From: Andrey Ryabinin ryabinin.a.a@gmail.com
mainline inclusion from mainline-v6.2-rc1 commit 3f148f3318140035e87decc1214795ff0755757b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I6C6UC CVE: CVE-2023-0597
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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KASAN maps shadow for the entire CPU-entry-area: [CPU_ENTRY_AREA_BASE, CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE]
This will explode once the per-cpu entry areas are randomized since it will increase CPU_ENTRY_AREA_MAP_SIZE to 512 GB and KASAN fails to allocate shadow for such big area.
Fix this by allocating KASAN shadow only for really used cpu entry area addresses mapped by cea_map_percpu_pages()
Thanks to the 0day folks for finding and reporting this to be an issue.
[ dhansen: tweak changelog since this will get committed before peterz's actual cpu-entry-area randomization ]
Signed-off-by: Andrey Ryabinin ryabinin.a.a@gmail.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Tested-by: Yujie Liu yujie.liu@intel.com Cc: kernel test robot yujie.liu@intel.com Link: https://lore.kernel.org/r/202210241508.2e203c3d-yujie.liu@intel.com Signed-off-by: Tong Tiangen tongtiangen@huawei.com Reviewed-by: Chen Wandun chenwandun@huawei.com Reviewed-by: Wang Weiyang wangweiyang2@huawei.com Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- arch/x86/include/asm/kasan.h | 3 +++ arch/x86/mm/cpu_entry_area.c | 8 +++++++- arch/x86/mm/kasan_init_64.c | 15 ++++++++++++--- 3 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h index 13e70da38bed..de75306b932e 100644 --- a/arch/x86/include/asm/kasan.h +++ b/arch/x86/include/asm/kasan.h @@ -28,9 +28,12 @@ #ifdef CONFIG_KASAN void __init kasan_early_init(void); void __init kasan_init(void); +void __init kasan_populate_shadow_for_vaddr(void *va, size_t size, int nid); #else static inline void kasan_early_init(void) { } static inline void kasan_init(void) { } +static inline void kasan_populate_shadow_for_vaddr(void *va, size_t size, + int nid) { } #endif
#endif diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index 98396a67958c..bf5786f3f3c4 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -10,6 +10,7 @@ #include <asm/cpu_entry_area.h> #include <asm/fixmap.h> #include <asm/desc.h> +#include <asm/kasan.h>
static DEFINE_PER_CPU_PAGE_ALIGNED(struct entry_stack_page, entry_stack_storage);
@@ -95,8 +96,13 @@ void cea_set_pte(void *cea_vaddr, phys_addr_t pa, pgprot_t flags) static void __init cea_map_percpu_pages(void *cea_vaddr, void *ptr, int pages, pgprot_t prot) { + phys_addr_t pa = per_cpu_ptr_to_phys(ptr); + + kasan_populate_shadow_for_vaddr(cea_vaddr, pages * PAGE_SIZE, + early_pfn_to_nid(PFN_DOWN(pa))); + for ( ; pages; pages--, cea_vaddr+= PAGE_SIZE, ptr += PAGE_SIZE) - cea_set_pte(cea_vaddr, per_cpu_ptr_to_phys(ptr), prot); + cea_set_pte(cea_vaddr, pa, prot); }
static void __init percpu_setup_debug_store(unsigned int cpu) diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index 1a50434c8a4d..18d574af30ef 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -318,6 +318,18 @@ void __init kasan_early_init(void) kasan_map_early_shadow(init_top_pgt); }
+void __init kasan_populate_shadow_for_vaddr(void *va, size_t size, int nid) +{ + unsigned long shadow_start, shadow_end; + + shadow_start = (unsigned long)kasan_mem_to_shadow(va); + shadow_start = round_down(shadow_start, PAGE_SIZE); + shadow_end = (unsigned long)kasan_mem_to_shadow(va + size); + shadow_end = round_up(shadow_end, PAGE_SIZE); + + kasan_populate_shadow(shadow_start, shadow_end, nid); +} + void __init kasan_init(void) { int i; @@ -395,9 +407,6 @@ void __init kasan_init(void) kasan_mem_to_shadow((void *)VMALLOC_END + 1), shadow_cpu_entry_begin);
- kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin, - (unsigned long)shadow_cpu_entry_end, 0); - kasan_populate_early_shadow(shadow_cpu_entry_end, kasan_mem_to_shadow((void *)__START_KERNEL_map));