1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2023 Huawei Device Co., Ltd.
4 */
5
6#include <internal.h>
7#include <linux/security.h>
8#include <linux/seq_file.h>
9#include <linux/mm_types.h>
10#include <linux/mm.h>
11#include <linux/mm_inline.h>
12#include <linux/hck/lite_hck_hideaddr.h>
13#include <linux/hck/lite_vendor_hooks.h>
14#include <linux/init.h>
15#include <linux/module.h>
16
17#include "avc.h"
18#include "objsec.h"
19#include "hideaddr.h"
20#include <linux/version.h>
21
22static bool is_anon_exec(struct vm_area_struct *vma)
23{
24	const char *name = NULL;
25	vm_flags_t flags = vma->vm_flags;
26
27	if (!(flags & VM_EXEC))
28		return false;
29
30	name = arch_vma_name(vma);
31	if (!name) {
32		struct anon_vma_name *anon_name;
33		anon_name = anon_vma_name(vma);
34		if (!anon_name)
35			return false;
36	}
37	return true;
38}
39
40static int hideaddr_avc_has_perm(u16 tclass, u32 requested, struct seq_file *m)
41{
42	struct av_decision avd;
43	struct inode *inode_task = file_inode(m->file);
44	struct task_struct *task = get_proc_task(inode_task);
45	u32 secid;
46
47	security_cred_getsecid(task->cred, &secid);
48#if (LINUX_VERSION_CODE < KERNEL_VERSION(6, 6, 0))
49	return avc_has_perm_noaudit(&selinux_state, secid, secid, tclass, requested,
50		AVC_STRICT, &avd);
51#else
52	return avc_has_perm_noaudit(secid, secid, tclass, requested,
53		AVC_STRICT, &avd);
54#endif
55}
56
57static void hideaddr_header_prefix(unsigned long *start, unsigned long *end,
58			vm_flags_t *flags, struct seq_file *m, struct vm_area_struct *vma)
59{
60	if (!is_anon_exec(vma))
61		return;
62
63	if (hideaddr_avc_has_perm(SECCLASS_HIDEADDR, HIDEADDR__HIDE_EXEC_ANON_MEM, m))
64		return;
65
66	if (!hideaddr_avc_has_perm(SECCLASS_HIDEADDR, HIDEADDR__HIDE_EXEC_ANON_MEM_DEBUG, m))
67		return;
68
69	*start = 0;
70	*end = 0;
71	*flags = 0;
72}
73
74void hideaddr_header_prefix_lhck_register(void)
75{
76	REGISTER_HCK_LITE_HOOK(hideaddr_header_prefix_lhck, hideaddr_header_prefix);
77}