mm/usercopy: Check kmap addresses properly
If you are copying to an address in the kmap region, you may not copy across a page boundary, no matter what the size of the underlying allocation. You can't kmap() a slab page because slab pages always come from low memory. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220110231530.665970-2-willy@infradead.org
This commit is contained in:
parent
a19944809f
commit
4e140f59d2
3 changed files with 21 additions and 6 deletions
|
@ -26,6 +26,7 @@
|
||||||
#include <asm/tlbflush.h>
|
#include <asm/tlbflush.h>
|
||||||
#include <asm/paravirt.h>
|
#include <asm/paravirt.h>
|
||||||
#include <asm/fixmap.h>
|
#include <asm/fixmap.h>
|
||||||
|
#include <asm/pgtable_areas.h>
|
||||||
|
|
||||||
/* declarations for highmem.c */
|
/* declarations for highmem.c */
|
||||||
extern unsigned long highstart_pfn, highend_pfn;
|
extern unsigned long highstart_pfn, highend_pfn;
|
||||||
|
|
|
@ -149,6 +149,11 @@ static inline void totalhigh_pages_add(long count)
|
||||||
atomic_long_add(count, &_totalhigh_pages);
|
atomic_long_add(count, &_totalhigh_pages);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
static inline bool is_kmap_addr(const void *x)
|
||||||
|
{
|
||||||
|
unsigned long addr = (unsigned long)x;
|
||||||
|
return addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP);
|
||||||
|
}
|
||||||
#else /* CONFIG_HIGHMEM */
|
#else /* CONFIG_HIGHMEM */
|
||||||
|
|
||||||
static inline struct page *kmap_to_page(void *addr)
|
static inline struct page *kmap_to_page(void *addr)
|
||||||
|
@ -234,6 +239,11 @@ static inline void __kunmap_atomic(void *addr)
|
||||||
static inline unsigned int nr_free_highpages(void) { return 0; }
|
static inline unsigned int nr_free_highpages(void) { return 0; }
|
||||||
static inline unsigned long totalhigh_pages(void) { return 0UL; }
|
static inline unsigned long totalhigh_pages(void) { return 0UL; }
|
||||||
|
|
||||||
|
static inline bool is_kmap_addr(const void *x)
|
||||||
|
{
|
||||||
|
return false;
|
||||||
|
}
|
||||||
|
|
||||||
#endif /* CONFIG_HIGHMEM */
|
#endif /* CONFIG_HIGHMEM */
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
|
|
@ -229,12 +229,16 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
|
||||||
if (!virt_addr_valid(ptr))
|
if (!virt_addr_valid(ptr))
|
||||||
return;
|
return;
|
||||||
|
|
||||||
/*
|
if (is_kmap_addr(ptr)) {
|
||||||
* When CONFIG_HIGHMEM=y, kmap_to_page() will give either the
|
unsigned long page_end = (unsigned long)ptr | (PAGE_SIZE - 1);
|
||||||
* highmem page or fallback to virt_to_page(). The following
|
|
||||||
* is effectively a highmem-aware virt_to_slab().
|
if ((unsigned long)ptr + n - 1 > page_end)
|
||||||
*/
|
usercopy_abort("kmap", NULL, to_user,
|
||||||
folio = page_folio(kmap_to_page((void *)ptr));
|
offset_in_page(ptr), n);
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
|
folio = virt_to_folio(ptr);
|
||||||
|
|
||||||
if (folio_test_slab(folio)) {
|
if (folio_test_slab(folio)) {
|
||||||
/* Check slab allocator for flags and size. */
|
/* Check slab allocator for flags and size. */
|
||||||
|
|
Loading…
Add table
Reference in a new issue