HookSysCallTable/monitor.c at master · bwmaples/HookSysCallTable · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

/*
 *  hello-1.c - The simplest kernel module.
 */


#include <linux/module.h>	/* Needed by all modules */
#include <linux/init.h>
#include <linux/string.h>
#include <asm/uaccess.h>
#include "monitor.h"
// #include <asm/tlbflush.h>

static struct {
	pmd_t *pmd;
	pte_t *pte;
	pmd_t saved_pmd;
	pte_t saved_pte;
	bool made_writeable;
} mem_unprotect;


static inline void m_flush_tlb_all(void)
{
	dsb(ishst);
	asm("tlbi	vmalle1is");
	dsb(ish);
	isb();
}


static inline void __m_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
	if (msm8994_needs_tlbi_wa()) {
		asm("tlbi	vmalle1is");
		dsb(sy);
		isb();
	} else {
		unsigned long addr;
		start >>= 12;
		end >>= 12;

		dsb(ishst);
		for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12))
			asm("tlbi vaae1is, %0" : : "r"(addr));
		dsb(ish);
		isb();
	}
}


static inline void m_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
	if ((end - start) <= MAX_TLB_RANGE)
		__m_flush_tlb_kernel_range(start, end);
	else
		m_flush_tlb_all();
}


void m_mem_text_address_writeable(u64 addr)
{
	printk(KERN_INFO "@bwmaples: Here 0 0...\n");

	// printk(KERN_INFO "@bwmaples: Here 0...\n");
	pgd_t *pgd = m_pgd_offset_k(addr);
	printk(KERN_INFO "@bwmaples: Here 0.1...\n");
	pud_t *pud = pud_offset(pgd, addr);
	u64 addr_aligned;
	printk(KERN_INFO "@bwmaples: Here 1...\n");
	mem_unprotect.made_writeable = 0;
	printk(KERN_INFO "@bwmaples: Here 2...\n");
	mem_unprotect.pmd = pmd_offset(pud, addr);
	addr_aligned = addr & PAGE_MASK;
	mem_unprotect.saved_pmd = *mem_unprotect.pmd;
	printk(KERN_INFO "@bwmaples: Here 3...\n");
	if ((mem_unprotect.saved_pmd & PMD_TYPE_MASK) == PMD_TYPE_SECT) {
		printk(KERN_INFO "@bwmaples: if...\n");
		set_pmd(mem_unprotect.pmd,
			__pmd(__pa(addr_aligned) | m_prot_sect_kernel));
	} else {
		printk(KERN_INFO "@bwmaples: else...\n");
		mem_unprotect.pte = pte_offset_kernel(mem_unprotect.pmd, addr);
		mem_unprotect.saved_pte = *mem_unprotect.pte;
		set_pte(mem_unprotect.pte, pfn_pte(__pa(addr) >> PAGE_SHIFT,
						   PAGE_KERNEL_EXEC));
	}
	m_flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
	printk(KERN_INFO "@bwmaples: Here 4...\n");
	mem_unprotect.made_writeable = 1;
}


asmlinkage long m_unlink_32(const char __user *pathname)
{
	printk(KERN_INFO "@bwmaples: Origin sys_unlink_32 called path name is %s\n",pathname);
	return origin_unlink_32(pathname);
}


asmlinkage long m_unlinkat_32 (int dfd, const char __user * pathname, int flag)
{
	printk(KERN_INFO "@bwmaples: Origin sys_unlinkat_32 called path name is %s\n",pathname);
	char fileName[1024] = {0};
	copy_from_user(fileName,pathname,256);
	if (strstr(fileName,"******")!=0)
	{
		printk(KERN_INFO "@bwmaples: ******* Found!\n");
		return 0;
	}
	return origin_unlinkat_32(dfd,pathname,flag);

}


static int __init minit_module(void)
{
	printk(KERN_INFO "@bwmaples: Process Start...\n");
	origin_unlink_32 = compat_syscall[__COMPAT_NR_unlink];
	origin_unlinkat_32 = compat_syscall[__COMPAT_NR_unlinkat];
	m_mem_text_address_writeable((uint64_t)compat_syscall);
	compat_syscall[__COMPAT_NR_unlink] = (void*)m_unlink_32;
	compat_syscall[__COMPAT_NR_unlinkat] = (void*)m_unlinkat_32;
	printk(KERN_INFO "@bwmaples: Replace Finish!\n");
	/*
	 * A non 0 return means init_module failed; module can't be loaded.
	 */
	return 0;
}


static void  __exit mcleanup_module(void)
{
	printk(KERN_INFO "Goodbye world 1.\n");
}

MODULE_LICENSE("GPL");

module_init(minit_module);
module_exit(mcleanup_module);