply offsets to the base addresses found in the base vmlinux or module. Signed-off-by: Seth Jennings <sjenning@redhat.com> Conflicts: kpatch-build/kpatch-build
120 lines
3.0 KiB
C
120 lines
3.0 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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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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extern char __kpatch_dynrelas, __kpatch_dynrelas_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, const 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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int ret;
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kpmod.mod = THIS_MODULE;
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kpmod.patches = (struct kpatch_patch *)&__kpatch_patches;
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kpmod.patches_nr = (&__kpatch_patches_end - &__kpatch_patches) /
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sizeof(*kpmod.patches);
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kpmod.dynrelas = (struct kpatch_dynrela *)&__kpatch_dynrelas;
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kpmod.dynrelas_nr = (&__kpatch_dynrelas_end - &__kpatch_dynrelas) /
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sizeof(*kpmod.dynrelas);
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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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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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}
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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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