mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-10-31 06:14:39 +01:00
Rui Qi
7203abb3f8
In livepatch_init(), if klp_enable_patch() fails, the previously created kobject and sysfs file are never cleaned up, causing a resource leak. Capture the return value and add proper cleanup on the error path. Signed-off-by: Rui Qi <[email protected]> Acked-by: Miroslav Benes <[email protected]> Reviewed-by: Petr Mladek <[email protected]> Link: https://patch.msgid.link/[email protected] Signed-off-by: Petr Mladek <[email protected]>
132 lines
2.9 KiB
C
132 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2017-2023 SUSE
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* Authors: Libor Pechacek <[email protected]>
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* Nicolai Stange <[email protected]>
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* Marcos Paulo de Souza <[email protected]>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/livepatch.h>
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/*
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* Before CONFIG_ARCH_HAS_SYSCALL_WRAPPER was introduced there were no
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* prefixes for system calls.
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* powerpc set this config based on configs, so it can be enabled or not.
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*/
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#if defined(CONFIG_ARCH_HAS_SYSCALL_WRAPPER)
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#if defined(__x86_64__)
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#define FN_PREFIX __x64_
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#elif defined(__s390x__)
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#define FN_PREFIX __s390x_
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#elif defined(__aarch64__)
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#define FN_PREFIX __arm64_
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#elif defined(__powerpc__)
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#define FN_PREFIX
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#else
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#error "Missing syscall wrapper for the given architecture."
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#endif
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#else
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/* Do not set a prefix for architectures that do not enable wrappers. */
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#define FN_PREFIX
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#endif
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/* Protects klp_pids */
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static DEFINE_MUTEX(kpid_mutex);
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static unsigned int npids, npids_pending;
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static int klp_pids[NR_CPUS];
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module_param_array(klp_pids, int, &npids_pending, 0);
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MODULE_PARM_DESC(klp_pids, "Array of pids to be transitioned to livepatched state.");
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static ssize_t npids_show(struct kobject *kobj, struct kobj_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%u\n", npids_pending);
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}
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static struct kobj_attribute klp_attr = __ATTR_RO(npids);
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static struct kobject *klp_kobj;
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static asmlinkage long lp_sys_getpid(void)
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{
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int i;
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mutex_lock(&kpid_mutex);
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if (npids_pending > 0) {
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for (i = 0; i < npids; i++) {
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if (current->pid == klp_pids[i]) {
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klp_pids[i] = 0;
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npids_pending--;
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break;
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}
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}
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}
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mutex_unlock(&kpid_mutex);
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return task_tgid_vnr(current);
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}
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static struct klp_func vmlinux_funcs[] = {
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{
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.old_name = __stringify(FN_PREFIX) "sys_getpid",
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.new_func = lp_sys_getpid,
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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 being NULL means vmlinux */
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.funcs = vmlinux_funcs,
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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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};
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static int livepatch_init(void)
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{
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int ret;
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klp_kobj = kobject_create_and_add("test_klp_syscall", kernel_kobj);
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if (!klp_kobj)
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return -ENOMEM;
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ret = sysfs_create_file(klp_kobj, &klp_attr.attr);
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if (ret) {
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kobject_put(klp_kobj);
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return ret;
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}
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/*
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* Save the number pids to transition to livepatched state before the
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* number of pending pids is decremented.
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*/
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npids = npids_pending;
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ret = klp_enable_patch(&patch);
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if (ret)
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kobject_put(klp_kobj);
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return ret;
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}
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static void livepatch_exit(void)
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{
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kobject_put(klp_kobj);
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}
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module_init(livepatch_init);
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module_exit(livepatch_exit);
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MODULE_LICENSE("GPL");
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MODULE_INFO(livepatch, "Y");
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MODULE_AUTHOR("Libor Pechacek <[email protected]>");
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MODULE_AUTHOR("Nicolai Stange <[email protected]>");
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MODULE_AUTHOR("Marcos Paulo de Souza <[email protected]>");
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MODULE_DESCRIPTION("Livepatch test: syscall transition");
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