1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
 4 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 5 */
 6
 7#include <linux/mm.h>
 8#include <linux/sched/signal.h>
 9#include <linux/slab.h>
10
11#include <asm/pgalloc.h>
12#include <asm/sections.h>
13#include <asm/mmu_context.h>
14#include <as-layout.h>
15#include <os.h>
16#include <skas.h>
17#include <stub-data.h>
18
19/* Ensure the stub_data struct covers the allocated area */
20static_assert(sizeof(struct stub_data) == STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);
21
22int init_new_context(struct task_struct *task, struct mm_struct *mm)
23{
24	struct mm_id *new_id = &mm->context.id;
 
25	unsigned long stack = 0;
26	int ret = -ENOMEM;
27
28	stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES));
29	if (stack == 0)
30		goto out;
31
32	new_id->stack = stack;
 
 
33
34	block_signals_trace();
35	new_id->pid = start_userspace(stack);
 
 
 
36	unblock_signals_trace();
37
38	if (new_id->pid < 0) {
39		ret = new_id->pid;
40		goto out_free;
41	}
42
43	/* Ensure the new MM is clean and nothing unwanted is mapped */
44	unmap(new_id, 0, STUB_START);
 
 
 
 
45
46	return 0;
47
48 out_free:
49	free_pages(new_id->stack, ilog2(STUB_DATA_PAGES));
 
50 out:
51	return ret;
52}
53
54void destroy_context(struct mm_struct *mm)
55{
56	struct mm_context *mmu = &mm->context;
57
58	/*
59	 * If init_new_context wasn't called, this will be
60	 * zero, resulting in a kill(0), which will result in the
61	 * whole UML suddenly dying.  Also, cover negative and
62	 * 1 cases, since they shouldn't happen either.
63	 */
64	if (mmu->id.pid < 2) {
65		printk(KERN_ERR "corrupt mm_context - pid = %d\n",
66		       mmu->id.pid);
67		return;
68	}
69	os_kill_ptraced_process(mmu->id.pid, 1);
70
71	free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));
 
72}

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
 4 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 5 */
 6
 7#include <linux/mm.h>
 8#include <linux/sched/signal.h>
 9#include <linux/slab.h>
10
11#include <asm/pgalloc.h>
12#include <asm/sections.h>
 
13#include <as-layout.h>
14#include <os.h>
15#include <skas.h>
 
 
 
 
16
17int init_new_context(struct task_struct *task, struct mm_struct *mm)
18{
19 	struct mm_context *from_mm = NULL;
20	struct mm_context *to_mm = &mm->context;
21	unsigned long stack = 0;
22	int ret = -ENOMEM;
23
24	stack = get_zeroed_page(GFP_KERNEL);
25	if (stack == 0)
26		goto out;
27
28	to_mm->id.stack = stack;
29	if (current->mm != NULL && current->mm != &init_mm)
30		from_mm = &current->mm->context;
31
32	block_signals_trace();
33	if (from_mm)
34		to_mm->id.u.pid = copy_context_skas0(stack,
35						     from_mm->id.u.pid);
36	else to_mm->id.u.pid = start_userspace(stack);
37	unblock_signals_trace();
38
39	if (to_mm->id.u.pid < 0) {
40		ret = to_mm->id.u.pid;
41		goto out_free;
42	}
43
44	ret = init_new_ldt(to_mm, from_mm);
45	if (ret < 0) {
46		printk(KERN_ERR "init_new_context_skas - init_ldt"
47		       " failed, errno = %d\n", ret);
48		goto out_free;
49	}
50
51	return 0;
52
53 out_free:
54	if (to_mm->id.stack != 0)
55		free_page(to_mm->id.stack);
56 out:
57	return ret;
58}
59
60void destroy_context(struct mm_struct *mm)
61{
62	struct mm_context *mmu = &mm->context;
63
64	/*
65	 * If init_new_context wasn't called, this will be
66	 * zero, resulting in a kill(0), which will result in the
67	 * whole UML suddenly dying.  Also, cover negative and
68	 * 1 cases, since they shouldn't happen either.
69	 */
70	if (mmu->id.u.pid < 2) {
71		printk(KERN_ERR "corrupt mm_context - pid = %d\n",
72		       mmu->id.u.pid);
73		return;
74	}
75	os_kill_ptraced_process(mmu->id.u.pid, 1);
76
77	free_page(mmu->id.stack);
78	free_ldt(mmu);
79}