cregit-Linux how code gets into the kernel

Release 4.11 arch/x86/mm/kasan_init_64.c

Directory: arch/x86/mm

#define DISABLE_BRANCH_PROFILING

#define pr_fmt(fmt) "kasan: " fmt
#include <linux/bootmem.h>
#include <linux/kasan.h>
#include <linux/kdebug.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/vmalloc.h>

#include <asm/tlbflush.h>
#include <asm/sections.h>

extern pgd_t early_level4_pgt[PTRS_PER_PGD];
extern struct range pfn_mapped[E820_X_MAX];


static int __init map_range(struct range *range) { unsigned long start; unsigned long end; start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start)); end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end)); /* * end + 1 here is intentional. We check several shadow bytes in advance * to slightly speed up fastpath. In some rare cases we could cross * boundary of mapped shadow, so we just map some more here. */ return vmemmap_populate(start, end + 1, NUMA_NO_NODE); }

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PersonTokensPropCommitsCommitProp
Andrey Ryabinin65100.00%1100.00%
Total65100.00%1100.00%


static void __init clear_pgds(unsigned long start, unsigned long end) { for (; start < end; start += PGDIR_SIZE) pgd_clear(pgd_offset_k(start)); }

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PersonTokensPropCommitsCommitProp
Andrey Ryabinin34100.00%1100.00%
Total34100.00%1100.00%


static void __init kasan_map_early_shadow(pgd_t *pgd) { int i; unsigned long start = KASAN_SHADOW_START; unsigned long end = KASAN_SHADOW_END; for (i = pgd_index(start); start < end; i++) { pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud) | _KERNPG_TABLE); start += PGDIR_SIZE; } }

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PersonTokensPropCommitsCommitProp
Andrey Ryabinin6298.41%150.00%
Alexander Popov11.59%150.00%
Total63100.00%2100.00%

#ifdef CONFIG_KASAN_INLINE
static int kasan_die_handler(struct notifier_block *self, unsigned long val, void *data) { if (val == DIE_GPF) { pr_emerg("CONFIG_KASAN_INLINE enabled\n"); pr_emerg("GPF could be caused by NULL-ptr deref or user memory access\n"); } return NOTIFY_OK; }

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PersonTokensPropCommitsCommitProp
Andrey Ryabinin3895.00%150.00%
Dmitriy Vyukov25.00%150.00%
Total40100.00%2100.00%

static struct notifier_block kasan_die_notifier = { .notifier_call = kasan_die_handler, }; #endif
void __init kasan_early_init(void) { int i; pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL; pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE; pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE; for (i = 0; i < PTRS_PER_PTE; i++) kasan_zero_pte[i] = __pte(pte_val); for (i = 0; i < PTRS_PER_PMD; i++) kasan_zero_pmd[i] = __pmd(pmd_val); for (i = 0; i < PTRS_PER_PUD; i++) kasan_zero_pud[i] = __pud(pud_val); kasan_map_early_shadow(early_level4_pgt); kasan_map_early_shadow(init_level4_pgt); }

Contributors

PersonTokensPropCommitsCommitProp
Alexander Popov120100.00%1100.00%
Total120100.00%1100.00%


void __init kasan_init(void) { int i; #ifdef CONFIG_KASAN_INLINE register_die_notifier(&kasan_die_notifier); #endif memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt)); load_cr3(early_level4_pgt); __flush_tlb_all(); clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); kasan_populate_zero_shadow((void *)KASAN_SHADOW_START, kasan_mem_to_shadow((void *)PAGE_OFFSET)); for (i = 0; i < E820_X_MAX; i++) { if (pfn_mapped[i].end == 0) break; if (map_range(&pfn_mapped[i])) panic("kasan: unable to allocate shadow!"); } kasan_populate_zero_shadow( kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), kasan_mem_to_shadow((void *)__START_KERNEL_map)); vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext), (unsigned long)kasan_mem_to_shadow(_end), NUMA_NO_NODE); kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), (void *)KASAN_SHADOW_END); load_cr3(init_level4_pgt); __flush_tlb_all(); /* * kasan_zero_page has been used as early shadow memory, thus it may * contain some garbage. Now we can clear and write protect it, since * after the TLB flush no one should write to it. */ memset(kasan_zero_page, 0, PAGE_SIZE); for (i = 0; i < PTRS_PER_PTE; i++) { pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO); set_pte(&kasan_zero_pte[i], pte); } /* Flush TLBs again to be sure that write protection applied. */ __flush_tlb_all(); init_task.kasan_depth = 0; pr_info("KernelAddressSanitizer initialized\n"); }

Contributors

PersonTokensPropCommitsCommitProp
Andrey Ryabinin24599.59%888.89%
Andrey Konovalov10.41%111.11%
Total246100.00%9100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Andrey Ryabinin51080.06%969.23%
Alexander Popov12119.00%17.69%
Ingo Molnar30.47%17.69%
Dmitriy Vyukov20.31%17.69%
Andrey Konovalov10.16%17.69%
Total637100.00%13100.00%
Directory: arch/x86/mm
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