Commit | Line | Data |
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85155229 | 1 | #define pr_fmt(fmt) "kasan: " fmt |
ef7f0d6a AR |
2 | #include <linux/bootmem.h> |
3 | #include <linux/kasan.h> | |
4 | #include <linux/kdebug.h> | |
5 | #include <linux/mm.h> | |
6 | #include <linux/sched.h> | |
9164bb4a | 7 | #include <linux/sched/task.h> |
ef7f0d6a AR |
8 | #include <linux/vmalloc.h> |
9 | ||
10 | #include <asm/tlbflush.h> | |
11 | #include <asm/sections.h> | |
12 | ||
13 | extern pgd_t early_level4_pgt[PTRS_PER_PGD]; | |
14 | extern struct range pfn_mapped[E820_X_MAX]; | |
15 | ||
ef7f0d6a AR |
16 | static int __init map_range(struct range *range) |
17 | { | |
18 | unsigned long start; | |
19 | unsigned long end; | |
20 | ||
21 | start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start)); | |
22 | end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end)); | |
23 | ||
24 | /* | |
25 | * end + 1 here is intentional. We check several shadow bytes in advance | |
26 | * to slightly speed up fastpath. In some rare cases we could cross | |
27 | * boundary of mapped shadow, so we just map some more here. | |
28 | */ | |
29 | return vmemmap_populate(start, end + 1, NUMA_NO_NODE); | |
30 | } | |
31 | ||
32 | static void __init clear_pgds(unsigned long start, | |
33 | unsigned long end) | |
34 | { | |
35 | for (; start < end; start += PGDIR_SIZE) | |
36 | pgd_clear(pgd_offset_k(start)); | |
37 | } | |
38 | ||
5d5aa3cf | 39 | static void __init kasan_map_early_shadow(pgd_t *pgd) |
ef7f0d6a AR |
40 | { |
41 | int i; | |
42 | unsigned long start = KASAN_SHADOW_START; | |
43 | unsigned long end = KASAN_SHADOW_END; | |
44 | ||
45 | for (i = pgd_index(start); start < end; i++) { | |
46 | pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud) | |
47 | | _KERNPG_TABLE); | |
48 | start += PGDIR_SIZE; | |
49 | } | |
50 | } | |
51 | ||
ef7f0d6a AR |
52 | #ifdef CONFIG_KASAN_INLINE |
53 | static int kasan_die_handler(struct notifier_block *self, | |
54 | unsigned long val, | |
55 | void *data) | |
56 | { | |
57 | if (val == DIE_GPF) { | |
2ba78056 DV |
58 | pr_emerg("CONFIG_KASAN_INLINE enabled\n"); |
59 | pr_emerg("GPF could be caused by NULL-ptr deref or user memory access\n"); | |
ef7f0d6a AR |
60 | } |
61 | return NOTIFY_OK; | |
62 | } | |
63 | ||
64 | static struct notifier_block kasan_die_notifier = { | |
65 | .notifier_call = kasan_die_handler, | |
66 | }; | |
67 | #endif | |
68 | ||
5d5aa3cf AP |
69 | void __init kasan_early_init(void) |
70 | { | |
71 | int i; | |
72 | pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL; | |
73 | pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE; | |
74 | pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE; | |
75 | ||
76 | for (i = 0; i < PTRS_PER_PTE; i++) | |
77 | kasan_zero_pte[i] = __pte(pte_val); | |
78 | ||
79 | for (i = 0; i < PTRS_PER_PMD; i++) | |
80 | kasan_zero_pmd[i] = __pmd(pmd_val); | |
81 | ||
82 | for (i = 0; i < PTRS_PER_PUD; i++) | |
83 | kasan_zero_pud[i] = __pud(pud_val); | |
84 | ||
85 | kasan_map_early_shadow(early_level4_pgt); | |
86 | kasan_map_early_shadow(init_level4_pgt); | |
87 | } | |
88 | ||
ef7f0d6a AR |
89 | void __init kasan_init(void) |
90 | { | |
91 | int i; | |
92 | ||
93 | #ifdef CONFIG_KASAN_INLINE | |
94 | register_die_notifier(&kasan_die_notifier); | |
95 | #endif | |
96 | ||
97 | memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt)); | |
98 | load_cr3(early_level4_pgt); | |
241d2c54 | 99 | __flush_tlb_all(); |
ef7f0d6a AR |
100 | |
101 | clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); | |
102 | ||
69786cdb | 103 | kasan_populate_zero_shadow((void *)KASAN_SHADOW_START, |
ef7f0d6a AR |
104 | kasan_mem_to_shadow((void *)PAGE_OFFSET)); |
105 | ||
106 | for (i = 0; i < E820_X_MAX; i++) { | |
107 | if (pfn_mapped[i].end == 0) | |
108 | break; | |
109 | ||
110 | if (map_range(&pfn_mapped[i])) | |
111 | panic("kasan: unable to allocate shadow!"); | |
112 | } | |
69786cdb AR |
113 | kasan_populate_zero_shadow( |
114 | kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), | |
115 | kasan_mem_to_shadow((void *)__START_KERNEL_map)); | |
c420f167 AR |
116 | |
117 | vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext), | |
118 | (unsigned long)kasan_mem_to_shadow(_end), | |
119 | NUMA_NO_NODE); | |
120 | ||
69786cdb | 121 | kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), |
c420f167 | 122 | (void *)KASAN_SHADOW_END); |
ef7f0d6a | 123 | |
ef7f0d6a | 124 | load_cr3(init_level4_pgt); |
241d2c54 | 125 | __flush_tlb_all(); |
85155229 | 126 | |
69e0210f AR |
127 | /* |
128 | * kasan_zero_page has been used as early shadow memory, thus it may | |
063fb3e5 AR |
129 | * contain some garbage. Now we can clear and write protect it, since |
130 | * after the TLB flush no one should write to it. | |
69e0210f AR |
131 | */ |
132 | memset(kasan_zero_page, 0, PAGE_SIZE); | |
063fb3e5 AR |
133 | for (i = 0; i < PTRS_PER_PTE; i++) { |
134 | pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO); | |
135 | set_pte(&kasan_zero_pte[i], pte); | |
136 | } | |
137 | /* Flush TLBs again to be sure that write protection applied. */ | |
138 | __flush_tlb_all(); | |
69e0210f AR |
139 | |
140 | init_task.kasan_depth = 0; | |
25add7ec | 141 | pr_info("KernelAddressSanitizer initialized\n"); |
ef7f0d6a | 142 | } |